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| author | Luis R. Rodriguez <mcgrof@kernel.org> | 2018-03-09 15:51:20 -0800 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2018-03-09 16:40:02 -0800 |
| commit | ac68b1b3b9c73e652dc7ce0585672e23c5a2dca4 (patch) | |
| tree | bff6f75c172acda7f0240223c222fb3d1af58aaa /lib | |
| parent | 0627be7d3c871035364923559543c9b2ff5357f2 (diff) | |
| download | lwn-ac68b1b3b9c73e652dc7ce0585672e23c5a2dca4.tar.gz lwn-ac68b1b3b9c73e652dc7ce0585672e23c5a2dca4.zip | |
lib/test_kmod.c: fix limit check on number of test devices created
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: d9c6a72d6fa2 ("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>
Diffstat (limited to 'lib')
| -rw-r--r-- | lib/test_kmod.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/lib/test_kmod.c b/lib/test_kmod.c index e372b97eee13..0e5b7a61460b 100644 --- a/lib/test_kmod.c +++ b/lib/test_kmod.c @@ -1141,7 +1141,7 @@ static struct kmod_test_device *register_test_dev_kmod(void) mutex_lock(®_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; } |