linux-kernel - Re: [PATCH v2] wifi: mt76: Fix strscpy buffer overflow in mt76_connac2_load

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [day] [month] [year] [list]

Message-ID: <9547b5e9-e6e8-4b24-82ac-e38327a54c45@kernel.org>
Date: Fri, 5 Dec 2025 12:14:13 -0600
From: Mario Limonciello <superm1@...nel.org>
To: Mikhail Gavrilov <mikhail.v.gavrilov@...il.com>
Cc: Felix Fietkau <nbd@....name>, Lorenzo Bianconi <lorenzo@...nel.org>,
 linux-wireless@...r.kernel.org, linux-mediatek@...ts.infradead.org,
 linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2] wifi: mt76: Fix strscpy buffer overflow in
 mt76_connac2_load_patch

On 12/5/25 10:12 AM, Mikhail Gavrilov wrote:
> Commit f804a5895eba ("wifi: mt76: Strip whitespace from build ddate") introduced
> a kernel panic/WARN on systems using MediaTek MT7921e (and potentially others
> using mt76_connac_lib) due to an incorrect buffer size calculation.
> 
> The error logged is:
> "strnlen: detected buffer overflow: 17 byte read of buffer size 16"
> 
> This occurs because the field 'hdr->build_date' is a fixed-size array of 16 bytes.
> The patch allocated a 17-byte local buffer 'build_date' but used 'sizeof(build_date)'
> (17) as the read limit for strscpy, causing Fortify Source to correctly detect
> an attempt to read 17 bytes from the 16-byte source field.
> 
> To fix this, replace strscpy with memcpy, which is appropriate for raw data
> copying, and explicitly use the size of the source field (sizeof(hdr->build_date) = 16)
> to limit the read, followed by manual null termination.
> 
> Fixes: f804a5895eba ("wifi: mt76: Strip whitespace from build ddate")
> Signed-off-by: Mikhail Gavrilov <mikhail.v.gavrilov@...il.com>

Reviewed-by: Mario Limonciello (AMD) <superm1@...nel.org>

> ---
>   drivers/net/wireless/mediatek/mt76/mt76_connac_mcu.c | 7 +++++--
>   1 file changed, 5 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/net/wireless/mediatek/mt76/mt76_connac_mcu.c b/drivers/net/wireless/mediatek/mt76/mt76_connac_mcu.c
> index ea99167765b0..d2c4c65ec464 100644
> --- a/drivers/net/wireless/mediatek/mt76/mt76_connac_mcu.c
> +++ b/drivers/net/wireless/mediatek/mt76/mt76_connac_mcu.c
> @@ -3125,8 +3125,11 @@ int mt76_connac2_load_patch(struct mt76_dev *dev, const char *fw_name)
>   	}
>   
>   	hdr = (const void *)fw->data;
> -	strscpy(build_date, hdr->build_date, sizeof(build_date));
> -	build_date[16] = '\0';
> +	/* hdr->build_date is 16 bytes. Copy exactly 16 bytes to the 17-byte buffer,
> +	 * and then add the null terminator at index 16.
> +	 */
> +	memcpy(build_date, hdr->build_date, sizeof(hdr->build_date));
> +	build_date[sizeof(hdr->build_date)] = '\0';
>   	strim(build_date);
>   	dev_info(dev->dev, "HW/SW Version: 0x%x, Build Time: %.16s\n",
>   		 be32_to_cpu(hdr->hw_sw_ver), build_date);