rsi: fix use-after-free on probe errors

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>

diff --git a/drivers/net/wireless/rsi/rsi_91x_hal.c b/drivers/net/wireless/rsi/rsi_91x_hal.c
index 01edf96..a7b341e 100644 (file)
--- a/drivers/net/wireless/rsi/rsi_91x_hal.c
+++ b/drivers/net/wireless/rsi/rsi_91x_hal.c
@@ -616,6 +616,7 @@ 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);
@@ -731,10 +732,9 @@ 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;
 }
 
@@ -822,10 +822,9 @@ 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;
 }
@@ -846,6 +845,7 @@ static int rsi_load_firmware(struct rsi_hw *adapter)
                status = hif_ops->master_reg_read(adapter, SWBL_REGOUT,
                                              &regout_val, 2);
                if (status < 0) {
+                       bl_stop_cmd_timer(adapter);
                        rsi_dbg(ERR_ZONE,
                                "%s: REGOUT read failed\n", __func__);
                        return status;