rsi: fix use-after-free on probe errors

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>

diff --git a/drivers/net/wireless/rsi/rsi_91x_hal.c b/drivers/net/wireless/rsi/rsi_91x_hal.c
index f84250bdb8cf85196bc517eb30c3ddfe263eefa0..6f8d5f9a9f7e6af270d49202a02b4d4a23bed2d4 100644 (file)
--- 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, u8 cmd, u8 exp_resp, char *str)
        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 *adapter, u8 cmd, u8 *addr, u32 size)
        }
 
        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 *adapter, u8 *flash_content,
 
        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 rsi_hw *adapter)
                                                  &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;