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 4D51DC4167E for ; Tue, 10 May 2022 13:35:13 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S244151AbiEJNg4 (ORCPT ); Tue, 10 May 2022 09:36:56 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:41372 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S243355AbiEJN0q (ORCPT ); Tue, 10 May 2022 09:26:46 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [145.40.68.75]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 74861235C19; Tue, 10 May 2022 06:19:31 -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 ams.source.kernel.org (Postfix) with ESMTPS id 923B9B81DA2; Tue, 10 May 2022 13:19:30 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id E3BD5C385A6; Tue, 10 May 2022 13:19:28 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1652188769; bh=YI5UjmM43NAUlBOvm8tcF0gqikdn9+lJvBigtD/JjAc=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=p8636/7F35T4k/cUxVIhY6ZYPBNUU5m4eL+BN9wsNldikQndNyHbY9xRZKZWTCaKK 1U10iGMbeAAdJap3gd880r/YwhMGqSAq2BPFsx/6atc946nOIws9DySH0Nm1b5BQ2q Z9JJzSdph5BxjnbmGcl12vv26ONfjimmt7nKpMJE= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Mikulas Patocka , Andy Shevchenko , Linus Torvalds Subject: [PATCH 4.19 21/88] hex2bin: fix access beyond string end Date: Tue, 10 May 2022 15:07:06 +0200 Message-Id: <20220510130734.364009494@linuxfoundation.org> X-Mailer: git-send-email 2.36.1 In-Reply-To: <20220510130733.735278074@linuxfoundation.org> References: <20220510130733.735278074@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Mikulas Patocka commit e4d8a29997731b3bb14059024b24df9f784288d0 upstream. If we pass too short string to "hex2bin" (and the string size without the terminating NUL character is even), "hex2bin" reads one byte after the terminating NUL character. This patch fixes it. Note that hex_to_bin returns -1 on error and hex2bin return -EINVAL on error - so we can't just return the variable "hi" or "lo" on error. This inconsistency may be fixed in the next merge window, but for the purpose of fixing this bug, we just preserve the existing behavior and return -1 and -EINVAL. Signed-off-by: Mikulas Patocka Reviewed-by: Andy Shevchenko Fixes: b78049831ffe ("lib: add error checking to hex2bin") Cc: stable@vger.kernel.org Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman --- lib/hexdump.c | 9 ++++++--- 1 file changed, 6 insertions(+), 3 deletions(-) --- a/lib/hexdump.c +++ b/lib/hexdump.c @@ -66,10 +66,13 @@ EXPORT_SYMBOL(hex_to_bin); int hex2bin(u8 *dst, const char *src, size_t count) { while (count--) { - int hi = hex_to_bin(*src++); - int lo = hex_to_bin(*src++); + int hi, lo; - if ((hi < 0) || (lo < 0)) + hi = hex_to_bin(*src++); + if (unlikely(hi < 0)) + return -EINVAL; + lo = hex_to_bin(*src++); + if (unlikely(lo < 0)) return -EINVAL; *dst++ = (hi << 4) | lo;