fix a braino in cmsghdr_from_user_compat_to_kern()

commit 547ce4cfb3 ("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: 547ce4cfb3 ("switch cmsghdr_from_user_compat_to_kern() to copy_from_user()")
Reported-by: Nick Bowler <nbowler@draconx.ca>
Tested-by: Nick Bowler <nbowler@draconx.ca>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Al Viro 2020-07-27 19:22:20 +01:00 committed by David S. Miller
parent 11d268107a
commit 181964e619

View File

@ -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);
}
/*