From mboxrd@z Thu Jan 1 00:00:00 1970
Return-Path: <w.bumiller@proxmox.com>
Received: from firstgate.proxmox.com (firstgate.proxmox.com [212.224.123.68])
(using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits)
key-exchange X25519 server-signature RSA-PSS (2048 bits))
(No client certificate requested)
by lists.proxmox.com (Postfix) with ESMTPS id 1A0F07E3FD
for <pve-devel@lists.proxmox.com>; Wed, 10 Nov 2021 13:49:06 +0100 (CET)
Received: from firstgate.proxmox.com (localhost [127.0.0.1])
by firstgate.proxmox.com (Proxmox) with ESMTP id 17A3F1BFD0
for <pve-devel@lists.proxmox.com>; Wed, 10 Nov 2021 13:49:06 +0100 (CET)
Received: from proxmox-new.maurer-it.com (proxmox-new.maurer-it.com
[94.136.29.106])
(using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits)
key-exchange X25519 server-signature RSA-PSS (2048 bits))
(No client certificate requested)
by firstgate.proxmox.com (Proxmox) with ESMTPS id 032A61BF60
for <pve-devel@lists.proxmox.com>; Wed, 10 Nov 2021 13:49:05 +0100 (CET)
Received: from proxmox-new.maurer-it.com (localhost.localdomain [127.0.0.1])
by proxmox-new.maurer-it.com (Proxmox) with ESMTP id CC53B44BC2
for <pve-devel@lists.proxmox.com>; Wed, 10 Nov 2021 13:49:04 +0100 (CET)
From: Wolfgang Bumiller <w.bumiller@proxmox.com>
To: pve-devel@lists.proxmox.com
Date: Wed, 10 Nov 2021 13:49:00 +0100
Message-Id: <20211110124904.164053-2-w.bumiller@proxmox.com>
X-Mailer: git-send-email 2.30.2
In-Reply-To: <20211110124904.164053-1-w.bumiller@proxmox.com>
References: <20211110124904.164053-1-w.bumiller@proxmox.com>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
X-SPAM-LEVEL: Spam detection results: 0
AWL 0.489 Adjusted score from AWL reputation of From: address
BAYES_00 -1.9 Bayes spam probability is 0 to 1%
KAM_DMARC_STATUS 0.01 Test Rule for DKIM or SPF Failure with Strict Alignment
SPF_HELO_NONE 0.001 SPF: HELO does not publish an SPF Record
SPF_PASS -0.001 SPF: sender matches SPF record
URIBL_BLOCKED 0.001 ADMINISTRATOR NOTICE: The query to URIBL was blocked. See
http://wiki.apache.org/spamassassin/DnsBlocklists#dnsbl-block for more
information. [accesscontrol.pm]
Subject: [pve-devel] [PATCH access-control 1/4] assert tfa/user config lock
order
X-BeenThere: pve-devel@lists.proxmox.com
X-Mailman-Version: 2.1.29
Precedence: list
List-Id: Proxmox VE development discussion <pve-devel.lists.proxmox.com>
List-Unsubscribe: <https://lists.proxmox.com/cgi-bin/mailman/options/pve-devel>,
<mailto:pve-devel-request@lists.proxmox.com?subject=unsubscribe>
List-Archive: <http://lists.proxmox.com/pipermail/pve-devel/>
List-Post: <mailto:pve-devel@lists.proxmox.com>
List-Help: <mailto:pve-devel-request@lists.proxmox.com?subject=help>
List-Subscribe: <https://lists.proxmox.com/cgi-bin/mailman/listinfo/pve-devel>,
<mailto:pve-devel-request@lists.proxmox.com?subject=subscribe>
X-List-Received-Date: Wed, 10 Nov 2021 12:49:06 -0000
Signed-off-by: Wolfgang Bumiller <w.bumiller@proxmox.com>
---
src/PVE/AccessControl.pm | 14 ++++++++++++++
1 file changed, 14 insertions(+)
diff --git a/src/PVE/AccessControl.pm b/src/PVE/AccessControl.pm
index 0b00847..49cef94 100644
--- a/src/PVE/AccessControl.pm
+++ b/src/PVE/AccessControl.pm
@@ -12,6 +12,7 @@ use Digest::SHA;
use IO::File;
use File::stat;
use JSON;
+use Scalar::Util 'weaken';
use PVE::OTP;
use PVE::Ticket;
@@ -68,10 +69,20 @@ sub pve_verify_realm {
PVE::Auth::Plugin::pve_verify_realm(@_);
}
+# Locking both config files together is only ever allowed in one order:
+# 1) tfa config
+# 2) user config
+# If we permit the other way round, too, we might end up deadlocking!
+my $user_config_locked;
sub lock_user_config {
my ($code, $errmsg) = @_;
+ my $locked = 1;
+ $user_config_locked = \$locked;
+ weaken $user_config_locked; # make this scope guard signal safe...
+
cfs_lock_file("user.cfg", undef, $code);
+ $user_config_locked = undef;
if (my $err = $@) {
$errmsg ? die "$errmsg: $err" : die $err;
}
@@ -80,6 +91,9 @@ sub lock_user_config {
sub lock_tfa_config {
my ($code, $errmsg) = @_;
+ die "tfa config lock cannot be acquired while holding user config lock\n"
+ if ($user_config_locked && $$user_config_locked);
+
my $res = cfs_lock_file("priv/tfa.cfg", undef, $code);
if (my $err = $@) {
$errmsg ? die "$errmsg: $err" : die $err;
--
2.30.2