diff options
| -rw-r--r-- | include/arpa/nameser.h | 1 | ||||
| -rw-r--r-- | libc/inet/resolv.c | 468 |
2 files changed, 469 insertions, 0 deletions
diff --git a/include/arpa/nameser.h b/include/arpa/nameser.h index 917ba19b9..cdc3df555 100644 --- a/include/arpa/nameser.h +++ b/include/arpa/nameser.h @@ -521,6 +521,7 @@ int ns_name_ntol (const u_char *, u_char *, size_t) __THROW; int ns_name_ntop (const u_char *, char *, size_t) __THROW; libc_hidden_proto(ns_name_ntop) int ns_name_pton (const char *, u_char *, size_t) __THROW; +libc_hidden_proto(ns_name_pton) int ns_name_unpack (const u_char *, const u_char *, const u_char *, u_char *, size_t) __THROW; libc_hidden_proto(ns_name_unpack) diff --git a/libc/inet/resolv.c b/libc/inet/resolv.c index a347ca5f6..64e99baa5 100644 --- a/libc/inet/resolv.c +++ b/libc/inet/resolv.c @@ -339,6 +339,9 @@ Domain name in a message can be represented as either: #define BUFSZ (80) /* one line */ #define SBUFSIZE (BUFSZ + 1 + (sizeof(char *) * MAXALIASES)) +#define NS_TYPE_ELT 0x40 /*%< EDNS0 extended label type */ +#define DNS_LABELTYPE_BITSTRING 0x41 + #undef DEBUG /* #define DEBUG */ @@ -2792,6 +2795,259 @@ int ns_name_ntop(const u_char *src, char *dst, size_t dstsiz) } libc_hidden_def(ns_name_ntop) +static const char digits[] = "0123456789"; + +static const char digitvalue[256] = { + -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, /*16*/ + -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, /*32*/ + -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, /*48*/ + 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, -1, -1, -1, -1, -1, -1, /*64*/ + -1, 10, 11, 12, 13, 14, 15, -1, -1, -1, -1, -1, -1, -1, -1, -1, /*80*/ + -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, /*96*/ + -1, 10, 11, 12, 13, 14, 15, -1, -1, -1, -1, -1, -1, -1, -1, -1, /*112*/ + -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, /*128*/ + -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, + -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, + -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, + -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, + -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, + -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, + -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, + -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, /*256*/ +}; + +static int encode_bitstring(const char **bp, const char *end, + unsigned char **labelp, + unsigned char ** dst, + unsigned const char *eom) +{ + int afterslash = 0; + const char *cp = *bp; + unsigned char *tp; + char c; + const char *beg_blen; + char *end_blen = NULL; + int value = 0, count = 0, tbcount = 0, blen = 0; + + beg_blen = end_blen = NULL; + + /* a bitstring must contain at least 2 characters */ + if (end - cp < 2) + return (EINVAL); + + /* XXX: currently, only hex strings are supported */ + if (*cp++ != 'x') + return (EINVAL); + if (!isxdigit((*cp) & 0xff)) /*%< reject '\[x/BLEN]' */ + return (EINVAL); + + for (tp = *dst + 1; cp < end && tp < eom; cp++) { + switch((c = *cp)) { + case ']': /*%< end of the bitstring */ + if (afterslash) { + if (beg_blen == NULL) + return (EINVAL); + blen = (int)strtol(beg_blen, &end_blen, 10); + if (*end_blen != ']') + return (EINVAL); + } + if (count) + *tp++ = ((value << 4) & 0xff); + cp++; /*%< skip ']' */ + goto done; + case '/': + afterslash = 1; + break; + default: + if (afterslash) { + if (!isdigit(c&0xff)) + return (EINVAL); + if (beg_blen == NULL) { + + if (c == '0') { + /* blen never begings with 0 */ + return (EINVAL); + } + beg_blen = cp; + } + } else { + if (!isxdigit(c&0xff)) + return (EINVAL); + value <<= 4; + value += digitvalue[(int)c]; + count += 4; + tbcount += 4; + if (tbcount > 256) + return (EINVAL); + if (count == 8) { + *tp++ = value; + count = 0; + } + } + break; + } + } + done: + if (cp >= end || tp >= eom) + return (EMSGSIZE); + + /* + * bit length validation: + * If a <length> is present, the number of digits in the <bit-data> + * MUST be just sufficient to contain the number of bits specified + * by the <length>. If there are insignificant bits in a final + * hexadecimal or octal digit, they MUST be zero. + * RFC2673, Section 3.2. + */ + if (blen > 0) { + int traillen; + + if (((blen + 3) & ~3) != tbcount) + return (EINVAL); + traillen = tbcount - blen; /*%< between 0 and 3 */ + if (((value << (8 - traillen)) & 0xff) != 0) + return (EINVAL); + } + else + blen = tbcount; + if (blen == 256) + blen = 0; + + /* encode the type and the significant bit fields */ + **labelp = DNS_LABELTYPE_BITSTRING; + **dst = blen; + + *bp = cp; + *dst = tp; + + return (0); +} + +int ns_name_pton(const char *src, u_char *dst, size_t dstsiz) +{ + u_char *label, *bp, *eom; + int c, n, escaped, e = 0; + char *cp; + + escaped = 0; + bp = dst; + eom = dst + dstsiz; + label = bp++; + + while ((c = *src++) != 0) { + if (escaped) { + if (c == '[') { /*%< start a bit string label */ + if ((cp = strchr(src, ']')) == NULL) { + errno = EINVAL; /*%< ??? */ + return (-1); + } + if ((e = encode_bitstring(&src, cp + 2, + &label, &bp, eom)) + != 0) { + errno = e; + return (-1); + } + escaped = 0; + label = bp++; + if ((c = *src++) == 0) + goto done; + else if (c != '.') { + errno = EINVAL; + return (-1); + } + continue; + } + else if ((cp = strchr(digits, c)) != NULL) { + n = (cp - digits) * 100; + if ((c = *src++) == 0 || + (cp = strchr(digits, c)) == NULL) { + errno = EMSGSIZE; + return (-1); + } + n += (cp - digits) * 10; + if ((c = *src++) == 0 || + (cp = strchr(digits, c)) == NULL) { + errno = EMSGSIZE; + return (-1); + } + n += (cp - digits); + if (n > 255) { + 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. */ + errno = EMSGSIZE; + return (-1); + } + if (label >= eom) { + errno = EMSGSIZE; + return (-1); + } + *label = c; + /* Fully qualified ? */ + if (*src == '\0') { + if (c != 0) { + if (bp >= eom) { + errno = EMSGSIZE; + return (-1); + } + *bp++ = '\0'; + } + if ((bp - dst) > MAXCDNAME) { + errno = EMSGSIZE; + return (-1); + } + + return (1); + } + if (c == 0 || *src == '.') { + errno = EMSGSIZE; + return (-1); + } + label = bp++; + continue; + } + if (bp >= eom) { + errno = EMSGSIZE; + return (-1); + } + *bp++ = (u_char)c; + } + c = (bp - label - 1); + if ((c & NS_CMPRSFLGS) != 0) { /*%< Label too big. */ + errno = EMSGSIZE; + return (-1); + } + done: + if (label >= eom) { + errno = EMSGSIZE; + return (-1); + } + *label = c; + if (c != 0) { + if (bp >= eom) { + errno = EMSGSIZE; + return (-1); + } + *bp++ = 0; + } + if ((bp - dst) > MAXCDNAME) { /*%< src too big */ + errno = EMSGSIZE; + return (-1); + } + + return (0); +} +libc_hidden_def(ns_name_pton) + /* * ns_name_unpack(msg, eom, src, dst, dstsiz) * Unpack a domain name from a message, source may be compressed. @@ -2866,6 +3122,218 @@ int ns_name_unpack(const u_char *msg, const u_char *eom, const u_char *src, return len; } libc_hidden_def(ns_name_unpack) + +static int labellen(const unsigned char *lp) +{ + int bitlen; + unsigned char l = *lp; + + if ((l & NS_CMPRSFLGS) == NS_CMPRSFLGS) { + /* should be avoided by the caller */ + return -1; + } + + if ((l & NS_CMPRSFLGS) == NS_TYPE_ELT) { + if (l == DNS_LABELTYPE_BITSTRING) { + if ((bitlen = *(lp + 1)) == 0) + bitlen = 256; + return ((bitlen + 7 ) / 8 + 1); + } + + return -1; /*%< unknwon ELT */ + } + + return l; +} + +static int mklower(int ch) +{ + if (ch >= 0x41 && ch <= 0x5A) + return (ch + 0x20); + + return (ch); +} + +static int dn_find(const unsigned char *domain, + const unsigned char *msg, + const unsigned char * const *dnptrs, + const unsigned char * const *lastdnptr) +{ + const unsigned char *dn, *cp, *sp; + const unsigned 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 (; 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 */ + errno = EMSGSIZE; + return -1; + } + } +next: + sp += *sp + 1; + } + } + + errno = ENOENT; + return -1; +} + +int ns_name_pack(const unsigned char *src, + unsigned char *dst, int dstsiz, + const unsigned char **dnptrs, + const unsigned char **lastdnptr) +{ + unsigned char *dstp; + const unsigned char **cpp, **lpp, *eob, *msg; + const unsigned 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++) + continue; + + 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) { + errno = EMSGSIZE; + return -1; + } + + if ((l0 = labellen(srcp)) < 0) { + errno = EINVAL; + return -1; + } + + l += l0 + 1; + if (l > MAXCDNAME) { + 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 unsigned char * const *) dnptrs, + (const unsigned char * const *) lpp); + if (l >= 0) { + if (dstp + 1 >= eob) { + goto cleanup; + } + + *dstp++ = ((u_int32_t)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 (dstp + 1 + n >= eob) { + goto cleanup; + } + + memcpy(dstp, srcp, (size_t)(n + 1)); + srcp += n + 1; + dstp += n + 1; + } while (n != 0); + + if (dstp > eob) { +cleanup: + if (msg != NULL) + *lpp = NULL; + + errno = EMSGSIZE; + return -1; + } + + return dstp - dst; +} + +int ns_name_compress(const char *src, + unsigned char *dst, size_t dstsiz, + const unsigned char **dnptrs, + const unsigned char **lastdnptr) +{ + unsigned char tmp[NS_MAXCDNAME]; + + if (ns_name_pton(src, tmp, sizeof(tmp)) == -1) + return -1; + + return ns_name_pack(tmp, dst, dstsiz, dnptrs, lastdnptr); +} #endif /* L_ns_name */ |