From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: 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 968EA74D03 for ; Tue, 22 Jun 2021 16:29:19 +0200 (CEST) Received: from firstgate.proxmox.com (localhost [127.0.0.1]) by firstgate.proxmox.com (Proxmox) with ESMTP id 8437928E21 for ; Tue, 22 Jun 2021 16:28:49 +0200 (CEST) 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) server-digest SHA256) (No client certificate requested) by firstgate.proxmox.com (Proxmox) with ESMTPS id CE29F28E16 for ; Tue, 22 Jun 2021 16:28:47 +0200 (CEST) Received: from proxmox-new.maurer-it.com (localhost.localdomain [127.0.0.1]) by proxmox-new.maurer-it.com (Proxmox) with ESMTP id 9BD23457EA for ; Tue, 22 Jun 2021 16:28:47 +0200 (CEST) From: Stoiko Ivanov To: pve-devel@lists.proxmox.com Date: Tue, 22 Jun 2021 16:28:24 +0200 Message-Id: <20210622142824.18773-1-s.ivanov@proxmox.com> X-Mailer: git-send-email 2.20.1 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-SPAM-LEVEL: Spam detection results: 0 AWL 0.670 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. [tools.pm, proxmox.com] Subject: [pve-devel] [PATCH common] run_command: untaint end of buffer X-BeenThere: pve-devel@lists.proxmox.com X-Mailman-Version: 2.1.29 Precedence: list List-Id: Proxmox VE development discussion List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 22 Jun 2021 14:29:19 -0000 The performance improvements added in cb9db10c1a9855cf40ff13e81f9dd97d6a9b2698 changed the output handling to not remove the taintedness (see perlsec (1)) of the complete output anymore. This results in a few bugs which show up every now and then, and are usually quite tedious to hunt down - usually they only occur when run via GUI (since pveproxy/pvedaemon run in taint-mode, whereas our CLI utilities usually do not) - see for example pve-storage commit 609f117ff24d2cff6b155e1d4b1175ceebe5bd7b or more recently the report in our community-forum: https://forum.proxmox.com/threads/cannot-clone-vm-or-move-disk-with-more-than-13-snapshots.89628/ (the magic number of 13 snapshots is the point where the output of `qemu-img info --output=json` grows to more than 4k) Given the doubtful security benefit of having to untaint output, only if it does not end in new-line or if it is longer than 4k (we read the output in 4k chunks) simply untaint the output unconditionally. Tested with the reproducer from the forum-thread Signed-off-by: Stoiko Ivanov --- Huge thanks to Dominik who pointed me in the right direction, after I spend far more time than I'm proud to admit in the JSON::XS source, perlsec(1), perlguts(1) and the surprisingly unhelpful output of debugperl -Du src/PVE/Tools.pm | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/src/PVE/Tools.pm b/src/PVE/Tools.pm index 8946e93..eb140ae 100644 --- a/src/PVE/Tools.pm +++ b/src/PVE/Tools.pm @@ -516,7 +516,7 @@ sub run_command { &$outfunc($line) if $outfunc; &$logfunc($line) if $logfunc; } - $outlog .= $buf; + ($outlog) .= ($buf =~ /(.*)/); #untaint }; my $err = $@; if ($err) { @@ -537,7 +537,7 @@ sub run_command { &$errfunc($line) if $errfunc; &$logfunc($line) if $logfunc; } - $errlog .= $buf; + ($errlog) .= ($buf =~ /(.*)/); #untaint }; my $err = $@; if ($err) { -- 2.20.1