From e8f8231824b5815f57ce62cba116e511b10196de Mon Sep 17 00:00:00 2001 From: Joas Antonio dos Santos Date: Tue, 18 Aug 2026 06:31:43 -0700 Subject: [PATCH] netfilter: nf_conntrack_sip: fix OOB read in sip_skip_whitespace() sip_skip_whitespace() returns dptr unchanged when its own loop exhausts the buffer (dptr == limit), instead of NULL like its sibling sip_follow_continuation() returns on its own "no more data" path. ct_sip_get_header() only checks for NULL after calling it: dptr = sip_skip_whitespace(dptr, limit); if (dptr == NULL) break; if (*dptr != ':' || ++dptr >= limit) break; so a recognized header name followed only by spaces/tabs running to the exact end of the SIP payload, with no colon, makes the very next statement read one byte past the buffer. Make both "no more data" outcomes return NULL, matching the convention sip_follow_continuation() already uses and that both existing callers already check for. Fixes: ea45f12a2766d ("[NETFILTER]: nf_conntrack_sip: parse SIP headers properly") Signed-off-by: Joas Antonio dos Santos Signed-off-by: Pablo Neira Ayuso --- 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 3ccf34fc1c53..64bc440b1181 100644 --- a/net/netfilter/nf_conntrack_sip.c +++ b/net/netfilter/nf_conntrack_sip.c @@ -423,7 +423,7 @@ static const char *sip_skip_whitespace(const char *dptr, const char *limit) dptr = sip_follow_continuation(dptr, limit); break; } - return dptr; + return dptr < limit ? dptr : NULL; } /* Search within a SIP header value, dealing with continuation lines */