Current parsing methods for SIP header Call-ID do not check correctly all
characters allowed by RFC 3261. In particular "," character is allowed
instead of "'" character. As a result Call-ID headers like the following
are discarded by IPVS SIP persistence engine.
Call-ID: -.!%*_+`'~()<>:\"/[]?{}
Above example is composed using all non-alphanumeric characters listed
in RFC 3261 for Call-ID header syntax.
Proposed fix is in nf_conntrack_sip module; function iswordc() checks this
range: (c >= '(' && c <= '/') which includes these characters: ()*+,-./
They are all allowed except ",". Instead "'" is not included in the list.
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>
---
net/netfilter/nf_conntrack_sip.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)
diff --git a/net/netfilter/nf_conntrack_sip.c b/net/netfilter/nf_conntrack_sip.c
index 4acd60e..8971109 100644
--- a/net/netfilter/nf_conntrack_sip.c
+++ b/net/netfilter/nf_conntrack_sip.c
@@ -83,9 +83,10 @@ static int digits_len(const struct nf_conn *ct, const char *dptr,
static int iswordc(const char c)
{
if (isalnum(c) || c == '!' || c == '"' || c == '%' ||
- (c >= '(' && c <= '/') || c == ':' || c == '<' || c == '>' ||
+ (c >= '(' && c <= '+') || c == ':' || c == '<' || c == '>' ||
c == '?' || (c >= '[' && c <= ']') || c == '_' || c == '`' ||
- c == '{' || c == '}' || c == '~')
+ c == '{' || c == '}' || c == '~' || (c >= '-' && c <= '/') ||
+ c == '\'')
return 1;
return 0;
}
--
1.8.3.1
--
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