From: Marco Angaroni <marcoangaroni@xxxxxxxxx>
Current parsing methods for SIP headers do not allow the presence of
tab characters between header name and header value. As a result Call-ID
SIP headers like the following are discarded by IPVS SIP persistence
engine:
"Call-ID\t: mycallid@abcde"
"Call-ID:\tmycallid@abcde"
In above examples Call-IDs are represented as strings in C language.
Obviously in real message we have byte "09" before/after colon (":").
Proposed fix is in nf_conntrack_sip module.
Function sip_skip_whitespace() should skip tabs in addition to spaces,
since in SIP grammar whitespace (WSP) corresponds to space or tab.
Below is an extract of relevant SIP ABNF syntax.
Call-ID = ( "Call-ID" / "i" ) HCOLON callid
callid = word [ "@" word ]
HCOLON = *( SP / HTAB ) ":" SWS
SWS = [LWS] ; sep whitespace
LWS = [*WSP CRLF] 1*WSP ; linear whitespace
WSP = SP / HTAB
word = 1*(alphanum / "-" / "." / "!" / "%" / "*" /
"_" / "+" / "`" / "'" / "~" /
"(" / ")" / "<" / ">" /
":" / "\" / DQUOTE /
"/" / "[" / "]" / "?" /
"{" / "}" )
Signed-off-by: Marco Angaroni <marcoangaroni@xxxxxxxxx>
Signed-off-by: Pablo Neira Ayuso <pablo@xxxxxxxxxxxxx>
---
net/netfilter/nf_conntrack_sip.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/net/netfilter/nf_conntrack_sip.c b/net/netfilter/nf_conntrack_sip.c
index d8035351aff5..621b81c7bddc 100644
--- a/net/netfilter/nf_conntrack_sip.c
+++ b/net/netfilter/nf_conntrack_sip.c
@@ -330,7 +330,7 @@ static const char *sip_follow_continuation(const char *dptr, const char *limit)
static const char *sip_skip_whitespace(const char *dptr, const char *limit)
{
for (; dptr < limit; dptr++) {
- if (*dptr == ' ')
+ if (*dptr == ' ' || *dptr == '\t')
continue;
if (*dptr != '\r' && *dptr != '\n')
break;
--
2.1.4
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