This is a note to let you know that I've just added the patch titled
libata: don't try to pass through NCQ commands to non-NCQ devices
to the 4.9-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:
libata-don-t-try-to-pass-through-ncq-commands-to-non-ncq-devices.patch
and it can be found in the queue-4.9 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 2c1ec6fda2d07044cda922ee25337cf5d4b429b3 Mon Sep 17 00:00:00 2001
From: Eric Biggers <ebiggers@xxxxxxxxxx>
Date: Sat, 3 Feb 2018 20:33:51 -0800
Subject: libata: don't try to pass through NCQ commands to non-NCQ devices
From: Eric Biggers <ebiggers@xxxxxxxxxx>
commit 2c1ec6fda2d07044cda922ee25337cf5d4b429b3 upstream.
syzkaller hit a WARN() in ata_bmdma_qc_issue() when writing to /dev/sg0.
This happened because it issued an ATA pass-through command (ATA_16)
where the protocol field indicated that NCQ should be used -- but the
device did not support NCQ.
We could just remove the WARN() from libata-sff.c, but the real problem
seems to be that the SCSI -> ATA translation code passes through NCQ
commands without verifying that the device actually supports NCQ.
Fix this by adding the appropriate check to ata_scsi_pass_thru().
Here's reproducer that works in QEMU when /dev/sg0 refers to a disk of
the default type ("82371SB PIIX3 IDE"):
#include <fcntl.h>
#include <unistd.h>
int main()
{
char buf[53] = { 0 };
buf[36] = 0x85; /* ATA_16 */
buf[37] = (12 << 1); /* FPDMA */
buf[38] = 0x1; /* Has data */
buf[51] = 0xC8; /* ATA_CMD_READ */
write(open("/dev/sg0", O_RDWR), buf, sizeof(buf));
}
Fixes: ee7fb331c3ac ("libata: add support for NCQ commands for SG interface")
Reported-by: syzbot+2f69ca28df61bdfc77cd36af2e789850355a221e@xxxxxxxxxxxxxxxxxxxxxxxxx
Cc: <stable@xxxxxxxxxxxxxxx> # v4.4+
Signed-off-by: Eric Biggers <ebiggers@xxxxxxxxxx>
Signed-off-by: Tejun Heo <tj@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/ata/libata-scsi.c | 6 ++++++
1 file changed, 6 insertions(+)
--- a/drivers/ata/libata-scsi.c
+++ b/drivers/ata/libata-scsi.c
@@ -3226,6 +3226,12 @@ static unsigned int ata_scsi_pass_thru(s
goto invalid_fld;
}
+ /* We may not issue NCQ commands to devices not supporting NCQ */
+ if (ata_is_ncq(tf->protocol) && !ata_ncq_enabled(dev)) {
+ fp = 1;
+ goto invalid_fld;
+ }
+
/* sanity check for pio multi commands */
if ((cdb[1] & 0xe0) && !is_multi_taskfile(tf)) {
fp = 1;
Patches currently in stable-queue which might be from ebiggers@xxxxxxxxxx are
queue-4.9/libata-fix-length-validation-of-atapi-relayed-scsi-commands.patch
queue-4.9/libata-remove-warn-for-dma-or-pio-command-without-data.patch
queue-4.9/libata-don-t-try-to-pass-through-ncq-commands-to-non-ncq-devices.patch