From patchwork Wed Mar 12 20:14:51 2025 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Kees Cook X-Patchwork-Id: 14013823 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 A22CA70809; Wed, 12 Mar 2025 20:14:56 +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=1741810496; cv=none; b=esF364nyyFdhnmlrN9opqHue+l4+YrJ9puk0ALQ/KKBO+Fvyl4WSBxfvyaX4is2r540CUNJhYmeqC+5LZSKyishfmOjOfmg7PvBAF5mOziM63Pl5z+er8uRQeO0TqSVMEBI+9JGqzETCm+o/f7DuCralWAOvUFDj5yvDKb1dsrI= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1741810496; c=relaxed/simple; bh=g1sFQOH1vPx9lrAH9SnoezGldeEVl4lvcdztzHQTJQM=; h=From:To:Cc:Subject:Date:Message-Id:MIME-Version; b=hMsMKQfo4+WxAKhgeK2ZlvEtmS/aY26NpoFGf399GkZxzpiXm/AByI69obEHnBKJ/Ei7VaUtBct9H5jM+eMVtcuqolPa3XD8xDA2A+5EHpRkxn+e22Pdjx9uV5xRgBu14g5AnUEU0lfd0Pd7rXHlPLLwfz0DLW6MZbFFjt66QO4= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=OFn15q3V; 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="OFn15q3V" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 21ECFC4CEDD; Wed, 12 Mar 2025 20:14:56 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1741810496; bh=g1sFQOH1vPx9lrAH9SnoezGldeEVl4lvcdztzHQTJQM=; h=From:To:Cc:Subject:Date:From; b=OFn15q3V51I45tB11gIJbA7lTjNOXPMlMTcbf2BddQlXzu75hspiWs8j4ox33V1Hg 9tA8oi9VKsliX9W0YM7TsNgOhxnqojnncAhKzjIwHK8gqUDKiowtX7BEgTUOFli7J/ ej31iIfZ4kA5r0hSr22Q6M7O3fscKcFgdMeNmLztdWqzoj0wC4WT8xxGxPATXQ3pn4 +hAaBk0JNBTmBKXxrRvawYiDQZaUVeZDacHz9KOgZnIe4u/iUVwkFgzd+Ifw2/0Fss pqjybBn3mMtxE6X9x6GduGbIL3zRpBZ1ixqvDQGrLDySVAb/UGQNsvdLC2ZbDb1wW7 cWMgqnKONaDWw== From: Kees Cook To: "Jason A . Donenfeld" Cc: Kees Cook , Andrew Lunn , "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , wireguard@lists.zx2c4.com, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, linux-hardening@vger.kernel.org Subject: [PATCH v2] wireguard: Add __nonstring annotations for unterminated strings Date: Wed, 12 Mar 2025 13:14:51 -0700 Message-Id: <20250312201447.it.157-kees@kernel.org> X-Mailer: git-send-email 2.34.1 Precedence: bulk X-Mailing-List: linux-hardening@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Developer-Signature: v=1; a=openpgp-sha256; l=4243; i=kees@kernel.org; h=from:subject:message-id; bh=g1sFQOH1vPx9lrAH9SnoezGldeEVl4lvcdztzHQTJQM=; b=owGbwMvMwCVmps19z/KJym7G02pJDOkXX1tPD95lfe6z11TDfzl7S1V6uT2N3ORrNnoKc+7fW mXgmB7VUcrCIMbFICumyBJk5x7n4vG2Pdx9riLMHFYmkCEMXJwCMBHvaYwM0+Z+anhwaO87nSqx BfJhqxcz3pi2w+bhZyGB5uClp206djAyLPv04EfStB6JU3OOcE5hdfwqyFWTtSdk2Q/1y0xrwzJ Z+QA= X-Developer-Key: i=kees@kernel.org; a=openpgp; fpr=A5C3F68F229DD60F723E6E138972F4DFDC6DC026 When a character array without a terminating NUL character has a static initializer, GCC 15's -Wunterminated-string-initialization will only warn if the array lacks the "nonstring" attribute[1]. Mark the arrays with __nonstring to correctly identify the char array as "not a C string" and thereby eliminate the warning: ../drivers/net/wireguard/cookie.c:29:56: warning: initializer-string for array of 'unsigned char' truncates NUL terminator but destination lacks 'nonstring' attribute (9 chars into 8 available) [-Wunterminated-string-initialization] 29 | static const u8 mac1_key_label[COOKIE_KEY_LABEL_LEN] = "mac1----"; | ^~~~~~~~~~ ../drivers/net/wireguard/cookie.c:30:58: warning: initializer-string for array of 'unsigned char' truncates NUL terminator but destination lacks 'nonstring' attribute (9 chars into 8 available) [-Wunterminated-string-initialization] 30 | static const u8 cookie_key_label[COOKIE_KEY_LABEL_LEN] = "cookie--"; | ^~~~~~~~~~ ../drivers/net/wireguard/noise.c:28:38: warning: initializer-string for array of 'unsigned char' truncates NUL terminator but destination lacks 'nonstring' attribute (38 chars into 37 available) [-Wunterminated-string-initialization] 28 | static const u8 handshake_name[37] = "Noise_IKpsk2_25519_ChaChaPoly_BLAKE2s"; | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ../drivers/net/wireguard/noise.c:29:39: warning: initializer-string for array of 'unsigned char' truncates NUL terminator but destination lacks 'nonstring' attribute (35 chars into 34 available) [-Wunterminated-string-initialization] 29 | static const u8 identifier_name[34] = "WireGuard v1 zx2c4 Jason@zx2c4.com"; | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ The arrays are always used with their fixed size, so use __nonstring. Link: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=117178 [1] Signed-off-by: Kees Cook --- v2: Improve commit log, add cookie nonstrings too v1: https://lore.kernel.org/lkml/20250310222249.work.154-kees@kernel.org/ Cc: Jason A. Donenfeld Cc: "Jason A. Donenfeld" Cc: Andrew Lunn Cc: "David S. Miller" Cc: Eric Dumazet Cc: Jakub Kicinski Cc: Paolo Abeni Cc: wireguard@lists.zx2c4.com Cc: netdev@vger.kernel.org --- drivers/net/wireguard/cookie.c | 4 ++-- drivers/net/wireguard/noise.c | 4 ++-- 2 files changed, 4 insertions(+), 4 deletions(-) diff --git a/drivers/net/wireguard/cookie.c b/drivers/net/wireguard/cookie.c index f89581b5e8cb..94d0a7206084 100644 --- a/drivers/net/wireguard/cookie.c +++ b/drivers/net/wireguard/cookie.c @@ -26,8 +26,8 @@ void wg_cookie_checker_init(struct cookie_checker *checker, } enum { COOKIE_KEY_LABEL_LEN = 8 }; -static const u8 mac1_key_label[COOKIE_KEY_LABEL_LEN] = "mac1----"; -static const u8 cookie_key_label[COOKIE_KEY_LABEL_LEN] = "cookie--"; +static const u8 mac1_key_label[COOKIE_KEY_LABEL_LEN] __nonstring = "mac1----"; +static const u8 cookie_key_label[COOKIE_KEY_LABEL_LEN] __nonstring = "cookie--"; static void precompute_key(u8 key[NOISE_SYMMETRIC_KEY_LEN], const u8 pubkey[NOISE_PUBLIC_KEY_LEN], diff --git a/drivers/net/wireguard/noise.c b/drivers/net/wireguard/noise.c index 202a33af5a72..7eb9a23a3d4d 100644 --- a/drivers/net/wireguard/noise.c +++ b/drivers/net/wireguard/noise.c @@ -25,8 +25,8 @@ * <- e, ee, se, psk, {} */ -static const u8 handshake_name[37] = "Noise_IKpsk2_25519_ChaChaPoly_BLAKE2s"; -static const u8 identifier_name[34] = "WireGuard v1 zx2c4 Jason@zx2c4.com"; +static const u8 handshake_name[37] __nonstring = "Noise_IKpsk2_25519_ChaChaPoly_BLAKE2s"; +static const u8 identifier_name[34] __nonstring = "WireGuard v1 zx2c4 Jason@zx2c4.com"; static u8 handshake_init_hash[NOISE_HASH_LEN] __ro_after_init; static u8 handshake_init_chaining_key[NOISE_HASH_LEN] __ro_after_init; static atomic64_t keypair_counter = ATOMIC64_INIT(0);