From f7068114d45ec55996b9040e98111afa56e010fe Mon Sep 17 00:00:00 2001
From: Jens Axboe <axboe@kernel.dk>
Date: Mon, 21 May 2018 12:21:14 -0600
Subject: [PATCH] sr: pass down correctly sized SCSI sense buffer
We're casting the CDROM layer request_sense to the SCSI sense
buffer, but the former is 64 bytes and the latter is 96 bytes.
As we generally allocate these on the stack, we end up blowing
up the stack.
Fix this by wrapping the scsi_execute() call with a properly
sized sense buffer, and copying back the bits for the CDROM
layer.
Cc: stable@vger.kernel.org
Reported-by: Piotr Gabriel Kosinski <pg.kosinski@gmail.com>
Reported-by: Daniel Shapira <daniel@twistlock.com>
Tested-by: Kees Cook <keescook@chromium.org>
Fixes: 82ed4db499b8 ("block: split scsi_request out of struct request")
Signed-off-by: Jens Axboe <axboe@kernel.dk>
---
drivers/scsi/sr_ioctl.c | 10 ++++++++--
1 file changed, 8 insertions(+), 2 deletions(-)
diff --git a/drivers/scsi/sr_ioctl.c b/drivers/scsi/sr_ioctl.c
index 2a21f2d485922..35fab1e18adc3 100644
--- a/drivers/scsi/sr_ioctl.c
+++ b/drivers/scsi/sr_ioctl.c
@@ -188,9 +188,13 @@ int sr_do_ioctl(Scsi_CD *cd, struct packet_command *cgc)
struct scsi_device *SDev;
struct scsi_sense_hdr sshdr;
int result, err = 0, retries = 0;
+ unsigned char sense_buffer[SCSI_SENSE_BUFFERSIZE], *senseptr = NULL;
SDev = cd->device;
+ if (cgc->sense)
+ senseptr = sense_buffer;
+
retry:
if (!scsi_block_when_processing_errors(SDev)) {
err = -ENODEV;
@@ -198,10 +202,12 @@ int sr_do_ioctl(Scsi_CD *cd, struct packet_command *cgc)
}
result = scsi_execute(SDev, cgc->cmd, cgc->data_direction,
- cgc->buffer, cgc->buflen,
- (unsigned char *)cgc->sense, &sshdr,
+ cgc->buffer, cgc->buflen, senseptr, &sshdr,
cgc->timeout, IOCTL_RETRIES, 0, 0, NULL);
+ if (cgc->sense)
+ memcpy(cgc->sense, sense_buffer, sizeof(*cgc->sense));
+
/* Minimal error checking. Ignore cases we know about, and report the rest. */
if (driver_byte(result) != 0) {
switch (sshdr.sense_key) {
--
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