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 --- drivers/scsi/sg.c | 3 +++ 1 file changed, 3 insertions(+) (limited to 'drivers/scsi/sg.c') diff --git a/drivers/scsi/sg.c b/drivers/scsi/sg.c index 4172f89..819c84b 100644 --- a/drivers/scsi/sg.c +++ b/drivers/scsi/sg.c @@ -543,6 +543,9 @@ sg_write(struct file *filp, const char __user *buf, size_t count, loff_t * ppos) sg_io_hdr_t *hp; unsigned char cmnd[MAX_COMMAND_SIZE]; + if (unlikely(segment_eq(get_fs(), KERNEL_DS))) + return -EINVAL; + if ((!(sfp = (Sg_fd *) filp->private_data)) || (!(sdp = sfp->parentdp))) return -ENXIO; SCSI_LOG_TIMEOUT(3, printk("sg_write: %s, count=%d\n", -- cgit v1.1