From 181964e619b76ae2e71bcdc6001cf977bec4cf6e Mon Sep 17 00:00:00 2001 From: Al Viro Date: Mon, 27 Jul 2020 19:22:20 +0100 Subject: fix a braino in cmsghdr_from_user_compat_to_kern() commit 547ce4cfb34c ("switch cmsghdr_from_user_compat_to_kern() to copy_from_user()") missed one of the places where ucmlen should've been replaced with cmsg.cmsg_len, now that we are fetching the entire struct rather than doing it field-by-field. As the result, compat sendmsg() with several different-sized cmsg attached started to fail with EINVAL. Trivial to fix, fortunately. Fixes: 547ce4cfb34c ("switch cmsghdr_from_user_compat_to_kern() to copy_from_user()") Reported-by: Nick Bowler Tested-by: Nick Bowler Signed-off-by: Al Viro Signed-off-by: David S. Miller --- net/compat.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'net') diff --git a/net/compat.c b/net/compat.c index 5e3041a2c37d..434838bef5f8 100644 --- a/net/compat.c +++ b/net/compat.c @@ -202,7 +202,7 @@ int cmsghdr_from_user_compat_to_kern(struct msghdr *kmsg, struct sock *sk, /* Advance. */ kcmsg = (struct cmsghdr *)((char *)kcmsg + tmp); - ucmsg = cmsg_compat_nxthdr(kmsg, ucmsg, ucmlen); + ucmsg = cmsg_compat_nxthdr(kmsg, ucmsg, cmsg.cmsg_len); } /* -- cgit