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From: Mike Christie <mchristi@redhat.com>
To: Dmitry Fomichev <dmitry.fomichev@wdc.com>,
	linux-scsi@vger.kernel.org,
	"Martin K . Petersen" <martin.petersen@oracle.com>,
	target-devel@vger.kernel.org,
	Bart Van Assche <bvanassche@acm.org>
Cc: Damien Le Moal <damien.lemoal@wdc.com>
Subject: Re: [PATCH v2] tcmu: avoid use-after-free after command timeout
Date: Mon, 12 Aug 2019 10:30:19 -0500	[thread overview]
Message-ID: <5D51860B.1060902@redhat.com> (raw)
In-Reply-To: <20190811182510.1706-1-dmitry.fomichev@wdc.com>

On 08/11/2019 01:25 PM, Dmitry Fomichev wrote:
> In tcmu_handle_completion() function, the variable called read_len is
> always initialized with a value taken from se_cmd structure. If this
> function is called to complete an expired (timed out) out command, the
> session command pointed by se_cmd is likely to be already deallocated by
> the target core at that moment. As the result, this access triggers a
> use-after-free warning from KASAN.
> 
> This patch fixes the code not to touch se_cmd when completing timed out
> TCMU commands. It also resets the pointer to se_cmd at the time when the
> TCMU_CMD_BIT_EXPIRED flag is set because it is going to become invalid
> after calling target_complete_cmd() later in the same function,
> tcmu_check_expired_cmd().
> 
> Signed-off-by: Dmitry Fomichev <dmitry.fomichev@wdc.com>
> ---

Acked-by: Mike Christie <mchristi@redhat.com>


WARNING: multiple messages have this Message-ID (diff)
From: Mike Christie <mchristi@redhat.com>
To: Dmitry Fomichev <dmitry.fomichev@wdc.com>,
	linux-scsi@vger.kernel.org,
	"Martin K . Petersen" <martin.petersen@oracle.com>,
	target-devel@vger.kernel.org,
	Bart Van Assche <bvanassche@acm.org>
Cc: Damien Le Moal <damien.lemoal@wdc.com>
Subject: Re: [PATCH v2] tcmu: avoid use-after-free after command timeout
Date: Mon, 12 Aug 2019 15:30:19 +0000	[thread overview]
Message-ID: <5D51860B.1060902@redhat.com> (raw)
In-Reply-To: <20190811182510.1706-1-dmitry.fomichev@wdc.com>

On 08/11/2019 01:25 PM, Dmitry Fomichev wrote:
> In tcmu_handle_completion() function, the variable called read_len is
> always initialized with a value taken from se_cmd structure. If this
> function is called to complete an expired (timed out) out command, the
> session command pointed by se_cmd is likely to be already deallocated by
> the target core at that moment. As the result, this access triggers a
> use-after-free warning from KASAN.
> 
> This patch fixes the code not to touch se_cmd when completing timed out
> TCMU commands. It also resets the pointer to se_cmd at the time when the
> TCMU_CMD_BIT_EXPIRED flag is set because it is going to become invalid
> after calling target_complete_cmd() later in the same function,
> tcmu_check_expired_cmd().
> 
> Signed-off-by: Dmitry Fomichev <dmitry.fomichev@wdc.com>
> ---

Acked-by: Mike Christie <mchristi@redhat.com>

  reply	other threads:[~2019-08-12 15:30 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-08-11 18:25 [PATCH v2] tcmu: avoid use-after-free after command timeout Dmitry Fomichev
2019-08-11 18:25 ` Dmitry Fomichev
2019-08-12 15:30 ` Mike Christie [this message]
2019-08-12 15:30   ` Mike Christie
2019-08-12 18:00 ` Damien Le Moal
2019-08-15  2:00 ` Martin K. Petersen
2019-08-15  2:00   ` Martin K. Petersen

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