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authorPatrick Valsecchi <pvalsecc@cisco.com>2013-04-15 20:28:01 (GMT)
committerDaniel Stenberg <daniel@haxx.se>2013-04-15 20:28:01 (GMT)
commit148c8e0353d93d7c00003da5a0b8eda2079bc8b9 (patch)
tree2b9dca4769d2fb1b380ac8b6beae6b1183d3b402
parent2004a7a1115e25128170e40470eba8603f7080da (diff)
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protocol parsing: check input data stricter
... so that bad length fields aren't blindly accepted Bug: http://c-ares.haxx.se/mail/c-ares-archive-2013-04/0016.shtml
-rw-r--r--ares_expand_name.c2
-rw-r--r--ares_parse_a_reply.c6
-rw-r--r--ares_parse_aaaa_reply.c6
-rw-r--r--ares_parse_mx_reply.c5
-rw-r--r--ares_parse_naptr_reply.c5
-rw-r--r--ares_parse_ns_reply.c6
-rw-r--r--ares_parse_ptr_reply.c8
-rw-r--r--ares_parse_srv_reply.c5
-rw-r--r--ares_parse_txt_reply.c11
9 files changed, 52 insertions, 2 deletions
diff --git a/ares_expand_name.c b/ares_expand_name.c
index a66dfa9..2aa12bc 100644
--- a/ares_expand_name.c
+++ b/ares_expand_name.c
@@ -143,7 +143,7 @@ static int name_length(const unsigned char *encoded, const unsigned char *abuf,
int n = 0, offset, indir = 0;
/* Allow the caller to pass us abuf + alen and have us check for it. */
- if (encoded == abuf + alen)
+ if (encoded >= abuf + alen)
return -1;
while (*encoded)
diff --git a/ares_parse_a_reply.c b/ares_parse_a_reply.c
index 9683ef5..a3ed69e 100644
--- a/ares_parse_a_reply.c
+++ b/ares_parse_a_reply.c
@@ -136,6 +136,12 @@ int ares_parse_a_reply(const unsigned char *abuf, int alen,
rr_len = DNS_RR_LEN(aptr);
rr_ttl = DNS_RR_TTL(aptr);
aptr += RRFIXEDSZ;
+ if (aptr + rr_len > abuf + alen)
+ {
+ free(rr_name);
+ status = ARES_EBADRESP;
+ break;
+ }
if (rr_class == C_IN && rr_type == T_A
&& rr_len == sizeof(struct in_addr)
diff --git a/ares_parse_aaaa_reply.c b/ares_parse_aaaa_reply.c
index 7731249..a34a307 100644
--- a/ares_parse_aaaa_reply.c
+++ b/ares_parse_aaaa_reply.c
@@ -136,6 +136,12 @@ int ares_parse_aaaa_reply(const unsigned char *abuf, int alen,
rr_len = DNS_RR_LEN(aptr);
rr_ttl = DNS_RR_TTL(aptr);
aptr += RRFIXEDSZ;
+ if (aptr + rr_len > abuf + alen)
+ {
+ free(rr_name);
+ status = ARES_EBADRESP;
+ break;
+ }
if (rr_class == C_IN && rr_type == T_AAAA
&& rr_len == sizeof(struct ares_in6_addr)
diff --git a/ares_parse_mx_reply.c b/ares_parse_mx_reply.c
index 32d3af4..95400dd 100644
--- a/ares_parse_mx_reply.c
+++ b/ares_parse_mx_reply.c
@@ -100,6 +100,11 @@ ares_parse_mx_reply (const unsigned char *abuf, int alen,
rr_class = DNS_RR_CLASS (aptr);
rr_len = DNS_RR_LEN (aptr);
aptr += RRFIXEDSZ;
+ if (aptr + rr_len > abuf + alen)
+ {
+ status = ARES_EBADRESP;
+ break;
+ }
/* Check if we are really looking at a MX record */
if (rr_class == C_IN && rr_type == T_MX)
diff --git a/ares_parse_naptr_reply.c b/ares_parse_naptr_reply.c
index 9315df7..4935366 100644
--- a/ares_parse_naptr_reply.c
+++ b/ares_parse_naptr_reply.c
@@ -105,6 +105,11 @@ ares_parse_naptr_reply (const unsigned char *abuf, int alen,
rr_class = DNS_RR_CLASS (aptr);
rr_len = DNS_RR_LEN (aptr);
aptr += RRFIXEDSZ;
+ if (aptr + rr_len > abuf + alen)
+ {
+ status = ARES_EBADRESP;
+ break;
+ }
/* Check if we are really looking at a NAPTR record */
if (rr_class == C_IN && rr_type == T_NAPTR)
diff --git a/ares_parse_ns_reply.c b/ares_parse_ns_reply.c
index 553f253..d331e67 100644
--- a/ares_parse_ns_reply.c
+++ b/ares_parse_ns_reply.c
@@ -105,6 +105,12 @@ int ares_parse_ns_reply( const unsigned char* abuf, int alen,
rr_class = DNS_RR_CLASS( aptr );
rr_len = DNS_RR_LEN( aptr );
aptr += RRFIXEDSZ;
+ if (aptr + rr_len > abuf + alen)
+ {
+ free(rr_name);
+ status = ARES_EBADRESP;
+ break;
+ }
if ( rr_class == C_IN && rr_type == T_NS )
{
diff --git a/ares_parse_ptr_reply.c b/ares_parse_ptr_reply.c
index b505b92..df21e40 100644
--- a/ares_parse_ptr_reply.c
+++ b/ares_parse_ptr_reply.c
@@ -103,6 +103,12 @@ int ares_parse_ptr_reply(const unsigned char *abuf, int alen, const void *addr,
rr_class = DNS_RR_CLASS(aptr);
rr_len = DNS_RR_LEN(aptr);
aptr += RRFIXEDSZ;
+ if (aptr + rr_len > abuf + alen)
+ {
+ free(rr_name);
+ status = ARES_EBADRESP;
+ break;
+ }
if (rr_class == C_IN && rr_type == T_PTR
&& strcasecmp(rr_name, ptrname) == 0)
@@ -203,7 +209,7 @@ int ares_parse_ptr_reply(const unsigned char *abuf, int alen, const void *addr,
status = ARES_ENOMEM;
}
for (i=0 ; i<aliascnt ; i++)
- if (aliases[i])
+ if (aliases[i])
free(aliases[i]);
free(aliases);
if (hostname)
diff --git a/ares_parse_srv_reply.c b/ares_parse_srv_reply.c
index 9f61f19..0739c27 100644
--- a/ares_parse_srv_reply.c
+++ b/ares_parse_srv_reply.c
@@ -105,6 +105,11 @@ ares_parse_srv_reply (const unsigned char *abuf, int alen,
rr_class = DNS_RR_CLASS (aptr);
rr_len = DNS_RR_LEN (aptr);
aptr += RRFIXEDSZ;
+ if (aptr + rr_len > abuf + alen)
+ {
+ status = ARES_EBADRESP;
+ break;
+ }
/* Check if we are really looking at a SRV record */
if (rr_class == C_IN && rr_type == T_SRV)
diff --git a/ares_parse_txt_reply.c b/ares_parse_txt_reply.c
index dcc6473..3a43d6a 100644
--- a/ares_parse_txt_reply.c
+++ b/ares_parse_txt_reply.c
@@ -106,6 +106,11 @@ ares_parse_txt_reply (const unsigned char *abuf, int alen,
rr_class = DNS_RR_CLASS (aptr);
rr_len = DNS_RR_LEN (aptr);
aptr += RRFIXEDSZ;
+ if (aptr + rr_len > abuf + alen)
+ {
+ status = ARES_EBADRESP;
+ break;
+ }
/* Check if we are really looking at a TXT record */
if (rr_class == C_IN && rr_type == T_TXT)
@@ -144,6 +149,12 @@ ares_parse_txt_reply (const unsigned char *abuf, int alen,
strptr += substr_len + 1;
}
+ if (strptr != (aptr + rr_len))
+ {
+ status = ARES_EBADRESP;
+ break;
+ }
+
/* Including null byte */
txt_curr->txt = malloc (txt_curr->length + 1);
if (txt_curr->txt == NULL)