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Merge pull request #34391 from poettering/dns-long-label-fix

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resolved: fixes when trying to serialize overly long DNS names
This commit is contained in:
Lennart Poettering 2024-10-29 10:47:14 +01:00 committed by GitHub
commit 815569791f
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GPG Key ID: B5690EEEBB952194
4 changed files with 147 additions and 22 deletions
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34
src/resolve/resolved-dns-packet.c
View File

@ -557,12 +557,19 @@ int dns_packet_append_name(
bool canonical_candidate,
size_t *start) {
size_t saved_size;
_cleanup_free_ char **added_entries = NULL; /* doesn't own the strings! this is just regular pointer array, not a NULL-terminated strv! */
size_t n_added_entries = 0, saved_size;
int r;
assert(p);
assert(name);
r = dns_name_is_valid(name);
if (r < 0)
return r;
if (r == 0)
return -EINVAL;
if (p->refuse_compression)
allow_compression = false;
@ -598,6 +605,11 @@ int dns_packet_append_name(
if (allow_compression) {
_cleanup_free_ char *s = NULL;
if (!GREEDY_REALLOC(added_entries, n_added_entries + 1)) {
r = -ENOMEM;
goto fail;
}
s = strdup(z);
if (!s) {
r = -ENOMEM;
@ -608,7 +620,8 @@ int dns_packet_append_name(
if (r < 0)
goto fail;
TAKE_PTR(s);
/* Keep track of the entries we just added (note that the string is owned by the hashtable, not this array!) */
added_entries[n_added_entries++] = TAKE_PTR(s);
}
}
@ -623,6 +636,12 @@ done:
return 0;
fail:
/* Remove all label compression names we added again */
FOREACH_ARRAY(s, added_entries, n_added_entries) {
hashmap_remove(p->names, *s);
free(*s);
}
dns_packet_truncate(p, saved_size);
return r;
}
@ -1506,7 +1525,7 @@ int dns_packet_read_name(
size_t after_rindex = 0, jump_barrier = p->rindex;
_cleanup_free_ char *name = NULL;
bool first = true;
size_t n = 0;
size_t n = 0, m = 0;
int r;
if (p->refuse_compression)
@ -1535,14 +1554,21 @@ int dns_packet_read_name(
if (first)
first = false;
else
else {
name[n++] = '.';
m++;
}
r = dns_label_escape(label, c, name + n, DNS_LABEL_ESCAPED_MAX);
if (r < 0)
return r;
n += r;
m += c;
if (m > DNS_HOSTNAME_MAX)
return -EBADMSG;
continue;
} else if (allow_compression && FLAGS_SET(c, 0xc0)) {
uint16_t ptr;

30
src/resolve/test-dns-packet-append.c
View File

@ -1267,4 +1267,34 @@ TEST(packet_append_answer_single_svcb) {
ASSERT_EQ(memcmp(DNS_PACKET_DATA(packet), data, sizeof(data)), 0);
}
static void dump_packet_data(DnsPacket *packet) {
assert(packet);
fprintf(stderr, "packet bytes:");
for (size_t i = 0; i < packet->size; i++)
fprintf(stderr, " %x", DNS_PACKET_DATA(packet)[i]);
fprintf(stderr, "\n");
}
TEST(packet_append_key_name_too_long) {
_cleanup_(dns_packet_unrefp) DnsPacket *packet = NULL;
_cleanup_(dns_resource_key_unrefp) DnsResourceKey *key = NULL;
int r;
ASSERT_OK(dns_packet_new(&packet, DNS_PROTOCOL_DNS, 0, DNS_PACKET_SIZE_MAX));
DNS_PACKET_ID(packet) = htobe16(42);
DNS_PACKET_HEADER(packet)->flags = htobe16(DNS_PACKET_MAKE_FLAGS(0, 0, 0, 0, 1, 0, 0, 0, 0));
DNS_PACKET_HEADER(packet)->qdcount = htobe16(1);
key = ASSERT_PTR(dns_resource_key_new(DNS_CLASS_IN, DNS_TYPE_A, "www.aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa.com"));
r = dns_packet_append_key(packet, key, 0, NULL);
log_debug("r = %d, size = %zu", r, packet->size);
log_debug("key name = <%s>", dns_resource_key_name(key));
dump_packet_data(packet);
ASSERT_EQ(r, -EINVAL);
ASSERT_EQ(packet->size, 12U);
}
DEFINE_TEST_MAIN(LOG_DEBUG)

93
src/resolve/test-dns-packet-extract.c
View File

@ -806,12 +806,7 @@ TEST(packet_query_single_long_domain) {
0x10, 'n', 'i', 't', 'r', 'o', 's', 'y', 'l', 's', 'u', 'l', 'f', 'u', 'r', 'i', 'c',
0x10, 'o', 'b', 'j', 'e', 'c', 't', 'l', 'e', 's', 's', 'n', 'e', 's', 's', 'e', 's',
0x10, 'p', 'a', 'r', 't', 'r', 'i', 'd', 'g', 'e', 'b', 'e', 'r', 'r', 'i', 'e', 's',
0x10, 'r', 'e', 'a', 's', 'o', 'n', 'l', 'e', 's', 's', 'n', 'e', 's', 's', 'e', 's',
0x10, 's', 'e', 'm', 'i', 'p', 'a', 't', 'h', 'o', 'l', 'o', 'g', 'i', 'c', 'a', 'l',
0x10, 't', 'o', 'm', 'f', 'o', 'o', 'l', 'i', 's', 'h', 'n', 'e', 's', 's', 'e', 's',
0x10, 'u', 'n', 'd', 'e', 'r', 'c', 'a', 'p', 'i', 't', 'a', 'l', 'i', 'z', 'e', 'd',
0x10, 'v', 'e', 'c', 't', 'o', 'r', 'c', 'a', 'r', 'd', 'i', 'o', 'g', 'r', 'a', 'm',
0x10, 'w', 'e', 'a', 't', 'h', 'e', 'r', 'p', 'r', 'o', 'o', 'f', 'n', 'e', 's', 's',
0x0F, 'r', 'e', 'a', 's', 'o', 'n', 'l', 'e', 's', 's', 'n', 'e', 's', 's', 'e',
0x00,
/* A */ 0x00, 0x01,
/* IN */ 0x00, 0x01
@ -823,12 +818,12 @@ TEST(packet_query_single_long_domain) {
ASSERT_EQ(dns_question_size(packet->question), 1u);
ASSERT_EQ(dns_answer_size(packet->answer), 0u);
key = dns_resource_key_new(DNS_CLASS_IN, DNS_TYPE_A,
"absorptivenesses.calligraphically.deacidifications.ecophysiological."
"falsifiabilities.heterochromatism.icositetrahedron.journalistically."
"kinaesthetically.lactovegetarians.misinterpretable.nitrosylsulfuric."
"objectlessnesses.partridgeberries.reasonlessnesses.semipathological."
"tomfoolishnesses.undercapitalized.vectorcardiogram.weatherproofness");
key = dns_resource_key_new(
DNS_CLASS_IN, DNS_TYPE_A,
"absorptivenesses.calligraphically.deacidifications.ecophysiological."
"falsifiabilities.heterochromatism.icositetrahedron.journalistically."
"kinaesthetically.lactovegetarians.misinterpretable.nitrosylsulfuric."
"objectlessnesses.partridgeberries.reasonlessnesse");
ASSERT_NOT_NULL(key);
ASSERT_TRUE(dns_question_contains_key(packet->question, key));
@ -4777,4 +4772,78 @@ TEST(format_dns_svc_param_key) {
ASSERT_STREQ(str, "ohttp");
}
TEST(overlong_domain) {
_cleanup_(dns_packet_unrefp) DnsPacket *packet = NULL;
ASSERT_OK(dns_packet_new(&packet, DNS_PROTOCOL_DNS, 0, DNS_PACKET_SIZE_MAX));
ASSERT_NOT_NULL(packet);
dns_packet_truncate(packet, 0);
const uint8_t data[] = {
0x00, 0x42, 0x00, 0x00,
0x00, 0x01, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
63, '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', '0', '1', '2',
63, '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', '0', '1', '2',
63, '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', '0', '1', '2',
63, '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', '0', '1', '2',
0x00,
0x00, DNS_TYPE_A,
0x00, DNS_CLASS_IN,
};
ASSERT_OK(dns_packet_append_blob(packet, data, sizeof(data), NULL));
ASSERT_OK(dns_packet_validate_query(packet));
_cleanup_(dns_resource_key_unrefp) DnsResourceKey *key = NULL;
ASSERT_ERROR(dns_packet_read_key(packet, &key, NULL, NULL), EBADMSG);
const uint8_t data2[] = {
0x00, 0x42, 0x00, 0x00,
0x00, 0x01, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
63, '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', '0', '1', '2',
63, '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', '0', '1', '2',
63, '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', '0', '1', '2',
62, '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', '0', '1',
0x00,
0x00, DNS_TYPE_A,
0x00, DNS_CLASS_IN,
};
packet = dns_packet_unref(packet);
ASSERT_OK(dns_packet_new(&packet, DNS_PROTOCOL_DNS, 0, DNS_PACKET_SIZE_MAX));
ASSERT_NOT_NULL(packet);
dns_packet_truncate(packet, 0);
ASSERT_OK(dns_packet_append_blob(packet, data2, sizeof(data2), NULL));
ASSERT_OK(dns_packet_validate_query(packet));
ASSERT_ERROR(dns_packet_read_key(packet, &key, NULL, NULL), EBADMSG);
const uint8_t data3[] = {
0x00, 0x42, 0x00, 0x00,
0x00, 0x01, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
63, '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', '0', '1', '2',
63, '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', '0', '1', '2',
63, '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', '0', '1', '2',
61, '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', '0',
0x00,
0x00, DNS_TYPE_A,
0x00, DNS_CLASS_IN,
};
packet = dns_packet_unref(packet);
ASSERT_OK(dns_packet_new(&packet, DNS_PROTOCOL_DNS, 0, DNS_PACKET_SIZE_MAX));
ASSERT_NOT_NULL(packet);
dns_packet_truncate(packet, 0);
ASSERT_OK(dns_packet_append_blob(packet, data3, sizeof(data3), NULL));
ASSERT_OK(dns_packet_validate_query(packet));
ASSERT_OK(dns_packet_read_key(packet, &key, NULL, NULL));
ASSERT_STREQ(dns_resource_key_name(key),
"012345678901234567890123456789012345678901234567890123456789012."
"012345678901234567890123456789012345678901234567890123456789012."
"012345678901234567890123456789012345678901234567890123456789012."
"0123456789012345678901234567890123456789012345678901234567890");
}
DEFINE_TEST_MAIN(LOG_DEBUG)

12
src/shared/dns-domain.c
View File

@ -480,17 +480,17 @@ finish:
return 0;
}
void dns_name_hash_func(const char *p, struct siphash *state) {
void dns_name_hash_func(const char *name, struct siphash *state) {
int r;
assert(p);
assert(name);
for (;;) {
for (const char *p = name;;) {
char label[DNS_LABEL_MAX+1];
r = dns_label_unescape(&p, label, sizeof label, 0);
if (r < 0)
break;
return string_hash_func(p, state); /* fallback for invalid DNS names */
if (r == 0)
break;
@ -516,13 +516,13 @@ int dns_name_compare_func(const char *a, const char *b) {
for (;;) {
char la[DNS_LABEL_MAX+1], lb[DNS_LABEL_MAX+1];
if (x == NULL && y == NULL)
if (!x && !y)
return 0;
r = dns_label_unescape_suffix(a, &x, la, sizeof(la));
q = dns_label_unescape_suffix(b, &y, lb, sizeof(lb));
if (r < 0 || q < 0)
return CMP(r, q);
return strcmp(a, b); /* if not valid DNS labels, then let's compare the whole strings as is */
r = ascii_strcasecmp_nn(la, r, lb, q);
if (r != 0)