| Message ID | 1460395381-14438-1-git-send-email-luis.henriques@canonical.com |
|---|---|
| State | New |
| Headers | show |
diff --git a/drivers/scsi/sg.c b/drivers/scsi/sg.c index 635b141c6c05..e1a6abe899f9 100644 --- a/drivers/scsi/sg.c +++ b/drivers/scsi/sg.c @@ -633,7 +633,8 @@ sg_write(struct file *filp, const char __user *buf, size_t count, loff_t * ppos) else hp->dxfer_direction = (mxsize > 0) ? SG_DXFER_FROM_DEV : SG_DXFER_NONE; hp->dxfer_len = mxsize; - if (hp->dxfer_direction == SG_DXFER_TO_DEV) + if ((hp->dxfer_direction == SG_DXFER_TO_DEV) || + (hp->dxfer_direction == SG_DXFER_TO_FROM_DEV)) hp->dxferp = (char __user *)buf + cmd_size; else hp->dxferp = NULL;
This is a note to let you know that I have just added a patch titled sg: fix dxferp in from_to case to the linux-3.16.y-queue branch of the 3.16.y-ckt extended stable tree which can be found at: http://kernel.ubuntu.com/git/ubuntu/linux.git/log/?h=linux-3.16.y-queue This patch is scheduled to be released in version 3.16.7-ckt27. If you, or anyone else, feels it should not be added to this tree, please reply to this email. For more information about the 3.16.y-ckt tree, see https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable Thanks. -Luis ---8<------------------------------------------------------------ From f14e70d521b1d7f766d102a1302ccac9b4d14073 Mon Sep 17 00:00:00 2001 From: Douglas Gilbert <dgilbert@interlog.com> Date: Thu, 3 Mar 2016 00:31:29 -0500 Subject: sg: fix dxferp in from_to case commit 5ecee0a3ee8d74b6950cb41e8989b0c2174568d4 upstream. One of the strange things that the original sg driver did was let the user provide both a data-out buffer (it followed the sg_header+cdb) _and_ specify a reply length greater than zero. What happened was that the user data-out buffer was copied into some kernel buffers and then the mid level was told a read type operation would take place with the data from the device overwriting the same kernel buffers. The user would then read those kernel buffers back into the user space. From what I can tell, the above action was broken by commit fad7f01e61bf ("sg: set dxferp to NULL for READ with the older SG interface") in 2008 and syzkaller found that out recently. Make sure that a user space pointer is passed through when data follows the sg_header structure and command. Fix the abnormal case when a non-zero reply_len is also given. Fixes: fad7f01e61bf737fe8a3740d803f000db57ecac6 Signed-off-by: Douglas Gilbert <dgilbert@interlog.com> Reviewed-by: Ewan Milne <emilne@redhat.com> Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com> Signed-off-by: Luis Henriques <luis.henriques@canonical.com> --- drivers/scsi/sg.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)