diff options
Diffstat (limited to 'resolv')
| -rw-r--r-- | resolv/nss_dns/dns-host.c | 320 |
1 files changed, 268 insertions, 52 deletions
diff --git a/resolv/nss_dns/dns-host.c b/resolv/nss_dns/dns-host.c index 544cffbecd..d384e1f82d 100644 --- a/resolv/nss_dns/dns-host.c +++ b/resolv/nss_dns/dns-host.c @@ -116,6 +116,11 @@ static enum nss_status getanswer_r (struct resolv_context *ctx, struct hostent *result, char *buffer, size_t buflen, int *errnop, int *h_errnop, int map, int32_t *ttlp, char **canonp); +static enum nss_status getanswer_ptr (const querybuf *answer, int anslen, + const char *qname, + struct hostent *result, char *buffer, + size_t buflen, int *errnop, + int *h_errnop, int32_t *ttlp); static enum nss_status gaih_getanswer (const querybuf *answer1, int anslen1, const querybuf *answer2, int anslen2, @@ -561,9 +566,8 @@ _nss_dns_gethostbyaddr2_r (const void *addr, socklen_t len, int af, return errno == ECONNREFUSED ? NSS_STATUS_UNAVAIL : NSS_STATUS_NOTFOUND; } - status = getanswer_r - (ctx, host_buffer.buf, n, qbuf, T_PTR, result, buffer, buflen, - errnop, h_errnop, 0 /* XXX */, ttlp, NULL); + status = getanswer_ptr (host_buffer.buf, n, qbuf, result, + buffer, buflen, errnop, h_errnop, ttlp); if (host_buffer.buf != orig_host_buffer) free (host_buffer.buf); if (status != NSS_STATUS_SUCCESS) @@ -659,8 +663,6 @@ getanswer_r (struct resolv_context *ctx, int haveanswer, had_error; char *bp, **ap, **hap; char tbuf[MAXDNAME]; - const char *tname; - int (*name_ok) (const char *); u_char packtmp[NS_MAXCDNAME]; int have_to_map = 0; uintptr_t pad = -(uintptr_t) buffer % __alignof__ (struct host_data); @@ -679,22 +681,8 @@ getanswer_r (struct resolv_context *ctx, if (buflen - sizeof (struct host_data) != linebuflen) linebuflen = INT_MAX; - tname = qname; result->h_name = NULL; end_of_message = answer->buf + anslen; - switch (qtype) - { - case T_A: - case T_AAAA: - name_ok = __libc_res_hnok; - break; - case T_PTR: - name_ok = __libc_res_dnok; - break; - default: - *errnop = ENOENT; - return NSS_STATUS_UNAVAIL; /* XXX should be abort(); */ - } /* * find first satisfactory answer @@ -729,7 +717,7 @@ getanswer_r (struct resolv_context *ctx, *h_errnop = NO_RECOVERY; return NSS_STATUS_UNAVAIL; } - if (__glibc_unlikely (name_ok (bp) == 0)) + if (__glibc_unlikely (__libc_res_hnok (bp) == 0)) { errno = EBADMSG; *errnop = EBADMSG; @@ -783,7 +771,7 @@ getanswer_r (struct resolv_context *ctx, n = -1; } - if (__glibc_unlikely (n < 0 || (*name_ok) (bp) == 0)) + if (__glibc_unlikely (n < 0 || __libc_res_hnok (bp) == 0)) { ++had_error; continue; @@ -816,7 +804,7 @@ getanswer_r (struct resolv_context *ctx, continue; /* XXX - had_error++ ? */ } - if ((qtype == T_A || qtype == T_AAAA) && type == T_CNAME) + if (type == T_CNAME) { /* A CNAME could also have a TTL entry. */ if (ttlp != NULL && ttl < *ttlp) @@ -826,7 +814,7 @@ getanswer_r (struct resolv_context *ctx, continue; n = __libc_dn_expand (answer->buf, end_of_message, cp, tbuf, sizeof tbuf); - if (__glibc_unlikely (n < 0 || (*name_ok) (tbuf) == 0)) + if (__glibc_unlikely (n < 0 || __libc_res_hnok (tbuf) == 0)) { ++had_error; continue; @@ -857,7 +845,260 @@ getanswer_r (struct resolv_context *ctx, continue; } - if (qtype == T_PTR && type == T_CNAME) + if (type == T_A && qtype == T_AAAA && map) + have_to_map = 1; + else if (__glibc_unlikely (type != qtype)) + { + cp += n; + continue; /* XXX - had_error++ ? */ + } + + switch (type) + { + case T_A: + case T_AAAA: + if (__glibc_unlikely (__strcasecmp (result->h_name, bp) != 0)) + { + cp += n; + continue; /* XXX - had_error++ ? */ + } + + /* Stop parsing at a record whose length is incorrect. */ + if (n != rrtype_to_rdata_length (type)) + { + ++had_error; + break; + } + + /* Skip records of the wrong type. */ + if (n != result->h_length) + { + cp += n; + continue; + } + if (!haveanswer) + { + int nn; + + /* We compose a single hostent out of the entire chain of + entries, so the TTL of the hostent is essentially the lowest + TTL in the chain. */ + if (ttlp != NULL && ttl < *ttlp) + *ttlp = ttl; + if (canonp != NULL) + *canonp = bp; + result->h_name = bp; + nn = strlen (bp) + 1; /* for the \0 */ + bp += nn; + linebuflen -= nn; + } + + /* Provide sufficient alignment for both address + families. */ + enum { align = 4 }; + _Static_assert ((align % __alignof__ (struct in_addr)) == 0, + "struct in_addr alignment"); + _Static_assert ((align % __alignof__ (struct in6_addr)) == 0, + "struct in6_addr alignment"); + { + char *new_bp = PTR_ALIGN_UP (bp, align); + linebuflen -= new_bp - bp; + bp = new_bp; + } + + if (__glibc_unlikely (n > linebuflen)) + goto too_small; + bp = __mempcpy (*hap++ = bp, cp, n); + cp += n; + linebuflen -= n; + break; + default: + abort (); + } + if (had_error == 0) + ++haveanswer; + } + + if (haveanswer > 0) + { + *ap = NULL; + *hap = NULL; + /* + * Note: we sort even if host can take only one address + * in its return structures - should give it the "best" + * address in that case, not some random one + */ + if (haveanswer > 1 && qtype == T_A + && __resolv_context_sort_count (ctx) > 0) + addrsort (ctx, host_data->h_addr_ptrs, haveanswer); + + if (result->h_name == NULL) + { + n = strlen (qname) + 1; /* For the \0. */ + if (n > linebuflen) + goto too_small; + if (n >= MAXHOSTNAMELEN) + goto no_recovery; + result->h_name = bp; + bp = __mempcpy (bp, qname, n); /* Cannot overflow. */ + linebuflen -= n; + } + + if (have_to_map) + if (map_v4v6_hostent (result, &bp, &linebuflen)) + goto too_small; + *h_errnop = NETDB_SUCCESS; + return NSS_STATUS_SUCCESS; + } + no_recovery: + *h_errnop = NO_RECOVERY; + *errnop = ENOENT; + /* Special case here: if the resolver sent a result but it only + contains a CNAME while we are looking for a T_A or T_AAAA record, + we fail with NOTFOUND instead of TRYAGAIN. */ + return ((qtype == T_A || qtype == T_AAAA) && ap != host_data->aliases + ? NSS_STATUS_NOTFOUND : NSS_STATUS_TRYAGAIN); +} + +static enum nss_status +getanswer_ptr (const querybuf *answer, int anslen, const char *qname, + struct hostent *result, char *buffer, size_t buflen, + int *errnop, int *h_errnop, int32_t *ttlp) +{ + struct host_data + { + char *aliases[MAX_NR_ALIASES]; + unsigned char host_addr[16]; /* IPv4 or IPv6 */ + char *h_addr_ptrs[0]; + } *host_data; + int linebuflen; + const HEADER *hp; + const u_char *end_of_message, *cp; + int n, ancount, qdcount; + int haveanswer, had_error; + char *bp, **ap, **hap; + char tbuf[MAXDNAME]; + const char *tname; + u_char packtmp[NS_MAXCDNAME]; + uintptr_t pad = -(uintptr_t) buffer % __alignof__ (struct host_data); + buffer += pad; + buflen = buflen > pad ? buflen - pad : 0; + if (__glibc_unlikely (buflen < sizeof (struct host_data))) + { + /* The buffer is too small. */ + too_small: + *errnop = ERANGE; + *h_errnop = NETDB_INTERNAL; + return NSS_STATUS_TRYAGAIN; + } + host_data = (struct host_data *) buffer; + linebuflen = buflen - sizeof (struct host_data); + if (buflen - sizeof (struct host_data) != linebuflen) + linebuflen = INT_MAX; + + tname = qname; + result->h_name = NULL; + end_of_message = answer->buf + anslen; + + /* + * find first satisfactory answer + */ + hp = &answer->hdr; + ancount = ntohs (hp->ancount); + qdcount = ntohs (hp->qdcount); + cp = answer->buf + HFIXEDSZ; + if (__glibc_unlikely (qdcount != 1)) + { + *h_errnop = NO_RECOVERY; + return NSS_STATUS_UNAVAIL; + } + if (sizeof (struct host_data) + (ancount + 1) * sizeof (char *) >= buflen) + goto too_small; + bp = (char *) &host_data->h_addr_ptrs[ancount + 1]; + linebuflen -= (ancount + 1) * sizeof (char *); + + n = __ns_name_unpack (answer->buf, end_of_message, cp, + packtmp, sizeof packtmp); + if (n != -1 && __ns_name_ntop (packtmp, bp, linebuflen) == -1) + { + if (__glibc_unlikely (errno == EMSGSIZE)) + goto too_small; + + n = -1; + } + + if (__glibc_unlikely (n < 0)) + { + *errnop = errno; + *h_errnop = NO_RECOVERY; + return NSS_STATUS_UNAVAIL; + } + if (__glibc_unlikely (__libc_res_dnok (bp) == 0)) + { + errno = EBADMSG; + *errnop = EBADMSG; + *h_errnop = NO_RECOVERY; + return NSS_STATUS_UNAVAIL; + } + cp += n + QFIXEDSZ; + + ap = host_data->aliases; + *ap = NULL; + result->h_aliases = host_data->aliases; + hap = host_data->h_addr_ptrs; + *hap = NULL; + result->h_addr_list = host_data->h_addr_ptrs; + haveanswer = 0; + had_error = 0; + + while (ancount-- > 0 && cp < end_of_message && had_error == 0) + { + int type, class; + + n = __ns_name_unpack (answer->buf, end_of_message, cp, + packtmp, sizeof packtmp); + if (n != -1 && __ns_name_ntop (packtmp, bp, linebuflen) == -1) + { + if (__glibc_unlikely (errno == EMSGSIZE)) + goto too_small; + + n = -1; + } + + if (__glibc_unlikely (n < 0 || __libc_res_dnok (bp) == 0)) + { + ++had_error; + continue; + } + cp += n; /* name */ + + if (__glibc_unlikely (cp + 10 > end_of_message)) + { + ++had_error; + continue; + } + + NS_GET16 (type, cp); + NS_GET16 (class, cp); + int32_t ttl; + NS_GET32 (ttl, cp); + NS_GET16 (n, cp); /* RDATA length. */ + + if (end_of_message - cp < n) + { + /* RDATA extends beyond the end of the packet. */ + ++had_error; + continue; + } + + if (__glibc_unlikely (class != C_IN)) + { + /* XXX - debug? syslog? */ + cp += n; + continue; /* XXX - had_error++ ? */ + } + + if (type == T_CNAME) { /* A CNAME could also have a TTL entry. */ if (ttlp != NULL && ttl < *ttlp) @@ -886,14 +1127,6 @@ getanswer_r (struct resolv_context *ctx, continue; } - if (type == T_A && qtype == T_AAAA && map) - have_to_map = 1; - else if (__glibc_unlikely (type != qtype)) - { - cp += n; - continue; /* XXX - had_error++ ? */ - } - switch (type) { case T_PTR: @@ -955,8 +1188,6 @@ getanswer_r (struct resolv_context *ctx, TTL in the chain. */ if (ttlp != NULL && ttl < *ttlp) *ttlp = ttl; - if (canonp != NULL) - *canonp = bp; result->h_name = bp; nn = strlen (bp) + 1; /* for the \0 */ bp += nn; @@ -983,7 +1214,8 @@ getanswer_r (struct resolv_context *ctx, linebuflen -= n; break; default: - abort (); + cp += n; + continue; /* XXX - had_error++ ? */ } if (had_error == 0) ++haveanswer; @@ -993,14 +1225,6 @@ getanswer_r (struct resolv_context *ctx, { *ap = NULL; *hap = NULL; - /* - * Note: we sort even if host can take only one address - * in its return structures - should give it the "best" - * address in that case, not some random one - */ - if (haveanswer > 1 && qtype == T_A - && __resolv_context_sort_count (ctx) > 0) - addrsort (ctx, host_data->h_addr_ptrs, haveanswer); if (result->h_name == NULL) { @@ -1014,23 +1238,15 @@ getanswer_r (struct resolv_context *ctx, linebuflen -= n; } - if (have_to_map) - if (map_v4v6_hostent (result, &bp, &linebuflen)) - goto too_small; *h_errnop = NETDB_SUCCESS; return NSS_STATUS_SUCCESS; } no_recovery: *h_errnop = NO_RECOVERY; *errnop = ENOENT; - /* Special case here: if the resolver sent a result but it only - contains a CNAME while we are looking for a T_A or T_AAAA record, - we fail with NOTFOUND instead of TRYAGAIN. */ - return ((qtype == T_A || qtype == T_AAAA) && ap != host_data->aliases - ? NSS_STATUS_NOTFOUND : NSS_STATUS_TRYAGAIN); + return NSS_STATUS_TRYAGAIN; } - static enum nss_status gaih_getanswer_slice (const querybuf *answer, int anslen, const char *qname, struct gaih_addrtuple ***patp, |