From: Macpaul Lin <macpaul.lin@mediatek.com>
To: Felipe Balbi <balbi@kernel.org>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Matthias Brugger <matthias.bgg@gmail.com>,
<linux-usb@vger.kernel.org>, <linux-kernel@vger.kernel.org>,
<linux-arm-kernel@lists.infradead.org>,
<linux-mediatek@lists.infradead.org>
Cc: Mediatek WSD Upstream <wsd_upstream@mediatek.com>,
Macpaul Lin <macpaul.lin@mediatek.com>,
Macpaul Lin <macpaul.lin@gmail.com>,
Eddie Hung <eddie.hung@mediatek.com>, <stable@vger.kernel.org>
Subject: [PATCH v2] usb: gadget: configfs: Fix use-after-free issue with udc_name
Date: Sat, 18 Jul 2020 10:45:03 +0800 [thread overview]
Message-ID: <1595040303-23046-1-git-send-email-macpaul.lin@mediatek.com> (raw)
In-Reply-To: <1594881666-8843-1-git-send-email-macpaul.lin@mediatek.com>
From: Eddie Hung <eddie.hung@mediatek.com>
There is a use-after-free issue, if access udc_name
in function gadget_dev_desc_UDC_store after another context
free udc_name in function unregister_gadget.
Context 1:
gadget_dev_desc_UDC_store()->unregister_gadget()->
free udc_name->set udc_name to NULL
Context 2:
gadget_dev_desc_UDC_show()-> access udc_name
Call trace:
dump_backtrace+0x0/0x340
show_stack+0x14/0x1c
dump_stack+0xe4/0x134
print_address_description+0x78/0x478
__kasan_report+0x270/0x2ec
kasan_report+0x10/0x18
__asan_report_load1_noabort+0x18/0x20
string+0xf4/0x138
vsnprintf+0x428/0x14d0
sprintf+0xe4/0x12c
gadget_dev_desc_UDC_show+0x54/0x64
configfs_read_file+0x210/0x3a0
__vfs_read+0xf0/0x49c
vfs_read+0x130/0x2b4
SyS_read+0x114/0x208
el0_svc_naked+0x34/0x38
Add mutex_lock to protect this kind of scenario.
Signed-off-by: Eddie Hung <eddie.hung@mediatek.com>
Signed-off-by: Macpaul Lin <macpaul.lin@mediatek.com>
Reviewed-by: Peter Chen <peter.chen@nxp.com>
Cc: stable@vger.kernel.org
---
Changes for v2:
- Fix typo %s/contex/context, Thanks Peter.
drivers/usb/gadget/configfs.c | 11 +++++++++--
1 file changed, 9 insertions(+), 2 deletions(-)
diff --git a/drivers/usb/gadget/configfs.c b/drivers/usb/gadget/configfs.c
index 9dc06a4e1b30..21110b2865b9 100644
--- a/drivers/usb/gadget/configfs.c
+++ b/drivers/usb/gadget/configfs.c
@@ -221,9 +221,16 @@ static ssize_t gadget_dev_desc_bcdUSB_store(struct config_item *item,
static ssize_t gadget_dev_desc_UDC_show(struct config_item *item, char *page)
{
- char *udc_name = to_gadget_info(item)->composite.gadget_driver.udc_name;
+ struct gadget_info *gi = to_gadget_info(item);
+ char *udc_name;
+ int ret;
+
+ mutex_lock(&gi->lock);
+ udc_name = gi->composite.gadget_driver.udc_name;
+ ret = sprintf(page, "%s\n", udc_name ?: "");
+ mutex_unlock(&gi->lock);
- return sprintf(page, "%s\n", udc_name ?: "");
+ return ret;
}
static int unregister_gadget(struct gadget_info *gi)
--
2.18.0
next prev parent reply other threads:[~2020-07-18 2:45 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-07-16 6:41 [PATCH] usb: gadget: configfs: Fix use-after-free issue with udc_name Macpaul Lin
2020-07-17 4:14 ` Peter Chen
2020-07-18 2:45 ` Macpaul Lin [this message]
2020-07-18 2:58 ` [PATCH v2] " Macpaul Lin
2020-07-21 11:33 ` Greg Kroah-Hartman
2020-07-22 1:59 ` Macpaul Lin
2020-10-20 6:36 ` Macpaul Lin
2020-10-27 9:23 ` Felipe Balbi
2020-11-01 5:37 ` [RESEND PATCH " Macpaul Lin
2020-12-29 10:53 ` [PATCH RESEND " Macpaul Lin
2020-10-28 17:55 [PATCH " Macpaul Lin
2020-10-28 17:59 ` Macpaul Lin
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