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 X-Spam-Level: X-Spam-Status: No, score=-9.0 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_PASS,URIBL_BLOCKED,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 7CCD9C43381 for ; Tue, 12 Mar 2019 17:14:47 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 43E612087C for ; Tue, 12 Mar 2019 17:14:47 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1552410887; bh=/woZIn+hBoixAdLXaF6zHUH3PDdkEW6WLWZyDawngfA=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=JIi9H4A7nnVau0PaVWAIPsH/WSnsMjbWQWKUlVfPzUBdSVlhWIaHQ9l//zkVr41np KahLXJs/yAyvDgOMoZkNr7vlnRZo0CRb8ONS7Sd/eUVC2qAsxz5kl+eCtphXBT/PbY zfjWA+jeZaUzCFMejLzv6B8FF2gxBywZqUhiCNt8= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728474AbfCLROp (ORCPT ); Tue, 12 Mar 2019 13:14:45 -0400 Received: from mail.kernel.org ([198.145.29.99]:54024 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728471AbfCLROp (ORCPT ); Tue, 12 Mar 2019 13:14:45 -0400 Received: from localhost (unknown [104.133.8.98]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id DA7492186A; Tue, 12 Mar 2019 17:14:44 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1552410885; bh=/woZIn+hBoixAdLXaF6zHUH3PDdkEW6WLWZyDawngfA=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=UN03aVVUTnfCpBpo5vhjTiu33XutxGGZEsEh1lyKOiDVm/8WquXo2HcJBydcvZ+83 hd9CQLbXUzxN6XdlJK9E0b6cM1I3I6RW7gKxUS9IkdhVi/uhtJelQbjmomBJFL2kNp UOtjqBeFPGFciVBnhQ6AuFRdCiAeq/5zQqrkSE9o= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Kees Cook , Tetsuo Handa , Andrew Morton , David Rientjes , Sasha Levin , syzbot+16c3a70e1e9b29346c43@syzkaller.appspotmail.com Subject: [PATCH 4.19 092/149] relay: check return of create_buf_file() properly Date: Tue, 12 Mar 2019 10:08:30 -0700 Message-Id: <20190312170357.398810898@linuxfoundation.org> X-Mailer: git-send-email 2.21.0 In-Reply-To: <20190312170349.421581206@linuxfoundation.org> References: <20190312170349.421581206@linuxfoundation.org> User-Agent: quilt/0.65 X-stable: review X-Patchwork-Hint: ignore MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org 4.19-stable review patch. If anyone has any objections, please let me know. ------------------ [ Upstream commit 2c1cf00eeacb784781cf1c9896b8af001246d339 ] If create_buf_file() returns an error, don't try to reference it later as a valid dentry pointer. This problem was exposed when debugfs started to return errors instead of just NULL for some calls when they do not succeed properly. Also, the check for WARN_ON(dentry) was just wrong :) Reported-by: Kees Cook Reported-and-tested-by: syzbot+16c3a70e1e9b29346c43@syzkaller.appspotmail.com Reported-by: Tetsuo Handa Cc: Andrew Morton Cc: David Rientjes Fixes: ff9fb72bc077 ("debugfs: return error values, not NULL") Signed-off-by: Greg Kroah-Hartman Signed-off-by: Sasha Levin --- kernel/relay.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/kernel/relay.c b/kernel/relay.c index 04f248644e06..9e0f52375487 100644 --- a/kernel/relay.c +++ b/kernel/relay.c @@ -428,6 +428,8 @@ static struct dentry *relay_create_buf_file(struct rchan *chan, dentry = chan->cb->create_buf_file(tmpname, chan->parent, S_IRUSR, buf, &chan->is_global); + if (IS_ERR(dentry)) + dentry = NULL; kfree(tmpname); @@ -461,7 +463,7 @@ static struct rchan_buf *relay_open_buf(struct rchan *chan, unsigned int cpu) dentry = chan->cb->create_buf_file(NULL, NULL, S_IRUSR, buf, &chan->is_global); - if (WARN_ON(dentry)) + if (IS_ERR_OR_NULL(dentry)) goto free_buf; } -- 2.19.1