From: Mateusz Guzik <mguzik@redhat.com>
Date: Tue, 28 Jan 2014 01:07:11 +0000 (-0800)
Subject: ipc: fix compat msgrcv with negative msgtyp
X-Git-Url: http://git.mmlx.us/?a=commitdiff_plain;h=1f55176763a6556916d4c41c80eba7c69d5d3e5a;p=linux-edison.git

ipc: fix compat msgrcv with negative msgtyp

commit e7ca2552369c1dfe0216c626baf82c3d83ec36bb upstream.

Compat function takes msgtyp argument as u32 and passes it down to
do_msgrcv which results in casting to long, thus the sign is lost and we
get a big positive number instead.

Cast the argument to signed type before passing it down.

Signed-off-by: Mateusz Guzik <mguzik@redhat.com>
Reported-by: Gabriellla Schmidt <gsc@bruker.de>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Davidlohr Bueso <davidlohr@hp.com>
Cc: Manfred Spraul <manfred@colorfullife.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Masanari Iida <standby24x7@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---

diff --git a/ipc/compat.c b/ipc/compat.c
index 892f6585dd6..d3b376025e9 100644
--- a/ipc/compat.c
+++ b/ipc/compat.c
@@ -381,7 +381,7 @@ COMPAT_SYSCALL_DEFINE6(ipc, u32, call, int, first, int, second,
 			uptr = compat_ptr(ipck.msgp);
 			fifth = ipck.msgtyp;
 		}
-		return do_msgrcv(first, uptr, second, fifth, third,
+		return do_msgrcv(first, uptr, second, (s32)fifth, third,
 				 compat_do_msg_fill);
 	}
 	case MSGGET: