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 AE396C19F2C for ; Mon, 1 Aug 2022 19:03:44 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233788AbiHATDm (ORCPT ); Mon, 1 Aug 2022 15:03:42 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:51194 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233325AbiHATDH (ORCPT ); Mon, 1 Aug 2022 15:03:07 -0400 Received: from sin.source.kernel.org (sin.source.kernel.org [IPv6:2604:1380:40e1:4800::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 8623F32EE6; Mon, 1 Aug 2022 12:02:47 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by sin.source.kernel.org (Postfix) with ESMTPS id E1ED7CE1795; Mon, 1 Aug 2022 19:02:44 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 79640C433C1; Mon, 1 Aug 2022 19:02:42 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1659380563; bh=AUD2YRSKrurU/v6HsvLglxCz/I21f5Z1sO8HDOk/ie0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=r2a3NniJN+r8qOXn+3nBo7a3KoV0zulqZYJiWqh6U2VGpg2dMylAqvCqy+HBk36UL hQL/V2PHLRlqHn2AMaUFJHW9E8HrnehYvNJ3nXjK6WnNNgc0fA1mfYU5uQLFFG6Wbo F0IEHYcaj56qnrSV3Zyea6QuNVJmw47o4XkApLzJuOxQID91Ki7nXxMjiiakHR7lRK MGQBTRZPLmZ0NBRf5sDFZPht4za96EU6ySUOZmzxSzH+SkQrxC27p7lHsWua88VfRJ NGrdHkC2aD9mc73bZxcYnOf2cWcwZrpBtOJkdhJwb7NoHGC5XZkfNsBn9H7IvxfXQO s6wRhwYwUNcDQ== From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: "Russell King (Oracle)" , Guenter Roeck , Sasha Levin , linux@armlinux.org.uk, linux-arm-kernel@lists.infradead.org Subject: [PATCH AUTOSEL 5.18 10/10] ARM: findbit: fix overflowing offset Date: Mon, 1 Aug 2022 15:02:22 -0400 Message-Id: <20220801190222.3818378-10-sashal@kernel.org> X-Mailer: git-send-email 2.35.1 In-Reply-To: <20220801190222.3818378-1-sashal@kernel.org> References: <20220801190222.3818378-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: "Russell King (Oracle)" [ Upstream commit ec85bd369fd2bfaed6f45dd678706429d4f75b48 ] When offset is larger than the size of the bit array, we should not attempt to access the array as we can perform an access beyond the end of the array. Fix this by changing the pre-condition. Using "cmp r2, r1; bhs ..." covers us for the size == 0 case, since this will always take the branch when r1 is zero, irrespective of the value of r2. This means we can fix this bug without adding any additional code! Tested-by: Guenter Roeck Signed-off-by: Russell King (Oracle) Signed-off-by: Sasha Levin --- arch/arm/lib/findbit.S | 16 ++++++++-------- 1 file changed, 8 insertions(+), 8 deletions(-) diff --git a/arch/arm/lib/findbit.S b/arch/arm/lib/findbit.S index b5e8b9ae4c7d..7fd3600db8ef 100644 --- a/arch/arm/lib/findbit.S +++ b/arch/arm/lib/findbit.S @@ -40,8 +40,8 @@ ENDPROC(_find_first_zero_bit_le) * Prototype: int find_next_zero_bit(void *addr, unsigned int maxbit, int offset) */ ENTRY(_find_next_zero_bit_le) - teq r1, #0 - beq 3b + cmp r2, r1 + bhs 3b ands ip, r2, #7 beq 1b @ If new byte, goto old routine ARM( ldrb r3, [r0, r2, lsr #3] ) @@ -81,8 +81,8 @@ ENDPROC(_find_first_bit_le) * Prototype: int find_next_zero_bit(void *addr, unsigned int maxbit, int offset) */ ENTRY(_find_next_bit_le) - teq r1, #0 - beq 3b + cmp r2, r1 + bhs 3b ands ip, r2, #7 beq 1b @ If new byte, goto old routine ARM( ldrb r3, [r0, r2, lsr #3] ) @@ -115,8 +115,8 @@ ENTRY(_find_first_zero_bit_be) ENDPROC(_find_first_zero_bit_be) ENTRY(_find_next_zero_bit_be) - teq r1, #0 - beq 3b + cmp r2, r1 + bhs 3b ands ip, r2, #7 beq 1b @ If new byte, goto old routine eor r3, r2, #0x18 @ big endian byte ordering @@ -149,8 +149,8 @@ ENTRY(_find_first_bit_be) ENDPROC(_find_first_bit_be) ENTRY(_find_next_bit_be) - teq r1, #0 - beq 3b + cmp r2, r1 + bhs 3b ands ip, r2, #7 beq 1b @ If new byte, goto old routine eor r3, r2, #0x18 @ big endian byte ordering -- 2.35.1 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 bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id DD8CEC19F2D for ; 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Mon, 01 Aug 2022 19:02:47 +0000 Received: from dfw.source.kernel.org ([2604:1380:4641:c500::1]) by bombadil.infradead.org with esmtps (Exim 4.94.2 #2 (Red Hat Linux)) id 1oIagd-009aPl-TB for linux-arm-kernel@lists.infradead.org; Mon, 01 Aug 2022 19:02:45 +0000 Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 69242611F3; Mon, 1 Aug 2022 19:02:43 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 79640C433C1; Mon, 1 Aug 2022 19:02:42 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1659380563; bh=AUD2YRSKrurU/v6HsvLglxCz/I21f5Z1sO8HDOk/ie0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=r2a3NniJN+r8qOXn+3nBo7a3KoV0zulqZYJiWqh6U2VGpg2dMylAqvCqy+HBk36UL hQL/V2PHLRlqHn2AMaUFJHW9E8HrnehYvNJ3nXjK6WnNNgc0fA1mfYU5uQLFFG6Wbo F0IEHYcaj56qnrSV3Zyea6QuNVJmw47o4XkApLzJuOxQID91Ki7nXxMjiiakHR7lRK MGQBTRZPLmZ0NBRf5sDFZPht4za96EU6ySUOZmzxSzH+SkQrxC27p7lHsWua88VfRJ NGrdHkC2aD9mc73bZxcYnOf2cWcwZrpBtOJkdhJwb7NoHGC5XZkfNsBn9H7IvxfXQO s6wRhwYwUNcDQ== From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: "Russell King (Oracle)" , Guenter Roeck , Sasha Levin , linux@armlinux.org.uk, linux-arm-kernel@lists.infradead.org Subject: [PATCH AUTOSEL 5.18 10/10] ARM: findbit: fix overflowing offset Date: Mon, 1 Aug 2022 15:02:22 -0400 Message-Id: <20220801190222.3818378-10-sashal@kernel.org> X-Mailer: git-send-email 2.35.1 In-Reply-To: <20220801190222.3818378-1-sashal@kernel.org> References: <20220801190222.3818378-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20220801_120244_000561_1B2D09E5 X-CRM114-Status: GOOD ( 13.77 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org From: "Russell King (Oracle)" [ Upstream commit ec85bd369fd2bfaed6f45dd678706429d4f75b48 ] When offset is larger than the size of the bit array, we should not attempt to access the array as we can perform an access beyond the end of the array. Fix this by changing the pre-condition. Using "cmp r2, r1; bhs ..." covers us for the size == 0 case, since this will always take the branch when r1 is zero, irrespective of the value of r2. This means we can fix this bug without adding any additional code! Tested-by: Guenter Roeck Signed-off-by: Russell King (Oracle) Signed-off-by: Sasha Levin --- arch/arm/lib/findbit.S | 16 ++++++++-------- 1 file changed, 8 insertions(+), 8 deletions(-) diff --git a/arch/arm/lib/findbit.S b/arch/arm/lib/findbit.S index b5e8b9ae4c7d..7fd3600db8ef 100644 --- a/arch/arm/lib/findbit.S +++ b/arch/arm/lib/findbit.S @@ -40,8 +40,8 @@ ENDPROC(_find_first_zero_bit_le) * Prototype: int find_next_zero_bit(void *addr, unsigned int maxbit, int offset) */ ENTRY(_find_next_zero_bit_le) - teq r1, #0 - beq 3b + cmp r2, r1 + bhs 3b ands ip, r2, #7 beq 1b @ If new byte, goto old routine ARM( ldrb r3, [r0, r2, lsr #3] ) @@ -81,8 +81,8 @@ ENDPROC(_find_first_bit_le) * Prototype: int find_next_zero_bit(void *addr, unsigned int maxbit, int offset) */ ENTRY(_find_next_bit_le) - teq r1, #0 - beq 3b + cmp r2, r1 + bhs 3b ands ip, r2, #7 beq 1b @ If new byte, goto old routine ARM( ldrb r3, [r0, r2, lsr #3] ) @@ -115,8 +115,8 @@ ENTRY(_find_first_zero_bit_be) ENDPROC(_find_first_zero_bit_be) ENTRY(_find_next_zero_bit_be) - teq r1, #0 - beq 3b + cmp r2, r1 + bhs 3b ands ip, r2, #7 beq 1b @ If new byte, goto old routine eor r3, r2, #0x18 @ big endian byte ordering @@ -149,8 +149,8 @@ ENTRY(_find_first_bit_be) ENDPROC(_find_first_bit_be) ENTRY(_find_next_bit_be) - teq r1, #0 - beq 3b + cmp r2, r1 + bhs 3b ands ip, r2, #7 beq 1b @ If new byte, goto old routine eor r3, r2, #0x18 @ big endian byte ordering -- 2.35.1 _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel