From patchwork Mon Jul 19 14:51:52 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg KH X-Patchwork-Id: 481325 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-20.2 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER, INCLUDES_PATCH, MAILING_LIST_MULTI, SPF_HELO_NONE, SPF_PASS, USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id A31CBC6377A for ; Mon, 19 Jul 2021 15:11:54 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 9131861165 for ; Mon, 19 Jul 2021 15:11:54 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S243805AbhGSObN (ORCPT ); Mon, 19 Jul 2021 10:31:13 -0400 Received: from mail.kernel.org ([198.145.29.99]:39738 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S245062AbhGSOaR (ORCPT ); Mon, 19 Jul 2021 10:30:17 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 5AB836024A; Mon, 19 Jul 2021 15:10:55 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1626707455; bh=n6nmUqmdKxTKnLhFD5LYShrjOaP+9FEZWtPmKcV9p/0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=2jJRQniC/NX+JfCu7M0+9DhjjT0cOpZmnLGCvvMkRqCbn8Wnb5m/UN8gDB+W5HLtm zDXRfa94ivUuqb90Y6JXIVRPstaKKXcsDZbN/+0LEZWzDqilSMpsqLZqMzSLKhRqS7 4Rosw9bvtETbgkquffAIShl+epf8OvZo2fPoMzLQ= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Yun Zhou , "Steven Rostedt (VMware)" Subject: [PATCH 4.9 170/245] seq_buf: Fix overflow in seq_buf_putmem_hex() Date: Mon, 19 Jul 2021 16:51:52 +0200 Message-Id: <20210719144945.899681500@linuxfoundation.org> X-Mailer: git-send-email 2.32.0 In-Reply-To: <20210719144940.288257948@linuxfoundation.org> References: <20210719144940.288257948@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Yun Zhou commit d3b16034a24a112bb83aeb669ac5b9b01f744bb7 upstream. There's two variables being increased in that loop (i and j), and i follows the raw data, and j follows what is being written into the buffer. We should compare 'i' to MAX_MEMHEX_BYTES or compare 'j' to HEX_CHARS. Otherwise, if 'j' goes bigger than HEX_CHARS, it will overflow the destination buffer. Link: https://lore.kernel.org/lkml/20210625122453.5e2fe304@oasis.local.home/ Link: https://lkml.kernel.org/r/20210626032156.47889-1-yun.zhou@windriver.com Cc: stable@vger.kernel.org Fixes: 5e3ca0ec76fce ("ftrace: introduce the "hex" output method") Signed-off-by: Yun Zhou Signed-off-by: Steven Rostedt (VMware) Signed-off-by: Greg Kroah-Hartman --- lib/seq_buf.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) --- a/lib/seq_buf.c +++ b/lib/seq_buf.c @@ -227,8 +227,10 @@ int seq_buf_putmem_hex(struct seq_buf *s WARN_ON(s->size == 0); + BUILD_BUG_ON(MAX_MEMHEX_BYTES * 2 >= HEX_CHARS); + while (len) { - start_len = min(len, HEX_CHARS - 1); + start_len = min(len, MAX_MEMHEX_BYTES); #ifdef __BIG_ENDIAN for (i = 0, j = 0; i < start_len; i++) { #else