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path: root/src/resolve/resolved-dns-packet.c
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Diffstat (limited to 'src/resolve/resolved-dns-packet.c')
-rw-r--r--src/resolve/resolved-dns-packet.c202
1 files changed, 134 insertions, 68 deletions
diff --git a/src/resolve/resolved-dns-packet.c b/src/resolve/resolved-dns-packet.c
index 12cd524c40..649e8b74e1 100644
--- a/src/resolve/resolved-dns-packet.c
+++ b/src/resolve/resolved-dns-packet.c
@@ -275,7 +275,7 @@ static void dns_packet_truncate(DnsPacket *p, size_t sz) {
if (p->size <= sz)
return;
- HASHMAP_FOREACH_KEY(s, n, p->names, i) {
+ HASHMAP_FOREACH_KEY(n, s, p->names, i) {
if (PTR_TO_SIZE(n) < sz)
continue;
@@ -761,7 +761,7 @@ int dns_packet_append_rr(DnsPacket *p, const DnsResourceRecord *rr, size_t *star
if (r < 0)
goto fail;
- r = dns_packet_append_blob(p, rr->sshfp.key, rr->sshfp.key_size, NULL);
+ r = dns_packet_append_blob(p, rr->sshfp.fingerprint, rr->sshfp.fingerprint_size, NULL);
break;
case DNS_TYPE_DNSKEY:
@@ -933,6 +933,42 @@ int dns_packet_read_blob(DnsPacket *p, void *d, size_t sz, size_t *start) {
return 0;
}
+static int dns_packet_read_memdup(
+ DnsPacket *p, size_t size,
+ void **ret, size_t *ret_size,
+ size_t *ret_start) {
+
+ const void *src;
+ size_t start;
+ int r;
+
+ assert(p);
+ assert(ret);
+
+ r = dns_packet_read(p, size, &src, &start);
+ if (r < 0)
+ return r;
+
+ if (size <= 0)
+ *ret = NULL;
+ else {
+ void *copy;
+
+ copy = memdup(src, size);
+ if (!copy)
+ return -ENOMEM;
+
+ *ret = copy;
+ }
+
+ if (ret_size)
+ *ret_size = size;
+ if (ret_start)
+ *ret_start = start;
+
+ return 0;
+}
+
int dns_packet_read_uint8(DnsPacket *p, uint8_t *ret, size_t *start) {
const void *d;
int r;
@@ -1172,9 +1208,12 @@ static int dns_packet_read_type_window(DnsPacket *p, Bitmap **types, size_t *sta
if (bitmap[i] & bitmask) {
uint16_t n;
- /* XXX: ignore pseudo-types? see RFC4034 section 4.1.2 */
n = (uint16_t) window << 8 | (uint16_t) bit;
+ /* Ignore pseudo-types. see RFC4034 section 4.1.2 */
+ if (dns_type_is_pseudo(n))
+ continue;
+
r = bitmap_set(*types, n);
if (r < 0)
goto fail;
@@ -1197,6 +1236,38 @@ fail:
return r;
}
+static int dns_packet_read_type_windows(DnsPacket *p, Bitmap **types, size_t size, size_t *start) {
+ size_t saved_rindex;
+ int r;
+
+ saved_rindex = p->rindex;
+
+ while (p->rindex < saved_rindex + size) {
+ r = dns_packet_read_type_window(p, types, NULL);
+ if (r < 0)
+ goto fail;
+
+ /* don't read past end of current RR */
+ if (p->rindex > saved_rindex + size) {
+ r = -EBADMSG;
+ goto fail;
+ }
+ }
+
+ if (p->rindex != saved_rindex + size) {
+ r = -EBADMSG;
+ goto fail;
+ }
+
+ if (start)
+ *start = saved_rindex;
+
+ return 0;
+fail:
+ dns_packet_rewind(p, saved_rindex);
+ return r;
+}
+
int dns_packet_read_key(DnsPacket *p, DnsResourceKey **ret, size_t *start) {
_cleanup_free_ char *name = NULL;
uint16_t class, type;
@@ -1239,26 +1310,6 @@ fail:
return r;
}
-static int dns_packet_read_public_key(DnsPacket *p, size_t length,
- void **dp, size_t *lengthp,
- size_t *start) {
- int r;
- const void *d;
- void *d2;
-
- r = dns_packet_read(p, length, &d, NULL);
- if (r < 0)
- return r;
-
- d2 = memdup(d, length);
- if (!d2)
- return -ENOMEM;
-
- *dp = d2;
- *lengthp = length;
- return 0;
-}
-
static bool loc_size_ok(uint8_t size) {
uint8_t m = size >> 4, e = size & 0xF;
@@ -1281,7 +1332,6 @@ int dns_packet_read_rr(DnsPacket *p, DnsResourceRecord **ret, size_t *start) {
_cleanup_(dns_resource_key_unrefp) DnsResourceKey *key = NULL;
size_t saved_rindex, offset;
uint16_t rdlength;
- const void *d;
int r;
assert(p);
@@ -1492,12 +1542,19 @@ int dns_packet_read_rr(DnsPacket *p, DnsResourceRecord **ret, size_t *start) {
if (r < 0)
goto fail;
- r = dns_packet_read_public_key(p, rdlength - 4,
- &rr->ds.digest, &rr->ds.digest_size,
- NULL);
+ r = dns_packet_read_memdup(p, rdlength - 4,
+ &rr->ds.digest, &rr->ds.digest_size,
+ NULL);
if (r < 0)
goto fail;
+ 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;
+ }
+
break;
case DNS_TYPE_SSHFP:
r = dns_packet_read_uint8(p, &rr->sshfp.algorithm, NULL);
@@ -1508,9 +1565,17 @@ int dns_packet_read_rr(DnsPacket *p, DnsResourceRecord **ret, size_t *start) {
if (r < 0)
goto fail;
- r = dns_packet_read_public_key(p, rdlength - 2,
- &rr->sshfp.key, &rr->sshfp.key_size,
- NULL);
+ r = dns_packet_read_memdup(p, rdlength - 2,
+ &rr->sshfp.fingerprint, &rr->sshfp.fingerprint_size,
+ NULL);
+
+ 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;
+ }
+
break;
case DNS_TYPE_DNSKEY: {
@@ -1539,9 +1604,17 @@ int dns_packet_read_rr(DnsPacket *p, DnsResourceRecord **ret, size_t *start) {
if (r < 0)
goto fail;
- r = dns_packet_read_public_key(p, rdlength - 4,
- &rr->dnskey.key, &rr->dnskey.key_size,
- NULL);
+ r = dns_packet_read_memdup(p, rdlength - 4,
+ &rr->dnskey.key, &rr->dnskey.key_size,
+ NULL);
+
+ 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;
+ }
+
break;
}
@@ -1578,9 +1651,17 @@ int dns_packet_read_rr(DnsPacket *p, DnsResourceRecord **ret, size_t *start) {
if (r < 0)
goto fail;
- r = dns_packet_read_public_key(p, offset + rdlength - p->rindex,
- &rr->rrsig.signature, &rr->rrsig.signature_size,
- NULL);
+ r = dns_packet_read_memdup(p, offset + rdlength - p->rindex,
+ &rr->rrsig.signature, &rr->rrsig.signature_size,
+ NULL);
+
+ 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;
+ }
+
break;
case DNS_TYPE_NSEC:
@@ -1588,11 +1669,12 @@ int dns_packet_read_rr(DnsPacket *p, DnsResourceRecord **ret, size_t *start) {
if (r < 0)
goto fail;
- while (p->rindex != offset + rdlength) {
- r = dns_packet_read_type_window(p, &rr->nsec.types, NULL);
- if (r < 0)
- goto fail;
- }
+ r = dns_packet_read_type_windows(p, &rr->nsec.types, offset + rdlength - p->rindex, NULL);
+ if (r < 0)
+ goto fail;
+
+ /* NSEC RRs with empty bitmpas makes no sense, but the RFC does not explicitly forbid them
+ so we allow it */
break;
@@ -1611,57 +1693,41 @@ int dns_packet_read_rr(DnsPacket *p, DnsResourceRecord **ret, size_t *start) {
if (r < 0)
goto fail;
+ /* this may be zero */
r = dns_packet_read_uint8(p, &size, NULL);
if (r < 0)
goto fail;
- rr->nsec3.salt_size = size;
-
- r = dns_packet_read_blob(p, &d, rr->nsec3.salt_size, NULL);
+ r = dns_packet_read_memdup(p, size, &rr->nsec3.salt, &rr->nsec3.salt_size, NULL);
if (r < 0)
goto fail;
- rr->nsec3.salt = memdup(d, rr->nsec3.salt_size);
- if (!rr->nsec3.salt) {
- r = -ENOMEM;
- goto fail;
- }
-
r = dns_packet_read_uint8(p, &size, NULL);
if (r < 0)
goto fail;
- rr->nsec3.next_hashed_name_size = size;
-
- r = dns_packet_read(p, rr->nsec3.next_hashed_name_size, &d, NULL);
- if (r < 0)
+ if (size <= 0) {
+ r = -EBADMSG;
goto fail;
+ }
- rr->nsec3.next_hashed_name = memdup(d, rr->nsec3.next_hashed_name_size);
- if (!rr->nsec3.next_hashed_name) {
- r = -ENOMEM;
+ r = dns_packet_read_memdup(p, size, &rr->nsec3.next_hashed_name, &rr->nsec3.next_hashed_name_size, NULL);
+ if (r < 0)
goto fail;
- }
- r = dns_packet_append_types(p, rr->nsec3.types, NULL);
+ r = dns_packet_read_type_windows(p, &rr->nsec.types, offset + rdlength - p->rindex, NULL);
if (r < 0)
goto fail;
+ /* empty non-terminals can have NSEC3 records, so empty bitmaps are allowed */
+
break;
}
default:
unparseable:
- r = dns_packet_read(p, rdlength, &d, NULL);
+ r = dns_packet_read_memdup(p, rdlength, &rr->generic.data, &rr->generic.size, NULL);
if (r < 0)
goto fail;
-
- rr->generic.data = memdup(d, rdlength);
- if (!rr->generic.data) {
- r = -ENOMEM;
- goto fail;
- }
-
- rr->generic.size = rdlength;
break;
}
if (r < 0)
generated by cgit v1.2.3-54-g00ecf (git 2.45.2) at 2024-12-19 08:07:51 +0000