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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org,
        syzbot+1d1597a5aa3679c65b9f@syzkaller.appspotmail.com,
        Prameela Rani Garnepudi <prameela.j04cs@gmail.com>,
        Amitkumar Karwar <amit.karwar@redpinesignals.com>,
        Johan Hovold <johan@kernel.org>,
        Kalle Valo <kvalo@codeaurora.org>
Subject: [PATCH 5.5 47/56] rsi: fix use-after-free on probe errors
Date:   Thu, 30 Jan 2020 19:39:04 +0100
Message-Id: <20200130183617.490446841@linuxfoundation.org>
In-Reply-To: <20200130183608.849023566@linuxfoundation.org>
References: <20200130183608.849023566@linuxfoundation.org>
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From: Johan Hovold <johan@kernel.org>

commit 92aafe77123ab478e5f5095878856ab0424910da upstream.

The driver would fail to stop the command timer in most error paths,
something which specifically could lead to the timer being freed while
still active on I/O errors during probe.

Fix this by making sure that each function starting the timer also stops
it in all relevant error paths.

Reported-by: syzbot+1d1597a5aa3679c65b9f@syzkaller.appspotmail.com
Fixes: b78e91bcfb33 ("rsi: Add new firmware loading method")
Cc: stable <stable@vger.kernel.org>     # 4.12
Cc: Prameela Rani Garnepudi <prameela.j04cs@gmail.com>
Cc: Amitkumar Karwar <amit.karwar@redpinesignals.com>
Signed-off-by: Johan Hovold <johan@kernel.org>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 drivers/net/wireless/rsi/rsi_91x_hal.c |   12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

--- a/drivers/net/wireless/rsi/rsi_91x_hal.c
+++ b/drivers/net/wireless/rsi/rsi_91x_hal.c
@@ -622,6 +622,7 @@ static int bl_cmd(struct rsi_hw *adapter
 	bl_start_cmd_timer(adapter, timeout);
 	status = bl_write_cmd(adapter, cmd, exp_resp, &regout_val);
 	if (status < 0) {
+		bl_stop_cmd_timer(adapter);
 		rsi_dbg(ERR_ZONE,
 			"%s: Command %s (%0x) writing failed..\n",
 			__func__, str, cmd);
@@ -737,10 +738,9 @@ static int ping_pong_write(struct rsi_hw
 	}
 
 	status = bl_cmd(adapter, cmd_req, cmd_resp, str);
-	if (status) {
-		bl_stop_cmd_timer(adapter);
+	if (status)
 		return status;
-	}
+
 	return 0;
 }
 
@@ -828,10 +828,9 @@ static int auto_fw_upgrade(struct rsi_hw
 
 	status = bl_cmd(adapter, EOF_REACHED, FW_LOADING_SUCCESSFUL,
 			"EOF_REACHED");
-	if (status) {
-		bl_stop_cmd_timer(adapter);
+	if (status)
 		return status;
-	}
+
 	rsi_dbg(INFO_ZONE, "FW loading is done and FW is running..\n");
 	return 0;
 }
@@ -849,6 +848,7 @@ static int rsi_hal_prepare_fwload(struct
 						  &regout_val,
 						  RSI_COMMON_REG_SIZE);
 		if (status < 0) {
+			bl_stop_cmd_timer(adapter);
 			rsi_dbg(ERR_ZONE,
 				"%s: REGOUT read failed\n", __func__);
 			return status;