This patch fixes the following issues: 1. memstick_free_host() will free the host, so the use of ms_dev(host) after it will be a problem. To fix this, move memstick_free_host() after when we are done with ms_dev(host). 2. if something bad happens in memstick_add_host() and we end up taking err_out in rtsx_usb_ms_drv_probe(), we'd better avoid running rtsx_usb_ms_drv_remove() 3. In rtsx_usb_ms_drv_remove(), pm need to be disabled before we remove and free host otherwise memstick_check will be called and UAF will happen. [ 11.351173] BUG: KASAN: use-after-free in rtsx_usb_ms_drv_remove+0x94/0x140 [rtsx_usb_ms] [ 11.357077] rtsx_usb_ms_drv_remove+0x94/0x140 [rtsx_usb_ms] [ 11.357376] platform_remove+0x2a/0x50 [ 11.367531] Freed by task 298: [ 11.368537] kfree+0xa4/0x2a0 [ 11.368711] device_release+0x51/0xe0 [ 11.368905] kobject_put+0xa2/0x120 [ 11.369090] rtsx_usb_ms_drv_remove+0x8c/0x140 [rtsx_usb_ms] [ 11.369386] platform_remove+0x2a/0x50 [ 12.038408] BUG: KASAN: use-after-free in __mutex_lock.isra.0+0x3ec/0x7c0 [ 12.045432] mutex_lock+0xc9/0xd0 [ 12.046080] memstick_check+0x6a/0x578 [memstick] [ 12.046509] process_one_work+0x46d/0x750 [ 12.052107] Freed by task 297: [ 12.053115] kfree+0xa4/0x2a0 [ 12.053272] device_release+0x51/0xe0 [ 12.053463] kobject_put+0xa2/0x120 [ 12.053647] rtsx_usb_ms_drv_remove+0xc4/0x140 [rtsx_usb_ms] [ 12.053939] platform_remove+0x2a/0x50 Signed-off-by: Tong Zhang <ztong0001@xxxxxxxxx> --- drivers/memstick/host/rtsx_usb_ms.c | 13 +++++++------ 1 file changed, 7 insertions(+), 6 deletions(-) diff --git a/drivers/memstick/host/rtsx_usb_ms.c b/drivers/memstick/host/rtsx_usb_ms.c index 102dbb8080da..851643d007b7 100644 --- a/drivers/memstick/host/rtsx_usb_ms.c +++ b/drivers/memstick/host/rtsx_usb_ms.c @@ -799,9 +799,10 @@ static int rtsx_usb_ms_drv_probe(struct platform_device *pdev) return 0; err_out: - memstick_free_host(msh); pm_runtime_disable(ms_dev(host)); pm_runtime_put_noidle(ms_dev(host)); + memstick_free_host(msh); + platform_set_drvdata(pdev, NULL); return err; } @@ -811,6 +812,8 @@ static int rtsx_usb_ms_drv_remove(struct platform_device *pdev) struct memstick_host *msh = host->msh; int err; + if (!host) + return 0; host->eject = true; cancel_work_sync(&host->handle_req); @@ -828,9 +831,6 @@ static int rtsx_usb_ms_drv_remove(struct platform_device *pdev) } mutex_unlock(&host->host_mutex); - memstick_remove_host(msh); - memstick_free_host(msh); - /* Balance possible unbalanced usage count * e.g. unconditional module removal */ @@ -838,10 +838,11 @@ static int rtsx_usb_ms_drv_remove(struct platform_device *pdev) pm_runtime_put(ms_dev(host)); pm_runtime_disable(ms_dev(host)); - platform_set_drvdata(pdev, NULL); - + memstick_remove_host(msh); dev_dbg(ms_dev(host), ": Realtek USB Memstick controller has been removed\n"); + memstick_free_host(msh); + platform_set_drvdata(pdev, NULL); return 0; } -- 2.25.1
