From: Arend Van Spriel <aspriel@gmail.com>
To: Dokyung Song <dokyung.song@gmail.com>, linux-wireless@vger.kernel.org
Cc: Jisoo Jang <jisoo.jang@yonsei.ac.kr>,
Minsuk Kang <linuxlovemin@yonsei.ac.kr>
Subject: Re: [PATCH] brcmfmac: Fixes potential buffer overflow in 'brcmf_fweh_event_worker'
Date: Thu, 20 Oct 2022 10:39:14 +0200 [thread overview]
Message-ID: <649de84e-6f9a-5c6b-9a94-a7c6462abd1f@gmail.com> (raw)
In-Reply-To: <20221020014907.GA338234@laguna>
On 10/20/2022 3:49 AM, Dokyung Song wrote:
> This patch fixes an intra-object buffer overflow in brcmfmac that occurs
> when the device provides a 'bsscfgidx' equal to or greater than the
> buffer size. The patch adds a check that leads to a safe failure if that
> is the case.
>
> Found by a modified version of syzkaller.
>
> UBSAN: array-index-out-of-bounds in drivers/net/wireless/broadcom/brcm80211/brcmfmac/fweh.c
> index 52 is out of range for type 'brcmf_if *[16]'
> CPU: 0 PID: 1898 Comm: kworker/0:2 Tainted: G O 5.14.0+ #132
[...]
> Kernel panic - not syncing: Fatal exception
>
> Reported-by: Dokyung Song <dokyungs@yonsei.ac.kr>
> Reported-by: Jisoo Jang <jisoo.jang@yonsei.ac.kr>
> Reported-by: Minsuk Kang <linuxlovemin@yonsei.ac.kr>
Not sure what the rules are for using 'Reported-by' tag, but it looks a
bit odd. I leave it to the wireless maintainer.
Reviewed-by: Arend van Spriel <aspriel@gmail.com>
> Signed-off-by: Dokyung Song <dokyung.song@gmail.com>
> ---
> drivers/net/wireless/broadcom/brcm80211/brcmfmac/fweh.c | 9 +++++++--
> 1 file changed, 7 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/net/wireless/broadcom/brcm80211/brcmfmac/fweh.c b/drivers/net/wireless/broadcom/brcm80211/brcmfmac/fweh.c
> index bc3f4e4edcdf..e035e9c5a1fa 100644
> --- a/drivers/net/wireless/broadcom/brcm80211/brcmfmac/fweh.c
> +++ b/drivers/net/wireless/broadcom/brcm80211/brcmfmac/fweh.c
> @@ -255,10 +255,15 @@ static void brcmf_fweh_event_worker(struct work_struct *work)
> goto event_free;
> }
>
> - if (event->code == BRCMF_E_TDLS_PEER_EVENT)
> + if (event->code == BRCMF_E_TDLS_PEER_EVENT) {
> ifp = drvr->iflist[0];
> - else
> + } else {
> + if (emsg.bsscfgidx >= BRCMF_MAX_IFS) {
> + bphy_err(drvr, "invalid bsscfg index: %u\n", emsg.bsscfgidx);
> + goto event_free;
> + }
probably better to do the validation before any other handling. So right
after converting the event message at line 245
https://elixir.bootlin.com/linux/latest/source/drivers/net/wireless/broadcom/brcm80211/brcmfmac/fweh.c#L245
> ifp = drvr->iflist[emsg.bsscfgidx];
> + }
> err = brcmf_fweh_call_event_handler(drvr, ifp, event->code,
> &emsg, event->data);
> if (err) {
next prev parent reply other threads:[~2022-10-20 8:39 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-10-20 1:49 [PATCH] brcmfmac: Fixes potential buffer overflow in 'brcmf_fweh_event_worker' Dokyung Song
2022-10-20 8:39 ` Arend Van Spriel [this message]
2022-10-20 8:41 ` Arend Van Spriel
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