redonkable
/
remarkable-linux
1
0
Fork 0
Code Releases Activity

lib/test_kmod.c: fix limit check on number of test devices created 

[ Upstream commit ac68b1b3b9 ]

As reported by Dan the parentheses is in the wrong place, and since
unlikely() call returns either 0 or 1 it's never less than zero.  The
second issue is that signed integer overflows like "INT_MAX + 1" are
undefined behavior.

Since num_test_devs represents the number of devices, we want to stop
prior to hitting the max, and not rely on the wrap arround at all.  So
just cap at num_test_devs + 1, prior to assigning a new device.

Link: http://lkml.kernel.org/r/20180224030046.24238-1-mcgrof@kernel.org
Fixes: d9c6a72d6f ("kmod: add test driver to stress test the module loader")
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Luis R. Rodriguez <mcgrof@kernel.org>
Acked-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
pull/10/head
Luis R. Rodriguez 2018-03-09 15:51:20 -08:00 committed by Greg Kroah-Hartman
parent 21ccc62ec7
commit e2d9442dfe
1 changed files with 1 additions and 1 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
lib/test_kmod.c
View File

@ -1149,7 +1149,7 @@ static struct kmod_test_device *register_test_dev_kmod(void)
mutex_lock(&reg_dev_mutex);
/* int should suffice for number of devices, test for wrap */
if (unlikely(num_test_devs + 1) < 0) {
if (num_test_devs + 1 == INT_MAX) {
pr_err("reached limit of number of test devices\n");
goto out;
}