| /* |
| * Copyright (c) 2004 by Internet Systems Consortium, Inc. ("ISC") |
| * Copyright (c) 1996,1999 by Internet Software Consortium. |
| * |
| * Permission to use, copy, modify, and distribute this software for any |
| * purpose with or without fee is hereby granted, provided that the above |
| * copyright notice and this permission notice appear in all copies. |
| * |
| * THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES |
| * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF |
| * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL ISC BE LIABLE FOR |
| * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES |
| * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN |
| * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT |
| * OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. |
| */ |
| |
| #include <sys/types.h> |
| |
| #include <netinet/in.h> |
| #include <arpa/nameser.h> |
| |
| #include <errno.h> |
| #include <resolv.h> |
| #include <string.h> |
| #include <ctype.h> |
| #include <stdlib.h> |
| #include <limits.h> |
| |
| # define SPRINTF(x) ((size_t)sprintf x) |
| |
| /* Data. */ |
| |
| static const char digits[] = "0123456789"; |
| |
| /* Forward. */ |
| |
| static int special(int); |
| static int printable(int); |
| static int dn_find(const u_char *, const u_char *, |
| const u_char * const *, |
| const u_char * const *); |
| static int labellen(const u_char *); |
| |
| /* Public. */ |
| |
| /*% |
| * Convert an encoded domain name to printable ascii as per RFC1035. |
| |
| * return: |
| *\li Number of bytes written to buffer, or -1 (with errno set) |
| * |
| * notes: |
| *\li The root is returned as "." |
| *\li All other domains are returned in non absolute form |
| */ |
| int |
| ns_name_ntop(const u_char *src, char *dst, size_t dstsiz) |
| { |
| const u_char *cp; |
| char *dn, *eom; |
| u_char c; |
| u_int n; |
| int l; |
| |
| cp = src; |
| dn = dst; |
| eom = dst + dstsiz; |
| |
| while ((n = *cp++) != 0) { |
| if ((n & NS_CMPRSFLGS) == NS_CMPRSFLGS) { |
| /* Some kind of compression pointer. */ |
| __set_errno (EMSGSIZE); |
| return (-1); |
| } |
| if (dn != dst) { |
| if (dn >= eom) { |
| __set_errno (EMSGSIZE); |
| return (-1); |
| } |
| *dn++ = '.'; |
| } |
| if ((l = labellen(cp - 1)) < 0) { |
| __set_errno (EMSGSIZE); |
| return(-1); |
| } |
| if (dn + l >= eom) { |
| __set_errno (EMSGSIZE); |
| return (-1); |
| } |
| for ((void)NULL; l > 0; l--) { |
| c = *cp++; |
| if (special(c)) { |
| if (dn + 1 >= eom) { |
| __set_errno (EMSGSIZE); |
| return (-1); |
| } |
| *dn++ = '\\'; |
| *dn++ = (char)c; |
| } else if (!printable(c)) { |
| if (dn + 3 >= eom) { |
| __set_errno (EMSGSIZE); |
| return (-1); |
| } |
| *dn++ = '\\'; |
| *dn++ = digits[c / 100]; |
| *dn++ = digits[(c % 100) / 10]; |
| *dn++ = digits[c % 10]; |
| } else { |
| if (dn >= eom) { |
| __set_errno (EMSGSIZE); |
| return (-1); |
| } |
| *dn++ = (char)c; |
| } |
| } |
| } |
| if (dn == dst) { |
| if (dn >= eom) { |
| __set_errno (EMSGSIZE); |
| return (-1); |
| } |
| *dn++ = '.'; |
| } |
| if (dn >= eom) { |
| __set_errno (EMSGSIZE); |
| return (-1); |
| } |
| *dn++ = '\0'; |
| return (dn - dst); |
| } |
| libresolv_hidden_def (ns_name_ntop) |
| strong_alias (ns_name_ntop, __ns_name_ntop) |
| |
| /*% |
| * Convert an ascii string into an encoded domain name as per RFC1035. |
| * |
| * return: |
| * |
| *\li -1 if it fails |
| *\li 1 if string was fully qualified |
| *\li 0 is string was not fully qualified |
| * |
| * notes: |
| *\li Enforces label and domain length limits. |
| */ |
| |
| int |
| ns_name_pton(const char *src, u_char *dst, size_t dstsiz) |
| { |
| u_char *label, *bp, *eom; |
| int c, n, escaped; |
| char *cp; |
| |
| escaped = 0; |
| bp = dst; |
| eom = dst + dstsiz; |
| label = bp++; |
| |
| while ((c = *src++) != 0) { |
| if (escaped) { |
| if ((cp = strchr(digits, c)) != NULL) { |
| n = (cp - digits) * 100; |
| if ((c = *src++) == 0 || |
| (cp = strchr(digits, c)) == NULL) { |
| __set_errno (EMSGSIZE); |
| return (-1); |
| } |
| n += (cp - digits) * 10; |
| if ((c = *src++) == 0 || |
| (cp = strchr(digits, c)) == NULL) { |
| __set_errno (EMSGSIZE); |
| return (-1); |
| } |
| n += (cp - digits); |
| if (n > 255) { |
| __set_errno (EMSGSIZE); |
| return (-1); |
| } |
| c = n; |
| } |
| escaped = 0; |
| } else if (c == '\\') { |
| escaped = 1; |
| continue; |
| } else if (c == '.') { |
| c = (bp - label - 1); |
| if ((c & NS_CMPRSFLGS) != 0) { /*%< Label too big. */ |
| __set_errno (EMSGSIZE); |
| return (-1); |
| } |
| if (label >= eom) { |
| __set_errno (EMSGSIZE); |
| return (-1); |
| } |
| *label = c; |
| /* Fully qualified ? */ |
| if (*src == '\0') { |
| if (c != 0) { |
| if (bp >= eom) { |
| __set_errno (EMSGSIZE); |
| return (-1); |
| } |
| *bp++ = '\0'; |
| } |
| if ((bp - dst) > MAXCDNAME) { |
| __set_errno (EMSGSIZE); |
| return (-1); |
| } |
| return (1); |
| } |
| if (c == 0 || *src == '.') { |
| __set_errno (EMSGSIZE); |
| return (-1); |
| } |
| label = bp++; |
| continue; |
| } |
| if (bp >= eom) { |
| __set_errno (EMSGSIZE); |
| return (-1); |
| } |
| *bp++ = (u_char)c; |
| } |
| if (escaped) { |
| /* Trailing backslash. */ |
| __set_errno (EMSGSIZE); |
| return -1; |
| } |
| c = (bp - label - 1); |
| if ((c & NS_CMPRSFLGS) != 0) { /*%< Label too big. */ |
| __set_errno (EMSGSIZE); |
| return (-1); |
| } |
| if (label >= eom) { |
| __set_errno (EMSGSIZE); |
| return (-1); |
| } |
| *label = c; |
| if (c != 0) { |
| if (bp >= eom) { |
| __set_errno (EMSGSIZE); |
| return (-1); |
| } |
| *bp++ = 0; |
| } |
| if ((bp - dst) > MAXCDNAME) { /*%< src too big */ |
| __set_errno (EMSGSIZE); |
| return (-1); |
| } |
| return (0); |
| } |
| libresolv_hidden_def (ns_name_pton) |
| |
| /*% |
| * Convert a network strings labels into all lowercase. |
| * |
| * return: |
| *\li Number of bytes written to buffer, or -1 (with errno set) |
| * |
| * notes: |
| *\li Enforces label and domain length limits. |
| */ |
| |
| int |
| ns_name_ntol(const u_char *src, u_char *dst, size_t dstsiz) |
| { |
| const u_char *cp; |
| u_char *dn, *eom; |
| u_char c; |
| u_int n; |
| int l; |
| |
| cp = src; |
| dn = dst; |
| eom = dst + dstsiz; |
| |
| if (dn >= eom) { |
| __set_errno (EMSGSIZE); |
| return (-1); |
| } |
| while ((n = *cp++) != 0) { |
| if ((n & NS_CMPRSFLGS) == NS_CMPRSFLGS) { |
| /* Some kind of compression pointer. */ |
| __set_errno (EMSGSIZE); |
| return (-1); |
| } |
| *dn++ = n; |
| if ((l = labellen(cp - 1)) < 0) { |
| __set_errno (EMSGSIZE); |
| return (-1); |
| } |
| if (dn + l >= eom) { |
| __set_errno (EMSGSIZE); |
| return (-1); |
| } |
| for ((void)NULL; l > 0; l--) { |
| c = *cp++; |
| if (isupper(c)) |
| *dn++ = tolower(c); |
| else |
| *dn++ = c; |
| } |
| } |
| *dn++ = '\0'; |
| return (dn - dst); |
| } |
| |
| /*% |
| * Unpack a domain name from a message, source may be compressed. |
| * |
| * return: |
| *\li -1 if it fails, or consumed octets if it succeeds. |
| */ |
| int |
| ns_name_unpack(const u_char *msg, const u_char *eom, const u_char *src, |
| u_char *dst, size_t dstsiz) |
| { |
| const u_char *srcp, *dstlim; |
| u_char *dstp; |
| int n, len, checked, l; |
| |
| len = -1; |
| checked = 0; |
| dstp = dst; |
| srcp = src; |
| dstlim = dst + dstsiz; |
| if (srcp < msg || srcp >= eom) { |
| __set_errno (EMSGSIZE); |
| return (-1); |
| } |
| /* Fetch next label in domain name. */ |
| while ((n = *srcp++) != 0) { |
| /* Check for indirection. */ |
| switch (n & NS_CMPRSFLGS) { |
| case 0: |
| /* Limit checks. */ |
| if ((l = labellen(srcp - 1)) < 0) { |
| __set_errno (EMSGSIZE); |
| return(-1); |
| } |
| if (dstp + l + 1 >= dstlim || srcp + l >= eom) { |
| __set_errno (EMSGSIZE); |
| return (-1); |
| } |
| checked += l + 1; |
| *dstp++ = n; |
| memcpy(dstp, srcp, l); |
| dstp += l; |
| srcp += l; |
| break; |
| |
| case NS_CMPRSFLGS: |
| if (srcp >= eom) { |
| __set_errno (EMSGSIZE); |
| return (-1); |
| } |
| if (len < 0) |
| len = srcp - src + 1; |
| srcp = msg + (((n & 0x3f) << 8) | (*srcp & 0xff)); |
| if (srcp < msg || srcp >= eom) { /*%< Out of range. */ |
| __set_errno (EMSGSIZE); |
| return (-1); |
| } |
| checked += 2; |
| /* |
| * Check for loops in the compressed name; |
| * if we've looked at the whole message, |
| * there must be a loop. |
| */ |
| if (checked >= eom - msg) { |
| __set_errno (EMSGSIZE); |
| return (-1); |
| } |
| break; |
| |
| default: |
| __set_errno (EMSGSIZE); |
| return (-1); /*%< flag error */ |
| } |
| } |
| *dstp = '\0'; |
| if (len < 0) |
| len = srcp - src; |
| return (len); |
| } |
| libresolv_hidden_def (ns_name_unpack) |
| strong_alias (ns_name_unpack, __ns_name_unpack) |
| |
| /*% |
| * Pack domain name 'domain' into 'comp_dn'. |
| * |
| * return: |
| *\li Size of the compressed name, or -1. |
| * |
| * notes: |
| *\li 'dnptrs' is an array of pointers to previous compressed names. |
| *\li dnptrs[0] is a pointer to the beginning of the message. The array |
| * ends with NULL. |
| *\li 'lastdnptr' is a pointer to the end of the array pointed to |
| * by 'dnptrs'. |
| * |
| * Side effects: |
| *\li The list of pointers in dnptrs is updated for labels inserted into |
| * the message as we compress the name. If 'dnptr' is NULL, we don't |
| * try to compress names. If 'lastdnptr' is NULL, we don't update the |
| * list. |
| */ |
| int |
| ns_name_pack(const u_char *src, u_char *dst, int dstsiz, |
| const u_char **dnptrs, const u_char **lastdnptr) |
| { |
| u_char *dstp; |
| const u_char **cpp, **lpp, *eob, *msg; |
| const u_char *srcp; |
| int n, l, first = 1; |
| |
| srcp = src; |
| dstp = dst; |
| eob = dstp + dstsiz; |
| lpp = cpp = NULL; |
| if (dnptrs != NULL) { |
| if ((msg = *dnptrs++) != NULL) { |
| for (cpp = dnptrs; *cpp != NULL; cpp++) |
| (void)NULL; |
| lpp = cpp; /*%< end of list to search */ |
| } |
| } else |
| msg = NULL; |
| |
| /* make sure the domain we are about to add is legal */ |
| l = 0; |
| do { |
| int l0; |
| |
| n = *srcp; |
| if ((n & NS_CMPRSFLGS) == NS_CMPRSFLGS) { |
| __set_errno (EMSGSIZE); |
| return (-1); |
| } |
| if ((l0 = labellen(srcp)) < 0) { |
| __set_errno (EINVAL); |
| return(-1); |
| } |
| l += l0 + 1; |
| if (l > MAXCDNAME) { |
| __set_errno (EMSGSIZE); |
| return (-1); |
| } |
| srcp += l0 + 1; |
| } while (n != 0); |
| |
| /* from here on we need to reset compression pointer array on error */ |
| srcp = src; |
| do { |
| /* Look to see if we can use pointers. */ |
| n = *srcp; |
| if (n != 0 && msg != NULL) { |
| l = dn_find(srcp, msg, (const u_char * const *)dnptrs, |
| (const u_char * const *)lpp); |
| if (l >= 0) { |
| if (dstp + 1 >= eob) { |
| goto cleanup; |
| } |
| *dstp++ = (l >> 8) | NS_CMPRSFLGS; |
| *dstp++ = l % 256; |
| return (dstp - dst); |
| } |
| /* Not found, save it. */ |
| if (lastdnptr != NULL && cpp < lastdnptr - 1 && |
| (dstp - msg) < 0x4000 && first) { |
| *cpp++ = dstp; |
| *cpp = NULL; |
| first = 0; |
| } |
| } |
| /* copy label to buffer */ |
| if ((n & NS_CMPRSFLGS) == NS_CMPRSFLGS) { |
| /* Should not happen. */ |
| goto cleanup; |
| } |
| n = labellen(srcp); |
| if (n + 1 > eob - dstp) { |
| goto cleanup; |
| } |
| memcpy(dstp, srcp, n + 1); |
| srcp += n + 1; |
| dstp += n + 1; |
| } while (n != 0); |
| |
| if (dstp > eob) { |
| cleanup: |
| if (msg != NULL) |
| *lpp = NULL; |
| __set_errno (EMSGSIZE); |
| return (-1); |
| } |
| return (dstp - dst); |
| } |
| libresolv_hidden_def (ns_name_pack) |
| |
| /*% |
| * Expand compressed domain name to presentation format. |
| * |
| * return: |
| *\li Number of bytes read out of `src', or -1 (with errno set). |
| * |
| * note: |
| *\li Root domain returns as "." not "". |
| */ |
| int |
| ns_name_uncompress(const u_char *msg, const u_char *eom, const u_char *src, |
| char *dst, size_t dstsiz) |
| { |
| u_char tmp[NS_MAXCDNAME]; |
| int n; |
| |
| if ((n = ns_name_unpack(msg, eom, src, tmp, sizeof tmp)) == -1) |
| return (-1); |
| if (ns_name_ntop(tmp, dst, dstsiz) == -1) |
| return (-1); |
| return (n); |
| } |
| libresolv_hidden_def (ns_name_uncompress) |
| |
| /*% |
| * Compress a domain name into wire format, using compression pointers. |
| * |
| * return: |
| *\li Number of bytes consumed in `dst' or -1 (with errno set). |
| * |
| * notes: |
| *\li 'dnptrs' is an array of pointers to previous compressed names. |
| *\li dnptrs[0] is a pointer to the beginning of the message. |
| *\li The list ends with NULL. 'lastdnptr' is a pointer to the end of the |
| * array pointed to by 'dnptrs'. Side effect is to update the list of |
| * pointers for labels inserted into the message as we compress the name. |
| *\li If 'dnptr' is NULL, we don't try to compress names. If 'lastdnptr' |
| * is NULL, we don't update the list. |
| */ |
| int |
| ns_name_compress(const char *src, u_char *dst, size_t dstsiz, |
| const u_char **dnptrs, const u_char **lastdnptr) |
| { |
| u_char tmp[NS_MAXCDNAME]; |
| |
| if (ns_name_pton(src, tmp, sizeof tmp) == -1) |
| return (-1); |
| return (ns_name_pack(tmp, dst, dstsiz, dnptrs, lastdnptr)); |
| } |
| libresolv_hidden_def (ns_name_compress) |
| |
| /*% |
| * Reset dnptrs so that there are no active references to pointers at or |
| * after src. |
| */ |
| void |
| ns_name_rollback(const u_char *src, const u_char **dnptrs, |
| const u_char **lastdnptr) |
| { |
| while (dnptrs < lastdnptr && *dnptrs != NULL) { |
| if (*dnptrs >= src) { |
| *dnptrs = NULL; |
| break; |
| } |
| dnptrs++; |
| } |
| } |
| |
| /*% |
| * Advance *ptrptr to skip over the compressed name it points at. |
| * |
| * return: |
| *\li 0 on success, -1 (with errno set) on failure. |
| */ |
| int |
| ns_name_skip(const u_char **ptrptr, const u_char *eom) |
| { |
| const u_char *cp; |
| u_int n; |
| |
| cp = *ptrptr; |
| while (cp < eom && (n = *cp++) != 0) { |
| /* Check for indirection. */ |
| switch (n & NS_CMPRSFLGS) { |
| case 0: /*%< normal case, n == len */ |
| cp += n; |
| continue; |
| case NS_CMPRSFLGS: /*%< indirection */ |
| cp++; |
| break; |
| default: /*%< illegal type */ |
| __set_errno (EMSGSIZE); |
| return (-1); |
| } |
| break; |
| } |
| if (cp > eom) { |
| __set_errno (EMSGSIZE); |
| return (-1); |
| } |
| *ptrptr = cp; |
| return (0); |
| } |
| libresolv_hidden_def (ns_name_skip) |
| |
| /* Private. */ |
| |
| /*% |
| * Thinking in noninternationalized USASCII (per the DNS spec), |
| * is this character special ("in need of quoting") ? |
| * |
| * return: |
| *\li boolean. |
| */ |
| static int |
| special(int ch) { |
| switch (ch) { |
| case 0x22: /*%< '"' */ |
| case 0x2E: /*%< '.' */ |
| case 0x3B: /*%< ';' */ |
| case 0x5C: /*%< '\\' */ |
| case 0x28: /*%< '(' */ |
| case 0x29: /*%< ')' */ |
| /* Special modifiers in zone files. */ |
| case 0x40: /*%< '@' */ |
| case 0x24: /*%< '$' */ |
| return (1); |
| default: |
| return (0); |
| } |
| } |
| |
| /*% |
| * Thinking in noninternationalized USASCII (per the DNS spec), |
| * is this character visible and not a space when printed ? |
| * |
| * return: |
| *\li boolean. |
| */ |
| static int |
| printable(int ch) { |
| return (ch > 0x20 && ch < 0x7f); |
| } |
| |
| /*% |
| * Thinking in noninternationalized USASCII (per the DNS spec), |
| * convert this character to lower case if it's upper case. |
| */ |
| static int |
| mklower(int ch) { |
| if (ch >= 0x41 && ch <= 0x5A) |
| return (ch + 0x20); |
| return (ch); |
| } |
| |
| /*% |
| * Search for the counted-label name in an array of compressed names. |
| * |
| * return: |
| *\li offset from msg if found, or -1. |
| * |
| * notes: |
| *\li dnptrs is the pointer to the first name on the list, |
| *\li not the pointer to the start of the message. |
| */ |
| static int |
| dn_find(const u_char *domain, const u_char *msg, |
| const u_char * const *dnptrs, |
| const u_char * const *lastdnptr) |
| { |
| const u_char *dn, *cp, *sp; |
| const u_char * const *cpp; |
| u_int n; |
| |
| for (cpp = dnptrs; cpp < lastdnptr; cpp++) { |
| sp = *cpp; |
| /* |
| * terminate search on: |
| * root label |
| * compression pointer |
| * unusable offset |
| */ |
| while (*sp != 0 && (*sp & NS_CMPRSFLGS) == 0 && |
| (sp - msg) < 0x4000) { |
| dn = domain; |
| cp = sp; |
| while ((n = *cp++) != 0) { |
| /* |
| * check for indirection |
| */ |
| switch (n & NS_CMPRSFLGS) { |
| case 0: /*%< normal case, n == len */ |
| n = labellen(cp - 1); /*%< XXX */ |
| if (n != *dn++) |
| goto next; |
| |
| for ((void)NULL; n > 0; n--) |
| if (mklower(*dn++) != |
| mklower(*cp++)) |
| goto next; |
| /* Is next root for both ? */ |
| if (*dn == '\0' && *cp == '\0') |
| return (sp - msg); |
| if (*dn) |
| continue; |
| goto next; |
| case NS_CMPRSFLGS: /*%< indirection */ |
| cp = msg + (((n & 0x3f) << 8) | *cp); |
| break; |
| |
| default: /*%< illegal type */ |
| __set_errno (EMSGSIZE); |
| return (-1); |
| } |
| } |
| next: ; |
| sp += *sp + 1; |
| } |
| } |
| __set_errno (ENOENT); |
| return (-1); |
| } |
| |
| /* Return the length of the encoded label starting at LP, or -1 for |
| compression references and extended label types. */ |
| static int |
| labellen (const unsigned char *lp) |
| { |
| if (*lp <= 63) |
| return *lp; |
| return -1; |
| } |
| |
| /*! \file */ |