| From 128394eff343fc6d2f32172f03e24829539c5835 Mon Sep 17 00:00:00 2001 |
| From: Al Viro <viro@zeniv.linux.org.uk> |
| Date: Fri, 16 Dec 2016 13:42:06 -0500 |
| Subject: sg_write()/bsg_write() is not fit to be called under KERNEL_DS |
| |
| From: Al Viro <viro@zeniv.linux.org.uk> |
| |
| commit 128394eff343fc6d2f32172f03e24829539c5835 upstream. |
| |
| 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. |
| |
| Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> |
| Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
| |
| --- |
| block/bsg.c | 3 +++ |
| drivers/scsi/sg.c | 3 +++ |
| 2 files changed, 6 insertions(+) |
| |
| --- a/block/bsg.c |
| +++ b/block/bsg.c |
| @@ -655,6 +655,9 @@ bsg_write(struct file *file, const char |
| |
| 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; |
| --- a/drivers/scsi/sg.c |
| +++ b/drivers/scsi/sg.c |
| @@ -592,6 +592,9 @@ sg_write(struct file *filp, const char _ |
| sg_io_hdr_t *hp; |
| unsigned char cmnd[SG_MAX_CDB_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, sg_printk(KERN_INFO, sdp, |