linux-kernel - [PATCH 4.19 114/206] scsi: target: tcmu: Fix a use after free in tcmu_check_expired_queue

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite for Android: free password hash cracker in your pocket

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <20200623195322.553626574@linuxfoundation.org>
Date:   Tue, 23 Jun 2020 21:57:22 +0200
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, Mike Christie <mchristi@...hat.com>,
        David Disseldorp <ddiss@...e.de>,
        Dan Carpenter <dan.carpenter@...cle.com>,
        "Martin K. Petersen" <martin.petersen@...cle.com>,
        Sasha Levin <sashal@...nel.org>
Subject: [PATCH 4.19 114/206] scsi: target: tcmu: Fix a use after free in tcmu_check_expired_queue_cmd()

From: Dan Carpenter <dan.carpenter@...cle.com>

[ Upstream commit 9d7464b18892332e35ff37f0b024429a1a9835e6 ]

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

Link: https://lore.kernel.org/r/20200523101129.GB98132@mwanda
Fixes: 61fb24822166 ("scsi: target: tcmu: Userspace must not complete queued commands")
Reviewed-by: Mike Christie <mchristi@...hat.com>
Reviewed-by: David Disseldorp <ddiss@...e.de>
Signed-off-by: Dan Carpenter <dan.carpenter@...cle.com>
Signed-off-by: Martin K. Petersen <martin.petersen@...cle.com>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
 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 ac523f247a9ca..8da89925a874d 100644
--- a/drivers/target/target_core_user.c
+++ b/drivers/target/target_core_user.c
@@ -1303,13 +1303,13 @@ 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);
 }
 
-- 
2.25.1