/* * 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; } 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 */