Re: [PATCH] ath11k: Fix buffer overflow when scanning with extraie

From: Kalle Valo <kvalo@kernel.org>
To: Sven Eckelmann <sven@narfation.org>
Cc: ath11k@lists.infradead.org, linux-wireless@vger.kernel.org,
	Wen Gong <quic_wgong@quicinc.com>,
	Sven Eckelmann <sven@narfation.org>,
	stable@vger.kernel.org
Subject: Re: [PATCH] ath11k: Fix buffer overflow when scanning with extraie
Date: Thu,  9 Dec 2021 07:59:19 +0000 (UTC)	[thread overview]
Message-ID: <163903675519.20904.4795349677435567607.kvalo@kernel.org> (raw)
In-Reply-To: <20211207142913.1734635-1-sven@narfation.org>

Sven Eckelmann <sven@narfation.org> wrote:

> If cfg80211 is providing extraie's for a scanning process then ath11k will
> copy that over to the firmware. The extraie.len is a 32 bit value in struct
> element_info and describes the amount of bytes for the vendor information
> elements.
> 
> The WMI_TLV packet is having a special WMI_TAG_ARRAY_BYTE section. This
> section can have a (payload) length up to 65535 bytes because the
> WMI_TLV_LEN can store up to 16 bits. The code was missing such a check and
> could have created a scan request which cannot be parsed correctly by the
> firmware.
> 
> But the bigger problem was the allocation of the buffer. It has to align
> the TLV sections by 4 bytes. But the code was using an u8 to store the
> newly calculated length of this section (with alignment). And the new
> calculated length was then used to allocate the skbuff. But the actual code
> to copy in the data is using the extraie.len and not the calculated
> "aligned" length.
> 
> The length of extraie with IEEE80211_HW_SINGLE_SCAN_ON_ALL_BANDS enabled
> was 264 bytes during tests with a QCA Milan card. But it only allocated 8
> bytes (264 bytes % 256) for it. As consequence, the code to memcpy the
> extraie into the skb was then just overwriting data after skb->end. Things
> like shinfo were therefore corrupted. This could usually be seen by a crash
> in skb_zcopy_clear which tried to call a ubuf_info callback (using a bogus
> address).
> 
> Tested-on: WCN6855 hw2.0 PCI WLAN.HSP.1.1-02892.1-QCAHSPSWPL_V1_V2_SILICONZ_LITE-1
> 
> Cc: stable@vger.kernel.org
> Fixes: d5c65159f289 ("ath11k: driver for Qualcomm IEEE 802.11ax devices")
> Signed-off-by: Sven Eckelmann <sven@narfation.org>
> Signed-off-by: Kalle Valo <quic_kvalo@quicinc.com>

Patch applied to ath-next branch of ath.git, thanks.

a658c929ded7 ath11k: Fix buffer overflow when scanning with extraie

-- 
https://patchwork.kernel.org/project/linux-wireless/patch/20211207142913.1734635-1-sven@narfation.org/

https://wireless.wiki.kernel.org/en/developers/documentation/submittingpatches