diff options
| -rw-r--r-- | src/resolve/resolved-dns-packet.c | 422 |
1 files changed, 178 insertions, 244 deletions
diff --git a/src/resolve/resolved-dns-packet.c b/src/resolve/resolved-dns-packet.c index abb9725b73..6a9a1f732d 100644 --- a/src/resolve/resolved-dns-packet.c +++ b/src/resolve/resolved-dns-packet.c @@ -30,6 +30,19 @@ #define EDNS0_OPT_DO (1<<15) +typedef struct DnsPacketRewinder { + DnsPacket *packet; + size_t saved_rindex; +} DnsPacketRewinder; + +static void rewind_dns_packet(DnsPacketRewinder *rewinder) { + if (rewinder->packet) + dns_packet_rewind(rewinder->packet, rewinder->saved_rindex); +} + +#define INIT_REWINDER(rewinder, p) do { rewinder.packet = p; rewinder.saved_rindex = p->rindex; } while(0) +#define CANCEL_REWINDER(rewinder) do { rewinder.packet = NULL; } while(0) + int dns_packet_new(DnsPacket **ret, DnsProtocol protocol, size_t mtu) { DnsPacket *p; size_t a; @@ -1231,80 +1244,67 @@ int dns_packet_read_uint32(DnsPacket *p, uint32_t *ret, size_t *start) { } int dns_packet_read_string(DnsPacket *p, char **ret, size_t *start) { - size_t saved_rindex; + _cleanup_(rewind_dns_packet) DnsPacketRewinder rewinder; const void *d; char *t; uint8_t c; int r; assert(p); - - saved_rindex = p->rindex; + INIT_REWINDER(rewinder, p); r = dns_packet_read_uint8(p, &c, NULL); if (r < 0) - goto fail; + return r; r = dns_packet_read(p, c, &d, NULL); if (r < 0) - goto fail; + return r; - if (memchr(d, 0, c)) { - r = -EBADMSG; - goto fail; - } + if (memchr(d, 0, c)) + return -EBADMSG; t = strndup(d, c); - if (!t) { - r = -ENOMEM; - goto fail; - } + if (!t) + return -ENOMEM; if (!utf8_is_valid(t)) { free(t); - r = -EBADMSG; - goto fail; + return -EBADMSG; } *ret = t; if (start) - *start = saved_rindex; + *start = rewinder.saved_rindex; + CANCEL_REWINDER(rewinder); return 0; - -fail: - dns_packet_rewind(p, saved_rindex); - return r; } int dns_packet_read_raw_string(DnsPacket *p, const void **ret, size_t *size, size_t *start) { - size_t saved_rindex; + _cleanup_(rewind_dns_packet) DnsPacketRewinder rewinder; uint8_t c; int r; assert(p); - - saved_rindex = p->rindex; + INIT_REWINDER(rewinder, p); r = dns_packet_read_uint8(p, &c, NULL); if (r < 0) - goto fail; + return r; r = dns_packet_read(p, c, ret, NULL); if (r < 0) - goto fail; + return r; if (size) *size = c; if (start) - *start = saved_rindex; + *start = rewinder.saved_rindex; + CANCEL_REWINDER(rewinder); return 0; - -fail: - dns_packet_rewind(p, saved_rindex); - return r; } int dns_packet_read_name( @@ -1313,7 +1313,8 @@ int dns_packet_read_name( bool allow_compression, size_t *start) { - size_t saved_rindex, after_rindex = 0, jump_barrier; + _cleanup_(rewind_dns_packet) DnsPacketRewinder rewinder; + size_t after_rindex = 0, jump_barrier; _cleanup_free_ char *ret = NULL; size_t n = 0, allocated = 0; bool first = true; @@ -1321,19 +1322,18 @@ int dns_packet_read_name( assert(p); assert(_ret); + INIT_REWINDER(rewinder, p); + jump_barrier = p->rindex; if (p->refuse_compression) allow_compression = false; - saved_rindex = p->rindex; - jump_barrier = p->rindex; - for (;;) { uint8_t c, d; r = dns_packet_read_uint8(p, &c, NULL); if (r < 0) - goto fail; + return r; if (c == 0) /* End of name */ @@ -1344,12 +1344,10 @@ int dns_packet_read_name( /* Literal label */ r = dns_packet_read(p, c, (const void**) &label, NULL); if (r < 0) - goto fail; + return r; - if (!GREEDY_REALLOC(ret, allocated, n + !first + DNS_LABEL_ESCAPED_MAX)) { - r = -ENOMEM; - goto fail; - } + if (!GREEDY_REALLOC(ret, allocated, n + !first + DNS_LABEL_ESCAPED_MAX)) + return -ENOMEM; if (first) first = false; @@ -1358,7 +1356,7 @@ int dns_packet_read_name( r = dns_label_escape(label, c, ret + n, DNS_LABEL_ESCAPED_MAX); if (r < 0) - goto fail; + return r; n += r; continue; @@ -1368,13 +1366,11 @@ int dns_packet_read_name( /* Pointer */ r = dns_packet_read_uint8(p, &d, NULL); if (r < 0) - goto fail; + return r; ptr = (uint16_t) (c & ~0xc0) << 8 | (uint16_t) d; - if (ptr < DNS_PACKET_HEADER_SIZE || ptr >= jump_barrier) { - r = -EBADMSG; - goto fail; - } + if (ptr < DNS_PACKET_HEADER_SIZE || ptr >= jump_barrier) + return -EBADMSG; if (after_rindex == 0) after_rindex = p->rindex; @@ -1382,16 +1378,12 @@ int dns_packet_read_name( /* Jumps are limited to a "prior occurrence" (RFC-1035 4.1.4) */ jump_barrier = ptr; p->rindex = ptr; - } else { - r = -EBADMSG; - goto fail; - } + } else + return -EBADMSG; } - if (!GREEDY_REALLOC(ret, allocated, n + 1)) { - r = -ENOMEM; - goto fail; - } + if (!GREEDY_REALLOC(ret, allocated, n + 1)) + return -ENOMEM; ret[n] = 0; @@ -1402,13 +1394,10 @@ int dns_packet_read_name( ret = NULL; if (start) - *start = saved_rindex; + *start = rewinder.saved_rindex; + CANCEL_REWINDER(rewinder); return 0; - -fail: - dns_packet_rewind(p, saved_rindex); - return r; } static int dns_packet_read_type_window(DnsPacket *p, Bitmap **types, size_t *start) { @@ -1418,32 +1407,31 @@ static int dns_packet_read_type_window(DnsPacket *p, Bitmap **types, size_t *sta uint8_t bit = 0; unsigned i; bool found = false; - size_t saved_rindex; + _cleanup_(rewind_dns_packet) DnsPacketRewinder rewinder; int r; assert(p); assert(types); - - saved_rindex = p->rindex; + INIT_REWINDER(rewinder, p); r = bitmap_ensure_allocated(types); if (r < 0) - goto fail; + return r; r = dns_packet_read_uint8(p, &window, NULL); if (r < 0) - goto fail; + return r; r = dns_packet_read_uint8(p, &length, NULL); if (r < 0) - goto fail; + return r; if (length == 0 || length > 32) return -EBADMSG; r = dns_packet_read(p, length, (const void **)&bitmap, NULL); if (r < 0) - goto fail; + return r; for (i = 0; i < length; i++) { uint8_t bitmask = 1 << 7; @@ -1468,7 +1456,7 @@ static int dns_packet_read_type_window(DnsPacket *p, Bitmap **types, size_t *sta r = bitmap_set(*types, n); if (r < 0) - goto fail; + return r; } bit ++; @@ -1480,70 +1468,61 @@ static int dns_packet_read_type_window(DnsPacket *p, Bitmap **types, size_t *sta return -EBADMSG; if (start) - *start = saved_rindex; + *start = rewinder.saved_rindex; + CANCEL_REWINDER(rewinder); return 0; -fail: - dns_packet_rewind(p, saved_rindex); - return r; } static int dns_packet_read_type_windows(DnsPacket *p, Bitmap **types, size_t size, size_t *start) { - size_t saved_rindex; + _cleanup_(rewind_dns_packet) DnsPacketRewinder rewinder; int r; - saved_rindex = p->rindex; + INIT_REWINDER(rewinder, p); - while (p->rindex < saved_rindex + size) { + while (p->rindex < rewinder.saved_rindex + size) { r = dns_packet_read_type_window(p, types, NULL); if (r < 0) - goto fail; + return r; /* don't read past end of current RR */ - if (p->rindex > saved_rindex + size) { - r = -EBADMSG; - goto fail; - } + if (p->rindex > rewinder.saved_rindex + size) + return -EBADMSG; } - if (p->rindex != saved_rindex + size) { - r = -EBADMSG; - goto fail; - } + if (p->rindex != rewinder.saved_rindex + size) + return -EBADMSG; if (start) - *start = saved_rindex; + *start = rewinder.saved_rindex; + CANCEL_REWINDER(rewinder); return 0; -fail: - dns_packet_rewind(p, saved_rindex); - return r; } int dns_packet_read_key(DnsPacket *p, DnsResourceKey **ret, bool *ret_cache_flush, size_t *start) { + _cleanup_(rewind_dns_packet) DnsPacketRewinder rewinder; _cleanup_free_ char *name = NULL; bool cache_flush = false; uint16_t class, type; DnsResourceKey *key; - size_t saved_rindex; int r; assert(p); assert(ret); - - saved_rindex = p->rindex; + INIT_REWINDER(rewinder, p); r = dns_packet_read_name(p, &name, true, NULL); if (r < 0) - goto fail; + return r; r = dns_packet_read_uint16(p, &type, NULL); if (r < 0) - goto fail; + return r; r = dns_packet_read_uint16(p, &class, NULL); if (r < 0) - goto fail; + return r; if (p->protocol == DNS_PROTOCOL_MDNS) { /* See RFC6762, Section 10.2 */ @@ -1555,10 +1534,8 @@ int dns_packet_read_key(DnsPacket *p, DnsResourceKey **ret, bool *ret_cache_flus } key = dns_resource_key_new_consume(class, type, name); - if (!key) { - r = -ENOMEM; - goto fail; - } + if (!key) + return -ENOMEM; name = NULL; *ret = key; @@ -1566,12 +1543,10 @@ int dns_packet_read_key(DnsPacket *p, DnsResourceKey **ret, bool *ret_cache_flus if (ret_cache_flush) *ret_cache_flush = cache_flush; if (start) - *start = saved_rindex; + *start = rewinder.saved_rindex; + CANCEL_REWINDER(rewinder); return 0; -fail: - dns_packet_rewind(p, saved_rindex); - return r; } static bool loc_size_ok(uint8_t size) { @@ -1583,7 +1558,8 @@ static bool loc_size_ok(uint8_t size) { int dns_packet_read_rr(DnsPacket *p, DnsResourceRecord **ret, bool *ret_cache_flush, size_t *start) { _cleanup_(dns_resource_record_unrefp) DnsResourceRecord *rr = NULL; _cleanup_(dns_resource_key_unrefp) DnsResourceKey *key = NULL; - size_t saved_rindex, offset; + _cleanup_(rewind_dns_packet) DnsPacketRewinder rewinder; + size_t offset; uint16_t rdlength; bool cache_flush; int r; @@ -1591,27 +1567,22 @@ int dns_packet_read_rr(DnsPacket *p, DnsResourceRecord **ret, bool *ret_cache_fl assert(p); assert(ret); - saved_rindex = p->rindex; + INIT_REWINDER(rewinder, p); r = dns_packet_read_key(p, &key, &cache_flush, NULL); if (r < 0) - goto fail; + return r; - if (!dns_class_is_valid_rr(key->class)|| - !dns_type_is_valid_rr(key->type)) { - r = -EBADMSG; - goto fail; - } + if (!dns_class_is_valid_rr(key->class) || !dns_type_is_valid_rr(key->type)) + return -EBADMSG; rr = dns_resource_record_new(key); - if (!rr) { - r = -ENOMEM; - goto fail; - } + if (!rr) + return -ENOMEM; r = dns_packet_read_uint32(p, &rr->ttl, NULL); if (r < 0) - goto fail; + return r; /* RFC 2181, Section 8, suggests to * treat a TTL with the MSB set as a zero TTL. */ @@ -1620,12 +1591,10 @@ int dns_packet_read_rr(DnsPacket *p, DnsResourceRecord **ret, bool *ret_cache_fl r = dns_packet_read_uint16(p, &rdlength, NULL); if (r < 0) - goto fail; + return r; - if (p->rindex + rdlength > p->size) { - r = -EBADMSG; - goto fail; - } + if (p->rindex + rdlength > p->size) + return -EBADMSG; offset = p->rindex; @@ -1634,13 +1603,13 @@ int dns_packet_read_rr(DnsPacket *p, DnsResourceRecord **ret, bool *ret_cache_fl case DNS_TYPE_SRV: r = dns_packet_read_uint16(p, &rr->srv.priority, NULL); if (r < 0) - goto fail; + return r; r = dns_packet_read_uint16(p, &rr->srv.weight, NULL); if (r < 0) - goto fail; + return r; r = dns_packet_read_uint16(p, &rr->srv.port, NULL); if (r < 0) - goto fail; + return r; r = dns_packet_read_name(p, &rr->srv.name, true, NULL); break; @@ -1654,7 +1623,7 @@ int dns_packet_read_rr(DnsPacket *p, DnsResourceRecord **ret, bool *ret_cache_fl case DNS_TYPE_HINFO: r = dns_packet_read_string(p, &rr->hinfo.cpu, NULL); if (r < 0) - goto fail; + return r; r = dns_packet_read_string(p, &rr->hinfo.os, NULL); break; @@ -1710,27 +1679,27 @@ int dns_packet_read_rr(DnsPacket *p, DnsResourceRecord **ret, bool *ret_cache_fl case DNS_TYPE_SOA: r = dns_packet_read_name(p, &rr->soa.mname, true, NULL); if (r < 0) - goto fail; + return r; r = dns_packet_read_name(p, &rr->soa.rname, true, NULL); if (r < 0) - goto fail; + return r; r = dns_packet_read_uint32(p, &rr->soa.serial, NULL); if (r < 0) - goto fail; + return r; r = dns_packet_read_uint32(p, &rr->soa.refresh, NULL); if (r < 0) - goto fail; + return r; r = dns_packet_read_uint32(p, &rr->soa.retry, NULL); if (r < 0) - goto fail; + return r; r = dns_packet_read_uint32(p, &rr->soa.expire, NULL); if (r < 0) - goto fail; + return r; r = dns_packet_read_uint32(p, &rr->soa.minimum, NULL); break; @@ -1738,7 +1707,7 @@ int dns_packet_read_rr(DnsPacket *p, DnsResourceRecord **ret, bool *ret_cache_fl case DNS_TYPE_MX: r = dns_packet_read_uint16(p, &rr->mx.priority, NULL); if (r < 0) - goto fail; + return r; r = dns_packet_read_name(p, &rr->mx.exchange, true, NULL); break; @@ -1749,49 +1718,43 @@ int dns_packet_read_rr(DnsPacket *p, DnsResourceRecord **ret, bool *ret_cache_fl r = dns_packet_read_uint8(p, &t, &pos); if (r < 0) - goto fail; + return r; if (t == 0) { rr->loc.version = t; r = dns_packet_read_uint8(p, &rr->loc.size, NULL); if (r < 0) - goto fail; + return r; - if (!loc_size_ok(rr->loc.size)) { - r = -EBADMSG; - goto fail; - } + if (!loc_size_ok(rr->loc.size)) + return -EBADMSG; r = dns_packet_read_uint8(p, &rr->loc.horiz_pre, NULL); if (r < 0) - goto fail; + return r; - if (!loc_size_ok(rr->loc.horiz_pre)) { - r = -EBADMSG; - goto fail; - } + if (!loc_size_ok(rr->loc.horiz_pre)) + return -EBADMSG; r = dns_packet_read_uint8(p, &rr->loc.vert_pre, NULL); if (r < 0) - goto fail; + return r; - if (!loc_size_ok(rr->loc.vert_pre)) { - r = -EBADMSG; - goto fail; - } + if (!loc_size_ok(rr->loc.vert_pre)) + return -EBADMSG; r = dns_packet_read_uint32(p, &rr->loc.latitude, NULL); if (r < 0) - goto fail; + return r; r = dns_packet_read_uint32(p, &rr->loc.longitude, NULL); if (r < 0) - goto fail; + return r; r = dns_packet_read_uint32(p, &rr->loc.altitude, NULL); if (r < 0) - goto fail; + return r; break; } else { @@ -1804,122 +1767,114 @@ int dns_packet_read_rr(DnsPacket *p, DnsResourceRecord **ret, bool *ret_cache_fl case DNS_TYPE_DS: r = dns_packet_read_uint16(p, &rr->ds.key_tag, NULL); if (r < 0) - goto fail; + return r; r = dns_packet_read_uint8(p, &rr->ds.algorithm, NULL); if (r < 0) - goto fail; + return r; r = dns_packet_read_uint8(p, &rr->ds.digest_type, NULL); if (r < 0) - goto fail; + return r; r = dns_packet_read_memdup(p, rdlength - 4, &rr->ds.digest, &rr->ds.digest_size, NULL); if (r < 0) - goto fail; + return r; - if (rr->ds.digest_size <= 0) { + if (rr->ds.digest_size <= 0) /* the accepted size depends on the algorithm, but for now just ensure that the value is greater than zero */ - r = -EBADMSG; - goto fail; - } + return -EBADMSG; break; case DNS_TYPE_SSHFP: r = dns_packet_read_uint8(p, &rr->sshfp.algorithm, NULL); if (r < 0) - goto fail; + return r; r = dns_packet_read_uint8(p, &rr->sshfp.fptype, NULL); if (r < 0) - goto fail; + return r; r = dns_packet_read_memdup(p, rdlength - 2, &rr->sshfp.fingerprint, &rr->sshfp.fingerprint_size, NULL); - if (rr->sshfp.fingerprint_size <= 0) { + if (rr->sshfp.fingerprint_size <= 0) /* the accepted size depends on the algorithm, but for now just ensure that the value is greater than zero */ - r = -EBADMSG; - goto fail; - } + return -EBADMSG; break; case DNS_TYPE_DNSKEY: r = dns_packet_read_uint16(p, &rr->dnskey.flags, NULL); if (r < 0) - goto fail; + return r; r = dns_packet_read_uint8(p, &rr->dnskey.protocol, NULL); if (r < 0) - goto fail; + return r; r = dns_packet_read_uint8(p, &rr->dnskey.algorithm, NULL); if (r < 0) - goto fail; + return r; r = dns_packet_read_memdup(p, rdlength - 4, &rr->dnskey.key, &rr->dnskey.key_size, NULL); - if (rr->dnskey.key_size <= 0) { + if (rr->dnskey.key_size <= 0) /* the accepted size depends on the algorithm, but for now just ensure that the value is greater than zero */ - r = -EBADMSG; - goto fail; - } + return -EBADMSG; break; case DNS_TYPE_RRSIG: r = dns_packet_read_uint16(p, &rr->rrsig.type_covered, NULL); if (r < 0) - goto fail; + return r; r = dns_packet_read_uint8(p, &rr->rrsig.algorithm, NULL); if (r < 0) - goto fail; + return r; r = dns_packet_read_uint8(p, &rr->rrsig.labels, NULL); if (r < 0) - goto fail; + return r; r = dns_packet_read_uint32(p, &rr->rrsig.original_ttl, NULL); if (r < 0) - goto fail; + return r; r = dns_packet_read_uint32(p, &rr->rrsig.expiration, NULL); if (r < 0) - goto fail; + return r; r = dns_packet_read_uint32(p, &rr->rrsig.inception, NULL); if (r < 0) - goto fail; + return r; r = dns_packet_read_uint16(p, &rr->rrsig.key_tag, NULL); if (r < 0) - goto fail; + return r; r = dns_packet_read_name(p, &rr->rrsig.signer, false, NULL); if (r < 0) - goto fail; + return r; r = dns_packet_read_memdup(p, offset + rdlength - p->rindex, &rr->rrsig.signature, &rr->rrsig.signature_size, NULL); - if (rr->rrsig.signature_size <= 0) { + if (rr->rrsig.signature_size <= 0) /* the accepted size depends on the algorithm, but for now just ensure that the value is greater than zero */ - r = -EBADMSG; - goto fail; - } + return -EBADMSG; break; @@ -1934,11 +1889,9 @@ int dns_packet_read_rr(DnsPacket *p, DnsResourceRecord **ret, bool *ret_cache_fl r = dns_packet_read_name(p, &rr->nsec.next_domain_name, allow_compressed, NULL); if (r < 0) - goto fail; + return r; r = dns_packet_read_type_windows(p, &rr->nsec.types, offset + rdlength - p->rindex, NULL); - if (r < 0) - goto fail; /* We accept empty NSEC bitmaps. The bit indicating the presence of the NSEC record itself * is redundant and in e.g., RFC4956 this fact is used to define a use for NSEC records @@ -1951,41 +1904,39 @@ int dns_packet_read_rr(DnsPacket *p, DnsResourceRecord **ret, bool *ret_cache_fl r = dns_packet_read_uint8(p, &rr->nsec3.algorithm, NULL); if (r < 0) - goto fail; + return r; r = dns_packet_read_uint8(p, &rr->nsec3.flags, NULL); if (r < 0) - goto fail; + return r; r = dns_packet_read_uint16(p, &rr->nsec3.iterations, NULL); if (r < 0) - goto fail; + return r; /* this may be zero */ r = dns_packet_read_uint8(p, &size, NULL); if (r < 0) - goto fail; + return r; r = dns_packet_read_memdup(p, size, &rr->nsec3.salt, &rr->nsec3.salt_size, NULL); if (r < 0) - goto fail; + return r; r = dns_packet_read_uint8(p, &size, NULL); if (r < 0) - goto fail; + return r; - if (size <= 0) { - r = -EBADMSG; - goto fail; - } + if (size <= 0) + return -EBADMSG; - r = dns_packet_read_memdup(p, size, &rr->nsec3.next_hashed_name, &rr->nsec3.next_hashed_name_size, NULL); + r = dns_packet_read_memdup(p, size, + &rr->nsec3.next_hashed_name, &rr->nsec3.next_hashed_name_size, + NULL); if (r < 0) - goto fail; + return r; r = dns_packet_read_type_windows(p, &rr->nsec3.types, offset + rdlength - p->rindex, NULL); - if (r < 0) - goto fail; /* empty non-terminals can have NSEC3 records, so empty bitmaps are allowed */ @@ -1995,25 +1946,24 @@ int dns_packet_read_rr(DnsPacket *p, DnsResourceRecord **ret, bool *ret_cache_fl case DNS_TYPE_TLSA: r = dns_packet_read_uint8(p, &rr->tlsa.cert_usage, NULL); if (r < 0) - goto fail; + return r; r = dns_packet_read_uint8(p, &rr->tlsa.selector, NULL); if (r < 0) - goto fail; + return r; r = dns_packet_read_uint8(p, &rr->tlsa.matching_type, NULL); if (r < 0) - goto fail; + return r; r = dns_packet_read_memdup(p, rdlength - 3, &rr->tlsa.data, &rr->tlsa.data_size, NULL); - if (rr->tlsa.data_size <= 0) { + + if (rr->tlsa.data_size <= 0) /* the accepted size depends on the algorithm, but for now just ensure that the value is greater than zero */ - r = -EBADMSG; - goto fail; - } + return -EBADMSG; break; @@ -2022,16 +1972,13 @@ int dns_packet_read_rr(DnsPacket *p, DnsResourceRecord **ret, bool *ret_cache_fl default: unparseable: r = dns_packet_read_memdup(p, rdlength, &rr->generic.data, &rr->generic.data_size, NULL); - if (r < 0) - goto fail; + break; } if (r < 0) - goto fail; - if (p->rindex != offset + rdlength) { - r = -EBADMSG; - goto fail; - } + return r; + if (p->rindex != offset + rdlength) + return -EBADMSG; *ret = rr; rr = NULL; @@ -2039,12 +1986,10 @@ int dns_packet_read_rr(DnsPacket *p, DnsResourceRecord **ret, bool *ret_cache_fl if (ret_cache_flush) *ret_cache_flush = cache_flush; if (start) - *start = saved_rindex; + *start = rewinder.saved_rindex; + CANCEL_REWINDER(rewinder); return 0; -fail: - dns_packet_rewind(p, saved_rindex); - return r; } static bool opt_is_good(DnsResourceRecord *rr, bool *rfc6975) { @@ -2092,23 +2037,21 @@ static bool opt_is_good(DnsResourceRecord *rr, bool *rfc6975) { int dns_packet_extract(DnsPacket *p) { _cleanup_(dns_question_unrefp) DnsQuestion *question = NULL; _cleanup_(dns_answer_unrefp) DnsAnswer *answer = NULL; - size_t saved_rindex; + _cleanup_(rewind_dns_packet) DnsPacketRewinder rewinder = {}; unsigned n, i; int r; if (p->extracted) return 0; - saved_rindex = p->rindex; + INIT_REWINDER(rewinder, p); dns_packet_rewind(p, DNS_PACKET_HEADER_SIZE); n = DNS_PACKET_QDCOUNT(p); if (n > 0) { question = dns_question_new(n); - if (!question) { - r = -ENOMEM; - goto finish; - } + if (!question) + return -ENOMEM; for (i = 0; i < n; i++) { _cleanup_(dns_resource_key_unrefp) DnsResourceKey *key = NULL; @@ -2116,21 +2059,17 @@ int dns_packet_extract(DnsPacket *p) { r = dns_packet_read_key(p, &key, &cache_flush, NULL); if (r < 0) - goto finish; + return r; - if (cache_flush) { - r = -EBADMSG; - goto finish; - } + if (cache_flush) + return -EBADMSG; - if (!dns_type_is_valid_query(key->type)) { - r = -EBADMSG; - goto finish; - } + if (!dns_type_is_valid_query(key->type)) + return -EBADMSG; r = dns_question_add(question, key); if (r < 0) - goto finish; + return r; } } @@ -2140,10 +2079,8 @@ int dns_packet_extract(DnsPacket *p) { bool bad_opt = false; answer = dns_answer_new(n); - if (!answer) { - r = -ENOMEM; - goto finish; - } + if (!answer) + return -ENOMEM; for (i = 0; i < n; i++) { _cleanup_(dns_resource_record_unrefp) DnsResourceRecord *rr = NULL; @@ -2151,7 +2088,7 @@ int dns_packet_extract(DnsPacket *p) { r = dns_packet_read_rr(p, &rr, &cache_flush, NULL); if (r < 0) - goto finish; + return r; /* Try to reduce memory usage a bit */ if (previous) @@ -2214,7 +2151,7 @@ int dns_packet_extract(DnsPacket *p) { (i < DNS_PACKET_ANCOUNT(p) ? DNS_ANSWER_CACHEABLE : 0) | (p->protocol == DNS_PROTOCOL_MDNS && !cache_flush ? DNS_ANSWER_SHARED_OWNER : 0)); if (r < 0) - goto finish; + return r; } /* Remember this RR, so that we potentically can merge it's ->key object with the next RR. Note @@ -2235,11 +2172,8 @@ int dns_packet_extract(DnsPacket *p) { p->extracted = true; - r = 0; - -finish: - p->rindex = saved_rindex; - return r; + /* no CANCEL, always rewind */ + return 0; } int dns_packet_is_reply_for(DnsPacket *p, const DnsResourceKey *key) { |