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third-party-mirror / systemd / refs/heads/master / . / src / shared / dissect-image.c
blob: 4749bdd2308a6594506acbef04bb1c94c18831d8 [file] [log] [blame]
/* SPDX-License-Identifier: LGPL-2.1-or-later */
#if HAVE_VALGRIND_MEMCHECK_H
#include <valgrind/memcheck.h>
#endif
#include <linux/dm-ioctl.h>
#include <linux/loop.h>
#include <sys/file.h>
#include <sys/mount.h>
#include <sys/prctl.h>
#include <sys/wait.h>
#include <sysexits.h>
#if HAVE_OPENSSL
#include <openssl/err.h>
#include <openssl/pem.h>
#include <openssl/x509.h>
#endif
#include "sd-device.h"
#include "sd-id128.h"
#include "architecture.h"
#include "ask-password-api.h"
#include "blkid-util.h"
#include "blockdev-util.h"
#include "btrfs-util.h"
#include "chase-symlinks.h"
#include "conf-files.h"
#include "constants.h"
#include "copy.h"
#include "cryptsetup-util.h"
#include "device-nodes.h"
#include "device-util.h"
#include "devnum-util.h"
#include "discover-image.h"
#include "dissect-image.h"
#include "dm-util.h"
#include "env-file.h"
#include "env-util.h"
#include "extension-release.h"
#include "fd-util.h"
#include "fileio.h"
#include "fs-util.h"
#include "fsck-util.h"
#include "gpt.h"
#include "hexdecoct.h"
#include "hostname-setup.h"
#include "id128-util.h"
#include "import-util.h"
#include "io-util.h"
#include "mkdir-label.h"
#include "mount-util.h"
#include "mountpoint-util.h"
#include "namespace-util.h"
#include "nulstr-util.h"
#include "openssl-util.h"
#include "os-util.h"
#include "path-util.h"
#include "process-util.h"
#include "raw-clone.h"
#include "resize-fs.h"
#include "signal-util.h"
#include "sparse-endian.h"
#include "stat-util.h"
#include "stdio-util.h"
#include "string-table.h"
#include "string-util.h"
#include "strv.h"
#include "tmpfile-util.h"
#include "udev-util.h"
#include "user-util.h"
#include "xattr-util.h"
/* how many times to wait for the device nodes to appear */
#define N_DEVICE_NODE_LIST_ATTEMPTS 10
int dissect_fstype_ok(const char *fstype) {
const char *e;
bool b;
/* When we automatically mount file systems, be a bit conservative by default what we are willing to
* mount, just as an extra safety net to not mount with badly maintained legacy file system
* drivers. */
e = secure_getenv("SYSTEMD_DISSECT_FILE_SYSTEMS");
if (e) {
_cleanup_strv_free_ char **l = NULL;
l = strv_split(e, ":");
if (!l)
return -ENOMEM;
b = strv_contains(l, fstype);
} else
b = STR_IN_SET(fstype,
"btrfs",
"erofs",
"ext4",
"squashfs",
"vfat",
"xfs");
if (b)
return true;
log_debug("File system type '%s' is not allowed to be mounted as result of automatic dissection.", fstype);
return false;
}
int probe_sector_size(int fd, uint32_t *ret) {
struct gpt_header {
char signature[8];
le32_t revision;
le32_t header_size;
le32_t crc32;
le32_t reserved;
le64_t my_lba;
le64_t alternate_lba;
le64_t first_usable_lba;
le64_t last_usable_lba;
sd_id128_t disk_guid;
le64_t partition_entry_lba;
le32_t number_of_partition_entries;
le32_t size_of_partition_entry;
le32_t partition_entry_array_crc32;
} _packed_;
/* Disk images might be for 512B or for 4096 sector sizes, let's try to auto-detect that by searching
* for the GPT headers at the relevant byte offsets */
assert_cc(sizeof(struct gpt_header) == 92);
/* We expect a sector size in the range 512…4096. The GPT header is located in the second
* sector. Hence it could be at byte 512 at the earliest, and at byte 4096 at the latest. And we must
* read with granularity of the largest sector size we care about. Which means 8K. */
uint8_t sectors[2 * 4096];
uint32_t found = 0;
ssize_t n;
assert(fd >= 0);
assert(ret);
n = pread(fd, sectors, sizeof(sectors), 0);
if (n < 0)
return -errno;
if (n != sizeof(sectors)) /* too short? */
goto not_found;
/* Let's see if we find the GPT partition header with various expected sector sizes */
for (uint32_t sz = 512; sz <= 4096; sz <<= 1) {
struct gpt_header *p;
assert(sizeof(sectors) >= sz * 2);
p = (struct gpt_header*) (sectors + sz);
if (memcmp(p->signature, (const char[8]) { 'E', 'F', 'I', ' ', 'P', 'A', 'R', 'T' }, 8) != 0)
continue;
if (le32toh(p->revision) != UINT32_C(0x00010000)) /* the only known revision of the spec: 1.0 */
continue;
if (le32toh(p->header_size) < sizeof(struct gpt_header))
continue;
if (le32toh(p->header_size) > 4096) /* larger than a sector? something is off… */
continue;
if (le64toh(p->my_lba) != 1) /* this sector must claim to be at sector offset 1 */
continue;
if (found != 0)
return log_debug_errno(SYNTHETIC_ERRNO(ENOTUNIQ),
"Detected valid partition table at offsets matching multiple sector sizes, refusing.");
found = sz;
}
if (found != 0) {
log_debug("Determined sector size %" PRIu32 " based on discovered partition table.", found);
*ret = found;
return 1; /* indicate we *did* find it */
}
not_found:
log_debug("Couldn't find any partition table to derive sector size of.");
*ret = 512; /* pick the traditional default */
return 0; /* indicate we didn't find it */
}
int probe_sector_size_prefer_ioctl(int fd, uint32_t *ret) {
struct stat st;
assert(fd >= 0);
assert(ret);
/* Just like probe_sector_size(), but if we are looking at a block device, will use the already
* configured sector size rather than probing by contents */
if (fstat(fd, &st) < 0)
return -errno;
if (S_ISBLK(st.st_mode))
return blockdev_get_sector_size(fd, ret);
return probe_sector_size(fd, ret);
}
int probe_filesystem_full(
int fd,
const char *path,
uint64_t offset,
uint64_t size,
char **ret_fstype) {
/* Try to find device content type and return it in *ret_fstype. If nothing is found,
* 0/NULL will be returned. -EUCLEAN will be returned for ambiguous results, and a
* different error otherwise. */
#if HAVE_BLKID
_cleanup_(blkid_free_probep) blkid_probe b = NULL;
_cleanup_free_ char *path_by_fd = NULL;
_cleanup_close_ int fd_close = -EBADF;
const char *fstype;
int r;
assert(fd >= 0 || path);
assert(ret_fstype);
if (fd < 0) {
fd_close = open(path, O_RDONLY|O_NONBLOCK|O_CLOEXEC|O_NOCTTY);
if (fd_close < 0)
return -errno;
fd = fd_close;
}
if (!path) {
r = fd_get_path(fd, &path_by_fd);
if (r < 0)
return r;
path = path_by_fd;
}
if (size == 0) /* empty size? nothing found! */
goto not_found;
b = blkid_new_probe();
if (!b)
return -ENOMEM;
errno = 0;
r = blkid_probe_set_device(
b,
fd,
offset,
size == UINT64_MAX ? 0 : size); /* when blkid sees size=0 it understands "everything". We prefer using UINT64_MAX for that */
if (r != 0)
return errno_or_else(ENOMEM);
blkid_probe_enable_superblocks(b, 1);
blkid_probe_set_superblocks_flags(b, BLKID_SUBLKS_TYPE);
errno = 0;
r = blkid_do_safeprobe(b);
if (r == _BLKID_SAFEPROBE_NOT_FOUND)
goto not_found;
if (r == _BLKID_SAFEPROBE_AMBIGUOUS)
return log_debug_errno(SYNTHETIC_ERRNO(EUCLEAN),
"Results ambiguous for partition %s", path);
if (r == _BLKID_SAFEPROBE_ERROR)
return log_debug_errno(errno_or_else(EIO), "Failed to probe partition %s: %m", path);
assert(r == _BLKID_SAFEPROBE_FOUND);
(void) blkid_probe_lookup_value(b, "TYPE", &fstype, NULL);
if (fstype) {
char *t;
log_debug("Probed fstype '%s' on partition %s.", fstype, path);
t = strdup(fstype);
if (!t)
return -ENOMEM;
*ret_fstype = t;
return 1;
}
not_found:
log_debug("No type detected on partition %s", path);
*ret_fstype = NULL;
return 0;
#else
return -EOPNOTSUPP;
#endif
}
#if HAVE_BLKID
static int dissected_image_probe_filesystems(DissectedImage *m, int fd) {
int r;
assert(m);
/* Fill in file system types if we don't know them yet. */
for (PartitionDesignator i = 0; i < _PARTITION_DESIGNATOR_MAX; i++) {
DissectedPartition *p = m->partitions + i;
if (!p->found)
continue;
if (!p->fstype) {
/* If we have an fd referring to the partition block device, use that. Otherwise go
* via the whole block device or backing regular file, and read via offset. */
if (p->mount_node_fd >= 0)
r = probe_filesystem_full(p->mount_node_fd, p->node, 0, UINT64_MAX, &p->fstype);
else
r = probe_filesystem_full(fd, p->node, p->offset, p->size, &p->fstype);
if (r < 0)
return r;
}
if (streq_ptr(p->fstype, "crypto_LUKS"))
m->encrypted = true;
if (p->fstype && fstype_is_ro(p->fstype))
p->rw = false;
if (!p->rw)
p->growfs = false;
}
return 0;
}
static void check_partition_flags(
const char *node,
unsigned long long pflags,
unsigned long long supported) {
assert(node);
/* Mask away all flags supported by this partition's type and the three flags the UEFI spec defines generically */
pflags &= ~(supported |
SD_GPT_FLAG_REQUIRED_PARTITION |
SD_GPT_FLAG_NO_BLOCK_IO_PROTOCOL |
SD_GPT_FLAG_LEGACY_BIOS_BOOTABLE);
if (pflags == 0)
return;
/* If there are other bits set, then log about it, to make things discoverable */
for (unsigned i = 0; i < sizeof(pflags) * 8; i++) {
unsigned long long bit = 1ULL << i;
if (!FLAGS_SET(pflags, bit))
continue;
log_debug("Unexpected partition flag %llu set on %s!", bit, node);
}
}
#endif
#if HAVE_BLKID
static int dissected_image_new(const char *path, DissectedImage **ret) {
_cleanup_(dissected_image_unrefp) DissectedImage *m = NULL;
_cleanup_free_ char *name = NULL;
int r;
assert(ret);
if (path) {
_cleanup_free_ char *filename = NULL;
r = path_extract_filename(path, &filename);
if (r < 0)
return r;
r = raw_strip_suffixes(filename, &name);
if (r < 0)
return r;
if (!image_name_is_valid(name)) {
log_debug("Image name %s is not valid, ignoring.", strna(name));
name = mfree(name);
}
}
m = new(DissectedImage, 1);
if (!m)
return -ENOMEM;
*m = (DissectedImage) {
.has_init_system = -1,
.image_name = TAKE_PTR(name),
};
for (PartitionDesignator i = 0; i < _PARTITION_DESIGNATOR_MAX; i++)
m->partitions[i] = DISSECTED_PARTITION_NULL;
*ret = TAKE_PTR(m);
return 0;
}
#endif
static void dissected_partition_done(DissectedPartition *p) {
assert(p);
free(p->fstype);
free(p->node);
free(p->label);
free(p->decrypted_fstype);
free(p->decrypted_node);
free(p->mount_options);
safe_close(p->mount_node_fd);
*p = DISSECTED_PARTITION_NULL;
}
#if HAVE_BLKID
static int make_partition_devname(
const char *whole_devname,
uint64_t diskseq,
int nr,
DissectImageFlags flags,
char **ret) {
_cleanup_free_ char *s = NULL;
int r;
assert(whole_devname);
assert(nr != 0); /* zero is not a valid partition nr */
assert(ret);
if (!FLAGS_SET(flags, DISSECT_IMAGE_DISKSEQ_DEVNODE) || diskseq == 0) {
/* Given a whole block device node name (e.g. /dev/sda or /dev/loop7) generate a partition
* device name (e.g. /dev/sda7 or /dev/loop7p5). The rule the kernel uses is simple: if whole
* block device node name ends in a digit, then suffix a 'p', followed by the partition
* number. Otherwise, just suffix the partition number without any 'p'. */
if (nr < 0) { /* whole disk? */
s = strdup(whole_devname);
if (!s)
return -ENOMEM;
} else {
size_t l = strlen(whole_devname);
if (l < 1) /* underflow check for the subtraction below */
return -EINVAL;
bool need_p = ascii_isdigit(whole_devname[l-1]); /* Last char a digit? */
if (asprintf(&s, "%s%s%i", whole_devname, need_p ? "p" : "", nr) < 0)
return -ENOMEM;
}
} else {
if (nr < 0) /* whole disk? */
r = asprintf(&s, "/dev/disk/by-diskseq/%" PRIu64, diskseq);
else
r = asprintf(&s, "/dev/disk/by-diskseq/%" PRIu64 "-part%i", diskseq, nr);
if (r < 0)
return -ENOMEM;
}
*ret = TAKE_PTR(s);
return 0;
}
static int open_partition(
const char *node,
bool is_partition,
const LoopDevice *loop) {
_cleanup_(sd_device_unrefp) sd_device *dev = NULL;
_cleanup_close_ int fd = -EBADF;
dev_t devnum;
int r;
assert(node);
assert(loop);
fd = open(node, O_RDONLY|O_NONBLOCK|O_CLOEXEC|O_NOCTTY);
if (fd < 0)
return -errno;
/* Check if the block device is a child of (or equivalent to) the originally provided one. */
r = block_device_new_from_fd(fd, is_partition ? BLOCK_DEVICE_LOOKUP_WHOLE_DISK : 0, &dev);
if (r < 0)
return r;
r = sd_device_get_devnum(dev, &devnum);
if (r < 0)
return r;
if (loop->devno != devnum)
return -ENXIO;
/* Also check diskseq. */
if (loop->diskseq != 0) {
uint64_t diskseq;
r = fd_get_diskseq(fd, &diskseq);
if (r < 0)
return r;
if (loop->diskseq != diskseq)
return -ENXIO;
}
log_debug("Opened %s (fd=%i, whole_block_devnum=" DEVNUM_FORMAT_STR ", diskseq=%" PRIu64 ").",
node, fd, DEVNUM_FORMAT_VAL(loop->devno), loop->diskseq);
return TAKE_FD(fd);
}
static int compare_arch(Architecture a, Architecture b) {
if (a == b)
return 0;
if (a == native_architecture())
return 1;
if (b == native_architecture())
return -1;
#ifdef ARCHITECTURE_SECONDARY
if (a == ARCHITECTURE_SECONDARY)
return 1;
if (b == ARCHITECTURE_SECONDARY)
return -1;
#endif
return 0;
}
static int dissect_image(
DissectedImage *m,
int fd,
const char *devname,
const VeritySettings *verity,
const MountOptions *mount_options,
DissectImageFlags flags) {
sd_id128_t root_uuid = SD_ID128_NULL, root_verity_uuid = SD_ID128_NULL;
sd_id128_t usr_uuid = SD_ID128_NULL, usr_verity_uuid = SD_ID128_NULL;
bool is_gpt, is_mbr, multiple_generic = false,
generic_rw = false, /* initialize to appease gcc */
generic_growfs = false;
_cleanup_(blkid_free_probep) blkid_probe b = NULL;
_cleanup_free_ char *generic_node = NULL;
sd_id128_t generic_uuid = SD_ID128_NULL;
const char *pttype = NULL, *sptuuid = NULL;
blkid_partlist pl;
int r, generic_nr = -1, n_partitions;
assert(m);
assert(fd >= 0);
assert(devname);
assert(!verity || verity->designator < 0 || IN_SET(verity->designator, PARTITION_ROOT, PARTITION_USR));
assert(!verity || verity->root_hash || verity->root_hash_size == 0);
assert(!verity || verity->root_hash_sig || verity->root_hash_sig_size == 0);
assert(!verity || (verity->root_hash || !verity->root_hash_sig));
assert(!((flags & DISSECT_IMAGE_GPT_ONLY) && (flags & DISSECT_IMAGE_NO_PARTITION_TABLE)));
assert(m->sector_size > 0);
/* Probes a disk image, and returns information about what it found in *ret.
*
* Returns -ENOPKG if no suitable partition table or file system could be found.
* Returns -EADDRNOTAVAIL if a root hash was specified but no matching root/verity partitions found.
* Returns -ENXIO if we couldn't find any partition suitable as root or /usr partition
* Returns -ENOTUNIQ if we only found multiple generic partitions and thus don't know what to do with that */
uint64_t diskseq = m->loop ? m->loop->diskseq : 0;
if (verity && verity->root_hash) {
sd_id128_t fsuuid, vuuid;
/* If a root hash is supplied, then we use the root partition that has a UUID that match the
* first 128bit of the root hash. And we use the verity partition that has a UUID that match
* the final 128bit. */
if (verity->root_hash_size < sizeof(sd_id128_t))
return -EINVAL;
memcpy(&fsuuid, verity->root_hash, sizeof(sd_id128_t));
memcpy(&vuuid, (const uint8_t*) verity->root_hash + verity->root_hash_size - sizeof(sd_id128_t), sizeof(sd_id128_t));
if (sd_id128_is_null(fsuuid))
return -EINVAL;
if (sd_id128_is_null(vuuid))
return -EINVAL;
/* If the verity data declares it's for the /usr partition, then search for that, in all
* other cases assume it's for the root partition. */
if (verity->designator == PARTITION_USR) {
usr_uuid = fsuuid;
usr_verity_uuid = vuuid;
} else {
root_uuid = fsuuid;
root_verity_uuid = vuuid;
}
}
b = blkid_new_probe();
if (!b)
return -ENOMEM;
errno = 0;
r = blkid_probe_set_device(b, fd, 0, 0);
if (r != 0)
return errno_or_else(ENOMEM);
errno = 0;
r = blkid_probe_set_sectorsize(b, m->sector_size);
if (r != 0)
return errno_or_else(EIO);
if ((flags & DISSECT_IMAGE_GPT_ONLY) == 0) {
/* Look for file system superblocks, unless we only shall look for GPT partition tables */
blkid_probe_enable_superblocks(b, 1);
blkid_probe_set_superblocks_flags(b, BLKID_SUBLKS_TYPE|BLKID_SUBLKS_USAGE|BLKID_SUBLKS_UUID);
}
blkid_probe_enable_partitions(b, 1);
blkid_probe_set_partitions_flags(b, BLKID_PARTS_ENTRY_DETAILS);
errno = 0;
r = blkid_do_safeprobe(b);
if (r == _BLKID_SAFEPROBE_ERROR)
return errno_or_else(EIO);
if (IN_SET(r, _BLKID_SAFEPROBE_AMBIGUOUS, _BLKID_SAFEPROBE_NOT_FOUND))
return log_debug_errno(SYNTHETIC_ERRNO(ENOPKG), "Failed to identify any partition table.");
assert(r == _BLKID_SAFEPROBE_FOUND);
if ((!(flags & DISSECT_IMAGE_GPT_ONLY) &&
(flags & DISSECT_IMAGE_GENERIC_ROOT)) ||
(flags & DISSECT_IMAGE_NO_PARTITION_TABLE)) {
const char *usage = NULL;
/* If flags permit this, also allow using non-partitioned single-filesystem images */
(void) blkid_probe_lookup_value(b, "USAGE", &usage, NULL);
if (STRPTR_IN_SET(usage, "filesystem", "crypto")) {
_cleanup_free_ char *t = NULL, *n = NULL, *o = NULL;
const char *fstype = NULL, *options = NULL, *suuid = NULL;
_cleanup_close_ int mount_node_fd = -EBADF;
sd_id128_t uuid = SD_ID128_NULL;
if (FLAGS_SET(flags, DISSECT_IMAGE_PIN_PARTITION_DEVICES)) {
mount_node_fd = open_partition(devname, /* is_partition = */ false, m->loop);
if (mount_node_fd < 0)
return mount_node_fd;
}
/* OK, we have found a file system, that's our root partition then. */
(void) blkid_probe_lookup_value(b, "TYPE", &fstype, NULL);
(void) blkid_probe_lookup_value(b, "UUID", &suuid, NULL);
if (fstype) {
t = strdup(fstype);
if (!t)
return -ENOMEM;
}
if (suuid) {
/* blkid will return FAT's serial number as UUID, hence it is quite possible
* that parsing this will fail. We'll ignore the ID, since it's just too
* short to be useful as tru identifier. */
r = sd_id128_from_string(suuid, &uuid);
if (r < 0)
log_debug_errno(r, "Failed to parse file system UUID '%s', ignoring: %m", suuid);
}
r = make_partition_devname(devname, diskseq, -1, flags, &n);
if (r < 0)
return r;
m->single_file_system = true;
m->encrypted = streq_ptr(fstype, "crypto_LUKS");
m->has_verity = verity && verity->data_path;
m->verity_ready = verity_settings_data_covers(verity, PARTITION_ROOT);
m->has_verity_sig = false; /* signature not embedded, must be specified */
m->verity_sig_ready = m->verity_ready && verity->root_hash_sig;
m->image_uuid = uuid;
options = mount_options_from_designator(mount_options, PARTITION_ROOT);
if (options) {
o = strdup(options);
if (!o)
return -ENOMEM;
}
m->partitions[PARTITION_ROOT] = (DissectedPartition) {
.found = true,
.rw = !m->verity_ready && !fstype_is_ro(fstype),
.partno = -1,
.architecture = _ARCHITECTURE_INVALID,
.fstype = TAKE_PTR(t),
.node = TAKE_PTR(n),
.mount_options = TAKE_PTR(o),
.mount_node_fd = TAKE_FD(mount_node_fd),
.offset = 0,
.size = UINT64_MAX,
};
return 0;
}
}
(void) blkid_probe_lookup_value(b, "PTTYPE", &pttype, NULL);
if (!pttype)
return -ENOPKG;
is_gpt = streq_ptr(pttype, "gpt");
is_mbr = streq_ptr(pttype, "dos");
if (!is_gpt && ((flags & DISSECT_IMAGE_GPT_ONLY) || !is_mbr))
return -ENOPKG;
/* We support external verity data partitions only if the image has no partition table */
if (verity && verity->data_path)
return -EBADR;
if (FLAGS_SET(flags, DISSECT_IMAGE_ADD_PARTITION_DEVICES)) {
/* Safety check: refuse block devices that carry a partition table but for which the kernel doesn't
* do partition scanning. */
r = blockdev_partscan_enabled(fd);
if (r < 0)
return r;
if (r == 0)
return -EPROTONOSUPPORT;
}
(void) blkid_probe_lookup_value(b, "PTUUID", &sptuuid, NULL);
if (sptuuid) {
r = sd_id128_from_string(sptuuid, &m->image_uuid);
if (r < 0)
log_debug_errno(r, "Failed to parse partition table UUID '%s', ignoring: %m", sptuuid);
}
errno = 0;
pl = blkid_probe_get_partitions(b);
if (!pl)
return errno_or_else(ENOMEM);
errno = 0;
n_partitions = blkid_partlist_numof_partitions(pl);
if (n_partitions < 0)
return errno_or_else(EIO);
for (int i = 0; i < n_partitions; i++) {
_cleanup_free_ char *node = NULL;
unsigned long long pflags;
blkid_loff_t start, size;
blkid_partition pp;
int nr;
errno = 0;
pp = blkid_partlist_get_partition(pl, i);
if (!pp)
return errno_or_else(EIO);
pflags = blkid_partition_get_flags(pp);
errno = 0;
nr = blkid_partition_get_partno(pp);
if (nr < 0)
return errno_or_else(EIO);
errno = 0;
start = blkid_partition_get_start(pp);
if (start < 0)
return errno_or_else(EIO);
assert((uint64_t) start < UINT64_MAX/512);
errno = 0;
size = blkid_partition_get_size(pp);
if (size < 0)
return errno_or_else(EIO);
assert((uint64_t) size < UINT64_MAX/512);
/* While probing we need the non-diskseq device node name to access the thing, hence mask off
* DISSECT_IMAGE_DISKSEQ_DEVNODE. */
r = make_partition_devname(devname, diskseq, nr, flags & ~DISSECT_IMAGE_DISKSEQ_DEVNODE, &node);
if (r < 0)
return r;
/* So here's the thing: after the main ("whole") block device popped up it might take a while
* before the kernel fully probed the partition table. Waiting for that to finish is icky in
* userspace. So here's what we do instead. We issue the BLKPG_ADD_PARTITION ioctl to add the
* partition ourselves, racing against the kernel. Good thing is: if this call fails with
* EBUSY then the kernel was quicker than us, and that's totally OK, the outcome is good for
* us: the device node will exist. If OTOH our call was successful we won the race. Which is
* also good as the outcome is the same: the partition block device exists, and we can use
* it.
*
* Kernel returns EBUSY if there's already a partition by that number or an overlapping
* partition already existent. */
if (FLAGS_SET(flags, DISSECT_IMAGE_ADD_PARTITION_DEVICES)) {
r = block_device_add_partition(fd, node, nr, (uint64_t) start * 512, (uint64_t) size * 512);
if (r < 0) {
if (r != -EBUSY)
return log_debug_errno(r, "BLKPG_ADD_PARTITION failed: %m");
log_debug_errno(r, "Kernel was quicker than us in adding partition %i.", nr);
} else
log_debug("We were quicker than kernel in adding partition %i.", nr);
}
if (is_gpt) {
const char *fstype = NULL, *label;
sd_id128_t type_id, id;
GptPartitionType type;
bool rw = true, growfs = false;
r = blkid_partition_get_uuid_id128(pp, &id);
if (r < 0) {
log_debug_errno(r, "Failed to read partition UUID, ignoring: %m");
continue;
}
r = blkid_partition_get_type_id128(pp, &type_id);
if (r < 0) {
log_debug_errno(r, "Failed to read partition type UUID, ignoring: %m");
continue;
}
type = gpt_partition_type_from_uuid(type_id);
label = blkid_partition_get_name(pp); /* libblkid returns NULL here if empty */
if (IN_SET(type.designator,
PARTITION_HOME,
PARTITION_SRV,
PARTITION_XBOOTLDR,
PARTITION_TMP)) {
check_partition_flags(node, pflags,
SD_GPT_FLAG_NO_AUTO | SD_GPT_FLAG_READ_ONLY | SD_GPT_FLAG_GROWFS);
if (pflags & SD_GPT_FLAG_NO_AUTO)
continue;
rw = !(pflags & SD_GPT_FLAG_READ_ONLY);
growfs = FLAGS_SET(pflags, SD_GPT_FLAG_GROWFS);
} else if (type.designator == PARTITION_ESP) {
/* Note that we don't check the SD_GPT_FLAG_NO_AUTO flag for the ESP, as it is
* not defined there. We instead check the SD_GPT_FLAG_NO_BLOCK_IO_PROTOCOL, as
* recommended by the UEFI spec (See "12.3.3 Number and Location of System
* Partitions"). */
if (pflags & SD_GPT_FLAG_NO_BLOCK_IO_PROTOCOL)
continue;
fstype = "vfat";
} else if (type.designator == PARTITION_ROOT) {
check_partition_flags(node, pflags,
SD_GPT_FLAG_NO_AUTO | SD_GPT_FLAG_READ_ONLY | SD_GPT_FLAG_GROWFS);
if (pflags & SD_GPT_FLAG_NO_AUTO)
continue;
/* If a root ID is specified, ignore everything but the root id */
if (!sd_id128_is_null(root_uuid) && !sd_id128_equal(root_uuid, id))
continue;
rw = !(pflags & SD_GPT_FLAG_READ_ONLY);
growfs = FLAGS_SET(pflags, SD_GPT_FLAG_GROWFS);
} else if (type.designator == PARTITION_ROOT_VERITY) {
check_partition_flags(node, pflags,
SD_GPT_FLAG_NO_AUTO | SD_GPT_FLAG_READ_ONLY);
if (pflags & SD_GPT_FLAG_NO_AUTO)
continue;
m->has_verity = true;
/* If no verity configuration is specified, then don't do verity */
if (!verity)
continue;
if (verity->designator >= 0 && verity->designator != PARTITION_ROOT)
continue;
/* If root hash is specified, then ignore everything but the root id */
if (!sd_id128_is_null(root_verity_uuid) && !sd_id128_equal(root_verity_uuid, id))
continue;
fstype = "DM_verity_hash";
rw = false;
} else if (type.designator == PARTITION_ROOT_VERITY_SIG) {
check_partition_flags(node, pflags,
SD_GPT_FLAG_NO_AUTO | SD_GPT_FLAG_READ_ONLY);
if (pflags & SD_GPT_FLAG_NO_AUTO)
continue;
m->has_verity_sig = true;
if (!verity)
continue;
if (verity->designator >= 0 && verity->designator != PARTITION_ROOT)
continue;
fstype = "verity_hash_signature";
rw = false;
} else if (type.designator == PARTITION_USR) {
check_partition_flags(node, pflags,
SD_GPT_FLAG_NO_AUTO | SD_GPT_FLAG_READ_ONLY | SD_GPT_FLAG_GROWFS);
if (pflags & SD_GPT_FLAG_NO_AUTO)
continue;
/* If a usr ID is specified, ignore everything but the usr id */
if (!sd_id128_is_null(usr_uuid) && !sd_id128_equal(usr_uuid, id))
continue;
rw = !(pflags & SD_GPT_FLAG_READ_ONLY);
growfs = FLAGS_SET(pflags, SD_GPT_FLAG_GROWFS);
} else if (type.designator == PARTITION_USR_VERITY) {
check_partition_flags(node, pflags,
SD_GPT_FLAG_NO_AUTO | SD_GPT_FLAG_READ_ONLY);
if (pflags & SD_GPT_FLAG_NO_AUTO)
continue;
m->has_verity = true;
if (!verity)
continue;
if (verity->designator >= 0 && verity->designator != PARTITION_USR)
continue;
/* If usr hash is specified, then ignore everything but the usr id */
if (!sd_id128_is_null(usr_verity_uuid) && !sd_id128_equal(usr_verity_uuid, id))
continue;
fstype = "DM_verity_hash";
rw = false;
} else if (type.designator == PARTITION_USR_VERITY_SIG) {
check_partition_flags(node, pflags,
SD_GPT_FLAG_NO_AUTO | SD_GPT_FLAG_READ_ONLY);
if (pflags & SD_GPT_FLAG_NO_AUTO)
continue;
m->has_verity_sig = true;
if (!verity)
continue;
if (verity->designator >= 0 && verity->designator != PARTITION_USR)
continue;
fstype = "verity_hash_signature";
rw = false;
} else if (type.designator == PARTITION_SWAP) {
check_partition_flags(node, pflags, SD_GPT_FLAG_NO_AUTO);
if (pflags & SD_GPT_FLAG_NO_AUTO)
continue;
/* Note: we don't set fstype = "swap" here, because we still need to probe if
* it might be encrypted (i.e. fstype "crypt_LUKS") or unencrypted
* (i.e. fstype "swap"), and the only way to figure that out is via fstype
* probing. */
/* We don't have a designator for SD_GPT_LINUX_GENERIC so check the UUID instead. */
} else if (sd_id128_equal(type.uuid, SD_GPT_LINUX_GENERIC)) {
check_partition_flags(node, pflags,
SD_GPT_FLAG_NO_AUTO | SD_GPT_FLAG_READ_ONLY | SD_GPT_FLAG_GROWFS);
if (pflags & SD_GPT_FLAG_NO_AUTO)
continue;
if (generic_node)
multiple_generic = true;
else {
generic_nr = nr;
generic_rw = !(pflags & SD_GPT_FLAG_READ_ONLY);
generic_growfs = FLAGS_SET(pflags, SD_GPT_FLAG_GROWFS);
generic_uuid = id;
generic_node = TAKE_PTR(node);
}
} else if (type.designator == PARTITION_VAR) {
check_partition_flags(node, pflags,
SD_GPT_FLAG_NO_AUTO | SD_GPT_FLAG_READ_ONLY | SD_GPT_FLAG_GROWFS);
if (pflags & SD_GPT_FLAG_NO_AUTO)
continue;
if (!FLAGS_SET(flags, DISSECT_IMAGE_RELAX_VAR_CHECK)) {
sd_id128_t var_uuid;
/* For /var we insist that the uuid of the partition matches the
* HMAC-SHA256 of the /var GPT partition type uuid, keyed by machine
* ID. Why? Unlike the other partitions /var is inherently
* installation specific, hence we need to be careful not to mount it
* in the wrong installation. By hashing the partition UUID from
* /etc/machine-id we can securely bind the partition to the
* installation. */
r = sd_id128_get_machine_app_specific(SD_GPT_VAR, &var_uuid);
if (r < 0)
return r;
if (!sd_id128_equal(var_uuid, id)) {
log_debug("Found a /var/ partition, but its UUID didn't match our expectations "
"(found: " SD_ID128_UUID_FORMAT_STR ", expected: " SD_ID128_UUID_FORMAT_STR "), ignoring.",
SD_ID128_FORMAT_VAL(id), SD_ID128_FORMAT_VAL(var_uuid));
continue;
}
}
rw = !(pflags & SD_GPT_FLAG_READ_ONLY);
growfs = FLAGS_SET(pflags, SD_GPT_FLAG_GROWFS);
}
if (type.designator != _PARTITION_DESIGNATOR_INVALID) {
_cleanup_free_ char *t = NULL, *o = NULL, *l = NULL, *n = NULL;
_cleanup_close_ int mount_node_fd = -EBADF;
const char *options = NULL;
if (m->partitions[type.designator].found) {
/* For most partition types the first one we see wins. Except for the
* rootfs and /usr, where we do a version compare of the label, and
* let the newest version win. This permits a simple A/B versioning
* scheme in OS images. */
if (compare_arch(type.arch, m->partitions[type.designator].architecture) <= 0)
continue;
if (!partition_designator_is_versioned(type.designator) ||
strverscmp_improved(m->partitions[type.designator].label, label) >= 0)
continue;
dissected_partition_done(m->partitions + type.designator);
}
if (FLAGS_SET(flags, DISSECT_IMAGE_PIN_PARTITION_DEVICES) &&
type.designator != PARTITION_SWAP) {
mount_node_fd = open_partition(node, /* is_partition = */ true, m->loop);
if (mount_node_fd < 0)
return mount_node_fd;
}
r = make_partition_devname(devname, diskseq, nr, flags, &n);
if (r < 0)
return r;
if (fstype) {
t = strdup(fstype);
if (!t)
return -ENOMEM;
}
if (label) {
l = strdup(label);
if (!l)
return -ENOMEM;
}
options = mount_options_from_designator(mount_options, type.designator);
if (options) {
o = strdup(options);
if (!o)
return -ENOMEM;
}
m->partitions[type.designator] = (DissectedPartition) {
.found = true,
.partno = nr,
.rw = rw,
.growfs = growfs,
.architecture = type.arch,
.node = TAKE_PTR(n),
.fstype = TAKE_PTR(t),
.label = TAKE_PTR(l),
.uuid = id,
.mount_options = TAKE_PTR(o),
.mount_node_fd = TAKE_FD(mount_node_fd),
.offset = (uint64_t) start * 512,
.size = (uint64_t) size * 512,
.gpt_flags = pflags,
};
}
} else if (is_mbr) {
switch (blkid_partition_get_type(pp)) {
case 0x83: /* Linux partition */
if (pflags != 0x80) /* Bootable flag */
continue;
if (generic_node)
multiple_generic = true;
else {
generic_nr = nr;
generic_rw = true;
generic_growfs = false;
generic_node = TAKE_PTR(node);
}
break;
case 0xEA: { /* Boot Loader Spec extended $BOOT partition */
_cleanup_close_ int mount_node_fd = -EBADF;
_cleanup_free_ char *o = NULL, *n = NULL;
sd_id128_t id = SD_ID128_NULL;
const char *options = NULL;
/* First one wins */
if (m->partitions[PARTITION_XBOOTLDR].found)
continue;
if (FLAGS_SET(flags, DISSECT_IMAGE_PIN_PARTITION_DEVICES)) {
mount_node_fd = open_partition(node, /* is_partition = */ true, m->loop);
if (mount_node_fd < 0)
return mount_node_fd;
}
(void) blkid_partition_get_uuid_id128(pp, &id);
r = make_partition_devname(devname, diskseq, nr, flags, &n);
if (r < 0)
return r;
options = mount_options_from_designator(mount_options, PARTITION_XBOOTLDR);
if (options) {
o = strdup(options);
if (!o)
return -ENOMEM;
}
m->partitions[PARTITION_XBOOTLDR] = (DissectedPartition) {
.found = true,
.partno = nr,
.rw = true,
.growfs = false,
.architecture = _ARCHITECTURE_INVALID,
.node = TAKE_PTR(n),
.uuid = id,
.mount_options = TAKE_PTR(o),
.mount_node_fd = TAKE_FD(mount_node_fd),
.offset = (uint64_t) start * 512,
.size = (uint64_t) size * 512,
};
break;
}}
}
}
if (!m->partitions[PARTITION_ROOT].found &&
(m->partitions[PARTITION_ROOT_VERITY].found ||
m->partitions[PARTITION_ROOT_VERITY_SIG].found))
return -EADDRNOTAVAIL; /* Verity found but no matching rootfs? Something is off, refuse. */
/* Hmm, we found a signature partition but no Verity data? Something is off. */
if (m->partitions[PARTITION_ROOT_VERITY_SIG].found && !m->partitions[PARTITION_ROOT_VERITY].found)
return -EADDRNOTAVAIL;
if (!m->partitions[PARTITION_USR].found &&
(m->partitions[PARTITION_USR_VERITY].found ||
m->partitions[PARTITION_USR_VERITY_SIG].found))
return -EADDRNOTAVAIL; /* as above */
/* as above */
if (m->partitions[PARTITION_USR_VERITY_SIG].found && !m->partitions[PARTITION_USR_VERITY].found)
return -EADDRNOTAVAIL;
/* If root and /usr are combined then insist that the architecture matches */
if (m->partitions[PARTITION_ROOT].found &&
m->partitions[PARTITION_USR].found &&
(m->partitions[PARTITION_ROOT].architecture >= 0 &&
m->partitions[PARTITION_USR].architecture >= 0 &&
m->partitions[PARTITION_ROOT].architecture != m->partitions[PARTITION_USR].architecture))
return -EADDRNOTAVAIL;
if (!m->partitions[PARTITION_ROOT].found &&
!m->partitions[PARTITION_USR].found &&
(flags & DISSECT_IMAGE_GENERIC_ROOT) &&
(!verity || !verity->root_hash || verity->designator != PARTITION_USR)) {
/* OK, we found nothing usable, then check if there's a single generic partition, and use
* that. If the root hash was set however, then we won't fall back to a generic node, because
* the root hash decides. */
/* If we didn't find a properly marked root partition, but we did find a single suitable
* generic Linux partition, then use this as root partition, if the caller asked for it. */
if (multiple_generic)
return -ENOTUNIQ;
/* If we didn't find a generic node, then we can't fix this up either */
if (generic_node) {
_cleanup_close_ int mount_node_fd = -EBADF;
_cleanup_free_ char *o = NULL, *n = NULL;
const char *options;
if (FLAGS_SET(flags, DISSECT_IMAGE_PIN_PARTITION_DEVICES)) {
mount_node_fd = open_partition(generic_node, /* is_partition = */ true, m->loop);
if (mount_node_fd < 0)
return mount_node_fd;
}
r = make_partition_devname(devname, diskseq, generic_nr, flags, &n);
if (r < 0)
return r;
options = mount_options_from_designator(mount_options, PARTITION_ROOT);
if (options) {
o = strdup(options);
if (!o)
return -ENOMEM;
}
assert(generic_nr >= 0);
m->partitions[PARTITION_ROOT] = (DissectedPartition) {
.found = true,
.rw = generic_rw,
.growfs = generic_growfs,
.partno = generic_nr,
.architecture = _ARCHITECTURE_INVALID,
.node = TAKE_PTR(n),
.uuid = generic_uuid,
.mount_options = TAKE_PTR(o),
.mount_node_fd = TAKE_FD(mount_node_fd),
.offset = UINT64_MAX,
.size = UINT64_MAX,
};
}
}
/* Check if we have a root fs if we are told to do check. /usr alone is fine too, but only if appropriate flag for that is set too */
if (FLAGS_SET(flags, DISSECT_IMAGE_REQUIRE_ROOT) &&
!(m->partitions[PARTITION_ROOT].found || (m->partitions[PARTITION_USR].found && FLAGS_SET(flags, DISSECT_IMAGE_USR_NO_ROOT))))
return -ENXIO;
if (m->partitions[PARTITION_ROOT_VERITY].found) {
/* We only support one verity partition per image, i.e. can't do for both /usr and root fs */
if (m->partitions[PARTITION_USR_VERITY].found)
return -ENOTUNIQ;
/* We don't support verity enabled root with a split out /usr. Neither with nor without
* verity there. (Note that we do support verity-less root with verity-full /usr, though.) */
if (m->partitions[PARTITION_USR].found)
return -EADDRNOTAVAIL;
}
if (verity) {
/* If a verity designator is specified, then insist that the matching partition exists */
if (verity->designator >= 0 && !m->partitions[verity->designator].found)
return -EADDRNOTAVAIL;
bool have_verity_sig_partition =
m->partitions[verity->designator == PARTITION_USR ? PARTITION_USR_VERITY_SIG : PARTITION_ROOT_VERITY_SIG].found;
if (verity->root_hash) {
/* If we have an explicit root hash and found the partitions for it, then we are ready to use
* Verity, set things up for it */
if (verity->designator < 0 || verity->designator == PARTITION_ROOT) {
if (!m->partitions[PARTITION_ROOT_VERITY].found || !m->partitions[PARTITION_ROOT].found)
return -EADDRNOTAVAIL;
/* If we found a verity setup, then the root partition is necessarily read-only. */
m->partitions[PARTITION_ROOT].rw = false;
m->verity_ready = true;
} else {
assert(verity->designator == PARTITION_USR);
if (!m->partitions[PARTITION_USR_VERITY].found || !m->partitions[PARTITION_USR].found)
return -EADDRNOTAVAIL;
m->partitions[PARTITION_USR].rw = false;
m->verity_ready = true;
}
if (m->verity_ready)
m->verity_sig_ready = verity->root_hash_sig || have_verity_sig_partition;
} else if (have_verity_sig_partition) {
/* If we found an embedded signature partition, we are ready, too. */
m->verity_ready = m->verity_sig_ready = true;
m->partitions[verity->designator == PARTITION_USR ? PARTITION_USR : PARTITION_ROOT].rw = false;
}
}
r = dissected_image_probe_filesystems(m, fd);
if (r < 0)
return r;
return 0;
}
#endif
int dissect_image_file(
const char *path,
const VeritySettings *verity,
const MountOptions *mount_options,
DissectImageFlags flags,
DissectedImage **ret) {
#if HAVE_BLKID
_cleanup_(dissected_image_unrefp) DissectedImage *m = NULL;
_cleanup_close_ int fd = -EBADF;
int r;
assert(path);
assert(ret);
fd = open(path, O_RDONLY|O_CLOEXEC|O_NONBLOCK|O_NOCTTY);
if (fd < 0)
return -errno;
r = fd_verify_regular(fd);
if (r < 0)
return r;
r = dissected_image_new(path, &m);
if (r < 0)
return r;
r = probe_sector_size(fd, &m->sector_size);
if (r < 0)
return r;
r = dissect_image(m, fd, path, verity, mount_options, flags);
if (r < 0)
return r;
*ret = TAKE_PTR(m);
return 0;
#else
return -EOPNOTSUPP;
#endif
}
DissectedImage* dissected_image_unref(DissectedImage *m) {
if (!m)
return NULL;
/* First, clear dissected partitions. */
for (PartitionDesignator i = 0; i < _PARTITION_DESIGNATOR_MAX; i++)
dissected_partition_done(m->partitions + i);
/* Second, free decrypted images. This must be after dissected_partition_done(), as freeing
* DecryptedImage may try to deactivate partitions. */
decrypted_image_unref(m->decrypted_image);
/* Third, unref LoopDevice. This must be called after the above two, as freeing LoopDevice may try to
* remove existing partitions on the loopback block device. */
loop_device_unref(m->loop);
free(m->image_name);
free(m->hostname);
strv_free(m->machine_info);
strv_free(m->os_release);
strv_free(m->initrd_release);
strv_free(m->extension_release);
return mfree(m);
}
static int is_loop_device(const char *path) {
char s[SYS_BLOCK_PATH_MAX("/../loop/")];
struct stat st;
assert(path);
if (stat(path, &st) < 0)
return -errno;
if (!S_ISBLK(st.st_mode))
return -ENOTBLK;
xsprintf_sys_block_path(s, "/loop/", st.st_dev);
if (access(s, F_OK) < 0) {
if (errno != ENOENT)
return -errno;
/* The device itself isn't a loop device, but maybe it's a partition and its parent is? */
xsprintf_sys_block_path(s, "/../loop/", st.st_dev);
if (access(s, F_OK) < 0)
return errno == ENOENT ? false : -errno;
}
return true;
}
static int run_fsck(int node_fd, const char *fstype) {
int r, exit_status;
pid_t pid;
assert(node_fd >= 0);
assert(fstype);
r = fsck_exists_for_fstype(fstype);
if (r < 0) {
log_debug_errno(r, "Couldn't determine whether fsck for %s exists, proceeding anyway.", fstype);
return 0;
}
if (r == 0) {
log_debug("Not checking partition %s, as fsck for %s does not exist.", FORMAT_PROC_FD_PATH(node_fd), fstype);
return 0;
}
r = safe_fork_full(
"(fsck)",
&node_fd, 1, /* Leave the node fd open */
FORK_RESET_SIGNALS|FORK_CLOSE_ALL_FDS|FORK_RLIMIT_NOFILE_SAFE|FORK_DEATHSIG|FORK_NULL_STDIO|FORK_CLOEXEC_OFF,
&pid);
if (r < 0)
return log_debug_errno(r, "Failed to fork off fsck: %m");
if (r == 0) {
/* Child */
execl("/sbin/fsck", "/sbin/fsck", "-aT", FORMAT_PROC_FD_PATH(node_fd), NULL);
log_open();
log_debug_errno(errno, "Failed to execl() fsck: %m");
_exit(FSCK_OPERATIONAL_ERROR);
}
exit_status = wait_for_terminate_and_check("fsck", pid, 0);
if (exit_status < 0)
return log_debug_errno(exit_status, "Failed to fork off /sbin/fsck: %m");
if ((exit_status & ~FSCK_ERROR_CORRECTED) != FSCK_SUCCESS) {
log_debug("fsck failed with exit status %i.", exit_status);
if ((exit_status & (FSCK_SYSTEM_SHOULD_REBOOT|FSCK_ERRORS_LEFT_UNCORRECTED)) != 0)
return log_debug_errno(SYNTHETIC_ERRNO(EUCLEAN), "File system is corrupted, refusing.");
log_debug("Ignoring fsck error.");
}
return 0;
}
static int fs_grow(const char *node_path, const char *mount_path) {
_cleanup_close_ int mount_fd = -EBADF, node_fd = -EBADF;
uint64_t size, newsize;
int r;
node_fd = open(node_path, O_RDONLY|O_CLOEXEC|O_NONBLOCK|O_NOCTTY);
if (node_fd < 0)
return log_debug_errno(errno, "Failed to open node device %s: %m", node_path);
if (ioctl(node_fd, BLKGETSIZE64, &size) != 0)
return log_debug_errno(errno, "Failed to get block device size of %s: %m", node_path);
mount_fd = open(mount_path, O_RDONLY|O_DIRECTORY|O_CLOEXEC);
if (mount_fd < 0)
return log_debug_errno(errno, "Failed to open mountd file system %s: %m", mount_path);
log_debug("Resizing \"%s\" to %"PRIu64" bytes...", mount_path, size);
r = resize_fs(mount_fd, size, &newsize);
if (r < 0)
return log_debug_errno(r, "Failed to resize \"%s\" to %"PRIu64" bytes: %m", mount_path, size);
if (newsize == size)
log_debug("Successfully resized \"%s\" to %s bytes.",
mount_path, FORMAT_BYTES(newsize));
else {
assert(newsize < size);
log_debug("Successfully resized \"%s\" to %s bytes (%"PRIu64" bytes lost due to blocksize).",
mount_path, FORMAT_BYTES(newsize), size - newsize);
}
return 0;
}
static int mount_partition(
DissectedPartition *m,
const char *where,
const char *directory,
uid_t uid_shift,
uid_t uid_range,
DissectImageFlags flags) {
_cleanup_free_ char *chased = NULL, *options = NULL;
const char *p, *node, *fstype;
bool rw, remap_uid_gid = false;
int r;
assert(m);
assert(where);
if (m->mount_node_fd < 0)
return 0;
/* Use decrypted node and matching fstype if available, otherwise use the original device */
node = FORMAT_PROC_FD_PATH(m->mount_node_fd);
fstype = m->decrypted_node ? m->decrypted_fstype: m->fstype;
if (!fstype)
return -EAFNOSUPPORT;
r = dissect_fstype_ok(fstype);
if (r < 0)
return r;
if (!r)
return -EIDRM; /* Recognizable error */
/* We are looking at an encrypted partition? This either means stacked encryption, or the caller
* didn't call dissected_image_decrypt() beforehand. Let's return a recognizable error for this
* case. */
if (streq(fstype, "crypto_LUKS"))
return -EUNATCH;
rw = m->rw && !(flags & DISSECT_IMAGE_MOUNT_READ_ONLY);
if (FLAGS_SET(flags, DISSECT_IMAGE_FSCK) && rw) {
r = run_fsck(m->mount_node_fd, fstype);
if (r < 0)
return r;
}
if (directory) {
/* Automatically create missing mount points inside the image, if necessary. */
r = mkdir_p_root(where, directory, uid_shift, (gid_t) uid_shift, 0755);
if (r < 0 && r != -EROFS)
return r;
r = chase_symlinks(directory, where, CHASE_PREFIX_ROOT, &chased, NULL);
if (r < 0)
return r;
p = chased;
} else {
/* Create top-level mount if missing – but only if this is asked for. This won't modify the
* image (as the branch above does) but the host hierarchy, and the created directory might
* survive our mount in the host hierarchy hence. */
if (FLAGS_SET(flags, DISSECT_IMAGE_MKDIR)) {
r = mkdir_p(where, 0755);
if (r < 0)
return r;
}
p = where;
}
/* If requested, turn on discard support. */
if (fstype_can_discard(fstype) &&
((flags & DISSECT_IMAGE_DISCARD) ||
((flags & DISSECT_IMAGE_DISCARD_ON_LOOP) && is_loop_device(m->node) > 0))) {
options = strdup("discard");
if (!options)
return -ENOMEM;
}
if (uid_is_valid(uid_shift) && uid_shift != 0) {
if (fstype_can_uid_gid(fstype)) {
_cleanup_free_ char *uid_option = NULL;
if (asprintf(&uid_option, "uid=" UID_FMT ",gid=" GID_FMT, uid_shift, (gid_t) uid_shift) < 0)
return -ENOMEM;
if (!strextend_with_separator(&options, ",", uid_option))
return -ENOMEM;
} else if (FLAGS_SET(flags, DISSECT_IMAGE_MOUNT_IDMAPPED))
remap_uid_gid = true;
}
if (!isempty(m->mount_options))
if (!strextend_with_separator(&options, ",", m->mount_options))
return -ENOMEM;
/* So, when you request MS_RDONLY from ext4, then this means nothing. It happily still writes to the
* backing storage. What's worse, the BLKRO[GS]ET flag and (in case of loopback devices)
* LO_FLAGS_READ_ONLY don't mean anything, they affect userspace accesses only, and write accesses
* from the upper file system still get propagated through to the underlying file system,
* unrestricted. To actually get ext4/xfs/btrfs to stop writing to the device we need to specify
* "norecovery" as mount option, in addition to MS_RDONLY. Yes, this sucks, since it means we need to
* carry a per file system table here.
*
* Note that this means that we might not be able to mount corrupted file systems as read-only
* anymore (since in some cases the kernel implementations will refuse mounting when corrupted,
* read-only and "norecovery" is specified). But I think for the case of automatically determined
* mount options for loopback devices this is the right choice, since otherwise using the same
* loopback file twice even in read-only mode, is going to fail badly sooner or later. The usecase of
* making reuse of the immutable images "just work" is more relevant to us than having read-only
* access that actually modifies stuff work on such image files. Or to say this differently: if
* people want their file systems to be fixed up they should just open them in writable mode, where
* all these problems don't exist. */
if (!rw && STRPTR_IN_SET(fstype, "ext3", "ext4", "xfs", "btrfs"))
if (!strextend_with_separator(&options, ",", "norecovery"))
return -ENOMEM;
r = mount_nofollow_verbose(LOG_DEBUG, node, p, fstype, MS_NODEV|(rw ? 0 : MS_RDONLY), options);
if (r < 0)
return r;
if (rw && m->growfs && FLAGS_SET(flags, DISSECT_IMAGE_GROWFS))
(void) fs_grow(node, p);
if (remap_uid_gid) {
r = remount_idmap(p, uid_shift, uid_range, UID_INVALID, REMOUNT_IDMAPPING_HOST_ROOT);
if (r < 0)
return r;
}
return 1;
}
static int mount_root_tmpfs(const char *where, uid_t uid_shift, DissectImageFlags flags) {
_cleanup_free_ char *options = NULL;
int r;
assert(where);
/* For images that contain /usr/ but no rootfs, let's mount rootfs as tmpfs */
if (FLAGS_SET(flags, DISSECT_IMAGE_MKDIR)) {
r = mkdir_p(where, 0755);
if (r < 0)
return r;
}
if (uid_is_valid(uid_shift)) {
if (asprintf(&options, "uid=" UID_FMT ",gid=" GID_FMT, uid_shift, (gid_t) uid_shift) < 0)
return -ENOMEM;
}
r = mount_nofollow_verbose(LOG_DEBUG, "rootfs", where, "tmpfs", MS_NODEV, options);
if (r < 0)
return r;
return 1;
}
int dissected_image_mount(
DissectedImage *m,
const char *where,
uid_t uid_shift,
uid_t uid_range,
DissectImageFlags flags) {
int r, xbootldr_mounted;
assert(m);
assert(where);
/* Returns:
*
* -ENXIO → No root partition found
* -EMEDIUMTYPE → DISSECT_IMAGE_VALIDATE_OS set but no os-release/extension-release file found
* -EUNATCH → Encrypted partition found for which no dm-crypt was set up yet
* -EUCLEAN → fsck for file system failed
* -EBUSY → File system already mounted/used elsewhere (kernel)
* -EAFNOSUPPORT → File system type not supported or not known
* -EIDRM → File system is not among allowlisted "common" file systems
*/
if (!(m->partitions[PARTITION_ROOT].found ||
(m->partitions[PARTITION_USR].found && FLAGS_SET(flags, DISSECT_IMAGE_USR_NO_ROOT))))
return -ENXIO; /* Require a root fs or at least a /usr/ fs (the latter is subject to a flag of its own) */
if ((flags & DISSECT_IMAGE_MOUNT_NON_ROOT_ONLY) == 0) {
/* First mount the root fs. If there's none we use a tmpfs. */
if (m->partitions[PARTITION_ROOT].found)
r = mount_partition(m->partitions + PARTITION_ROOT, where, NULL, uid_shift, uid_range, flags);
else
r = mount_root_tmpfs(where, uid_shift, flags);
if (r < 0)
return r;
/* For us mounting root always means mounting /usr as well */
r = mount_partition(m->partitions + PARTITION_USR, where, "/usr", uid_shift, uid_range, flags);
if (r < 0)
return r;
if ((flags & (DISSECT_IMAGE_VALIDATE_OS|DISSECT_IMAGE_VALIDATE_OS_EXT)) != 0) {
/* If either one of the validation flags are set, ensure that the image qualifies
* as one or the other (or both). */
bool ok = false;
if (FLAGS_SET(flags, DISSECT_IMAGE_VALIDATE_OS)) {
r = path_is_os_tree(where);
if (r < 0)
return r;
if (r > 0)
ok = true;
}
if (!ok && FLAGS_SET(flags, DISSECT_IMAGE_VALIDATE_OS_EXT)) {
r = path_is_extension_tree(where, m->image_name, FLAGS_SET(flags, DISSECT_IMAGE_RELAX_SYSEXT_CHECK));
if (r < 0)
return r;
if (r > 0)
ok = true;
}
if (!ok)
return -ENOMEDIUM;
}
}
if (flags & DISSECT_IMAGE_MOUNT_ROOT_ONLY)
return 0;
r = mount_partition(m->partitions + PARTITION_HOME, where, "/home", uid_shift, uid_range, flags);
if (r < 0)
return r;
r = mount_partition(m->partitions + PARTITION_SRV, where, "/srv", uid_shift, uid_range, flags);
if (r < 0)
return r;
r = mount_partition(m->partitions + PARTITION_VAR, where, "/var", uid_shift, uid_range, flags);
if (r < 0)
return r;
r = mount_partition(m->partitions + PARTITION_TMP, where, "/var/tmp", uid_shift, uid_range, flags);
if (r < 0)
return r;
xbootldr_mounted = mount_partition(m->partitions + PARTITION_XBOOTLDR, where, "/boot", uid_shift, uid_range, flags);
if (xbootldr_mounted < 0)
return xbootldr_mounted;
if (m->partitions[PARTITION_ESP].found) {
int esp_done = false;
/* Mount the ESP to /efi if it exists. If it doesn't exist, use /boot instead, but only if it
* exists and is empty, and we didn't already mount the XBOOTLDR partition into it. */
r = chase_symlinks("/efi", where, CHASE_PREFIX_ROOT, NULL, NULL);
if (r < 0) {
if (r != -ENOENT)
return r;
/* /efi doesn't exist. Let's see if /boot is suitable then */
if (!xbootldr_mounted) {
_cleanup_free_ char *p = NULL;
r = chase_symlinks("/boot", where, CHASE_PREFIX_ROOT, &p, NULL);
if (r < 0) {
if (r != -ENOENT)
return r;
} else if (dir_is_empty(p, /* ignore_hidden_or_backup= */ false) > 0) {
/* It exists and is an empty directory. Let's mount the ESP there. */
r = mount_partition(m->partitions + PARTITION_ESP, where, "/boot", uid_shift, uid_range, flags);
if (r < 0)
return r;
esp_done = true;
}
}
}
if (!esp_done) {
/* OK, let's mount the ESP now to /efi (possibly creating the dir if missing) */
r = mount_partition(m->partitions + PARTITION_ESP, where, "/efi", uid_shift, uid_range, flags);
if (r < 0)
return r;
}
}
return 0;
}
int dissected_image_mount_and_warn(
DissectedImage *m,
const char *where,
uid_t uid_shift,
uid_t uid_range,
DissectImageFlags flags) {
int r;
assert(m);
assert(where);
r = dissected_image_mount(m, where, uid_shift, uid_range, flags);
if (r == -ENXIO)
return log_error_errno(r, "Not root file system found in image.");
if (r == -EMEDIUMTYPE)
return log_error_errno(r, "No suitable os-release/extension-release file in image found.");
if (r == -EUNATCH)
return log_error_errno(r, "Encrypted file system discovered, but decryption not requested.");
if (r == -EUCLEAN)
return log_error_errno(r, "File system check on image failed.");
if (r == -EBUSY)
return log_error_errno(r, "File system already mounted elsewhere.");
if (r == -EAFNOSUPPORT)
return log_error_errno(r, "File system type not supported or not known.");
if (r == -EIDRM)
return log_error_errno(r, "File system is too uncommon, refused.");
if (r < 0)
return log_error_errno(r, "Failed to mount image: %m");
return r;
}
#if HAVE_LIBCRYPTSETUP
struct DecryptedPartition {
struct crypt_device *device;
char *name;
bool relinquished;
};
#endif
typedef struct DecryptedPartition DecryptedPartition;
struct DecryptedImage {
unsigned n_ref;
DecryptedPartition *decrypted;
size_t n_decrypted;
};
static DecryptedImage* decrypted_image_free(DecryptedImage *d) {
#if HAVE_LIBCRYPTSETUP
int r;
if (!d)
return NULL;
for (size_t i = 0; i < d->n_decrypted; i++) {
DecryptedPartition *p = d->decrypted + i;
if (p->device && p->name && !p->relinquished) {
_cleanup_free_ char *node = NULL;
node = path_join("/dev/mapper", p->name);
if (node) {
r = btrfs_forget_device(node);
if (r < 0 && r != -ENOENT)
log_debug_errno(r, "Failed to forget btrfs device %s, ignoring: %m", node);
} else
log_oom_debug();
/* Let's deactivate lazily, as the dm volume may be already/still used by other processes. */
r = sym_crypt_deactivate_by_name(p->device, p->name, CRYPT_DEACTIVATE_DEFERRED);
if (r < 0)
log_debug_errno(r, "Failed to deactivate encrypted partition %s", p->name);
}
if (p->device)
sym_crypt_free(p->device);
free(p->name);
}
free(d->decrypted);
free(d);
#endif
return NULL;
}
DEFINE_TRIVIAL_REF_UNREF_FUNC(DecryptedImage, decrypted_image, decrypted_image_free);
#if HAVE_LIBCRYPTSETUP
static int decrypted_image_new(DecryptedImage **ret) {
_cleanup_(decrypted_image_unrefp) DecryptedImage *d = NULL;
assert(ret);
d = new(DecryptedImage, 1);
if (!d)
return -ENOMEM;
*d = (DecryptedImage) {
.n_ref = 1,
};
*ret = TAKE_PTR(d);
return 0;
}
static int make_dm_name_and_node(const void *original_node, const char *suffix, char **ret_name, char **ret_node) {
_cleanup_free_ char *name = NULL, *node = NULL;
const char *base;
assert(original_node);
assert(suffix);
assert(ret_name);
assert(ret_node);
base = strrchr(original_node, '/');
if (!base)
base = original_node;
else
base++;
if (isempty(base))
return -EINVAL;
name = strjoin(base, suffix);
if (!name)
return -ENOMEM;
if (!filename_is_valid(name))
return -EINVAL;
node = path_join(sym_crypt_get_dir(), name);
if (!node)
return -ENOMEM;
*ret_name = TAKE_PTR(name);
*ret_node = TAKE_PTR(node);
return 0;
}
static int decrypt_partition(
DissectedPartition *m,
const char *passphrase,
DissectImageFlags flags,
DecryptedImage *d) {
_cleanup_free_ char *node = NULL, *name = NULL;
_cleanup_(sym_crypt_freep) struct crypt_device *cd = NULL;
_cleanup_close_ int fd = -EBADF;
int r;
assert(m);
assert(d);
if (!m->found || !m->node || !m->fstype)
return 0;
if (!streq(m->fstype, "crypto_LUKS"))
return 0;
if (!passphrase)
return -ENOKEY;
r = dlopen_cryptsetup();
if (r < 0)
return r;
r = make_dm_name_and_node(m->node, "-decrypted", &name, &node);
if (r < 0)
return r;
if (!GREEDY_REALLOC0(d->decrypted, d->n_decrypted + 1))
return -ENOMEM;
r = sym_crypt_init(&cd, m->node);
if (r < 0)
return log_debug_errno(r, "Failed to initialize dm-crypt: %m");
cryptsetup_enable_logging(cd);
r = sym_crypt_load(cd, CRYPT_LUKS, NULL);
if (r < 0)
return log_debug_errno(r, "Failed to load LUKS metadata: %m");
r = sym_crypt_activate_by_passphrase(cd, name, CRYPT_ANY_SLOT, passphrase, strlen(passphrase),
((flags & DISSECT_IMAGE_DEVICE_READ_ONLY) ? CRYPT_ACTIVATE_READONLY : 0) |
((flags & DISSECT_IMAGE_DISCARD_ON_CRYPTO) ? CRYPT_ACTIVATE_ALLOW_DISCARDS : 0));
if (r < 0) {
log_debug_errno(r, "Failed to activate LUKS device: %m");
return r == -EPERM ? -EKEYREJECTED : r;
}
fd = open(node, O_RDONLY|O_NONBLOCK|O_CLOEXEC|O_NOCTTY);
if (fd < 0)
return log_debug_errno(errno, "Failed to open %s: %m", node);
d->decrypted[d->n_decrypted++] = (DecryptedPartition) {
.name = TAKE_PTR(name),
.device = TAKE_PTR(cd),
};
m->decrypted_node = TAKE_PTR(node);
close_and_replace(m->mount_node_fd, fd);
return 0;
}
static int verity_can_reuse(
const VeritySettings *verity,
const char *name,
struct crypt_device **ret_cd) {
/* If the same volume was already open, check that the root hashes match, and reuse it if they do */
_cleanup_free_ char *root_hash_existing = NULL;
_cleanup_(sym_crypt_freep) struct crypt_device *cd = NULL;
struct crypt_params_verity crypt_params = {};
size_t root_hash_existing_size;
int r;
assert(verity);
assert(name);
assert(ret_cd);
r = sym_crypt_init_by_name(&cd, name);
if (r < 0)
return log_debug_errno(r, "Error opening verity device, crypt_init_by_name failed: %m");
cryptsetup_enable_logging(cd);
r = sym_crypt_get_verity_info(cd, &crypt_params);
if (r < 0)
return log_debug_errno(r, "Error opening verity device, crypt_get_verity_info failed: %m");
root_hash_existing_size = verity->root_hash_size;
root_hash_existing = malloc0(root_hash_existing_size);
if (!root_hash_existing)
return -ENOMEM;
r = sym_crypt_volume_key_get(cd, CRYPT_ANY_SLOT, root_hash_existing, &root_hash_existing_size, NULL, 0);
if (r < 0)
return log_debug_errno(r, "Error opening verity device, crypt_volume_key_get failed: %m");
if (verity->root_hash_size != root_hash_existing_size ||
memcmp(root_hash_existing, verity->root_hash, verity->root_hash_size) != 0)
return log_debug_errno(SYNTHETIC_ERRNO(EINVAL), "Error opening verity device, it already exists but root hashes are different.");
#if HAVE_CRYPT_ACTIVATE_BY_SIGNED_KEY
/* Ensure that, if signatures are supported, we only reuse the device if the previous mount used the
* same settings, so that a previous unsigned mount will not be reused if the user asks to use
* signing for the new one, and vice versa. */
if (!!verity->root_hash_sig != !!(crypt_params.flags & CRYPT_VERITY_ROOT_HASH_SIGNATURE))
return log_debug_errno(SYNTHETIC_ERRNO(EINVAL), "Error opening verity device, it already exists but signature settings are not the same.");
#endif
*ret_cd = TAKE_PTR(cd);
return 0;
}
static inline char* dm_deferred_remove_clean(char *name) {
if (!name)
return NULL;
(void) sym_crypt_deactivate_by_name(NULL, name, CRYPT_DEACTIVATE_DEFERRED);
return mfree(name);
}
DEFINE_TRIVIAL_CLEANUP_FUNC(char *, dm_deferred_remove_clean);
static int validate_signature_userspace(const VeritySettings *verity) {
#if HAVE_OPENSSL
_cleanup_(sk_X509_free_allp) STACK_OF(X509) *sk = NULL;
_cleanup_strv_free_ char **certs = NULL;
_cleanup_(PKCS7_freep) PKCS7 *p7 = NULL;
_cleanup_free_ char *s = NULL;
_cleanup_(BIO_freep) BIO *bio = NULL; /* 'bio' must be freed first, 's' second, hence keep this order
* of declaration in place, please */
const unsigned char *d;
int r;
assert(verity);
assert(verity->root_hash);
assert(verity->root_hash_sig);
/* Because installing a signature certificate into the kernel chain is so messy, let's optionally do
* userspace validation. */
r = conf_files_list_nulstr(&certs, ".crt", NULL, CONF_FILES_REGULAR|CONF_FILES_FILTER_MASKED, CONF_PATHS_NULSTR("verity.d"));
if (r < 0)
return log_debug_errno(r, "Failed to enumerate certificates: %m");
if (strv_isempty(certs)) {
log_debug("No userspace dm-verity certificates found.");
return 0;
}
d = verity->root_hash_sig;
p7 = d2i_PKCS7(NULL, &d, (long) verity->root_hash_sig_size);
if (!p7)
return log_debug_errno(SYNTHETIC_ERRNO(EINVAL), "Failed to parse PKCS7 DER signature data.");
s = hexmem(verity->root_hash, verity->root_hash_size);
if (!s)
return log_oom_debug();
bio = BIO_new_mem_buf(s, strlen(s));
if (!bio)
return log_oom_debug();
sk = sk_X509_new_null();
if (!sk)
return log_oom_debug();
STRV_FOREACH(i, certs) {
_cleanup_(X509_freep) X509 *c = NULL;
_cleanup_fclose_ FILE *f = NULL;
f = fopen(*i, "re");
if (!f) {
log_debug_errno(errno, "Failed to open '%s', ignoring: %m", *i);
continue;
}
c = PEM_read_X509(f, NULL, NULL, NULL);
if (!c) {
log_debug("Failed to load X509 certificate '%s', ignoring.", *i);
continue;
}
if (sk_X509_push(sk, c) == 0)
return log_oom_debug();
TAKE_PTR(c);
}
r = PKCS7_verify(p7, sk, NULL, bio, NULL, PKCS7_NOINTERN|PKCS7_NOVERIFY);
if (r)
log_debug("Userspace PKCS#7 validation succeeded.");
else
log_debug("Userspace PKCS#7 validation failed: %s", ERR_error_string(ERR_get_error(), NULL));
return r;
#else
log_debug("Not doing client-side validation of dm-verity root hash signatures, OpenSSL support disabled.");
return 0;
#endif
}
static int do_crypt_activate_verity(
struct crypt_device *cd,
const char *name,
const VeritySettings *verity) {
bool check_signature;
int r;
assert(cd);
assert(name);
assert(verity);
if (verity->root_hash_sig) {
r = getenv_bool_secure("SYSTEMD_DISSECT_VERITY_SIGNATURE");
if (r < 0 && r != -ENXIO)
log_debug_errno(r, "Failed to parse $SYSTEMD_DISSECT_VERITY_SIGNATURE");
check_signature = r != 0;
} else
check_signature = false;
if (check_signature) {
#if HAVE_CRYPT_ACTIVATE_BY_SIGNED_KEY
/* First, if we have support for signed keys in the kernel, then try that first. */
r = sym_crypt_activate_by_signed_key(
cd,
name,
verity->root_hash,
verity->root_hash_size,
verity->root_hash_sig,
verity->root_hash_sig_size,
CRYPT_ACTIVATE_READONLY);
if (r >= 0)
return r;
log_debug("Validation of dm-verity signature failed via the kernel, trying userspace validation instead.");
#else
log_debug("Activation of verity device with signature requested, but not supported via the kernel by %s due to missing crypt_activate_by_signed_key(), trying userspace validation instead.",
program_invocation_short_name);
#endif
/* So this didn't work via the kernel, then let's try userspace validation instead. If that
* works we'll try to activate without telling the kernel the signature. */
r = validate_signature_userspace(verity);
if (r < 0)
return r;
if (r == 0)
return log_debug_errno(SYNTHETIC_ERRNO(ENOKEY),
"Activation of signed Verity volume worked neither via the kernel nor in userspace, can't activate.");
}
return sym_crypt_activate_by_volume_key(
cd,
name,
verity->root_hash,
verity->root_hash_size,
CRYPT_ACTIVATE_READONLY);
}
static usec_t verity_timeout(void) {
usec_t t = 100 * USEC_PER_MSEC;
const char *e;
int r;
/* On slower machines, like non-KVM vm, setting up device may take a long time.
* Let's make the timeout configurable. */
e = getenv("SYSTEMD_DISSECT_VERITY_TIMEOUT_SEC");
if (!e)
return t;
r = parse_sec(e, &t);
if (r < 0)
log_debug_errno(r,
"Failed to parse timeout specified in $SYSTEMD_DISSECT_VERITY_TIMEOUT_SEC, "
"using the default timeout (%s).",
FORMAT_TIMESPAN(t, USEC_PER_MSEC));
return t;
}
static int verity_partition(
PartitionDesignator designator,
DissectedPartition *m,
DissectedPartition *v,
const VeritySettings *verity,
DissectImageFlags flags,
DecryptedImage *d) {
_cleanup_(sym_crypt_freep) struct crypt_device *cd = NULL;
_cleanup_(dm_deferred_remove_cleanp) char *restore_deferred_remove = NULL;
_cleanup_free_ char *node = NULL, *name = NULL;
_cleanup_close_ int mount_node_fd = -EBADF;
int r;
assert(m);
assert(v || (verity && verity->data_path));
if (!verity || !verity->root_hash)
return 0;
if (!((verity->designator < 0 && designator == PARTITION_ROOT) ||
(verity->designator == designator)))
return 0;
if (!m->found || !m->node || !m->fstype)
return 0;
if (!verity->data_path) {
if (!v->found || !v->node || !v->fstype)
return 0;
if (!streq(v->fstype, "DM_verity_hash"))
return 0;
}
r = dlopen_cryptsetup();
if (r < 0)
return r;
if (FLAGS_SET(flags, DISSECT_IMAGE_VERITY_SHARE)) {
/* Use the roothash, which is unique per volume, as the device node name, so that it can be reused */
_cleanup_free_ char *root_hash_encoded = NULL;
root_hash_encoded = hexmem(verity->root_hash, verity->root_hash_size);
if (!root_hash_encoded)
return -ENOMEM;
r = make_dm_name_and_node(root_hash_encoded, "-verity", &name, &node);
} else
r = make_dm_name_and_node(m->node, "-verity", &name, &node);
if (r < 0)
return r;
r = sym_crypt_init(&cd, verity->data_path ?: v->node);
if (r < 0)
return r;
cryptsetup_enable_logging(cd);
r = sym_crypt_load(cd, CRYPT_VERITY, NULL);
if (r < 0)
return r;
r = sym_crypt_set_data_device(cd, m->node);
if (r < 0)
return r;
if (!GREEDY_REALLOC0(d->decrypted, d->n_decrypted + 1))
return -ENOMEM;
/* If activating fails because the device already exists, check the metadata and reuse it if it matches.
* In case of ENODEV/ENOENT, which can happen if another process is activating at the exact same time,
* retry a few times before giving up. */
for (unsigned i = 0; i < N_DEVICE_NODE_LIST_ATTEMPTS; i++) {
_cleanup_(sym_crypt_freep) struct crypt_device *existing_cd = NULL;
_cleanup_close_ int fd = -EBADF;
/* First, check if the device already exists. */
fd = open(node, O_RDONLY|O_NONBLOCK|O_CLOEXEC|O_NOCTTY);
if (fd < 0 && !ERRNO_IS_DEVICE_ABSENT(errno))
return log_debug_errno(errno, "Failed to open verity device %s: %m", node);
if (fd >= 0)
goto check; /* The device already exists. Let's check it. */
/* The symlink to the device node does not exist yet. Assume not activated, and let's activate it. */
r = do_crypt_activate_verity(cd, name, verity);
if (r >= 0)
goto try_open; /* The device is activated. Let's open it. */
/* libdevmapper can return EINVAL when the device is already in the activation stage.
* There's no way to distinguish this situation from a genuine error due to invalid
* parameters, so immediately fall back to activating the device with a unique name.
* Improvements in libcrypsetup can ensure this never happens:
* https://gitlab.com/cryptsetup/cryptsetup/-/merge_requests/96 */
if (r == -EINVAL && FLAGS_SET(flags, DISSECT_IMAGE_VERITY_SHARE))
break;
if (r == -ENODEV) /* Volume is being opened but not ready, crypt_init_by_name would fail, try to open again */
goto try_again;
if (!IN_SET(r,
-EEXIST, /* Volume has already been opened and ready to be used. */
-EBUSY /* Volume is being opened but not ready, crypt_init_by_name() can fetch details. */))
return log_debug_errno(r, "Failed to activate verity device %s: %m", node);
check:
if (!restore_deferred_remove){
/* To avoid races, disable automatic removal on umount while setting up the new device. Restore it on failure. */
r = dm_deferred_remove_cancel(name);
/* -EBUSY and -ENXIO: the device has already been removed or being removed. We cannot
* use the device, try to open again. See target_message() in drivers/md/dm-ioctl.c
* and dm_cancel_deferred_remove() in drivers/md/dm.c */
if (IN_SET(r, -EBUSY, -ENXIO))
goto try_again;
if (r < 0)
return log_debug_errno(r, "Failed to disable automated deferred removal for verity device %s: %m", node);
restore_deferred_remove = strdup(name);
if (!restore_deferred_remove)
return log_oom_debug();
}
r = verity_can_reuse(verity, name, &existing_cd);
/* Same as above, -EINVAL can randomly happen when it actually means -EEXIST */
if (r == -EINVAL && FLAGS_SET(flags, DISSECT_IMAGE_VERITY_SHARE))
break;
if (IN_SET(r,
-ENOENT, /* Removed?? */
-EBUSY, /* Volume is being opened but not ready, crypt_init_by_name() can fetch details. */
-ENODEV /* Volume is being opened but not ready, crypt_init_by_name() would fail, try to open again. */ ))
goto try_again;
if (r < 0)
return log_debug_errno(r, "Failed to check if existing verity device %s can be reused: %m", node);
if (fd < 0) {
/* devmapper might say that the device exists, but the devlink might not yet have been
* created. Check and wait for the udev event in that case. */
r = device_wait_for_devlink(node, "block", verity_timeout(), NULL);
/* Fallback to activation with a unique device if it's taking too long */
if (r == -ETIMEDOUT && FLAGS_SET(flags, DISSECT_IMAGE_VERITY_SHARE))
break;
if (r < 0)
return log_debug_errno(r, "Failed to wait device node symlink %s: %m", node);
}
try_open:
if (fd < 0) {
/* Now, the device is activated and devlink is created. Let's open it. */
fd = open(node, O_RDONLY|O_NONBLOCK|O_CLOEXEC|O_NOCTTY);
if (fd < 0) {
if (!ERRNO_IS_DEVICE_ABSENT(errno))
return log_debug_errno(errno, "Failed to open verity device %s: %m", node);
/* The device has already been removed?? */
goto try_again;
}
}
mount_node_fd = TAKE_FD(fd);
if (existing_cd)
crypt_free_and_replace(cd, existing_cd);
goto success;
try_again:
/* Device is being removed by another process. Let's wait for a while. */
(void) usleep(2 * USEC_PER_MSEC);
}
/* All trials failed or a conflicting verity device exists. Let's try to activate with a unique name. */
if (FLAGS_SET(flags, DISSECT_IMAGE_VERITY_SHARE)) {
/* Before trying to activate with unique name, we need to free crypt_device object.
* Otherwise, we get error from libcryptsetup like the following:
* ------
* systemd[1234]: Cannot use device /dev/loop5 which is in use (already mapped or mounted).
* ------
*/
sym_crypt_free(cd);
cd = NULL;
return verity_partition(designator, m, v, verity, flags & ~DISSECT_IMAGE_VERITY_SHARE, d);
}
return log_debug_errno(SYNTHETIC_ERRNO(EBUSY), "All attempts to activate verity device %s failed.", name);
success:
/* Everything looks good and we'll be able to mount the device, so deferred remove will be re-enabled at that point. */
restore_deferred_remove = mfree(restore_deferred_remove);
d->decrypted[d->n_decrypted++] = (DecryptedPartition) {
.name = TAKE_PTR(name),
.device = TAKE_PTR(cd),
};
m->decrypted_node = TAKE_PTR(node);
close_and_replace(m->mount_node_fd, mount_node_fd);
return 0;
}
#endif
int dissected_image_decrypt(
DissectedImage *m,
const char *passphrase,
const VeritySettings *verity,
DissectImageFlags flags) {
#if HAVE_LIBCRYPTSETUP
_cleanup_(decrypted_image_unrefp) DecryptedImage *d = NULL;
int r;
#endif
assert(m);
assert(!verity || verity->root_hash || verity->root_hash_size == 0);
/* Returns:
*
* = 0 → There was nothing to decrypt
* > 0 → Decrypted successfully
* -ENOKEY → There's something to decrypt but no key was supplied
* -EKEYREJECTED → Passed key was not correct
*/
if (verity && verity->root_hash && verity->root_hash_size < sizeof(sd_id128_t))
return -EINVAL;
if (!m->encrypted && !m->verity_ready)
return 0;
#if HAVE_LIBCRYPTSETUP
r = decrypted_image_new(&d);
if (r < 0)
return r;
for (PartitionDesignator i = 0; i < _PARTITION_DESIGNATOR_MAX; i++) {
DissectedPartition *p = m->partitions + i;
PartitionDesignator k;
if (!p->found)
continue;
r = decrypt_partition(p, passphrase, flags, d);
if (r < 0)
return r;
k = partition_verity_of(i);
if (k >= 0) {
r = verity_partition(i, p, m->partitions + k, verity, flags | DISSECT_IMAGE_VERITY_SHARE, d);
if (r < 0)
return r;
}
if (!p->decrypted_fstype && p->mount_node_fd >= 0 && p->decrypted_node) {
r = probe_filesystem_full(p->mount_node_fd, p->decrypted_node, 0, UINT64_MAX, &p->decrypted_fstype);
if (r < 0 && r != -EUCLEAN)
return r;
}
}
m->decrypted_image = TAKE_PTR(d);
return 1;
#else
return -EOPNOTSUPP;
#endif
}
int dissected_image_decrypt_interactively(
DissectedImage *m,
const char *passphrase,
const VeritySettings *verity,
DissectImageFlags flags) {
_cleanup_strv_free_erase_ char **z = NULL;
int n = 3, r;
if (passphrase)
n--;
for (;;) {
r = dissected_image_decrypt(m, passphrase, verity, flags);
if (r >= 0)
return r;
if (r == -EKEYREJECTED)
log_error_errno(r, "Incorrect passphrase, try again!");
else if (r != -ENOKEY)
return log_error_errno(r, "Failed to decrypt image: %m");
if (--n < 0)
return log_error_errno(SYNTHETIC_ERRNO(EKEYREJECTED),
"Too many retries.");
z = strv_free(z);
r = ask_password_auto("Please enter image passphrase:", NULL, "dissect", "dissect", "dissect.passphrase", USEC_INFINITY, 0, &z);
if (r < 0)
return log_error_errno(r, "Failed to query for passphrase: %m");
passphrase = z[0];
}
}
static int decrypted_image_relinquish(DecryptedImage *d) {
assert(d);
/* Turns on automatic removal after the last use ended for all DM devices of this image, and sets a
* boolean so that we don't clean it up ourselves either anymore */
#if HAVE_LIBCRYPTSETUP
int r;
for (size_t i = 0; i < d->n_decrypted; i++) {
DecryptedPartition *p = d->decrypted + i;
if (p->relinquished)
continue;
r = sym_crypt_deactivate_by_name(NULL, p->name, CRYPT_DEACTIVATE_DEFERRED);
if (r < 0)
return log_debug_errno(r, "Failed to mark %s for auto-removal: %m", p->name);
p->relinquished = true;
}
#endif
return 0;
}
int dissected_image_relinquish(DissectedImage *m) {
int r;
assert(m);
if (m->decrypted_image) {
r = decrypted_image_relinquish(m->decrypted_image);
if (r < 0)
return r;
}
if (m->loop)
loop_device_relinquish(m->loop);
return 0;
}
static char *build_auxiliary_path(const char *image, const char *suffix) {
const char *e;
char *n;
assert(image);
assert(suffix);
e = endswith(image, ".raw");
if (!e)
return strjoin(e, suffix);
n = new(char, e - image + strlen(suffix) + 1);
if (!n)
return NULL;
strcpy(mempcpy(n, image, e - image), suffix);
return n;
}
void verity_settings_done(VeritySettings *v) {
assert(v);
v->root_hash = mfree(v->root_hash);
v->root_hash_size = 0;
v->root_hash_sig = mfree(v->root_hash_sig);
v->root_hash_sig_size = 0;
v->data_path = mfree(v->data_path);
}
int verity_settings_load(
VeritySettings *verity,
const char *image,
const char *root_hash_path,
const char *root_hash_sig_path) {
_cleanup_free_ void *root_hash = NULL, *root_hash_sig = NULL;
size_t root_hash_size = 0, root_hash_sig_size = 0;
_cleanup_free_ char *verity_data_path = NULL;
PartitionDesignator designator;
int r;
assert(verity);
assert(image);
assert(verity->designator < 0 || IN_SET(verity->designator, PARTITION_ROOT, PARTITION_USR));
/* If we are asked to load the root hash for a device node, exit early */
if (is_device_path(image))
return 0;
r = getenv_bool_secure("SYSTEMD_DISSECT_VERITY_SIDECAR");
if (r < 0 && r != -ENXIO)
log_debug_errno(r, "Failed to parse $SYSTEMD_DISSECT_VERITY_SIDECAR, ignoring: %m");
if (r == 0)
return 0;
designator = verity->designator;
/* We only fill in what isn't already filled in */
if (!verity->root_hash) {
_cleanup_free_ char *text = NULL;
if (root_hash_path) {
/* If explicitly specified it takes precedence */
r = read_one_line_file(root_hash_path, &text);
if (r < 0)
return r;
if (designator < 0)
designator = PARTITION_ROOT;
} else {
/* Otherwise look for xattr and separate file, and first for the data for root and if
* that doesn't exist for /usr */
if (designator < 0 || designator == PARTITION_ROOT) {
r = getxattr_malloc(image, "user.verity.roothash", &text);
if (r < 0) {
_cleanup_free_ char *p = NULL;
if (r != -ENOENT && !ERRNO_IS_XATTR_ABSENT(r))
return r;
p = build_auxiliary_path(image, ".roothash");
if (!p)
return -ENOMEM;
r = read_one_line_file(p, &text);
if (r < 0 && r != -ENOENT)
return r;
}
if (text)
designator = PARTITION_ROOT;
}
if (!text && (designator < 0 || designator == PARTITION_USR)) {
/* So in the "roothash" xattr/file name above the "root" of course primarily
* refers to the root of the Verity Merkle tree. But coincidentally it also
* is the hash for the *root* file system, i.e. the "root" neatly refers to
* two distinct concepts called "root". Taking benefit of this happy
* coincidence we call the file with the root hash for the /usr/ file system
* `usrhash`, because `usrroothash` or `rootusrhash` would just be too
* confusing. We thus drop the reference to the root of the Merkle tree, and
* just indicate which file system it's about. */
r = getxattr_malloc(image, "user.verity.usrhash", &text);
if (r < 0) {
_cleanup_free_ char *p = NULL;
if (r != -ENOENT && !ERRNO_IS_XATTR_ABSENT(r))
return r;
p = build_auxiliary_path(image, ".usrhash");
if (!p)
return -ENOMEM;
r = read_one_line_file(p, &text);
if (r < 0 && r != -ENOENT)
return r;
}
if (text)
designator = PARTITION_USR;
}
}
if (text) {
r = unhexmem(text, strlen(text), &root_hash, &root_hash_size);
if (r < 0)
return r;
if (root_hash_size < sizeof(sd_id128_t))
return -EINVAL;
}
}
if ((root_hash || verity->root_hash) && !verity->root_hash_sig) {
if (root_hash_sig_path) {
r = read_full_file(root_hash_sig_path, (char**) &root_hash_sig, &root_hash_sig_size);
if (r < 0 && r != -ENOENT)
return r;
if (designator < 0)
designator = PARTITION_ROOT;
} else {
if (designator < 0 || designator == PARTITION_ROOT) {
_cleanup_free_ char *p = NULL;
/* Follow naming convention recommended by the relevant RFC:
* https://tools.ietf.org/html/rfc5751#section-3.2.1 */
p = build_auxiliary_path(image, ".roothash.p7s");
if (!p)
return -ENOMEM;
r = read_full_file(p, (char**) &root_hash_sig, &root_hash_sig_size);
if (r < 0 && r != -ENOENT)
return r;
if (r >= 0)
designator = PARTITION_ROOT;
}
if (!root_hash_sig && (designator < 0 || designator == PARTITION_USR)) {
_cleanup_free_ char *p = NULL;
p = build_auxiliary_path(image, ".usrhash.p7s");
if (!p)
return -ENOMEM;
r = read_full_file(p, (char**) &root_hash_sig, &root_hash_sig_size);
if (r < 0 && r != -ENOENT)
return r;
if (r >= 0)
designator = PARTITION_USR;
}
}
if (root_hash_sig && root_hash_sig_size == 0) /* refuse empty size signatures */
return -EINVAL;
}
if (!verity->data_path) {
_cleanup_free_ char *p = NULL;
p = build_auxiliary_path(image, ".verity");
if (!p)
return -ENOMEM;
if (access(p, F_OK) < 0) {
if (errno != ENOENT)
return -errno;
} else
verity_data_path = TAKE_PTR(p);
}
if (root_hash) {
verity->root_hash = TAKE_PTR(root_hash);
verity->root_hash_size = root_hash_size;
}
if (root_hash_sig) {
verity->root_hash_sig = TAKE_PTR(root_hash_sig);
verity->root_hash_sig_size = root_hash_sig_size;
}
if (verity_data_path)
verity->data_path = TAKE_PTR(verity_data_path);
if (verity->designator < 0)
verity->designator = designator;
return 1;
}
int dissected_image_load_verity_sig_partition(
DissectedImage *m,
int fd,
VeritySettings *verity) {
_cleanup_free_ void *root_hash = NULL, *root_hash_sig = NULL;
_cleanup_(json_variant_unrefp) JsonVariant *v = NULL;
size_t root_hash_size, root_hash_sig_size;
_cleanup_free_ char *buf = NULL;
PartitionDesignator d;
DissectedPartition *p;
JsonVariant *rh, *sig;
ssize_t n;
char *e;
int r;
assert(m);
assert(fd >= 0);
assert(verity);
if (verity->root_hash && verity->root_hash_sig) /* Already loaded? */
return 0;
r = getenv_bool_secure("SYSTEMD_DISSECT_VERITY_EMBEDDED");
if (r < 0 && r != -ENXIO)
log_debug_errno(r, "Failed to parse $SYSTEMD_DISSECT_VERITY_EMBEDDED, ignoring: %m");
if (r == 0)
return 0;
d = partition_verity_sig_of(verity->designator < 0 ? PARTITION_ROOT : verity->designator);
assert(d >= 0);
p = m->partitions + d;
if (!p->found)
return 0;
if (p->offset == UINT64_MAX || p->size == UINT64_MAX)
return -EINVAL;
if (p->size > 4*1024*1024) /* Signature data cannot possible be larger than 4M, refuse that */
return -EFBIG;
buf = new(char, p->size+1);
if (!buf)
return -ENOMEM;
n = pread(fd, buf, p->size, p->offset);
if (n < 0)
return -ENOMEM;
if ((uint64_t) n != p->size)
return -EIO;
e = memchr(buf, 0, p->size);
if (e) {
/* If we found a NUL byte then the rest of the data must be NUL too */
if (!memeqzero(e, p->size - (e - buf)))
return log_debug_errno(SYNTHETIC_ERRNO(EINVAL), "Signature data contains embedded NUL byte.");
} else
buf[p->size] = 0;
r = json_parse(buf, 0, &v, NULL, NULL);
if (r < 0)
return log_debug_errno(r, "Failed to parse signature JSON data: %m");
rh = json_variant_by_key(v, "rootHash");
if (!rh)
return log_debug_errno(SYNTHETIC_ERRNO(EINVAL), "Signature JSON object lacks 'rootHash' field.");
if (!json_variant_is_string(rh))
return log_debug_errno(SYNTHETIC_ERRNO(EINVAL), "'rootHash' field of signature JSON object is not a string.");
r = unhexmem(json_variant_string(rh), SIZE_MAX, &root_hash, &root_hash_size);
if (r < 0)
return log_debug_errno(r, "Failed to parse root hash field: %m");
/* Check if specified root hash matches if it is specified */
if (verity->root_hash &&
memcmp_nn(verity->root_hash, verity->root_hash_size, root_hash, root_hash_size) != 0) {
_cleanup_free_ char *a = NULL, *b = NULL;
a = hexmem(root_hash, root_hash_size);
b = hexmem(verity->root_hash, verity->root_hash_size);
return log_debug_errno(r, "Root hash in signature JSON data (%s) doesn't match configured hash (%s).", strna(a), strna(b));
}
sig = json_variant_by_key(v, "signature");
if (!sig)
return log_debug_errno(SYNTHETIC_ERRNO(EINVAL), "Signature JSON object lacks 'signature' field.");
if (!json_variant_is_string(sig))
return log_debug_errno(SYNTHETIC_ERRNO(EINVAL), "'signature' field of signature JSON object is not a string.");
r = unbase64mem(json_variant_string(sig), SIZE_MAX, &root_hash_sig, &root_hash_sig_size);
if (r < 0)
return log_debug_errno(r, "Failed to parse signature field: %m");
free_and_replace(verity->root_hash, root_hash);
verity->root_hash_size = root_hash_size;
free_and_replace(verity->root_hash_sig, root_hash_sig);
verity->root_hash_sig_size = root_hash_sig_size;
return 1;
}
int dissected_image_acquire_metadata(DissectedImage *m, DissectImageFlags extra_flags) {
enum {
META_HOSTNAME,
META_MACHINE_ID,
META_MACHINE_INFO,
META_OS_RELEASE,
META_INITRD_RELEASE,
META_EXTENSION_RELEASE,
META_HAS_INIT_SYSTEM,
_META_MAX,
};
static const char *const paths[_META_MAX] = {
[META_HOSTNAME] = "/etc/hostname\0",
[META_MACHINE_ID] = "/etc/machine-id\0",
[META_MACHINE_INFO] = "/etc/machine-info\0",
[META_OS_RELEASE] = ("/etc/os-release\0"
"/usr/lib/os-release\0"),
[META_INITRD_RELEASE] = ("/etc/initrd-release\0"
"/usr/lib/initrd-release\0"),
[META_EXTENSION_RELEASE] = "extension-release\0", /* Used only for logging. */
[META_HAS_INIT_SYSTEM] = "has-init-system\0", /* ditto */
};
_cleanup_strv_free_ char **machine_info = NULL, **os_release = NULL, **initrd_release = NULL, **extension_release = NULL;
_cleanup_close_pair_ int error_pipe[2] = PIPE_EBADF;
_cleanup_(rmdir_and_freep) char *t = NULL;
_cleanup_(sigkill_waitp) pid_t child = 0;
sd_id128_t machine_id = SD_ID128_NULL;
_cleanup_free_ char *hostname = NULL;
unsigned n_meta_initialized = 0;
int fds[2 * _META_MAX], r, v;
int has_init_system = -1;
ssize_t n;
BLOCK_SIGNALS(SIGCHLD);
assert(m);
for (; n_meta_initialized < _META_MAX; n_meta_initialized ++) {
if (!paths[n_meta_initialized]) {
fds[2*n_meta_initialized] = fds[2*n_meta_initialized+1] = -EBADF;
continue;
}
if (pipe2(fds + 2*n_meta_initialized, O_CLOEXEC) < 0) {
r = -errno;
goto finish;
}
}
r = mkdtemp_malloc("/tmp/dissect-XXXXXX", &t);
if (r < 0)
goto finish;
if (pipe2(error_pipe, O_CLOEXEC) < 0) {
r = -errno;
goto finish;
}
r = safe_fork("(sd-dissect)", FORK_RESET_SIGNALS|FORK_DEATHSIG|FORK_NEW_MOUNTNS|FORK_MOUNTNS_SLAVE, &child);
if (r < 0)
goto finish;
if (r == 0) {
/* Child in a new mount namespace */
error_pipe[0] = safe_close(error_pipe[0]);
r = dissected_image_mount(
m,
t,
UID_INVALID,
UID_INVALID,
extra_flags |
DISSECT_IMAGE_READ_ONLY |
DISSECT_IMAGE_MOUNT_ROOT_ONLY |
DISSECT_IMAGE_USR_NO_ROOT);
if (r < 0) {
log_debug_errno(r, "Failed to mount dissected image: %m");
goto inner_fail;
}
for (unsigned k = 0; k < _META_MAX; k++) {
_cleanup_close_ int fd = -ENOENT;
if (!paths[k])
continue;
fds[2*k] = safe_close(fds[2*k]);
switch (k) {
case META_EXTENSION_RELEASE:
/* As per the os-release spec, if the image is an extension it will have a file
* named after the image name in extension-release.d/ - we use the image name
* and try to resolve it with the extension-release helpers, as sometimes
* the image names are mangled on deployment and do not match anymore.
* Unlike other paths this is not fixed, and the image name
* can be mangled on deployment, so by calling into the helper
* we allow a fallback that matches on the first extension-release
* file found in the directory, if one named after the image cannot
* be found first. */
r = open_extension_release(t, m->image_name, /* relax_extension_release_check= */ false, NULL, &fd);
if (r < 0)
fd = r; /* Propagate the error. */
break;
case META_HAS_INIT_SYSTEM: {
bool found = false;
FOREACH_STRING(init,
"/usr/lib/systemd/systemd", /* systemd on /usr merged system */
"/lib/systemd/systemd", /* systemd on /usr non-merged systems */
"/sbin/init") { /* traditional path the Linux kernel invokes */
r = chase_symlinks(init, t, CHASE_PREFIX_ROOT, NULL, NULL);
if (r < 0) {
if (r != -ENOENT)
log_debug_errno(r, "Failed to resolve %s, ignoring: %m", init);
} else {
found = true;
break;
}
}
r = loop_write(fds[2*k+1], &found, sizeof(found), false);
if (r < 0)
goto inner_fail;
continue;
}
default:
NULSTR_FOREACH(p, paths[k]) {
fd = chase_symlinks_and_open(p, t, CHASE_PREFIX_ROOT, O_RDONLY|O_CLOEXEC|O_NOCTTY, NULL);
if (fd >= 0)
break;
}
}
if (fd < 0) {
log_debug_errno(fd, "Failed to read %s file of image, ignoring: %m", paths[k]);
fds[2*k+1] = safe_close(fds[2*k+1]);
continue;
}
r = copy_bytes(fd, fds[2*k+1], UINT64_MAX, 0);
if (r < 0)
goto inner_fail;
fds[2*k+1] = safe_close(fds[2*k+1]);
}
_exit(EXIT_SUCCESS);
inner_fail:
/* Let parent know the error */
(void) write(error_pipe[1], &r, sizeof(r));
_exit(EXIT_FAILURE);
}
error_pipe[1] = safe_close(error_pipe[1]);
for (unsigned k = 0; k < _META_MAX; k++) {
_cleanup_fclose_ FILE *f = NULL;
if (!paths[k])
continue;
fds[2*k+1] = safe_close(fds[2*k+1]);
f = take_fdopen(&fds[2*k], "r");
if (!f) {
r = -errno;
goto finish;
}
switch (k) {
case META_HOSTNAME:
r = read_etc_hostname_stream(f, &hostname);
if (r < 0)
log_debug_errno(r, "Failed to read /etc/hostname of image: %m");
break;
case META_MACHINE_ID: {
_cleanup_free_ char *line = NULL;
r = read_line(f, LONG_LINE_MAX, &line);
if (r < 0)
log_debug_errno(r, "Failed to read /etc/machine-id of image: %m");
else if (r == 33) {
r = sd_id128_from_string(line, &machine_id);
if (r < 0)
log_debug_errno(r, "Image contains invalid /etc/machine-id: %s", line);
} else if (r == 0)
log_debug("/etc/machine-id file of image is empty.");
else if (streq(line, "uninitialized"))
log_debug("/etc/machine-id file of image is uninitialized (likely aborted first boot).");
else
log_debug("/etc/machine-id file of image has unexpected length %i.", r);
break;
}
case META_MACHINE_INFO:
r = load_env_file_pairs(f, "machine-info", &machine_info);
if (r < 0)
log_debug_errno(r, "Failed to read /etc/machine-info of image: %m");
break;
case META_OS_RELEASE:
r = load_env_file_pairs(f, "os-release", &os_release);
if (r < 0)
log_debug_errno(r, "Failed to read OS release file of image: %m");
break;
case META_INITRD_RELEASE:
r = load_env_file_pairs(f, "initrd-release", &initrd_release);
if (r < 0)
log_debug_errno(r, "Failed to read initrd release file of image: %m");
break;
case META_EXTENSION_RELEASE:
r = load_env_file_pairs(f, "extension-release", &extension_release);
if (r < 0)
log_debug_errno(r, "Failed to read extension release file of image: %m");
break;
case META_HAS_INIT_SYSTEM: {
bool b = false;
size_t nr;
errno = 0;
nr = fread(&b, 1, sizeof(b), f);
if (nr != sizeof(b))
log_debug_errno(errno_or_else(EIO), "Failed to read has-init-system boolean: %m");
else
has_init_system = b;
break;
}}
}
r = wait_for_terminate_and_check("(sd-dissect)", child, 0);
child = 0;
if (r < 0)
return r;
n = read(error_pipe[0], &v, sizeof(v));
if (n < 0)
return -errno;
if (n == sizeof(v))
return v; /* propagate error sent to us from child */
if (n != 0)
return -EIO;
if (r != EXIT_SUCCESS)
return -EPROTO;
free_and_replace(m->hostname, hostname);
m->machine_id = machine_id;
strv_free_and_replace(m->machine_info, machine_info);
strv_free_and_replace(m->os_release, os_release);
strv_free_and_replace(m->initrd_release, initrd_release);
strv_free_and_replace(m->extension_release, extension_release);
m->has_init_system = has_init_system;
finish:
for (unsigned k = 0; k < n_meta_initialized; k++)
safe_close_pair(fds + 2*k);
return r;
}
int dissect_loop_device(
LoopDevice *loop,
const VeritySettings *verity,
const MountOptions *mount_options,
DissectImageFlags flags,
DissectedImage **ret) {
#if HAVE_BLKID
_cleanup_(dissected_image_unrefp) DissectedImage *m = NULL;
int r;
assert(loop);
assert(ret);
r = dissected_image_new(loop->backing_file ?: loop->node, &m);
if (r < 0)
return r;
m->loop = loop_device_ref(loop);
m->sector_size = m->loop->sector_size;
r = dissect_image(m, loop->fd, loop->node, verity, mount_options, flags);
if (r < 0)
return r;
*ret = TAKE_PTR(m);
return 0;
#else
return -EOPNOTSUPP;
#endif
}
int dissect_loop_device_and_warn(
LoopDevice *loop,
const VeritySettings *verity,
const MountOptions *mount_options,
DissectImageFlags flags,
DissectedImage **ret) {
const char *name;
int r;
assert(loop);
assert(loop->fd >= 0);
name = ASSERT_PTR(loop->backing_file ?: loop->node);
r = dissect_loop_device(loop, verity, mount_options, flags, ret);
switch (r) {
case -EOPNOTSUPP:
return log_error_errno(r, "Dissecting images is not supported, compiled without blkid support.");
case -ENOPKG:
return log_error_errno(r, "%s: Couldn't identify a suitable partition table or file system.", name);
case -ENOMEDIUM:
return log_error_errno(r, "%s: The image does not pass validation.", name);
case -EADDRNOTAVAIL:
return log_error_errno(r, "%s: No root partition for specified root hash found.", name);
case -ENOTUNIQ:
return log_error_errno(r, "%s: Multiple suitable root partitions found in image.", name);
case -ENXIO:
return log_error_errno(r, "%s: No suitable root partition found in image.", name);
case -EPROTONOSUPPORT:
return log_error_errno(r, "Device '%s' is loopback block device with partition scanning turned off, please turn it on.", name);
case -ENOTBLK:
return log_error_errno(r, "%s: Image is not a block device.", name);
case -EBADR:
return log_error_errno(r,
"Combining partitioned images (such as '%s') with external Verity data (such as '%s') not supported. "
"(Consider setting $SYSTEMD_DISSECT_VERITY_SIDECAR=0 to disable automatic discovery of external Verity data.)",
name, strna(verity ? verity->data_path : NULL));
default:
if (r < 0)
return log_error_errno(r, "Failed to dissect image '%s': %m", name);
return r;
}
}
bool dissected_image_verity_candidate(const DissectedImage *image, PartitionDesignator partition_designator) {
assert(image);
/* Checks if this partition could theoretically do Verity. For non-partitioned images this only works
* if there's an external verity file supplied, for which we can consult .has_verity. For partitioned
* images we only check the partition type.
*
* This call is used to decide whether to suppress or show a verity column in tabular output of the
* image. */
if (image->single_file_system)
return partition_designator == PARTITION_ROOT && image->has_verity;
return partition_verity_of(partition_designator) >= 0;
}
bool dissected_image_verity_ready(const DissectedImage *image, PartitionDesignator partition_designator) {
PartitionDesignator k;
assert(image);
/* Checks if this partition has verity data available that we can activate. For non-partitioned this
* works for the root partition, for others only if the associated verity partition was found. */
if (!image->verity_ready)
return false;
if (image->single_file_system)
return partition_designator == PARTITION_ROOT;
k = partition_verity_of(partition_designator);
return k >= 0 && image->partitions[k].found;
}
bool dissected_image_verity_sig_ready(const DissectedImage *image, PartitionDesignator partition_designator) {
PartitionDesignator k;
assert(image);
/* Checks if this partition has verity signature data available that we can use. */
if (!image->verity_sig_ready)
return false;
if (image->single_file_system)
return partition_designator == PARTITION_ROOT;
k = partition_verity_sig_of(partition_designator);
return k >= 0 && image->partitions[k].found;
}
MountOptions* mount_options_free_all(MountOptions *options) {
MountOptions *m;
while ((m = options)) {
LIST_REMOVE(mount_options, options, m);
free(m->options);
free(m);
}
return NULL;
}
const char* mount_options_from_designator(const MountOptions *options, PartitionDesignator designator) {
LIST_FOREACH(mount_options, m, options)
if (designator == m->partition_designator && !isempty(m->options))
return m->options;
return NULL;
}
int mount_image_privately_interactively(
const char *image,
DissectImageFlags flags,
char **ret_directory,
LoopDevice **ret_loop_device) {
_cleanup_(verity_settings_done) VeritySettings verity = VERITY_SETTINGS_DEFAULT;
_cleanup_(loop_device_unrefp) LoopDevice *d = NULL;
_cleanup_(dissected_image_unrefp) DissectedImage *dissected_image = NULL;
_cleanup_(rmdir_and_freep) char *created_dir = NULL;
_cleanup_free_ char *temp = NULL;
int r;
/* Mounts an OS image at a temporary place, inside a newly created mount namespace of our own. This
* is used by tools such as systemd-tmpfiles or systemd-firstboot to operate on some disk image
* easily. */
assert(image);
assert(ret_directory);
assert(ret_loop_device);
/* We intend to mount this right-away, hence add the partitions if needed and pin them. */
flags |= DISSECT_IMAGE_ADD_PARTITION_DEVICES |
DISSECT_IMAGE_PIN_PARTITION_DEVICES;
r = verity_settings_load(&verity, image, NULL, NULL);
if (r < 0)
return log_error_errno(r, "Failed to load root hash data: %m");
r = tempfn_random_child(NULL, program_invocation_short_name, &temp);
if (r < 0)
return log_error_errno(r, "Failed to generate temporary mount directory: %m");
r = loop_device_make_by_path(
image,
FLAGS_SET(flags, DISSECT_IMAGE_DEVICE_READ_ONLY) ? O_RDONLY : O_RDWR,
/* sector_size= */ UINT32_MAX,
FLAGS_SET(flags, DISSECT_IMAGE_NO_PARTITION_TABLE) ? 0 : LO_FLAGS_PARTSCAN,
LOCK_SH,
&d);
if (r < 0)
return log_error_errno(r, "Failed to set up loopback device for %s: %m", image);
r = dissect_loop_device_and_warn(d, &verity, NULL, flags, &dissected_image);
if (r < 0)
return r;
r = dissected_image_load_verity_sig_partition(dissected_image, d->fd, &verity);
if (r < 0)
return r;
r = dissected_image_decrypt_interactively(dissected_image, NULL, &verity, flags);
if (r < 0)
return r;
r = detach_mount_namespace();
if (r < 0)
return log_error_errno(r, "Failed to detach mount namespace: %m");
r = mkdir_p(temp, 0700);
if (r < 0)
return log_error_errno(r, "Failed to create mount point: %m");
created_dir = TAKE_PTR(temp);
r = dissected_image_mount_and_warn(dissected_image, created_dir, UID_INVALID, UID_INVALID, flags);
if (r < 0)
return r;
r = loop_device_flock(d, LOCK_UN);
if (r < 0)
return r;
r = dissected_image_relinquish(dissected_image);
if (r < 0)
return log_error_errno(r, "Failed to relinquish DM and loopback block devices: %m");
*ret_directory = TAKE_PTR(created_dir);
*ret_loop_device = TAKE_PTR(d);
return 0;
}
static bool mount_options_relax_extension_release_checks(const MountOptions *options) {
if (!options)
return false;
return string_contains_word(mount_options_from_designator(options, PARTITION_ROOT), ",", "x-systemd.relax-extension-release-check") ||
string_contains_word(mount_options_from_designator(options, PARTITION_USR), ",", "x-systemd.relax-extension-release-check") ||
string_contains_word(options->options, ",", "x-systemd.relax-extension-release-check");
}
int verity_dissect_and_mount(
int src_fd,
const char *src,
const char *dest,
const MountOptions *options,
const char *required_host_os_release_id,
const char *required_host_os_release_version_id,
const char *required_host_os_release_sysext_level,
const char *required_sysext_scope) {
_cleanup_(loop_device_unrefp) LoopDevice *loop_device = NULL;
_cleanup_(dissected_image_unrefp) DissectedImage *dissected_image = NULL;
_cleanup_(verity_settings_done) VeritySettings verity = VERITY_SETTINGS_DEFAULT;
DissectImageFlags dissect_image_flags;
bool relax_extension_release_check;
int r;
assert(src);
assert(dest);
relax_extension_release_check = mount_options_relax_extension_release_checks(options);
/* We might get an FD for the image, but we use the original path to look for the dm-verity files */
r = verity_settings_load(&verity, src, NULL, NULL);
if (r < 0)
return log_debug_errno(r, "Failed to load root hash: %m");
dissect_image_flags = (verity.data_path ? DISSECT_IMAGE_NO_PARTITION_TABLE : 0) |
(relax_extension_release_check ? DISSECT_IMAGE_RELAX_SYSEXT_CHECK : 0) |
DISSECT_IMAGE_ADD_PARTITION_DEVICES |
DISSECT_IMAGE_PIN_PARTITION_DEVICES;
/* Note that we don't use loop_device_make here, as the FD is most likely O_PATH which would not be
* accepted by LOOP_CONFIGURE, so just let loop_device_make_by_path reopen it as a regular FD. */
r = loop_device_make_by_path(
src_fd >= 0 ? FORMAT_PROC_FD_PATH(src_fd) : src,
/* open_flags= */ -1,
/* sector_size= */ UINT32_MAX,
verity.data_path ? 0 : LO_FLAGS_PARTSCAN,
LOCK_SH,
&loop_device);
if (r < 0)
return log_debug_errno(r, "Failed to create loop device for image: %m");
r = dissect_loop_device(
loop_device,
&verity,
options,
dissect_image_flags,
&dissected_image);
/* No partition table? Might be a single-filesystem image, try again */
if (!verity.data_path && r == -ENOPKG)
r = dissect_loop_device(
loop_device,
&verity,
options,
dissect_image_flags | DISSECT_IMAGE_NO_PARTITION_TABLE,
&dissected_image);
if (r < 0)
return log_debug_errno(r, "Failed to dissect image: %m");
r = dissected_image_load_verity_sig_partition(dissected_image, loop_device->fd, &verity);
if (r < 0)
return r;
r = dissected_image_decrypt(
dissected_image,
NULL,
&verity,
dissect_image_flags);
if (r < 0)
return log_debug_errno(r, "Failed to decrypt dissected image: %m");
r = mkdir_p_label(dest, 0755);
if (r < 0)
return log_debug_errno(r, "Failed to create destination directory %s: %m", dest);
r = umount_recursive(dest, 0);
if (r < 0)
return log_debug_errno(r, "Failed to umount under destination directory %s: %m", dest);
r = dissected_image_mount(dissected_image, dest, UID_INVALID, UID_INVALID, dissect_image_flags);
if (r < 0)
return log_debug_errno(r, "Failed to mount image: %m");
r = loop_device_flock(loop_device, LOCK_UN);
if (r < 0)
return log_debug_errno(r, "Failed to unlock loopback device: %m");
/* If we got os-release values from the caller, then we need to match them with the image's
* extension-release.d/ content. Return -EINVAL if there's any mismatch.
* First, check the distro ID. If that matches, then check the new SYSEXT_LEVEL value if
* available, or else fallback to VERSION_ID. If neither is present (eg: rolling release),
* then a simple match on the ID will be performed. */
if (required_host_os_release_id) {
_cleanup_strv_free_ char **extension_release = NULL;
assert(!isempty(required_host_os_release_id));
r = load_extension_release_pairs(dest, dissected_image->image_name, relax_extension_release_check, &extension_release);
if (r < 0)
return log_debug_errno(r, "Failed to parse image %s extension-release metadata: %m", dissected_image->image_name);
r = extension_release_validate(
dissected_image->image_name,
required_host_os_release_id,
required_host_os_release_version_id,
required_host_os_release_sysext_level,
required_sysext_scope,
extension_release);
if (r == 0)
return log_debug_errno(SYNTHETIC_ERRNO(ESTALE), "Image %s extension-release metadata does not match the root's", dissected_image->image_name);
if (r < 0)
return log_debug_errno(r, "Failed to compare image %s extension-release metadata with the root's os-release: %m", dissected_image->image_name);
}
r = dissected_image_relinquish(dissected_image);
if (r < 0)
return log_debug_errno(r, "Failed to relinquish dissected image: %m");
return 0;
}