This is a note to let you know that I've just added the patch titled
sg_write()/bsg_write() is not fit to be called under KERNEL_DS
to the 4.4-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
sg_write-bsg_write-is-not-fit-to-be-called-under-kernel_ds.patch
and it can be found in the queue-4.4 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 128394eff343fc6d2f32172f03e24829539c5835 Mon Sep 17 00:00:00 2001
From: Al Viro <viro@xxxxxxxxxxxxxxxxxx>
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@xxxxxxxxxxxxxxxxxx>
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@xxxxxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
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,
Patches currently in stable-queue which might be from viro@xxxxxxxxxxxxxxxxxx are
queue-4.4/sg_write-bsg_write-is-not-fit-to-be-called-under-kernel_ds.patch
queue-4.4/nfs_write_end-fix-handling-of-short-copies.patch
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