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 80029C77B73 for ; Sat, 6 May 2023 06:42:05 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230283AbjEFGmD (ORCPT ); Sat, 6 May 2023 02:42:03 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:48384 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231172AbjEFGl4 (ORCPT ); Sat, 6 May 2023 02:41:56 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 352281BDC for ; Fri, 5 May 2023 23:41:55 -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 dfw.source.kernel.org (Postfix) with ESMTPS id BAEFA61777 for ; Sat, 6 May 2023 06:41:54 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id D9822C433D2; Sat, 6 May 2023 06:41:52 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1683355314; bh=in4K3pKpXMyOd83pJkHQsVO/egZy/hD8roFmkGwIfFU=; h=Subject:To:Cc:From:Date:From; b=uWG7WwmgEhOfPKZM5O0EapdJpRmjGDhR7juK7v6ZBWMXp4bR4iZB0vXgeIXAARI5e ZnM2WyFbLPqbzFcH+RW1e3fATj1TuYkM1Gy804NQT5s1Hjucr1hHe7O7VDQisXgO4O sI0dVjdVjcyghguC01vpIxTFXr4cMKjh47/BNuh8= Subject: FAILED: patch "[PATCH] relayfs: fix out-of-bounds access in relay_file_read" failed to apply to 4.19-stable tree To: zhang.zhengming@h3c.com, akpm@linux-foundation.org, axboe@kernel.dk, stable@vger.kernel.org, yangpc@wangsu.com, zhao_lei1@hoperun.com, zhou.kete@h3c.com Cc: From: Date: Sat, 06 May 2023 11:33:28 +0900 Message-ID: <2023050628-relation-jump-9a3c@gregkh> MIME-Version: 1.0 Content-Type: text/plain; charset=ANSI_X3.4-1968 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org The patch below does not apply to the 4.19-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to . To reproduce the conflict and resubmit, you may use the following commands: git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-4.19.y git checkout FETCH_HEAD git cherry-pick -x 43ec16f1450f4936025a9bdf1a273affdb9732c1 # git commit -s git send-email --to '' --in-reply-to '2023050628-relation-jump-9a3c@gregkh' --subject-prefix 'PATCH 4.19.y' HEAD^.. Possible dependencies: thanks, greg k-h ------------------ original commit in Linus's tree ------------------ >From 43ec16f1450f4936025a9bdf1a273affdb9732c1 Mon Sep 17 00:00:00 2001 From: Zhang Zhengming Date: Wed, 19 Apr 2023 12:02:03 +0800 Subject: [PATCH] relayfs: fix out-of-bounds access in relay_file_read There is a crash in relay_file_read, as the var from point to the end of last subbuf. The oops looks something like: pc : __arch_copy_to_user+0x180/0x310 lr : relay_file_read+0x20c/0x2c8 Call trace: __arch_copy_to_user+0x180/0x310 full_proxy_read+0x68/0x98 vfs_read+0xb0/0x1d0 ksys_read+0x6c/0xf0 __arm64_sys_read+0x20/0x28 el0_svc_common.constprop.3+0x84/0x108 do_el0_svc+0x74/0x90 el0_svc+0x1c/0x28 el0_sync_handler+0x88/0xb0 el0_sync+0x148/0x180 We get the condition by analyzing the vmcore: 1). The last produced byte and last consumed byte both at the end of the last subbuf 2). A softirq calls function(e.g __blk_add_trace) to write relay buffer occurs when an program is calling relay_file_read_avail(). relay_file_read relay_file_read_avail relay_file_read_consume(buf, 0, 0); //interrupted by softirq who will write subbuf .... return 1; //read_start point to the end of the last subbuf read_start = relay_file_read_start_pos //avail is equal to subsize avail = relay_file_read_subbuf_avail //from points to an invalid memory address from = buf->start + read_start //system is crashed copy_to_user(buffer, from, avail) Link: https://lkml.kernel.org/r/20230419040203.37676-1-zhang.zhengming@h3c.com Fixes: 8d62fdebdaf9 ("relay file read: start-pos fix") Signed-off-by: Zhang Zhengming Reviewed-by: Zhao Lei Reviewed-by: Zhou Kete Reviewed-by: Pengcheng Yang Cc: Jens Axboe Cc: Signed-off-by: Andrew Morton diff --git a/kernel/relay.c b/kernel/relay.c index 9aa70ae53d24..a80fa01042e9 100644 --- a/kernel/relay.c +++ b/kernel/relay.c @@ -989,7 +989,8 @@ static size_t relay_file_read_start_pos(struct rchan_buf *buf) size_t subbuf_size = buf->chan->subbuf_size; size_t n_subbufs = buf->chan->n_subbufs; size_t consumed = buf->subbufs_consumed % n_subbufs; - size_t read_pos = consumed * subbuf_size + buf->bytes_consumed; + size_t read_pos = (consumed * subbuf_size + buf->bytes_consumed) + % (n_subbufs * subbuf_size); read_subbuf = read_pos / subbuf_size; padding = buf->padding[read_subbuf];