target: Check for LBA + sectors wrap-around in sbc_parse_cdb

This patch adds a check to sbc_parse_cdb() in order to detect when
an LBA + sector vs. end-of-device calculation wraps when the LBA is
sufficently large enough (eg: 0xFFFFFFFFFFFFFFFF).

Cc: Martin Petersen <martin.petersen@oracle.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: stable@vger.kernel.org
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>

1 files changed, 2 insertions, 1 deletions

diff --git a/drivers/target/target_core_sbc.c b/drivers/target/target_core_sbc.c
index b26b52f441a1..17259c05450e 100644
--- a/drivers/target/target_core_sbc.c
+++ b/drivers/target/target_core_sbc.c
@@ -982,7 +982,8 @@ sbc_parse_cdb(struct se_cmd *cmd, struct sbc_ops *ops)
                 }
 check_lba:
                 end_lba = dev->transport->get_blocks(dev) + 1;
-                if (cmd->t_task_lba + sectors > end_lba) {
+                if (((cmd->t_task_lba + sectors) < cmd->t_task_lba) ||
+                    ((cmd->t_task_lba + sectors) > end_lba)) {
                         pr_err("cmd exceeds last lba %llu "
                                 "(lba %llu, sectors %u)\n",
                                 end_lba, cmd->t_task_lba, sectors);