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From: Dan Carpenter <dan.carpenter@oracle.com>
To: "Martin K. Petersen" <martin.petersen@oracle.com>,
	Bodo Stroesser <bstroesser@ts.fujitsu.com>
Cc: Mike Christie <mchristi@redhat.com>,
	linux-scsi@vger.kernel.org, target-devel@vger.kernel.org,
	kernel-janitors@vger.kernel.org
Subject: [PATCH] scsi: target: tcmu: Fix a use after free in tcmu_check_expired_queue_cmd()
Date: Sat, 23 May 2020 13:11:29 +0300	[thread overview]
Message-ID: <20200523101129.GB98132@mwanda> (raw)

The pr_debug() dereferences "cmd" after we already freed it by calling
tcmu_free_cmd(cmd).  The debug printk needs to be done earlier.

Fixes: 61fb24822166 ("scsi: target: tcmu: Userspace must not complete queued commands")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
---
 drivers/target/target_core_user.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/target/target_core_user.c b/drivers/target/target_core_user.c
index 904d8a8373f2..28fb9441de7a 100644
--- a/drivers/target/target_core_user.c
+++ b/drivers/target/target_core_user.c
@@ -1292,13 +1292,13 @@ static void tcmu_check_expired_queue_cmd(struct tcmu_cmd *cmd)
 	if (!time_after(jiffies, cmd->deadline))
 		return;
 
+	pr_debug("Timing out queued cmd %p on dev %s.\n",
+		  cmd, cmd->tcmu_dev->name);
+
 	list_del_init(&cmd->queue_entry);
 	se_cmd = cmd->se_cmd;
 	tcmu_free_cmd(cmd);
 
-	pr_debug("Timing out queued cmd %p on dev %s.\n",
-		  cmd, cmd->tcmu_dev->name);
-
 	target_complete_cmd(se_cmd, SAM_STAT_TASK_SET_FULL);
 }
 
-- 
2.26.2


             reply	other threads:[~2020-05-23 10:11 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-05-23 10:11 Dan Carpenter [this message]
2020-05-23 13:03 ` [PATCH] scsi: target: tcmu: Fix a use after free in tcmu_check_expired_queue_cmd() David Disseldorp
2020-05-23 19:04 ` Mike Christie
2020-05-25  9:11 ` Bodo Stroesser
2020-05-26 12:26   ` Dan Carpenter
2020-05-27  2:12 ` Martin K. Petersen

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