Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67;
To:     Corey Minyard <minyard@acm.org>
CC:     Dimitri Sivanich <sivanich@hpe.com>,
        "Anderson, Russ" <russ.anderson@hpe.com>,
        Mike Travis <mike.travis@hpe.com>,
        <openipmi-developer@lists.sourceforge.net>,
        <linux-kernel@vger.kernel.org>
From:   Andrew Banman <abanman@hpe.com>
Subject: [PATCH] drivers/char/ipmi_si: prevent null deref during module exit
Message-ID: <988aec06-2127-3120-47a4-5d0131f59a61@hpe.com>
Date:   Wed, 8 Nov 2017 11:06:03 -0600
User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.12; rv:52.0)
 Gecko/20100101 Thunderbird/52.4.0
MIME-Version: 1.0
Content-Type: text/plain; charset=utf-8; format=flowed
Content-Language: en-US
Content-Transfer-Encoding: 7bit
Received-SPF: None (protection.outlook.com: hpe.com does not designate
 permitted sender hosts)
SpamDiagnosticOutput: 1:99
SpamDiagnosticMetadata: NSPM
X-MS-Exchange-CrossTenant-OriginalArrivalTime: 08 Nov 2017 17:06:13.7974 (UTC)
X-MS-Exchange-CrossTenant-Network-Message-Id: 1acae910-067f-46b4-6660-08d526cb04bf
X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted
X-MS-Exchange-CrossTenant-Id: 105b2061-b669-4b31-92ac-24d304d195dc
X-MS-Exchange-Transport-CrossTenantHeadersStamped: AT5PR8401MB0353
X-OriginatorOrg: hpe.com
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk
List-ID: <linux-kernel.vger.kernel.org>
X-Mailing-List: linux-kernel@vger.kernel.org

If there are uninitialized SMIs in the smi_infos list, i.e. with no
handlers set, then disable_si_irq() in cleanup_smi_one() will hit a null
pointer dereference when the former attempts to start the check enables
transaction. Thus, we panic during module exit.

Avoid panicking when there are uninitialized SMIs by checking for a handler
pointer before starting the check enables transaction.

Signed-off-by: Andrew Banman <abanman@hpe.com>
---
  drivers/char/ipmi/ipmi_si_intf.c | 2 +-
  1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/char/ipmi/ipmi_si_intf.c b/drivers/char/ipmi/ipmi_si_intf.c
index cb5719e..6c0b1b3 100644
--- a/drivers/char/ipmi/ipmi_si_intf.c
+++ b/drivers/char/ipmi/ipmi_si_intf.c
@@ -442,7 +442,7 @@ static void start_check_enables(struct smi_info *smi_info, 
bool start_timer)

  	if (start_timer)
  		start_new_msg(smi_info, msg, 2);
-	else
+	else if (smi_info->handlers)
  		smi_info->handlers->start_transaction(smi_info->si_sm, msg, 2);
  	smi_info->si_state = SI_CHECKING_ENABLES;
  }
-- 
1.8.2.1

From 1583622245827870972@xxx Thu Nov 09 20:37:42 +0000 2017
X-GM-THRID: 1583622245827870972
X-Gmail-Labels: Inbox,Category Forums,HistoricalUnread