From patchwork Fri Jul 10 05:01:16 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Paul Aurich X-Patchwork-Id: 11655613 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id CCD7B6C1 for ; Fri, 10 Jul 2020 05:01:21 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id B372E2076A for ; Fri, 10 Jul 2020 05:01:21 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=darkrain42.org header.i=@darkrain42.org header.b="MHUmRSvK" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1725943AbgGJFBV (ORCPT ); Fri, 10 Jul 2020 01:01:21 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:40808 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725802AbgGJFBV (ORCPT ); Fri, 10 Jul 2020 01:01:21 -0400 Received: from mail.darkrain42.org (o-chul.darkrain42.org [IPv6:2600:3c01::f03c:91ff:fe96:292c]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 3ACEBC08C5CE for ; Thu, 9 Jul 2020 22:01:21 -0700 (PDT) Received: from [127.0.0.1] (localhost [127.0.0.1]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (Client did not present a certificate) by o-chul.darkrain42.org (Postfix) with ESMTPSA id 6359180F3; Thu, 9 Jul 2020 22:01:20 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=darkrain42.org; s=a; t=1594357280; bh=8CMJ8ypzQKOKWMm+qNoVZLFpiLA4av3EJA9cEZhP9yU=; h=From:To:Cc:Subject:Date:From; b=MHUmRSvKbhfBHZ9+6HLEepUOrFV7c1aR3bhqkSeFyd4aiQIwIyNfvbMeiNXXES8sh 2o4tQjk4V1PTzeSZyKqc4wR3gDHjbCoovDhtco4OyoK6WwkoDlWLo/a/8EHFlgSP0y WpZe1YAVHrB+l1ApEmT3/Cvsz1/Hckuy9bMmh/hyAoEjMbUQuONrGwNV8uhR9rOmH1 2rfZGHPmaO3bpWhg1pddwRdMvhjvLo8bywlPVtxlC/TCcDl79dUJPDg974ymLhghhq kz5gXbaYd4ADqYCMYu4VOOaVqtuTozJH+SGeGzHTZNLKi0AE9rH5/BWBKxYsDJXgvK wXOUf2fuaJNYQ== From: Paul Aurich To: linux-cifs@vger.kernel.org, sfrench@samba.org Cc: paul@darkrain42.org, Ronnie Sahlberg , =?utf-8?q?Au?= =?utf-8?q?r=C3=A9lien_Aptel?= Subject: [PATCH v4] cifs: Fix leak when handling lease break for cached root fid Date: Thu, 9 Jul 2020 22:01:16 -0700 Message-Id: <20200710050116.623540-1-paul@darkrain42.org> X-Mailer: git-send-email 2.27.0 MIME-Version: 1.0 Sender: linux-cifs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-cifs@vger.kernel.org Handling a lease break for the cached root didn't free the smb2_lease_break_work allocation, resulting in a leak: unreferenced object 0xffff98383a5af480 (size 128): comm "cifsd", pid 684, jiffies 4294936606 (age 534.868s) hex dump (first 32 bytes): c0 ff ff ff 1f 00 00 00 88 f4 5a 3a 38 98 ff ff ..........Z:8... 88 f4 5a 3a 38 98 ff ff 80 88 d6 8a ff ff ff ff ..Z:8........... backtrace: [<0000000068957336>] smb2_is_valid_oplock_break+0x1fa/0x8c0 [<0000000073b70b9e>] cifs_demultiplex_thread+0x73d/0xcc0 [<00000000905fa372>] kthread+0x11c/0x150 [<0000000079378e4e>] ret_from_fork+0x22/0x30 Avoid this leak by only allocating when necessary. Fixes: a93864d93977 ("cifs: add lease tracking to the cached root fid") Signed-off-by: Paul Aurich CC: Stable # v4.18+ Reviewed-by: Aurelien Aptel --- Changes from v3: - refactor pending open lease handling into separate functions so that the core spinlock handling can occur all in smb2_is_valid_lease_break fs/cifs/smb2misc.c | 73 +++++++++++++++++++++++++++++++++------------- 1 file changed, 52 insertions(+), 21 deletions(-) diff --git a/fs/cifs/smb2misc.c b/fs/cifs/smb2misc.c index 6a39451973f8..865cd248c605 100644 --- a/fs/cifs/smb2misc.c +++ b/fs/cifs/smb2misc.c @@ -504,15 +504,31 @@ cifs_ses_oplock_break(struct work_struct *work) kfree(lw); } +static void +smb2_queue_pending_open_break(struct tcon_link *tlink, __u8 *lease_key, + __le32 new_lease_state) +{ + struct smb2_lease_break_work *lw; + + lw = kmalloc(sizeof(struct smb2_lease_break_work), GFP_KERNEL); + if (!lw) { + cifs_put_tlink(tlink); + return; + } + + INIT_WORK(&lw->lease_break, cifs_ses_oplock_break); + lw->tlink = tlink; + lw->lease_state = new_lease_state; + memcpy(lw->lease_key, lease_key, SMB2_LEASE_KEY_SIZE); + queue_work(cifsiod_wq, &lw->lease_break); +} + static bool -smb2_tcon_has_lease(struct cifs_tcon *tcon, struct smb2_lease_break *rsp, - struct smb2_lease_break_work *lw) +smb2_tcon_has_lease(struct cifs_tcon *tcon, struct smb2_lease_break *rsp) { - bool found; __u8 lease_state; struct list_head *tmp; struct cifsFileInfo *cfile; - struct cifs_pending_open *open; struct cifsInodeInfo *cinode; int ack_req = le32_to_cpu(rsp->Flags & SMB2_NOTIFY_BREAK_LEASE_FLAG_ACK_REQUIRED); @@ -542,22 +558,29 @@ smb2_tcon_has_lease(struct cifs_tcon *tcon, struct smb2_lease_break *rsp, cfile->oplock_level = lease_state; cifs_queue_oplock_break(cfile); - kfree(lw); return true; } - found = false; + return false; +} + +static struct cifs_pending_open * +smb2_tcon_find_pending_open_lease(struct cifs_tcon *tcon, + struct smb2_lease_break *rsp) +{ + __u8 lease_state = le32_to_cpu(rsp->NewLeaseState); + int ack_req = le32_to_cpu(rsp->Flags & + SMB2_NOTIFY_BREAK_LEASE_FLAG_ACK_REQUIRED); + struct cifs_pending_open *open; + struct cifs_pending_open *found = NULL; + list_for_each_entry(open, &tcon->pending_opens, olist) { if (memcmp(open->lease_key, rsp->LeaseKey, SMB2_LEASE_KEY_SIZE)) continue; if (!found && ack_req) { - found = true; - memcpy(lw->lease_key, open->lease_key, - SMB2_LEASE_KEY_SIZE); - lw->tlink = cifs_get_tlink(open->tlink); - queue_work(cifsiod_wq, &lw->lease_break); + found = open; } cifs_dbg(FYI, "found in the pending open list\n"); @@ -578,14 +601,7 @@ smb2_is_valid_lease_break(char *buffer) struct TCP_Server_Info *server; struct cifs_ses *ses; struct cifs_tcon *tcon; - struct smb2_lease_break_work *lw; - - lw = kmalloc(sizeof(struct smb2_lease_break_work), GFP_KERNEL); - if (!lw) - return false; - - INIT_WORK(&lw->lease_break, cifs_ses_oplock_break); - lw->lease_state = rsp->NewLeaseState; + struct cifs_pending_open *open; cifs_dbg(FYI, "Checking for lease break\n"); @@ -603,11 +619,27 @@ smb2_is_valid_lease_break(char *buffer) spin_lock(&tcon->open_file_lock); cifs_stats_inc( &tcon->stats.cifs_stats.num_oplock_brks); - if (smb2_tcon_has_lease(tcon, rsp, lw)) { + if (smb2_tcon_has_lease(tcon, rsp)) { spin_unlock(&tcon->open_file_lock); spin_unlock(&cifs_tcp_ses_lock); return true; } + open = smb2_tcon_find_pending_open_lease(tcon, + rsp); + if (open) { + __u8 lease_key[SMB2_LEASE_KEY_SIZE]; + struct tcon_link *tlink; + + tlink = cifs_get_tlink(open->tlink); + memcpy(lease_key, open->lease_key, + SMB2_LEASE_KEY_SIZE); + spin_unlock(&tcon->open_file_lock); + spin_unlock(&cifs_tcp_ses_lock); + smb2_queue_pending_open_break(tlink, + lease_key, + rsp->NewLeaseState); + return true; + } spin_unlock(&tcon->open_file_lock); if (tcon->crfid.is_valid && @@ -625,7 +657,6 @@ smb2_is_valid_lease_break(char *buffer) } } spin_unlock(&cifs_tcp_ses_lock); - kfree(lw); cifs_dbg(FYI, "Can not process lease break - no lease matched\n"); return false; }