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 CD92745C12 for ; Wed, 15 Nov 2023 22:03:16 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="qZBuBeNh" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 77CB4C433CB; Wed, 15 Nov 2023 22:03:16 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1700085796; bh=7p3+PvEga5tnB5wox6NAT5zK60WGZ73cy2u3LZZovGA=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=qZBuBeNhNReH2ltLd6sla/uuRC2rN8wht8kPxZGcs3is6TSsDfcnojLsh1sDOan9o wPzKocvrNsyq0rzFAJTS2HBzCXFEujW6a6j0LYyD+5xbVBSC4P7s6tTwyarelZVJPa Oq/vIgC97ROqN8T7l3iME9i5VEP88AExumqsVwIA= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Ard Biesheuvel , Linus Walleij , Kursad Oney , "Russell King (Oracle)" , Sasha Levin Subject: [PATCH 5.4 059/119] ARM: 9321/1: memset: cast the constant byte to unsigned char Date: Wed, 15 Nov 2023 17:00:49 -0500 Message-ID: <20231115220134.456617465@linuxfoundation.org> X-Mailer: git-send-email 2.42.1 In-Reply-To: <20231115220132.607437515@linuxfoundation.org> References: <20231115220132.607437515@linuxfoundation.org> User-Agent: quilt/0.67 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 5.4-stable review patch. If anyone has any objections, please let me know. ------------------ From: Kursad Oney [ Upstream commit c0e824661f443b8cab3897006c1bbc69fd0e7bc4 ] memset() description in ISO/IEC 9899:1999 (and elsewhere) says: The memset function copies the value of c (converted to an unsigned char) into each of the first n characters of the object pointed to by s. The kernel's arm32 memset does not cast c to unsigned char. This results in the following code to produce erroneous output: char a[128]; memset(a, -128, sizeof(a)); This is because gcc will generally emit the following code before it calls memset() : mov r0, r7 mvn r1, #127 ; 0x7f bl 00000000 r1 ends up with 0xffffff80 before being used by memset() and the 'a' array will have -128 once in every four bytes while the other bytes will be set incorrectly to -1 like this (printing the first 8 bytes) : test_module: -128 -1 -1 -1 test_module: -1 -1 -1 -128 The change here is to 'and' r1 with 255 before it is used. Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Reviewed-by: Ard Biesheuvel Reviewed-by: Linus Walleij Signed-off-by: Kursad Oney Signed-off-by: Russell King (Oracle) Signed-off-by: Sasha Levin --- arch/arm/lib/memset.S | 1 + 1 file changed, 1 insertion(+) diff --git a/arch/arm/lib/memset.S b/arch/arm/lib/memset.S index 6ca4535c47fb6..e36d053a8a903 100644 --- a/arch/arm/lib/memset.S +++ b/arch/arm/lib/memset.S @@ -16,6 +16,7 @@ ENTRY(mmioset) ENTRY(memset) UNWIND( .fnstart ) + and r1, r1, #255 @ cast to unsigned char ands r3, r0, #3 @ 1 unaligned? mov ip, r0 @ preserve r0 as return value bne 6f @ 1 -- 2.42.0