* [PATCH 0/2] netfilter: allow tab character in SIP headers
@ 2016-08-30 16:52 Marco Angaroni
2016-09-07 11:56 ` Pablo Neira Ayuso
0 siblings, 1 reply; 3+ messages in thread
From: Marco Angaroni @ 2016-08-30 16:52 UTC (permalink / raw)
To: lvs-devel, netfilter-devel
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@gmail.com>
---
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 f72ba55..4acd60e 100644
--- a/net/netfilter/nf_conntrack_sip.c
+++ b/net/netfilter/nf_conntrack_sip.c
@@ -329,7 +329,7 @@ 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;
--
1.8.3.1
^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [PATCH 0/2] netfilter: allow tab character in SIP headers
2016-08-30 16:52 [PATCH 0/2] netfilter: allow tab character in SIP headers Marco Angaroni
@ 2016-09-07 11:56 ` Pablo Neira Ayuso
2016-09-07 20:00 ` Marco Angaroni
0 siblings, 1 reply; 3+ messages in thread
From: Pablo Neira Ayuso @ 2016-09-07 11:56 UTC (permalink / raw)
To: Marco Angaroni; +Cc: lvs-devel, netfilter-devel
On Tue, Aug 30, 2016 at 06:52:22PM +0200, Marco Angaroni wrote:
> 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 /
> "/" / "[" / "]" / "?" /
> "{" / "}" )
Applied this one too. I got confused because patch 0/x is usually the
cover letter, I suggest you don't use 0/x for patch series in the future.
Thanks!
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