On Sun, Jun 17, 2012 at 8:53 AM, FUJITA Tomonori
<fujita.tomonori@xxxxxxxxxxxxx> wrote:
> 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?
For example if LBA == 0xffffffffffffffff and TL == 2, then LBA+TL == 1
My iscsi test tool has this as the third subtest in :
0204_read16_beyond_eol
printf("Test that READ16 fails if reading beyond
end-of-lun.\n");
printf("1, Read 1-256 blocks one block beyond end-of-lun.\n");
printf("2, Read 1-256 blocks at LBA 2^63\n");
printf("3, Read 1-256 blocks at LBA -1\n");
printf("\n");
return 0;
>
>> + || (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
>>
--
To unsubscribe from this list: send the line "unsubscribe stgt" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
