From 76cfc6fa0d819e7caca86c8299947cea1af9d6bc Mon Sep 17 00:00:00 2001 From: "Alexander V. Chernikov" Date: Fri, 14 May 2021 16:03:08 +0000 Subject: [PATCH] Fix a use after free in update_rtm_from_rc(). update_rtm_from_rc() calls update_rtm_from_info() internally. The latter one may update provided prtm pointer with a new rtm. Reassign rtm from prtm afeter calling update_rtm_from_info() to avoid touching the freed rtm. PR: 255871 Submitted by: lylgood@foxmail.com MFC after: 3 days --- sys/net/rtsock.c | 1 + 1 file changed, 1 insertion(+) diff --git a/sys/net/rtsock.c b/sys/net/rtsock.c index 6930bd167ac..3cb645f42e4 100644 --- a/sys/net/rtsock.c +++ b/sys/net/rtsock.c @@ -976,6 +976,7 @@ update_rtm_from_rc(struct rt_addrinfo *info, struct rt_msghdr **prtm, if ((error = update_rtm_from_info(info, prtm, alloc_len)) != 0) return (error); + rtm = *prtm; rtm->rtm_flags = rc->rc_rt->rte_flags | nhop_get_rtflags(nh); if (rtm->rtm_flags & RTF_GWFLAG_COMPAT) rtm->rtm_flags = RTF_GATEWAY | -- 2.45.0