From: "Sönke Huster" <soenke.huster@eknoes.de>
To: Marcel Holtmann <marcel@holtmann.org>,
Johan Hedberg <johan.hedberg@gmail.com>,
Luiz Augusto von Dentz <luiz.dentz@gmail.com>,
"David S. Miller" <davem@davemloft.net>,
Jakub Kicinski <kuba@kernel.org>
Cc: linux-bluetooth@vger.kernel.org, netdev@vger.kernel.org,
linux-kernel@vger.kernel.org
Subject: Re: [RFC PATCH] Bluetooth: hci_event: Ignore multiple conn complete events
Date: Fri, 21 Jan 2022 19:22:10 +0100 [thread overview]
Message-ID: <4f3d6dcf-c142-9a99-df97-6190c8f2abc9@eknoes.de> (raw)
In-Reply-To: <20220121173622.192744-1-soenke.huster@eknoes.de>
I just noticed that just checking for handle does not work, as obviously 0x0 could also be a handle value and therefore it can't be distinguished, whether it is not set yet or it is 0x0.
On 21.01.22 18:36, Soenke Huster wrote:
> When a HCI_CONNECTION_COMPLETE event is received multiple times
> for the same handle, the device is registered multiple times which leads
> to memory corruptions. Therefore, consequent events for a single
> connection are ignored.
>
> The conn->state can hold different values so conn->handle is
> checked to detect whether a connection is already set up.
>
> Buglink: https://bugzilla.kernel.org/show_bug.cgi?id=215497
> Signed-off-by: Soenke Huster <soenke.huster@eknoes.de>
> ---
> This fixes the referenced bug and several use-after-free issues I discovered.
> I tagged it as RFC, as I am not 100% sure if checking the existence of the
> handle is the correct approach, but to the best of my knowledge it must be
> set for the first time in this function for valid connections of this event,
> therefore it should be fine.
>
> net/bluetooth/hci_event.c | 11 +++++++++++
> 1 file changed, 11 insertions(+)
>
> diff --git a/net/bluetooth/hci_event.c b/net/bluetooth/hci_event.c
> index 681c623aa380..71ccb12c928d 100644
> --- a/net/bluetooth/hci_event.c
> +++ b/net/bluetooth/hci_event.c
> @@ -3106,6 +3106,17 @@ static void hci_conn_complete_evt(struct hci_dev *hdev, void *data,
> }
> }
>
> + /* The HCI_Connection_Complete event is only sent once per connection.
> + * Processing it more than once per connection can corrupt kernel memory.
> + *
> + * As the connection handle is set here for the first time, it indicates
> + * whether the connection is already set up.
> + */
> + if (conn->handle) {
> + bt_dev_err(hdev, "Ignoring HCI_Connection_Complete for existing connection");
> + goto unlock;
> + }
> +
> if (!ev->status) {
> conn->handle = __le16_to_cpu(ev->handle);
>
next prev parent reply other threads:[~2022-01-21 18:22 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-01-21 17:36 [RFC PATCH] Bluetooth: hci_event: Ignore multiple conn complete events Soenke Huster
2022-01-21 18:04 ` [RFC] " bluez.test.bot
2022-01-21 18:22 ` Sönke Huster [this message]
2022-01-21 21:31 ` [RFC PATCH] " Luiz Augusto von Dentz
2022-01-21 23:18 ` Sönke Huster
2022-01-21 23:32 ` Luiz Augusto von Dentz
2022-01-21 23:52 ` Sönke Huster
2022-01-22 0:06 ` Luiz Augusto von Dentz
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=4f3d6dcf-c142-9a99-df97-6190c8f2abc9@eknoes.de \
--to=soenke.huster@eknoes.de \
--cc=davem@davemloft.net \
--cc=johan.hedberg@gmail.com \
--cc=kuba@kernel.org \
--cc=linux-bluetooth@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=luiz.dentz@gmail.com \
--cc=marcel@holtmann.org \
--cc=netdev@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;
as well as URLs for NNTP newsgroup(s).