Commit ac367740 authored by Patrick McHardy's avatar Patrick McHardy Committed by David S. Miller
Browse files

[NETFILTER]: nf_conntrack_sip: kill request URI "header" definitions



The request URI is not a header and needs to be treated differently than
real SIP headers. Add a seperate function for parsing it and get rid of
the POS_REQ_URI/POS_REG_REQ_URI definitions.
Signed-off-by: default avatarPatrick McHardy <kaber@trash.net>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 3e9b4600
......@@ -6,8 +6,6 @@
#define SIP_TIMEOUT 3600
enum sip_header_pos {
POS_REG_REQ_URI,
POS_REQ_URI,
POS_FROM,
POS_TO,
POS_VIA,
......@@ -59,6 +57,9 @@ extern unsigned int (*nf_nat_sdp_hook)(struct sk_buff *skb,
unsigned int *datalen,
struct nf_conntrack_expect *exp);
extern int ct_sip_parse_request(const struct nf_conn *ct,
const char *dptr, unsigned int datalen,
unsigned int *matchoff, unsigned int *matchlen);
extern int ct_sip_get_info(const struct nf_conn *ct, const char *dptr,
size_t dlen, unsigned int *matchoff,
unsigned int *matchlen, enum sip_header_pos pos);
......
......@@ -78,20 +78,17 @@ static unsigned int mangle_packet(struct sk_buff *skb,
return 1;
}
static int map_sip_addr(struct sk_buff *skb,
const char **dptr, unsigned int *datalen,
enum sip_header_pos pos, struct addr_map *map)
static int map_addr(struct sk_buff *skb,
const char **dptr, unsigned int *datalen,
unsigned int matchoff, unsigned int matchlen,
struct addr_map *map)
{
enum ip_conntrack_info ctinfo;
struct nf_conn *ct = nf_ct_get(skb, &ctinfo);
struct nf_conn *ct __maybe_unused = nf_ct_get(skb, &ctinfo);
enum ip_conntrack_dir dir = CTINFO2DIR(ctinfo);
unsigned int matchlen, matchoff, addrlen;
unsigned int addrlen;
char *addr;
if (ct_sip_get_info(ct, *dptr, *datalen, &matchoff, &matchlen,
pos) <= 0)
return 1;
if ((matchlen == map->addr[dir].srciplen ||
matchlen == map->addr[dir].srclen) &&
strncmp(*dptr + matchoff, map->addr[dir].src, matchlen) == 0) {
......@@ -109,13 +106,27 @@ static int map_sip_addr(struct sk_buff *skb,
addr, addrlen);
}
static int map_sip_addr(struct sk_buff *skb,
const char **dptr, unsigned int *datalen,
enum sip_header_pos pos, struct addr_map *map)
{
enum ip_conntrack_info ctinfo;
struct nf_conn *ct = nf_ct_get(skb, &ctinfo);
unsigned int matchlen, matchoff;
if (ct_sip_get_info(ct, *dptr, *datalen, &matchoff, &matchlen,
pos) <= 0)
return 1;
return map_addr(skb, dptr, datalen, matchoff, matchlen, map);
}
static unsigned int ip_nat_sip(struct sk_buff *skb,
const char **dptr, unsigned int *datalen)
{
enum ip_conntrack_info ctinfo;
struct nf_conn *ct = nf_ct_get(skb, &ctinfo);
enum sip_header_pos pos;
struct addr_map map;
unsigned int matchoff, matchlen;
if (*datalen < strlen("SIP/2.0"))
return NF_ACCEPT;
......@@ -124,18 +135,9 @@ static unsigned int ip_nat_sip(struct sk_buff *skb,
/* Basic rules: requests and responses. */
if (strnicmp(*dptr, "SIP/2.0", strlen("SIP/2.0")) != 0) {
/* 10.2: Constructing the REGISTER Request:
*
* The "userinfo" and "@" components of the SIP URI MUST NOT
* be present.
*/
if (*datalen >= strlen("REGISTER") &&
strnicmp(*dptr, "REGISTER", strlen("REGISTER")) == 0)
pos = POS_REG_REQ_URI;
else
pos = POS_REQ_URI;
if (!map_sip_addr(skb, dptr, datalen, pos, &map))
if (ct_sip_parse_request(ct, *dptr, *datalen,
&matchoff, &matchlen) > 0 &&
!map_addr(skb, dptr, datalen, matchoff, matchlen, &map))
return NF_DROP;
}
......
......@@ -65,20 +65,6 @@ struct sip_header_nfo {
};
static const struct sip_header_nfo ct_sip_hdrs[] = {
[POS_REG_REQ_URI] = { /* SIP REGISTER request URI */
.lname = "sip:",
.lnlen = sizeof("sip:") - 1,
.ln_str = ":",
.ln_strlen = sizeof(":") - 1,
.match_len = epaddr_len,
},
[POS_REQ_URI] = { /* SIP request URI */
.lname = "sip:",
.lnlen = sizeof("sip:") - 1,
.ln_str = "@",
.ln_strlen = sizeof("@") - 1,
.match_len = epaddr_len,
},
[POS_FROM] = { /* SIP From header */
.lname = "From:",
.lnlen = sizeof("From:") - 1,
......@@ -164,6 +150,18 @@ const char *ct_sip_search(const char *needle, const char *haystack,
}
EXPORT_SYMBOL_GPL(ct_sip_search);
static int string_len(const struct nf_conn *ct, const char *dptr,
const char *limit, int *shift)
{
int len = 0;
while (dptr < limit && isalpha(*dptr)) {
dptr++;
len++;
}
return len;
}
static int digits_len(const struct nf_conn *ct, const char *dptr,
const char *limit, int *shift)
{
......@@ -258,6 +256,44 @@ static int skp_epaddr_len(const struct nf_conn *ct, const char *dptr,
return epaddr_len(ct, dptr, limit, shift);
}
/* Parse a SIP request line of the form:
*
* Request-Line = Method SP Request-URI SP SIP-Version CRLF
*
* and return the offset and length of the address contained in the Request-URI.
*/
int ct_sip_parse_request(const struct nf_conn *ct,
const char *dptr, unsigned int datalen,
unsigned int *matchoff, unsigned int *matchlen)
{
const char *start = dptr, *limit = dptr + datalen;
unsigned int mlen;
int shift = 0;
/* Skip method and following whitespace */
mlen = string_len(ct, dptr, limit, NULL);
if (!mlen)
return 0;
dptr += mlen;
if (++dptr >= limit)
return 0;
/* Find SIP URI */
limit -= strlen("sip:");
for (; dptr < limit; dptr++) {
if (*dptr == '\r' || *dptr == '\n')
return -1;
if (strnicmp(dptr, "sip:", strlen("sip:")) == 0)
break;
}
*matchlen = skp_epaddr_len(ct, dptr, limit, &shift);
if (!*matchlen)
return 0;
*matchoff = dptr - start + shift;
return 1;
}
EXPORT_SYMBOL_GPL(ct_sip_parse_request);
/* Returns 0 if not found, -1 error parsing. */
int ct_sip_get_info(const struct nf_conn *ct,
const char *dptr, size_t dlen,
......
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