From: Tong Zhang <ztong0001@gmail.com>
Subject: [PATCH] memstick: rtsx_usb_ms: fix UAF
Git-commit: 42933c8aa14be1caa9eda41f65cde8a3a95d3e39
Patch-mainline: v5.14-rc1
References: bsc#1194516
Signed-off-by: Tong Zhang <ztong0001@gmail.com>
Co-Developed-by: Ulf Hansson <ulf.hansson@linaro.org>
Signed-off-by: Vasant Karasulli <vkarasulli@suse.de>
---
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. 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
drivers/memstick/host/rtsx_usb_ms.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)
--- a/drivers/memstick/host/rtsx_usb_ms.c
+++ b/drivers/memstick/host/rtsx_usb_ms.c
@@ -798,8 +798,6 @@ static int rtsx_usb_ms_drv_remove(struct
mutex_unlock(&host->host_mutex);
wait_for_completion(&host->detect_ms_exit);
- memstick_remove_host(msh);
- memstick_free_host(msh);
/* Balance possible unbalanced usage count
* e.g. unconditional module removal
@@ -808,10 +806,12 @@ static int rtsx_usb_ms_drv_remove(struct
pm_runtime_put(ms_dev(host));
pm_runtime_disable(&pdev->dev);
- platform_set_drvdata(pdev, NULL);
+ memstick_remove_host(msh);
dev_dbg(&(pdev->dev),
": Realtek USB Memstick controller has been removed\n");
+ memstick_free_host(msh);
+ platform_set_drvdata(pdev, NULL);
return 0;
}