From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 76C091FBEA8; Sat, 6 Jun 2026 11:13:50 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1780744431; cv=none; b=T8VF3BK0KYuTr18ucvvxNtbKEsoMx9fzJaGCAHU/mZjhg+Lrp+PeYL+eErMOwTt0ERaMsB33vkUMpu9m9qxuHqjR4hYOQEWas4ayz15N8VMeqsTXH9qTzCNyLz7QGa+FzatbgQwsZblDPQtp+oUWEP7KYPjG08R8Y9jGyIpY8Zg= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1780744431; c=relaxed/simple; bh=nW2HdQZ6n+UZ+FOPTHxUrUewVTTRRSTQSZZk2cIXkkU=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=SwyypiuHEi4a+ZbvvapgUugidQB8vZaAnGfClGqE5ygMidXdlHQd+D4yMGKGB0fXfQohF88vP2iofmJRjGOgp1IFEPe915exVl2Qh8370C9L2eEIlp/fedJvMaJDGeSvo0iJg2dhPzITkoF/kLy/IqU8i9PFUxQAbgiBPob5fNs= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=cS4kPnx2; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="cS4kPnx2" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 529941F00893; Sat, 6 Jun 2026 11:13:48 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1780744430; bh=PheX0ujO7m4BxaxU1tH0lqegKY0NzktsHsQZuyOOZ9c=; h=Date:Subject:To:Cc:References:From:In-Reply-To; b=cS4kPnx2dsb94QH+UZ4va0+wLDPRKESEBr73rr/2ZfEW7g7zDWOx5P+5msqwJkCdr wN2H4AsD8FG9XQ6sI8RB37qyh5I4MZCBYc/WWpwea7aXC2lsa+kmt+hfgJ3Sb/Mn1i 5Hb3Me4s4lqsyzlTXuhgMeMaSivgZtAZu46/PFt1ICOJgHTLVRleePiXa/25rrpMc1 U6xBM9h5BO+GPHwlGxGf/BJOJL9+T0jQcZgee5eFt+7p57gsvUL3FHy/324089C+p/ Arv8Sfwl0KPJVZSDK9/suQQviIHue1zrTvojpU589LRNlaFUv+ZW9iV1ktZnZtVcFM t6xG/3Wp9MsGg== Message-ID: <537d4aa4-789b-4962-ab0f-78602d2b5f1a@kernel.org> Date: Sat, 6 Jun 2026 12:13:46 +0100 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v4 3/3] media: iris: Add Gen2 firmware autodetect and fallback To: Dmitry Baryshkov Cc: Dikshita Agarwal , Vikash Garodia , Abhinav Kumar , Mauro Carvalho Chehab , Vishnu Reddy , Hans Verkuil , linux-media@vger.kernel.org, linux-arm-msm@vger.kernel.org, linux-kernel@vger.kernel.org References: <20260429-kodiak-gen2-support-v4-v4-0-1b607d13f9b8@oss.qualcomm.com> <20260429-kodiak-gen2-support-v4-v4-3-1b607d13f9b8@oss.qualcomm.com> <178018459824.10222.12026103622148092471.b4-reply@b4> From: Bryan O'Donoghue Content-Language: en-US Autocrypt: addr=bod@kernel.org; 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charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit On 06/06/2026 11:51, Dmitry Baryshkov wrote: >> version = strnstr(data, marker, size); > strnstr is defined to search for the substring in another string. There > is no promise that it will work if data contains \0 chars (which would > terminate the string). I mean... we'd want to terminate on a NULL here I'd have thought. The subsequent strscpy, strncmp and sscanf in this routine would imply NULL termination. No wait I see - the strscpy() in the original creates a putatively NULL terminated string from potentially non-NULL terminated data. The key question is if this is a NULL terminated string or not. If not we would expect a header somewhere telling us the field length. >> if (version) { >> marker_off = version - data; >> version += marker_len; >> size -= marker_off + marker_len; >> >> if (version < terminator-3) { >> /* This is safe because we bounds check */ >> if (strncmp("vfw", version, size) == 0) >> return true; >> } >> >> /* To do your sscanf() you need to create a zeorised buffer */ >> fat_buf = kzalloc(size+1, GFP_KERNEL); >> if (!fat_buf) >> return false; >> >> memcpy(fat_buf, version, size); > Creating a copy of about the half of the image is definitely an > overkill. The image size part I wasn't sure about - were we dealing with a defined header or the _entire_ image with the given size. That said - why are we scanning the entire image if size == sizeof(fw) anyway ? There must be a maximum header size and if not a maximum we would be prepared to parse in-kernel - say the first 1k or 4k at max. ... >> /* sscanf is now guaranteed to terminate on NULL */ >> if (sscanf(fat_buf, "video-firmware.%d.%d", &major, &minor) == 2) { > I think we can replace this with string comparisons too. No need to > sscanf it. > > WDYT? I'm just as happy with that. It was really this code "looked wrong" and so I dug into it a little bit. The overflow is real. The size you pointed out is true. Take the suggested changes with a pinch of salt. This is the part that really pinged me + for (size_t i = 0; i < max; i++) { + if (!memcmp(data + i, marker, mlen)) { Iterating a string for a memcmp() instead of using standard string libs, only then when I looked did I see the overflow. So long as that gets fixed I'm sanguine about the rest. --- bod