On Mon, 4 Jun 2012 19:10:12 +1000
ronnie sahlberg <ronniesahlberg@xxxxxxxxx> wrote:
> From efc1f1720ad9a00e69f7935a001df906e609afe5 Mon Sep 17 00:00:00 2001
> From: Ronnie Sahlberg <ronniesahlberg@xxxxxxxxx>
> Date: Mon, 4 Jun 2012 18:56:18 +1000
> Subject: [PATCH] SBC: LBA range check, fix some bugs in the LBA out of range check
>
> We can not shift the LBA << 9 and compare to the file size since this means
> that for a HUGE LBA, like LBA==2^63 this will cause the 64 bit integer
> to overflow and we suddenly pass all the tests and LBA sudddenly becomes LBA 0 instead.
> Several targets have this bug as far as I can tell in testing.
>
> Instead, use LBA as is and instead shift the filesize >> 9 before the check
> to avoid this overflow.
>
> Also, if both LBA and tranfser length are huge, LBA + TL can wrap too
> so we need to check for that too and return check condition if
> lba+tl < lba
>
> Signed-off-by: Ronnie Sahlberg <ronniesahlberg@xxxxxxxxx>
> ---
> usr/sbc.c | 13 +++++++------
> 1 files changed, 7 insertions(+), 6 deletions(-)
>
> diff --git a/usr/sbc.c b/usr/sbc.c
> index 248a547..bc9e3d6 100644
> --- a/usr/sbc.c
> +++ b/usr/sbc.c
> @@ -297,27 +297,28 @@ static int sbc_rw(int host_no, struct scsi_cmd *cmd)
> }
> }
>
> - lba = scsi_rw_offset(cmd->scb) << cmd->dev->blk_shift;
> - tl = scsi_rw_count(cmd->scb) << cmd->dev->blk_shift;
> + lba = scsi_rw_offset(cmd->scb);
> + tl = scsi_rw_count(cmd->scb);
>
> /* Verify that we are not doing i/o beyond
> the end-of-lun */
> if (tl) {
> - if (lba + tl > lu->size) {
> + if ((lba + tl < lba)
How this could happen?
> + || (lba + tl > (lu->size >> cmd->dev->blk_shift))) {
> key = ILLEGAL_REQUEST;
> asc = ASC_LBA_OUT_OF_RANGE;
> goto sense;
> }
> } else {
> - if (lba >= lu->size) {
> + if (lba >= (lu->size >> cmd->dev->blk_shift)) {
> key = ILLEGAL_REQUEST;
> asc = ASC_LBA_OUT_OF_RANGE;
> goto sense;
> }
> }
>
> - cmd->offset = lba;
> - cmd->tl = tl;
> + cmd->offset = lba << cmd->dev->blk_shift;
> + cmd->tl = tl << cmd->dev->blk_shift;
>
> ret = cmd->dev->bst->bs_cmd_submit(cmd);
> if (ret) {
> --
> 1.7.3.1
>
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