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=-19.4 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,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 CD81EC49EBB for ; Mon, 28 Jun 2021 14:45:41 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id BCB086144B for ; Mon, 28 Jun 2021 14:45:41 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234805AbhF1OsG (ORCPT ); Mon, 28 Jun 2021 10:48:06 -0400 Received: from mail.kernel.org ([198.145.29.99]:51692 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234748AbhF1OmE (ORCPT ); Mon, 28 Jun 2021 10:42:04 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 3094361CCA; Mon, 28 Jun 2021 14:33:32 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1624890813; bh=303Y9u18xTpqWbTEYGa8hsuqC3zXRn/9rMN8GwPyrn8=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=KMEA3NudRCjK13syMzQdbB4JYWN7jRV/yhbF78OPezb+TRiVl2iJqzVDpIn3/tOIH AeYTmEC3miLnI4kw+lr5gZz9PaMAp8r2KQPUgWxVJ9jRKtegT7ssIIl6iYtxK2BJQp qU1frpFqrNgzR51rIh+4bp7WttnvG3UzzMtA526sbEGsGaTHHBLsnmxCUpFgIk8zvZ yIevL6x2J423d9P/iBJrdIXdztXcnTrZG0i/z9jf4N+qqun0SWqiQlmnIShS5QUVA6 t+dRTtAc7JzeUV1RcV7s3r+5A3eAoq9VZERbHlnKxYDd5L4hDxwqC3v7qOvWPNvpGS nRkF1slY/EhpQ== From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Pavel Skripkin , syzbot+5134cdf021c4ed5aaa5f@syzkaller.appspotmail.com, =?UTF-8?q?H=C3=A5kon=20Bugge?= , Santosh Shilimkar , "David S . Miller" , Sasha Levin Subject: [PATCH 4.19 028/109] net: rds: fix memory leak in rds_recvmsg Date: Mon, 28 Jun 2021 10:31:44 -0400 Message-Id: <20210628143305.32978-29-sashal@kernel.org> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20210628143305.32978-1-sashal@kernel.org> References: <20210628143305.32978-1-sashal@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 X-KernelTest-Patch: http://kernel.org/pub/linux/kernel/v4.x/stable-review/patch-4.19.196-rc1.gz X-KernelTest-Tree: git://git.kernel.org/pub/scm/linux/kernel/git/stable/linux-stable-rc.git X-KernelTest-Branch: linux-4.19.y X-KernelTest-Patches: git://git.kernel.org/pub/scm/linux/kernel/git/stable/stable-queue.git X-KernelTest-Version: 4.19.196-rc1 X-KernelTest-Deadline: 2021-06-30T14:32+00:00 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Pavel Skripkin [ Upstream commit 49bfcbfd989a8f1f23e705759a6bb099de2cff9f ] Syzbot reported memory leak in rds. The problem was in unputted refcount in case of error. int rds_recvmsg(struct socket *sock, struct msghdr *msg, size_t size, int msg_flags) { ... if (!rds_next_incoming(rs, &inc)) { ... } After this "if" inc refcount incremented and if (rds_cmsg_recv(inc, msg, rs)) { ret = -EFAULT; goto out; } ... out: return ret; } in case of rds_cmsg_recv() fail the refcount won't be decremented. And it's easy to see from ftrace log, that rds_inc_addref() don't have rds_inc_put() pair in rds_recvmsg() after rds_cmsg_recv() 1) | rds_recvmsg() { 1) 3.721 us | rds_inc_addref(); 1) 3.853 us | rds_message_inc_copy_to_user(); 1) + 10.395 us | rds_cmsg_recv(); 1) + 34.260 us | } Fixes: bdbe6fbc6a2f ("RDS: recv.c") Reported-and-tested-by: syzbot+5134cdf021c4ed5aaa5f@syzkaller.appspotmail.com Signed-off-by: Pavel Skripkin Reviewed-by: Håkon Bugge Acked-by: Santosh Shilimkar Signed-off-by: David S. Miller Signed-off-by: Sasha Levin --- net/rds/recv.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/net/rds/recv.c b/net/rds/recv.c index 3ca278988b52..ccf0bf283002 100644 --- a/net/rds/recv.c +++ b/net/rds/recv.c @@ -705,7 +705,7 @@ int rds_recvmsg(struct socket *sock, struct msghdr *msg, size_t size, if (rds_cmsg_recv(inc, msg, rs)) { ret = -EFAULT; - goto out; + break; } rds_recvmsg_zcookie(rs, msg); -- 2.30.2