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 38150346AED; Fri, 29 May 2026 07:24:59 +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=1780039500; cv=none; b=O8u27qeQluxbh8BShDuR57begRTsW4hqaFQ136oAcxhCHOzGvQYqwUFujSRKjal+iNyGawhk21b+/tHk7s8ndqNDJE6zttCOXey5oGYZKKVcaqygWLWf0pBdZBMxAoOs1KU9Vywn8k5vsvG5OcPwHzxtIP2Q3bF0bsAS3slHLaQ= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1780039500; c=relaxed/simple; bh=2R5oHGU5OdKZY1fD25B4PhKEE4T7fbngpgZK5vskLTA=; h=Message-ID:Date:MIME-Version:Subject:From:To:Cc:References: In-Reply-To:Content-Type; b=qK014oMERfEkkQM5CmzBw+maYJYaBNrbrvY2Is4I/HC5OhRq99pQElqh/G708A7LA9eao1S8mDHptMGNrtB4uTg6de8lt8mLYCylVfWgUGoc+kykV1nPC9YpLPFydr6jnQD7I7Q6HzKUmwcJCe5Efxnz1kQJZkEtY3dr5Y1vBtw= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=O1pmhqHk; 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="O1pmhqHk" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 4A0531F00893; Fri, 29 May 2026 07:24:57 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1780039498; bh=jR+xvQdEmfj6RfdjxBg9oj+w5NnlUyFOZVS8ITNSMgU=; h=Date:Subject:From:To:Cc:References:In-Reply-To; b=O1pmhqHkAOn+lEzZWZokVLkWzIXavWRolKOwQlXIBVZfFRs2WZVjOXCII+NMfKvOB A9KPGFCqlthc4o8nWnfwS6lzIbNy0QCJITp7CnoKqVP8sRBnG9eaxNzOqX3/abQbuj JeV8mwAlsbOO+ImszvIwy81ZaSwqMtDjytAm98OzDLxU8+M1fX9SEHP9Oid1yKfa/a JMOvi1QUewsOGDZDI69cdu2Wx+cZ0hiuM8aNOPRJh105xnZs889zAmb7AHCju/zz+G HlpWIjKW2JiOWhzwubTdIiF79MDjp7VqR7fDaD4Ce6jQWjRkBigiqFeBA6304bQbvI kQsSdqqxUT2QA== Message-ID: <79e9e913-0fb1-4110-804b-c3b5d0edafe4@kernel.org> Date: Fri, 29 May 2026 09:24:55 +0200 Precedence: bulk X-Mailing-List: linux-hardening@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH] ACPICA: Replace strncpy() with strscpy_pad() in acpi_ut_safe_strncpy() From: Jiri Slaby To: "Rafael J. Wysocki" , Kees Cook Cc: Robert Moore , Len Brown , linux-kernel@vger.kernel.org, linux-acpi@vger.kernel.org, acpica-devel@lists.linux.dev, linux-hardening@vger.kernel.org References: <20260323172451.work.079-kees@kernel.org> <405e97ae-72a1-4086-bef3-cf462619f661@kernel.org> Content-Language: en-US Autocrypt: addr=jirislaby@kernel.org; keydata= xsFNBE6S54YBEACzzjLwDUbU5elY4GTg/NdotjA0jyyJtYI86wdKraekbNE0bC4zV+ryvH4j rrcDwGs6tFVrAHvdHeIdI07s1iIx5R/ndcHwt4fvI8CL5PzPmn5J+h0WERR5rFprRh6axhOk rSD5CwQl19fm4AJCS6A9GJtOoiLpWn2/IbogPc71jQVrupZYYx51rAaHZ0D2KYK/uhfc6neJ i0WqPlbtIlIrpvWxckucNu6ZwXjFY0f3qIRg3Vqh5QxPkojGsq9tXVFVLEkSVz6FoqCHrUTx wr+aw6qqQVgvT/McQtsI0S66uIkQjzPUrgAEtWUv76rM4ekqL9stHyvTGw0Fjsualwb0Gwdx ReTZzMgheAyoy/umIOKrSEpWouVoBt5FFSZUyjuDdlPPYyPav+hpI6ggmCTld3u2hyiHji2H cDpcLM2LMhlHBipu80s9anNeZhCANDhbC5E+NZmuwgzHBcan8WC7xsPXPaiZSIm7TKaVoOcL 9tE5aN3jQmIlrT7ZUX52Ff/hSdx/JKDP3YMNtt4B0cH6ejIjtqTd+Ge8sSttsnNM0CQUkXps w98jwz+Lxw/bKMr3NSnnFpUZaxwji3BC9vYyxKMAwNelBCHEgS/OAa3EJoTfuYOK6wT6nadm YqYjwYbZE5V/SwzMbpWu7Jwlvuwyfo5mh7w5iMfnZE+vHFwp/wARAQABzSFKaXJpIFNsYWJ5 IDxqaXJpc2xhYnlAa2VybmVsLm9yZz7CwXcEEwEIACEFAlW3RUwCGwMFCwkIBwIGFQgJCgsC BBYCAwECHgECF4AACgkQvSWxBAa0cEnVTg//TQpdIAr8Tn0VAeUjdVIH9XCFw+cPSU+zMSCH eCZoA/N6gitEcnvHoFVVM7b3hK2HgoFUNbmYC0RdcSc80pOF5gCnACSP9XWHGWzeKCARRcQR 4s5YD8I4VV5hqXcKo2DFAtIOVbHDW+0okOzcecdasCakUTr7s2fXz97uuoc2gIBB7bmHUGAH XQXHvdnCLjDjR+eJN+zrtbqZKYSfj89s/ZHn5Slug6w8qOPT1sVNGG+eWPlc5s7XYhT9z66E l5C0rG35JE4PhC+tl7BaE5IwjJlBMHf/cMJxNHAYoQ1hWQCKOfMDQ6bsEr++kGUCbHkrEFwD UVA72iLnnnlZCMevwE4hc0zVhseWhPc/KMYObU1sDGqaCesRLkE3tiE7X2cikmj/qH0CoMWe gjnwnQ2qVJcaPSzJ4QITvchEQ+tbuVAyvn9H+9MkdT7b7b2OaqYsUP8rn/2k1Td5zknUz7iF oJ0Z9wPTl6tDfF8phaMIPISYrhceVOIoL+rWfaikhBulZTIT5ihieY9nQOw6vhOfWkYvv0Dl o4GRnb2ybPQpfEs7WtetOsUgiUbfljTgILFw3CsPW8JESOGQc0Pv8ieznIighqPPFz9g+zSu Ss/rpcsqag5n9rQp/H3WW5zKUpeYcKGaPDp/vSUovMcjp8USIhzBBrmI7UWAtuedG9prjqfO wU0ETpLnhgEQAM+cDWLL+Wvc9cLhA2OXZ/gMmu7NbYKjfth1UyOuBd5emIO+d4RfFM02XFTI t4MxwhAryhsKQQcA4iQNldkbyeviYrPKWjLTjRXT5cD2lpWzr+Jx7mX7InV5JOz1Qq+P+nJW YIBjUKhI03ux89p58CYil24Zpyn2F5cX7U+inY8lJIBwLPBnc9Z0An/DVnUOD+0wIcYVnZAK DiIXODkGqTg3fhZwbbi+KAhtHPFM2fGw2VTUf62IHzV+eBSnamzPOBc1XsJYKRo3FHNeLuS8 f4wUe7bWb9O66PPFK/RkeqNX6akkFBf9VfrZ1rTEKAyJ2uqf1EI1olYnENk4+00IBa+BavGQ 8UW9dGW3nbPrfuOV5UUvbnsSQwj67pSdrBQqilr5N/5H9z7VCDQ0dhuJNtvDSlTf2iUFBqgk 3smln31PUYiVPrMP0V4ja0i9qtO/TB01rTfTyXTRtqz53qO5dGsYiliJO5aUmh8swVpotgK4 /57h3zGsaXO9PGgnnAdqeKVITaFTLY1ISg+Ptb4KoliiOjrBMmQUSJVtkUXMrCMCeuPDGHo7 39Xc75lcHlGuM3yEB//htKjyprbLeLf1y4xPyTeeF5zg/0ztRZNKZicgEmxyUNBHHnBKHQxz 1j+mzH0HjZZtXjGu2KLJ18G07q0fpz2ZPk2D53Ww39VNI/J9ABEBAAHCwV8EGAECAAkFAk6S 54YCGwwACgkQvSWxBAa0cEk3tRAAgO+DFpbyIa4RlnfpcW17AfnpZi9VR5+zr496n2jH/1ld wRO/S+QNSA8qdABqMb9WI4BNaoANgcg0AS429Mq0taaWKkAjkkGAT7mD1Q5PiLr06Y/+Kzdr 90eUVneqM2TUQQbK+Kh7JwmGVrRGNqQrDk+gRNvKnGwFNeTkTKtJ0P8jYd7P1gZb9Fwj9YLx jhn/sVIhNmEBLBoI7PL+9fbILqJPHgAwW35rpnq4f/EYTykbk1sa13Tav6btJ+4QOgbcezWI wZ5w/JVfEJW9JXp3BFAVzRQ5nVrrLDAJZ8Y5ioWcm99JtSIIxXxt9FJaGc1Bgsi5K/+dyTKL wLMJgiBzbVx8G+fCJJ9YtlNOPWhbKPlrQ8+AY52Aagi9WNhe6XfJdh5g6ptiOILm330mkR4g W6nEgZVyIyTq3ekOuruftWL99qpP5zi+eNrMmLRQx9iecDNgFr342R9bTDlb1TLuRb+/tJ98 f/bIWIr0cqQmqQ33FgRhrG1+Xml6UXyJ2jExmlO8JljuOGeXYh6ZkIEyzqzffzBLXZCujlYQ DFXpyMNVJ2ZwPmX2mWEoYuaBU0JN7wM+/zWgOf2zRwhEuD3A2cO2PxoiIfyUEfB9SSmffaK/ S4xXoB6wvGENZ85Hg37C7WDNdaAt6Xh2uQIly5grkgvWppkNy4ZHxE+jeNsU7tg= In-Reply-To: <405e97ae-72a1-4086-bef3-cf462619f661@kernel.org> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit On 29. 05. 26, 9:20, Jiri Slaby wrote: > On 23. 03. 26, 18:31, Rafael J. Wysocki wrote: >> On Mon, Mar 23, 2026 at 6:24 PM Kees Cook wrote: >>> >>> Replace the deprecated[1] strncpy() with strscpy_pad() in >>> acpi_ut_safe_strncpy(). >>> >>> The function is a "safe strncpy" wrapper that does >>> strncpy(dest, source, dest_size) followed by manual NUL-termination >>> at dest[dest_size - 1]. strscpy_pad() is a direct replacement: it >>> NUL-terminates, zero-pads the remainder, and the manual termination >>> is no longer needed. >>> >>> All callers pass NUL-terminated source strings (C string literals, >>> __FILE__ via ACPI_MODULE_NAME, or user-provided filenames that have >>> already been validated). The destinations are fixed-size char arrays >>> in ACPICA internal structures (allocation->module, aml_op_name, >>> acpi_gbl_db_debug_filename), all consumed as C strings. >>> >>> No behavioral change: strscpy_pad() produces identical output to >>> strncpy() + manual NUL-termination for NUL-terminated sources that >>> are shorter than dest_size. For sources longer than dest_size, >>> strncpy() wrote dest_size non-NUL bytes then the manual termination >>> overwrote the last byte with NUL; strscpy_pad() writes dest_size-1 >>> bytes plus NUL: same result. >>> >>> Link: https://github.com/KSPP/linux/issues/90 [1] >>> Signed-off-by: Kees Cook >>> --- >>> This touches the ACPICA component shared with the upstream ACPICA >>> project (https://github.com/acpica/acpica), where the function >>> is named AcpiUtSafeStrncpy(). The upstream codebase uses its own >>> platform abstraction layer (acenv.h/acgcc.h) where I've mapped various >>> kernel APIs before like ACPI_FLEX_ARRAY and similar helpers. However, >>> acpi_ut_safe_strncpy() is an explicit function implementation rather >>> than a macro mapping, so the approach for upstreaming this change to >>> ACPICA is not clear. What's the best way to land this? >> >> I can apply this directly, it shouldn't be a major problem for porting >> patches from the upstream. > > As I reported in https://github.com/acpica/acpica/issues/1158 (but got > no reply), this patch breaks build of acpica against 7.1-rc*: > > ../../../../../drivers/acpi/acpica/utnonansi.c:171:9: error: implicit > declaration of function ‘strscpy_pad’ [-Wimplicit-function-declaration] > > Is strscpy_pad() supposed to be emulated in acpica? No, I misread the log, it's the in-kernel acpidump failing to build: ~/linux/tools/power/acpi/tools/acpidump> make MKDIR include CP include CC tools/acpidump/apdump.o CC tools/acpidump/apfiles.o CC tools/acpidump/apmain.o CC tools/acpidump/osunixdir.o CC tools/acpidump/osunixmap.o CC tools/acpidump/osunixxf.o CC tools/acpidump/tbprint.o CC tools/acpidump/tbxfroot.o CC tools/acpidump/utascii.o CC tools/acpidump/utbuffer.o CC tools/acpidump/utcksum.o CC tools/acpidump/utdebug.o CC tools/acpidump/utexcep.o CC tools/acpidump/utglobal.o CC tools/acpidump/uthex.o CC tools/acpidump/utmath.o CC tools/acpidump/utnonansi.o ../../../../../drivers/acpi/acpica/utnonansi.c: In function ‘acpi_ut_safe_strncpy’: ../../../../../drivers/acpi/acpica/utnonansi.c:171:9: error: implicit declaration of function ‘strscpy_pad’ [-Wimplicit-function-declaration] 171 | strscpy_pad(dest, source, dest_size); | ^~~~~~~~~~~ make: *** [../../Makefile.rules:25: /home/xslaby/linux/tools/power/acpi/tools/acpidump/utnonansi.o] Chyba 1 >>> (This is one of the last users of strncpy in the kernel.) >>> --- >>>   drivers/acpi/acpica/utnonansi.c | 3 +-- >>>   1 file changed, 1 insertion(+), 2 deletions(-) >>> >>> diff --git a/drivers/acpi/acpica/utnonansi.c b/drivers/acpi/acpica/ >>> utnonansi.c >>> index ff0802ace19b..3a7952be6545 100644 >>> --- a/drivers/acpi/acpica/utnonansi.c >>> +++ b/drivers/acpi/acpica/utnonansi.c >>> @@ -168,8 +168,7 @@ void acpi_ut_safe_strncpy(char *dest, char >>> *source, acpi_size dest_size) >>>   { >>>          /* Always terminate destination string */ >>> >>> -       strncpy(dest, source, dest_size); >>> -       dest[dest_size - 1] = 0; >>> +       strscpy_pad(dest, source, dest_size); >>>   } >>> >>>   #endif >>> -- >> > > thanks, -- js suse labs