From 58880025e3362024f6d8ea01cb0c7a5df6c84ba6 Mon Sep 17 00:00:00 2001 From: Jordy Zomer Date: Sat, 29 Jan 2022 15:58:39 +0100 Subject: [PATCH] dm ioctl: prevent potential spectre v1 gadget [ 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 Signed-off-by: Mike Snitzer Signed-off-by: Sasha Levin --- 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 2f020401d5ba..ddfea5324b58 100644 --- a/drivers/md/dm-ioctl.c +++ b/drivers/md/dm-ioctl.c @@ -17,6 +17,7 @@ #include #include #include +#include #include @@ -1669,6 +1670,7 @@ 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