From patchwork Mon Jun 7 19:41:02 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Pavel Skripkin X-Patchwork-Id: 455681 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=-15.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=unavailable 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 C12E2C47082 for ; Mon, 7 Jun 2021 19:41:28 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id AA03D611BD for ; Mon, 7 Jun 2021 19:41:28 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231532AbhFGTnS (ORCPT ); Mon, 7 Jun 2021 15:43:18 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:37950 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231265AbhFGTnS (ORCPT ); Mon, 7 Jun 2021 15:43:18 -0400 Received: from mail-lj1-x22b.google.com (mail-lj1-x22b.google.com [IPv6:2a00:1450:4864:20::22b]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id CB627C061574; Mon, 7 Jun 2021 12:41:15 -0700 (PDT) Received: by mail-lj1-x22b.google.com with SMTP id e11so23759596ljn.13; Mon, 07 Jun 2021 12:41:15 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:to:cc:subject:date:message-id:mime-version :content-transfer-encoding; bh=Z8D7EP2ZXRo81V/Iibvxl9tc2KeLwiTlPeliqLE5Xwg=; b=Sqb1NYOa8vHwXP3ElbXmXIQUG9dhhuJtAdEv1ZZa1iQF+yHfhAwGBWXzd4x0FSrF5i xc4u7/dPLXxCCamCLIYTyx9HoXPBV/+EdFlDOfPHqWRWL5qE/1LWYlita4PVUw4nHhzA XhF3NbLx+eJ0ItCMTma0mkNDUbm72PyewEw9Yqc/nLCugMghg/CNkZSxkST9e60HnQ3c 1rCv/ClYQrZOAyKYCq9AZiUa8CuC7Tuy6n8w3mNfI6O0he9dvS79olfTvUbF2UumoTJD Xb2SJvIt97DysKYl2475kcoR+tji2SVDzU81StRI5uTXR1nJLzEhOxXZT/GUQbaER9y0 F7uQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:mime-version :content-transfer-encoding; bh=Z8D7EP2ZXRo81V/Iibvxl9tc2KeLwiTlPeliqLE5Xwg=; b=el6kLLHEGb4BFHPVeYcnFc3lkxIifkw7toSc66VUBcZ+VokWdUqPJ+sjzCUi4LIvbx /KCILDrgkWPd9ouegr3B4x9zYWfSYzQUt1h5n3VRTEgWnTlyrYM8feCoakFBWGujKp8A 0eamnZzEc1hHs+AtLJdgYi1BqarNuBO5M2qVfUvyF4jr6Rgm2VjPCSnUCw0F4tfeGnAp pOi6WV2mhZjEUDX2GFos9uY/e3fQJbZKuosYgm+U2UBE6MN+dG4+YTEmvJ9BVDYhM4wZ UUK+JrrazWCbj7Z4XJmZtq2K6He98khVI83HhXq8PgI8OFf+DbFlNApTRSdEnrxxPrlZ r9dw== X-Gm-Message-State: AOAM530SxLdqeSkLZWhYi4lZC7vqeCgaxtcM+g7Bbzg7t74M2X3cf+LC G4oQZF591K5f7KjK+jedPHI= X-Google-Smtp-Source: ABdhPJw0gv5os//4zZ7uIHsRUPvsAoxDmXosX1GUW6X5G9iPQpPEnuEUpRJig52/WV+foGZSojv2cg== X-Received: by 2002:a2e:9e57:: with SMTP id g23mr15942260ljk.123.1623094874132; Mon, 07 Jun 2021 12:41:14 -0700 (PDT) Received: from localhost.localdomain ([94.103.224.40]) by smtp.gmail.com with ESMTPSA id k10sm1118272ljm.39.2021.06.07.12.41.13 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 07 Jun 2021 12:41:13 -0700 (PDT) From: Pavel Skripkin To: santosh.shilimkar@oracle.com, davem@davemloft.net, kuba@kernel.org Cc: netdev@vger.kernel.org, linux-rdma@vger.kernel.org, rds-devel@oss.oracle.com, linux-kernel@vger.kernel.org, Pavel Skripkin , syzbot+5134cdf021c4ed5aaa5f@syzkaller.appspotmail.com Subject: [PATCH] net: rds: fix memory leak in rds_recvmsg Date: Mon, 7 Jun 2021 22:41:02 +0300 Message-Id: <20210607194102.2883-1-paskripkin@gmail.com> X-Mailer: git-send-email 2.31.1 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org 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 --- net/rds/recv.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/net/rds/recv.c b/net/rds/recv.c index 4db109fb6ec2..3fa16c339bfe 100644 --- a/net/rds/recv.c +++ b/net/rds/recv.c @@ -714,7 +714,7 @@ int rds_recvmsg(struct socket *sock, struct msghdr *msg, size_t size, if (rds_cmsg_recv(inc, msg, rs)) { ret = -EFAULT; - goto out; + goto out_put; } rds_recvmsg_zcookie(rs, msg); @@ -740,6 +740,7 @@ int rds_recvmsg(struct socket *sock, struct msghdr *msg, size_t size, break; } +out_put: if (inc) rds_inc_put(inc);