From 9a7fc3e07911d1eceef278ecaa95c7f5f2d4bf37 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. Change-Id: I0d2f3b1ed4e763c559ecec98af32767360985e91 Cc: stable@vger.kernel.org Signed-off-by: Al Viro --- block/bsg.c | 3 +++ 1 file changed, 3 insertions(+) (limited to 'block') diff --git a/block/bsg.c b/block/bsg.c index 792ead66675..73e5eb4f2da 100644 --- a/block/bsg.c +++ b/block/bsg.c @@ -675,6 +675,9 @@ 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