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: 13+ 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 6:42 ` Macpaul Lin
2021-03-11 6:42 ` Macpaul Lin
2021-03-11 6:53 ` Macpaul Lin
2021-03-11 6:53 ` Macpaul Lin
2021-03-11 6:53 ` Macpaul Lin
2021-03-11 10:52 ` Thadeu Lima de Souza Cascardo
2021-03-11 10:52 ` Thadeu Lima de Souza Cascardo
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 an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.