From: Felipe Balbi <balbi@kernel.org>
To: Jim Lin <jilin@nvidia.com>
Cc: linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org,
Jim Lin <jilin@nvidia.com>
Subject: Re: [PATCH v3] usb: gadget: configfs: Fix KASAN use-after-free
Date: Tue, 17 Jan 2017 12:29:09 +0200 [thread overview]
Message-ID: <878tqakmiy.fsf@linux.intel.com> (raw)
In-Reply-To: <1484647168-30135-1-git-send-email-jilin@nvidia.com>
[-- Attachment #1: Type: text/plain, Size: 1688 bytes --]
Hi,
Jim Lin <jilin@nvidia.com> writes:
> When gadget is disconnected, running sequence is like this.
> . composite_disconnect
> . Call trace:
> usb_string_copy+0xd0/0x128
> gadget_config_name_configuration_store+0x4
> gadget_config_name_attr_store+0x40/0x50
> configfs_write_file+0x198/0x1f4
> vfs_write+0x100/0x220
> SyS_write+0x58/0xa8
> . configfs_composite_unbind
> . configfs_composite_bind
>
> In configfs_composite_bind, it has
> "cn->strings.s = cn->configuration;"
>
> When usb_string_copy is invoked. it would
> allocate memory, copy input string, release previous pointed memory space,
> and use new allocated memory.
>
> When gadget is connected, host sends down request to get information.
> Call trace:
> usb_gadget_get_string+0xec/0x168
> lookup_string+0x64/0x98
> composite_setup+0xa34/0x1ee8
>
> If gadget is disconnected and connected quickly, in the failed case,
> cn->configuration memory has been released by usb_string_copy kfree but
> configfs_composite_bind hasn't been run in time to assign new allocated
> "cn->configuration" pointer to "cn->strings.s".
>
> When "strlen(s->s) of usb_gadget_get_string is being executed, the dangling
> memory is accessed, "BUG: KASAN: use-after-free" error occurs.
>
> Signed-off-by: Jim Lin <jilin@nvidia.com>
> ---
> Changes in v2:
> Changes in v3:
> Change commit description
well, I need to be sure you tested this with Linus' tree. The reason I'm
asking is because this could be a bug caused by Android changes. From
your previous patch, the problem started with android_setup().
Please test with v4.10-rc4 and any configfs-based gadget.
--
balbi
[-- Attachment #2: signature.asc --]
[-- Type: application/pgp-signature, Size: 832 bytes --]
next prev parent reply other threads:[~2017-01-17 10:31 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-01-17 9:59 [PATCH v3] usb: gadget: configfs: Fix KASAN use-after-free Jim Lin
2017-01-17 10:29 ` Felipe Balbi [this message]
2017-02-10 6:44 ` Macpaul Lin
2021-02-22 23:47 ` Thadeu Lima de Souza Cascardo
2021-03-11 6:42 ` [PATCH v4] " Macpaul Lin
2021-03-11 6:53 ` Macpaul Lin
2021-03-11 10:52 ` Thadeu Lima de Souza Cascardo
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=878tqakmiy.fsf@linux.intel.com \
--to=balbi@kernel.org \
--cc=jilin@nvidia.com \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-usb@vger.kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox