This is a note to let you know that I've just added the patch titled scsi: sg: only check for dxfer_len greater than 256M to the 4.12-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: scsi-sg-only-check-for-dxfer_len-greater-than-256m.patch and it can be found in the queue-4.12 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. >From f930c7043663188429cd9b254e9d761edfc101ce Mon Sep 17 00:00:00 2001 From: Johannes Thumshirn <jthumshirn@xxxxxxx> Date: Thu, 27 Jul 2017 09:11:26 +0200 Subject: scsi: sg: only check for dxfer_len greater than 256M From: Johannes Thumshirn <jthumshirn@xxxxxxx> commit f930c7043663188429cd9b254e9d761edfc101ce upstream. Don't make any assumptions on the sg_io_hdr_t::dxfer_direction or the sg_io_hdr_t::dxferp in order to determine if it is a valid request. The only way we can check for bad requests is by checking if the length exceeds 256M. Signed-off-by: Johannes Thumshirn <jthumshirn@xxxxxxx> Fixes: 28676d869bbb (scsi: sg: check for valid direction before starting the request) Reported-by: Jason L Tibbitts III <tibbs@xxxxxxxxxxx> Tested-by: Jason L Tibbitts III <tibbs@xxxxxxxxxxx> Suggested-by: Doug Gilbert <dgilbert@xxxxxxxxxxxx> Cc: Doug Gilbert <dgilbert@xxxxxxxxxxxx> Reviewed-by: Hannes Reinecke <hare@xxxxxxxx> Signed-off-by: Martin K. Petersen <martin.petersen@xxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- drivers/scsi/sg.c | 25 +------------------------ 1 file changed, 1 insertion(+), 24 deletions(-) --- a/drivers/scsi/sg.c +++ b/drivers/scsi/sg.c @@ -751,29 +751,6 @@ sg_new_write(Sg_fd *sfp, struct file *fi return count; } -static bool sg_is_valid_dxfer(sg_io_hdr_t *hp) -{ - switch (hp->dxfer_direction) { - case SG_DXFER_NONE: - if (hp->dxferp || hp->dxfer_len > 0) - return false; - return true; - case SG_DXFER_TO_DEV: - case SG_DXFER_FROM_DEV: - case SG_DXFER_TO_FROM_DEV: - if (!hp->dxferp || hp->dxfer_len == 0) - return false; - return true; - case SG_DXFER_UNKNOWN: - if ((!hp->dxferp && hp->dxfer_len) || - (hp->dxferp && hp->dxfer_len == 0)) - return false; - return true; - default: - return false; - } -} - static int sg_common_write(Sg_fd * sfp, Sg_request * srp, unsigned char *cmnd, int timeout, int blocking) @@ -794,7 +771,7 @@ sg_common_write(Sg_fd * sfp, Sg_request "sg_common_write: scsi opcode=0x%02x, cmd_size=%d\n", (int) cmnd[0], (int) hp->cmd_len)); - if (!sg_is_valid_dxfer(hp)) + if (hp->dxfer_len >= SZ_256M) return -EINVAL; k = sg_start_req(srp, cmnd); Patches currently in stable-queue which might be from jthumshirn@xxxxxxx are queue-4.12/scsi-sg-only-check-for-dxfer_len-greater-than-256m.patch