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authorLennart Poettering <lennart@poettering.net>2015-07-23 04:04:19 +0200
committerLennart Poettering <lennart@poettering.net>2015-07-23 04:50:19 +0200
commitf5430a3ef308f3a102899fcaf7fbece757082f2a (patch)
treeca31992b7c4fff12ebcf2ec4f254a2b964b0ccd6 /src
parent6aafa9483d167f55a50e01f4dc5984866f12c8ec (diff)
resolve: unify memdup() code when parsing RRs
Let's make dns_packet_read_public_key() more generic by renaming it to dns_packet_read_memdup() (which more accurately describes what it does...). Then, patch all cases where we memdup() RR data to use this new call. This specifically checks for zero-length objects, and handles them gracefully. It will set zero length payload fields as a result. Special care should be taken to ensure that any code using this call can handle the returned allocated field to be NULL if the size is specified as 0!
Diffstat (limited to 'src')
-rw-r--r--src/resolve/resolved-dns-packet.c111
-rw-r--r--src/resolve/resolved-dns-rr.c6
-rw-r--r--src/resolve/resolved-dns-rr.h2
3 files changed, 55 insertions, 64 deletions
diff --git a/src/resolve/resolved-dns-packet.c b/src/resolve/resolved-dns-packet.c
index b1cde4ab35..563b9563e9 100644
--- a/src/resolve/resolved-dns-packet.c
+++ b/src/resolve/resolved-dns-packet.c
@@ -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;
@@ -1239,26 +1275,6 @@ 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 +1297,6 @@ 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);
@@ -1492,9 +1507,9 @@ 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;
@@ -1508,9 +1523,9 @@ 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.key, &rr->sshfp.key_size,
+ NULL);
break;
case DNS_TYPE_DNSKEY: {
@@ -1539,9 +1554,9 @@ 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);
break;
}
@@ -1578,9 +1593,9 @@ 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);
break;
case DNS_TYPE_NSEC:
@@ -1615,34 +1630,18 @@ int dns_packet_read_rr(DnsPacket *p, DnsResourceRecord **ret, size_t *start) {
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);
+ r = dns_packet_read_memdup(p, size, &rr->nsec3.next_hashed_name, &rr->nsec3.next_hashed_name_size, NULL);
if (r < 0)
goto fail;
- rr->nsec3.next_hashed_name = memdup(d, rr->nsec3.next_hashed_name_size);
- if (!rr->nsec3.next_hashed_name) {
- r = -ENOMEM;
- goto fail;
- }
-
r = dns_packet_append_types(p, rr->nsec3.types, NULL);
if (r < 0)
goto fail;
@@ -1651,17 +1650,9 @@ int dns_packet_read_rr(DnsPacket *p, DnsResourceRecord **ret, size_t *start) {
}
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)
diff --git a/src/resolve/resolved-dns-rr.c b/src/resolve/resolved-dns-rr.c
index 859b3f7339..e489688b85 100644
--- a/src/resolve/resolved-dns-rr.c
+++ b/src/resolve/resolved-dns-rr.c
@@ -776,7 +776,7 @@ int dns_resource_record_to_string(const DnsResourceRecord *rr, char **ret) {
case DNS_TYPE_NSEC3: {
_cleanup_free_ char *salt = NULL, *hash = NULL;
- if (rr->nsec3.salt_size) {
+ if (rr->nsec3.salt_size > 0) {
salt = hexmem(rr->nsec3.salt, rr->nsec3.salt_size);
if (!salt)
return -ENOMEM;
@@ -795,7 +795,7 @@ int dns_resource_record_to_string(const DnsResourceRecord *rr, char **ret) {
rr->nsec3.algorithm,
rr->nsec3.flags,
rr->nsec3.iterations,
- rr->nsec3.salt_size ? salt : "-",
+ rr->nsec3.salt_size > 0 ? salt : "-",
hash,
t);
if (r < 0)
@@ -809,7 +809,7 @@ int dns_resource_record_to_string(const DnsResourceRecord *rr, char **ret) {
if (!t)
return -ENOMEM;
- r = asprintf(&s, "%s \\# %"PRIu8" %s", k, rr->generic.size, t);
+ r = asprintf(&s, "%s \\# %zu %s", k, rr->generic.size, t);
if (r < 0)
return -ENOMEM;
break;
diff --git a/src/resolve/resolved-dns-rr.h b/src/resolve/resolved-dns-rr.h
index bdd5a5c824..dc51126f97 100644
--- a/src/resolve/resolved-dns-rr.h
+++ b/src/resolve/resolved-dns-rr.h
@@ -53,7 +53,7 @@ struct DnsResourceRecord {
union {
struct {
void *data;
- uint16_t size;
+ size_t size;
} generic;
struct {