From 128394eff343fc6d2f32172f03e24829539c5835 Mon Sep 17 00:00:00 2001 From: Al Viro Date: Fri, 16 Dec 2016 13:42:06 -0500 Subject: sg_write()/bsg_write() is not fit to be called under KERNEL_DS Both damn things interpret userland pointers embedded into the payload; worse, they are actually traversing those. Leaving aside the bad API design, this is very much _not_ safe to call with KERNEL_DS. Bail out early if that happens. Cc: stable@vger.kernel.org Signed-off-by: Al Viro --- block/bsg.c | 3 +++ 1 file changed, 3 insertions(+) (limited to 'block/bsg.c') diff --git a/block/bsg.c b/block/bsg.c index 8a05a404ae70..a57046de2f07 100644 --- a/block/bsg.c +++ b/block/bsg.c @@ -655,6 +655,9 @@ bsg_write(struct file *file, const char __user *buf, size_t count, loff_t *ppos) dprintk("%s: write %Zd bytes\n", bd->name, count); + if (unlikely(segment_eq(get_fs(), KERNEL_DS))) + return -EINVAL; + bsg_set_block(bd, file); bytes_written = 0; -- cgit v1.2.3-55-g7522