netfilter: nf_conntrack_sip: fix off-by-one in compact header parsing

In a string like "v:SIP/2.0..." it was checking for !isalpha('S') when it
meant to be inspecting the ':'.

Patch by Greg Alexander <greqcs@galexander.org>

Signed-off-by: Patrick McHardy <kaber@trash.net>

1 files changed, 1 insertions, 1 deletions

diff --git a/net/netfilter/nf_conntrack_sip.c b/net/netfilter/nf_conntrack_sip.c
index 4b572163784b..023966b569bf 100644
--- a/net/netfilter/nf_conntrack_sip.c
+++ b/net/netfilter/nf_conntrack_sip.c
@@ -376,7 +376,7 @@ int ct_sip_get_header(const struct nf_conn *ct, const char *dptr,
                         dptr += hdr->len;
                 else if (hdr->cname && limit - dptr >= hdr->clen + 1 &&
                          strnicmp(dptr, hdr->cname, hdr->clen) == 0 &&
-                         !isalpha(*(dptr + hdr->clen + 1)))
+                         !isalpha(*(dptr + hdr->clen)))
                         dptr += hdr->clen;
                 else
                         continue;