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

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

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

From: Alexei Potashnik <alexei@purestorage.com>

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@purestorage.com>
Signed-off-by: Spencer Baugh <sbaugh@catern.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
[ luis: backported to 3.16:
  - kept brackets as they are needed in 3.16 kernel ]
Signed-off-by: Luis Henriques <luis.henriques@canonical.com>
---
 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++;
 		spin_unlock_bh(&conn->sess->ttt_lock);
-	} 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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[PATCH 3.16.y-ckt 091/130] target/iscsi: Fix double free of a TUR followed by a solicited NOPOUT Luis Henriques <luis.henriques@canonical.com> - 2015-09-04 15:30 +0200

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