[PATCH 3.16.y-ckt 091/130] target/iscsi: Fix double free of a TUR followed by a solicited NOPOUT

From: Luis Henriques
Date: Fri Sep 04 2015 - 09:22:37 EST

3.16.7-ckt17 -stable review patch. If anyone has any objections, please let me know.


From: Alexei Potashnik <alexei@xxxxxxxxxxxxxxx>

commit 9547308bda296b6f69876c840a0291fcfbeddbb8 upstream.

Make sure all non-READ SCSI commands get targ_xfer_tag initialized
to 0xffffffff, not just WRITEs.

Double-free of a TUR cmd object occurs under the following scenario:

1. TUR received (targ_xfer_tag is uninitialized and left at 0)
2. TUR status sent
3. First unsolicited NOPIN is sent to initiator (gets targ_xfer_tag of 0)
4. NOPOUT for NOPIN (with TTT=0) arrives
- its ExpStatSN acks TUR status, TUR is queued for removal
- LIO tries to find NOPIN with TTT=0, but finds the same TUR instead,
TUR is queued for removal for the 2nd time

(Drop unbalanced conditional bracket usage - nab)

Signed-off-by: Alexei Potashnik <alexei@xxxxxxxxxxxxxxx>
Signed-off-by: Spencer Baugh <sbaugh@xxxxxxxxxx>
Signed-off-by: Nicholas Bellinger <nab@xxxxxxxxxxxxxxx>
[ luis: backported to 3.16:
- kept brackets as they are needed in 3.16 kernel ]
Signed-off-by: Luis Henriques <luis.henriques@xxxxxxxxxxxxx>
drivers/target/iscsi/iscsi_target.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/target/iscsi/iscsi_target.c b/drivers/target/iscsi/iscsi_target.c
index ce87bdcb1843..9f299c7fe73f 100644
--- a/drivers/target/iscsi/iscsi_target.c
+++ b/drivers/target/iscsi/iscsi_target.c
@@ -966,7 +966,7 @@ int iscsit_setup_scsi_cmd(struct iscsi_conn *conn, struct iscsi_cmd *cmd,
if (cmd->targ_xfer_tag == 0xFFFFFFFF)
cmd->targ_xfer_tag = conn->sess->targ_xfer_tag++;
- } else if (hdr->flags & ISCSI_FLAG_CMD_WRITE)
+ } else
cmd->targ_xfer_tag = 0xFFFFFFFF;
cmd->cmd_sn = be32_to_cpu(hdr->cmdsn);
cmd->exp_stat_sn = be32_to_cpu(hdr->exp_statsn);
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