[PATCH 3.19 057/177] target: Check for LBA + sectors wrap-around in sbc_parse_cdb

[Greg Kroah-Hartman]

3.19-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Nicholas Bellinger <nab@xxxxxxxxxxxxxxx>

commit aa179935edea9a64dec4b757090c8106a3907ffa upstream.

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@xxxxxxxxxx>
Cc: Christoph Hellwig <hch@xxxxxx>
Signed-off-by: Nicholas Bellinger <nab@xxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
 drivers/target/target_core_sbc.c |    3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

--- a/drivers/target/target_core_sbc.c
+++ b/drivers/target/target_core_sbc.c
@@ -967,7 +967,8 @@ sbc_parse_cdb(struct se_cmd *cmd, struct
 		unsigned long long end_lba;
 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);


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