From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 7E6313BF037; Tue, 16 Dec 2025 13:17:19 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1765891039; cv=none; b=GYRLEBtCleE4rn+BhoJ+MK5aKQUIOhgFASvWL5DPC4Aa0FZWhQQ92CV4olpaOZGH0Hp3Wq/nVXhG6b7Tt69XmWTsY6dcdxnHSuce+zTeU2KREpumdgJEVUGbf+MLCmstqkF2UL/jIuC353VJuDS5PCUVRZaNpYzC2OFUjQ5NVD4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1765891039; c=relaxed/simple; bh=Uzy0fgkcQX6f9t0271Mwmb8XTbZ+/4XqFmPzVEey6CI=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=gMYfUEcj1RpLFbvXa206MQ0bNy5OEneB3ABZ3rh69JVVPJPnKrJw7nLJs5eoO35/f5vVIsFyu1BN/JhNFUL8Bs1hzaWWWF0q4frENWQgXh7kgFDFi/NdoUXRg9dizzFTKqSYf0gkBr2lkRcVGfL7Ex5SYUSmgfYnQriOevYTiHQ= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=Jv+AxyKx; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="Jv+AxyKx" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 38472C4CEF1; Tue, 16 Dec 2025 13:17:17 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1765891038; bh=Uzy0fgkcQX6f9t0271Mwmb8XTbZ+/4XqFmPzVEey6CI=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=Jv+AxyKxxfDwbbrc2i7GVrbe7mDxAji4gm5OsvxDzAMDAPJ7zD3lLGU7rsiVvxBIa B7nuRyum+JV6tgIoNGYbJpq6FgjxybHvUl6IEmSLrLkXdo8ddGmf4hoKvcdp+Zgn89 /NOJnmAxCqR7X/lsV1+YDnPdxj4E/vQk3V3kkUo52aZ7HZ6Qr40JnAQjR0cmdxJwTm rnZOQWjm3JPpd9NtTqj0hVW3v5jy3h0zFrjq0tde1jgHwpPZf2VAFgkd0JfKRQhoUv Ocvi/wH97J01bRzqXOPDQW/fiGz3Kub60dCNFjDY+mHECat4k1vWeE2iFfzaT743dW zEKuZEee8ABYw== Message-ID: <1f17a863-20c9-4004-ae8a-08cab5bde237@kernel.org> Date: Tue, 16 Dec 2025 14:17:15 +0100 Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v4] w1: therm: Fix off-by-one buffer overflow in alarms_store To: Thorsten Blum Cc: David Laight , Huisong Li , Akira Shimahara , Greg Kroah-Hartman , stable@vger.kernel.org, linux-kernel@vger.kernel.org References: <20251111204422.41993-2-thorsten.blum@linux.dev> <243ec26f-1fe1-4b3c-ab24-a6ebab163cde@kernel.org> <2434C572-231F-416D-AE42-BAE8AA86B52E@linux.dev> From: Krzysztof Kozlowski Content-Language: en-US Autocrypt: addr=krzk@kernel.org; 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charset=UTF-8 Content-Transfer-Encoding: 7bit On 16/12/2025 13:30, Thorsten Blum wrote: > On 16. Dec 2025, at 08:11, Krzysztof Kozlowski wrote: >> On 11/11/2025 21:44, Thorsten Blum wrote: >>> The sysfs buffer passed to alarms_store() is allocated with 'size + 1' >>> bytes and a NUL terminator is appended. However, the 'size' argument >>> does not account for this extra byte. The original code then allocated >>> 'size' bytes and used strcpy() to copy 'buf', which always writes one >>> byte past the allocated buffer since strcpy() copies until the NUL >>> terminator at index 'size'. >>> >>> Fix this by parsing the 'buf' parameter directly using simple_strtoll() >>> without allocating any intermediate memory or string copying. This >>> removes the overflow while simplifying the code. >>> >>> Cc: stable@vger.kernel.org >>> Fixes: e2c94d6f5720 ("w1_therm: adding alarm sysfs entry") >>> Signed-off-by: Thorsten Blum >>> --- >>> [...] >>> >>> + if (p == endp || *endp != ' ') >>> + ret = -EINVAL; >>> + else if (temp < INT_MIN || temp > INT_MAX) >>> + ret = -ERANGE; >>> if (ret) { >>> dev_info(device, >>> "%s: error parsing args %d\n", __func__, ret); >>> - goto free_m; >>> + goto err; >> >> So this is just return size. > > Yes, all 'goto err' could be replaced with 'return size'. I only renamed > the label to keep the changes minimal. You do not write commits to have minimal changes. That's not the goal. You organize commits in logical chunks doing one thing and doing it correctly. Empty goto label is not correct, thus should not stay. Best regards, Krzysztof