From: Jordy Zomer <jordy@jordyzomer.github.io> stable inclusion from stable-v5.10.111 commit 71c8df33fd777c7628f6fbc09b14e84806c55914 category: bugfix bugzilla: https://gitee.com/openeuler/kernel/issues/I5GL1Z Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=... -------------------------------- [ Upstream commit cd9c88da171a62c4b0f1c70e50c75845969fbc18 ] It appears like cmd could be a Spectre v1 gadget as it's supplied by a user and used as an array index. Prevent the contents of kernel memory from being leaked to userspace via speculative execution by using array_index_nospec. Signed-off-by: Jordy Zomer <jordy@pwning.systems> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Sasha Levin <sashal@kernel.org> Signed-off-by: Zheng Zengkai <zhengzengkai@huawei.com> Reviewed-by: Wei Li <liwei391@huawei.com> --- drivers/md/dm-ioctl.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/drivers/md/dm-ioctl.c b/drivers/md/dm-ioctl.c index 1ca65b434f1f..b839705654d4 100644 --- a/drivers/md/dm-ioctl.c +++ b/drivers/md/dm-ioctl.c @@ -17,6 +17,7 @@ #include <linux/dm-ioctl.h> #include <linux/hdreg.h> #include <linux/compat.h> +#include <linux/nospec.h> #include <linux/uaccess.h> @@ -1696,6 +1697,7 @@ static ioctl_fn lookup_ioctl(unsigned int cmd, int *ioctl_flags) if (unlikely(cmd >= ARRAY_SIZE(_ioctls))) return NULL; + cmd = array_index_nospec(cmd, ARRAY_SIZE(_ioctls)); *ioctl_flags = _ioctls[cmd].flags; return _ioctls[cmd].fn; } -- 2.20.1