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From:   Felipe Balbi <balbi@kernel.org>
To:     Macpaul Lin <macpaul.lin@mediatek.com>,
        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: Re: [PATCH v2] usb: gadget: configfs: Fix use-after-free issue with
 udc_name
In-Reply-To: <1595040303-23046-1-git-send-email-macpaul.lin@mediatek.com>
References: <1594881666-8843-1-git-send-email-macpaul.lin@mediatek.com>
 <1595040303-23046-1-git-send-email-macpaul.lin@mediatek.com>
Date:   Tue, 27 Oct 2020 11:23:49 +0200
Message-ID: <87eelkc996.fsf@kernel.org>
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Hi,

Macpaul Lin <macpaul.lin@mediatek.com> writes:
> 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

patch doesn't apply:

$ patch -p1 --dry-run
/usr/bin/patch: **** Only garbage was found in the patch input.

Please resend using git send-email and make sure your smtp server sends
it as plain text, not base64.

=2D-=20
balbi

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