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-rw-r--r--net/netfilter/nf_conntrack_sip.c152
-rw-r--r--net/netfilter/nf_nat_sip.c1
2 files changed, 119 insertions, 34 deletions
diff --git a/net/netfilter/nf_conntrack_sip.c b/net/netfilter/nf_conntrack_sip.c
index 182cfb119448..1eb55907d470 100644
--- a/net/netfilter/nf_conntrack_sip.c
+++ b/net/netfilter/nf_conntrack_sip.c
@@ -181,6 +181,57 @@ static int sip_parse_addr(const struct nf_conn *ct, const char *cp,
return 1;
}
+/* Parse optional port number after IP address.
+ * Returns false on malformed input, true otherwise.
+ * If port is non-NULL, stores parsed port in network byte order.
+ * If no port is present, sets *port to default SIP port.
+ */
+static bool sip_parse_port(const char *dptr, const char **endp,
+ const char *limit, __be16 *port)
+{
+ unsigned int p = 0;
+ int len = 0;
+
+ if (dptr >= limit)
+ return false;
+
+ if (*dptr != ':') {
+ if (port)
+ *port = htons(SIP_PORT);
+ if (endp)
+ *endp = dptr;
+ return true;
+ }
+
+ dptr++; /* skip ':' */
+
+ while (dptr < limit && isdigit(*dptr)) {
+ p = p * 10 + (*dptr - '0');
+ dptr++;
+ len++;
+ if (len > 5) /* max "65535" */
+ return false;
+ }
+
+ if (len == 0)
+ return false;
+
+ /* reached limit while parsing port */
+ if (dptr >= limit)
+ return false;
+
+ if (p < 1024 || p > 65535)
+ return false;
+
+ if (port)
+ *port = htons(p);
+
+ if (endp)
+ *endp = dptr;
+
+ return true;
+}
+
/* skip ip address. returns its length. */
static int epaddr_len(const struct nf_conn *ct, const char *dptr,
const char *limit, int *shift)
@@ -193,11 +244,8 @@ static int epaddr_len(const struct nf_conn *ct, const char *dptr,
return 0;
}
- /* Port number */
- if (*dptr == ':') {
- dptr++;
- dptr += digits_len(ct, dptr, limit, shift);
- }
+ if (!sip_parse_port(dptr, &dptr, limit, NULL))
+ return 0;
return dptr - aux;
}
@@ -228,6 +276,51 @@ static int skp_epaddr_len(const struct nf_conn *ct, const char *dptr,
return epaddr_len(ct, dptr, limit, shift);
}
+/* simple_strtoul stops after first non-number character.
+ * But as we're not dealing with c-strings, we can't rely on
+ * hitting \r,\n,\0 etc. before moving past end of buffer.
+ *
+ * This is a variant of simple_strtoul, but doesn't require
+ * a c-string.
+ *
+ * If value exceeds UINT_MAX, 0 is returned.
+ */
+static unsigned int sip_strtouint(const char *cp, unsigned int len, char **endp)
+{
+ const unsigned int max = sizeof("4294967295");
+ unsigned int olen = len;
+ const char *s = cp;
+ u64 result = 0;
+
+ if (len > max)
+ len = max;
+
+ while (olen > 0 && isdigit(*s)) {
+ unsigned int value;
+
+ if (len == 0)
+ goto err;
+
+ value = *s - '0';
+ result = result * 10 + value;
+
+ if (result > UINT_MAX)
+ goto err;
+ s++;
+ len--;
+ olen--;
+ }
+
+ if (endp)
+ *endp = (char *)s;
+
+ return result;
+err:
+ if (endp)
+ *endp = (char *)cp;
+ return 0;
+}
+
/* Parse a SIP request line of the form:
*
* Request-Line = Method SP Request-URI SP SIP-Version CRLF
@@ -241,7 +334,6 @@ int ct_sip_parse_request(const struct nf_conn *ct,
{
const char *start = dptr, *limit = dptr + datalen, *end;
unsigned int mlen;
- unsigned int p;
int shift = 0;
/* Skip method and following whitespace */
@@ -267,14 +359,8 @@ int ct_sip_parse_request(const struct nf_conn *ct,
if (!sip_parse_addr(ct, dptr, &end, addr, limit, true))
return -1;
- if (end < limit && *end == ':') {
- end++;
- p = simple_strtoul(end, (char **)&end, 10);
- if (p < 1024 || p > 65535)
- return -1;
- *port = htons(p);
- } else
- *port = htons(SIP_PORT);
+ if (!sip_parse_port(end, &end, limit, port))
+ return -1;
if (end == dptr)
return 0;
@@ -509,7 +595,6 @@ int ct_sip_parse_header_uri(const struct nf_conn *ct, const char *dptr,
union nf_inet_addr *addr, __be16 *port)
{
const char *c, *limit = dptr + datalen;
- unsigned int p;
int ret;
ret = ct_sip_walk_headers(ct, dptr, dataoff ? *dataoff : 0, datalen,
@@ -520,14 +605,8 @@ int ct_sip_parse_header_uri(const struct nf_conn *ct, const char *dptr,
if (!sip_parse_addr(ct, dptr + *matchoff, &c, addr, limit, true))
return -1;
- if (*c == ':') {
- c++;
- p = simple_strtoul(c, (char **)&c, 10);
- if (p < 1024 || p > 65535)
- return -1;
- *port = htons(p);
- } else
- *port = htons(SIP_PORT);
+ if (!sip_parse_port(c, &c, limit, port))
+ return -1;
if (dataoff)
*dataoff = c - dptr;
@@ -609,7 +688,7 @@ int ct_sip_parse_numerical_param(const struct nf_conn *ct, const char *dptr,
return 0;
start += strlen(name);
- *val = simple_strtoul(start, &end, 0);
+ *val = sip_strtouint(start, limit - start, (char **)&end);
if (start == end)
return -1;
if (matchoff && matchlen) {
@@ -1064,6 +1143,8 @@ static int process_sdp(struct sk_buff *skb, unsigned int protoff,
mediaoff = sdpoff;
for (i = 0; i < ARRAY_SIZE(sdp_media_types); ) {
+ char *end;
+
if (ct_sip_get_sdp_header(ct, *dptr, mediaoff, *datalen,
SDP_HDR_MEDIA, SDP_HDR_UNSPEC,
&mediaoff, &medialen) <= 0)
@@ -1079,8 +1160,8 @@ static int process_sdp(struct sk_buff *skb, unsigned int protoff,
mediaoff += t->len;
medialen -= t->len;
- port = simple_strtoul(*dptr + mediaoff, NULL, 10);
- if (port == 0)
+ port = sip_strtouint(*dptr + mediaoff, *datalen - mediaoff, (char **)&end);
+ if (port == 0 || *dptr + mediaoff == end)
continue;
if (port < 1024 || port > 65535) {
nf_ct_helper_log(skb, ct, "wrong port %u", port);
@@ -1254,7 +1335,7 @@ static int process_register_request(struct sk_buff *skb, unsigned int protoff,
*/
if (ct_sip_get_header(ct, *dptr, 0, *datalen, SIP_HDR_EXPIRES,
&matchoff, &matchlen) > 0)
- expires = simple_strtoul(*dptr + matchoff, NULL, 10);
+ expires = sip_strtouint(*dptr + matchoff, *datalen - matchoff, NULL);
ret = ct_sip_parse_header_uri(ct, *dptr, NULL, *datalen,
SIP_HDR_CONTACT, NULL,
@@ -1358,7 +1439,7 @@ static int process_register_response(struct sk_buff *skb, unsigned int protoff,
if (ct_sip_get_header(ct, *dptr, 0, *datalen, SIP_HDR_EXPIRES,
&matchoff, &matchlen) > 0)
- expires = simple_strtoul(*dptr + matchoff, NULL, 10);
+ expires = sip_strtouint(*dptr + matchoff, *datalen - matchoff, NULL);
while (1) {
unsigned int c_expires = expires;
@@ -1418,10 +1499,12 @@ static int process_sip_response(struct sk_buff *skb, unsigned int protoff,
struct nf_conn *ct = nf_ct_get(skb, &ctinfo);
unsigned int matchoff, matchlen, matchend;
unsigned int code, cseq, i;
+ char *end;
if (*datalen < strlen("SIP/2.0 200"))
return NF_ACCEPT;
- code = simple_strtoul(*dptr + strlen("SIP/2.0 "), NULL, 10);
+ code = sip_strtouint(*dptr + strlen("SIP/2.0 "),
+ *datalen - strlen("SIP/2.0 "), NULL);
if (!code) {
nf_ct_helper_log(skb, ct, "cannot get code");
return NF_DROP;
@@ -1432,8 +1515,8 @@ static int process_sip_response(struct sk_buff *skb, unsigned int protoff,
nf_ct_helper_log(skb, ct, "cannot parse cseq");
return NF_DROP;
}
- cseq = simple_strtoul(*dptr + matchoff, NULL, 10);
- if (!cseq && *(*dptr + matchoff) != '0') {
+ cseq = sip_strtouint(*dptr + matchoff, *datalen - matchoff, (char **)&end);
+ if (*dptr + matchoff == end) {
nf_ct_helper_log(skb, ct, "cannot get cseq");
return NF_DROP;
}
@@ -1482,6 +1565,7 @@ static int process_sip_request(struct sk_buff *skb, unsigned int protoff,
for (i = 0; i < ARRAY_SIZE(sip_handlers); i++) {
const struct sip_handler *handler;
+ char *end;
handler = &sip_handlers[i];
if (handler->request == NULL)
@@ -1498,8 +1582,8 @@ static int process_sip_request(struct sk_buff *skb, unsigned int protoff,
nf_ct_helper_log(skb, ct, "cannot parse cseq");
return NF_DROP;
}
- cseq = simple_strtoul(*dptr + matchoff, NULL, 10);
- if (!cseq && *(*dptr + matchoff) != '0') {
+ cseq = sip_strtouint(*dptr + matchoff, *datalen - matchoff, (char **)&end);
+ if (*dptr + matchoff == end) {
nf_ct_helper_log(skb, ct, "cannot get cseq");
return NF_DROP;
}
@@ -1575,7 +1659,7 @@ static int sip_help_tcp(struct sk_buff *skb, unsigned int protoff,
&matchoff, &matchlen) <= 0)
break;
- clen = simple_strtoul(dptr + matchoff, (char **)&end, 10);
+ clen = sip_strtouint(dptr + matchoff, datalen - matchoff, (char **)&end);
if (dptr + matchoff == end)
break;
diff --git a/net/netfilter/nf_nat_sip.c b/net/netfilter/nf_nat_sip.c
index c845b6d1a2bd..9fbfc6bff0c2 100644
--- a/net/netfilter/nf_nat_sip.c
+++ b/net/netfilter/nf_nat_sip.c
@@ -246,6 +246,7 @@ static unsigned int nf_nat_sip(struct sk_buff *skb, unsigned int protoff,
if (ct_sip_parse_numerical_param(ct, *dptr, matchend, *datalen,
"rport=", &poff, &plen,
&n) > 0 &&
+ n >= 1024 && n <= 65535 &&
htons(n) == ct->tuplehash[dir].tuple.dst.u.udp.port &&
htons(n) != ct->tuplehash[!dir].tuple.src.u.udp.port) {
__be16 p = ct->tuplehash[!dir].tuple.src.u.udp.port;
generated by cgit v1.2.3 (git 2.0.4) at 2026-05-08 21:53:50 +0000