From 96e99be40e4cff870a83233731121ec0f7f95075 Mon Sep 17 00:00:00 2001
From: Eric Biggers <ebiggers@google.com>
Date: Tue, 6 Feb 2018 15:42:00 -0800
Subject: pipe: reject F_SETPIPE_SZ with size over UINT_MAX

A pipe's size is represented as an 'unsigned int'.  As expected, writing a
value greater than UINT_MAX to /proc/sys/fs/pipe-max-size fails with
EINVAL.  However, the F_SETPIPE_SZ fcntl silently truncates such values to
32 bits, rather than failing with EINVAL as expected.  (It *does* fail
with EINVAL for values above (1 << 31) but <= UINT_MAX.)

Fix this by moving the check against UINT_MAX into round_pipe_size() which
is called in both cases.

Link: http://lkml.kernel.org/r/20180111052902.14409-6-ebiggers3@gmail.com
Signed-off-by: Eric Biggers <ebiggers@google.com>
Acked-by: Kees Cook <keescook@chromium.org>
Acked-by: Joe Lawrence <joe.lawrence@redhat.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: "Luis R . Rodriguez" <mcgrof@kernel.org>
Cc: Michael Kerrisk <mtk.manpages@gmail.com>
Cc: Mikulas Patocka <mpatocka@redhat.com>
Cc: Willy Tarreau <w@1wt.eu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---
 kernel/sysctl.c | 3 ---
 1 file changed, 3 deletions(-)

(limited to 'kernel')

diff --git a/kernel/sysctl.c b/kernel/sysctl.c
index 59f09ea3ca3e..f98f28c12020 100644
--- a/kernel/sysctl.c
+++ b/kernel/sysctl.c
@@ -2623,9 +2623,6 @@ static int do_proc_dopipe_max_size_conv(unsigned long *lvalp,
 	if (write) {
 		unsigned int val;
 
-		if (*lvalp > UINT_MAX)
-			return -EINVAL;
-
 		val = round_pipe_size(*lvalp);
 		if (val == 0)
 			return -EINVAL;
-- 
cgit