From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 0195EC5AE4B for ; Wed, 15 Nov 2023 20:58:53 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1344766AbjKOU6z (ORCPT ); Wed, 15 Nov 2023 15:58:55 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:52928 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1344619AbjKOU5p (ORCPT ); Wed, 15 Nov 2023 15:57:45 -0500 Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 299171BCD for ; Wed, 15 Nov 2023 12:57:32 -0800 (PST) Received: by smtp.kernel.org (Postfix) with ESMTPSA id E58EBC4E67B; Wed, 15 Nov 2023 20:50:55 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1700081456; bh=CCCv3bsOU59DT3YOAulrZk/ZbrMuyZ7wbMy9bZnkkXM=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=SpJBRzBi6IrNrsEMmWXcu2hiuwbiKytkqBaLSr0Jx3iRIGsFCeMu7iMV+Ete48j17 iqvoA3N9JXe2eXuYK3dbZNDKgKwBybM6nO2dKqfJhKtZeXgcLp+xxVGbwmOLYbvtPK yOh1useHvUJZBOpc6BMAGL9eq2EMlB5Vxs0c4+w4= 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 5.15 138/244] ARM: 9321/1: memset: cast the constant byte to unsigned char Date: Wed, 15 Nov 2023 15:35:30 -0500 Message-ID: <20231115203556.634704177@linuxfoundation.org> X-Mailer: git-send-email 2.42.1 In-Reply-To: <20231115203548.387164783@linuxfoundation.org> References: <20231115203548.387164783@linuxfoundation.org> User-Agent: quilt/0.67 X-stable: review X-Patchwork-Hint: ignore MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org 5.15-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 9817cb258c1a5..0481b9bbbd004 100644 --- a/arch/arm/lib/memset.S +++ b/arch/arm/lib/memset.S @@ -17,6 +17,7 @@ ENTRY(__memset) ENTRY(mmioset) WEAK(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