From ca41f7eaa58d3f63a3df58d812b3cec32343ab6a Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Marc-Andr=C3=A9=20Lureau?= Date: Fri, 4 Jun 2021 16:40:23 +0400 Subject: [PATCH 7/7] udp: check upd_input buffer size MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Fixes: CVE-2021-3594 Fixes: https://gitlab.freedesktop.org/slirp/libslirp/-/issues/47 Signed-off-by: Marc-André Lureau (cherry picked from commit 74572be49247c8c5feae7c6e0b50c4f569ca9824) --- src/udp.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/src/udp.c b/src/udp.c index 050cee4..e4578aa 100644 --- a/src/udp.c +++ b/src/udp.c @@ -94,7 +94,10 @@ void udp_input(register struct mbuf *m, int iphlen) /* * Get IP and UDP header together in first mbuf. */ - ip = mtod(m, struct ip *); + ip = mtod_check(m, iphlen + sizeof(struct udphdr)); + if (ip == NULL) { + goto bad; + } uh = (struct udphdr *)((char *)ip + iphlen); /* -- 2.29.0