From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <pve-devel-bounces@lists.proxmox.com>
Received: from firstgate.proxmox.com (firstgate.proxmox.com [212.224.123.68])
	by lore.proxmox.com (Postfix) with ESMTPS id 731A21FF390
	for <inbox@lore.proxmox.com>; Fri, 24 May 2024 15:22:02 +0200 (CEST)
Received: from firstgate.proxmox.com (localhost [127.0.0.1])
	by firstgate.proxmox.com (Proxmox) with ESMTP id 685C88B9B;
	Fri, 24 May 2024 15:22:14 +0200 (CEST)
From: Dominik Csapak <d.csapak@proxmox.com>
To: pve-devel@lists.proxmox.com
Date: Fri, 24 May 2024 15:21:48 +0200
Message-Id: <20240524132209.703402-5-d.csapak@proxmox.com>
X-Mailer: git-send-email 2.39.2
In-Reply-To: <20240524132209.703402-1-d.csapak@proxmox.com>
References: <20240524132209.703402-1-d.csapak@proxmox.com>
MIME-Version: 1.0
X-SPAM-LEVEL: Spam detection results:  0
 AWL 0.016 Adjusted score from AWL reputation of From: address
 BAYES_00                 -1.9 Bayes spam probability is 0 to 1%
 DMARC_MISSING             0.1 Missing DMARC policy
 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
Subject: [pve-devel] [PATCH storage v4 04/12] ovf: improve and simplify path
 checking code
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>
Reply-To: Proxmox VE development discussion <pve-devel@lists.proxmox.com>
Content-Type: text/plain; charset="us-ascii"
Content-Transfer-Encoding: 7bit
Errors-To: pve-devel-bounces@lists.proxmox.com
Sender: "pve-devel" <pve-devel-bounces@lists.proxmox.com>

moves the filepath code a bit more closer to where it's actually used
checks the contained path before trying to find it's absolute path
properly add error handling to realpath

instead of checking the combined ovf_path + filepath, just make sure
filepath can't point to anythign besides a file in this directory
by checking for '.' and '..' (slashes are not allowed in SAFE_CHAR_CLASS_RE)

Signed-off-by: Dominik Csapak <d.csapak@proxmox.com>
---
 src/PVE/GuestImport/OVF.pm | 36 ++++++++++++++++++------------------
 1 file changed, 18 insertions(+), 18 deletions(-)

diff --git a/src/PVE/GuestImport/OVF.pm b/src/PVE/GuestImport/OVF.pm
index 0728684..ed1c870 100644
--- a/src/PVE/GuestImport/OVF.pm
+++ b/src/PVE/GuestImport/OVF.pm
@@ -220,15 +220,6 @@ ovf:Disk[\@ovf:diskId='%s']/\@ovf:capacityAllocationUnits", $disk_id);
 	    next;
 	}
 
-	# from Disk Node, find corresponding filepath
-	my $xpath_find_filepath = sprintf("/ovf:Envelope/ovf:References/ovf:File[\@ovf:id='%s']/\@ovf:href", $fileref);
-	my $filepath = $xpc->findvalue($xpath_find_filepath);
-	if (!$filepath) {
-	    warn "invalid file reference $fileref, skipping\n";
-	    next;
-	}
-	print "file path: $filepath\n" if $debug;
-
 	# from Item, find owning Controller type
 	my $controller_id = $xpc->findvalue('rasd:Parent', $item_node);
 	my $xpath_find_parent_type = sprintf("/ovf:Envelope/ovf:VirtualSystem/ovf:VirtualHardwareSection/\
@@ -244,22 +235,31 @@ ovf:Item[rasd:InstanceID='%s']/rasd:ResourceType", $controller_id);
 	my $adress_on_controller = $xpc->findvalue('rasd:AddressOnParent', $item_node);
 	my $pve_disk_address = id_to_pve($controller_type) . $adress_on_controller;
 
+	# from Disk Node, find corresponding filepath
+	my $xpath_find_filepath = sprintf("/ovf:Envelope/ovf:References/ovf:File[\@ovf:id='%s']/\@ovf:href", $fileref);
+	my $filepath = $xpc->findvalue($xpath_find_filepath);
+	if (!$filepath) {
+	    warn "invalid file reference $fileref, skipping\n";
+	    next;
+	}
+	print "file path: $filepath\n" if $debug;
+	my $original_filepath = $filepath;
+	($filepath) = $filepath =~ m|^(${PVE::Storage::SAFE_CHAR_CLASS_RE}+)$|; # untaint & check no sub/parent dirs
+	die "referenced path '$original_filepath' is invalid\n" if !$filepath || $filepath eq "." || $filepath eq "..";
+
 	# resolve symlinks and relative path components
 	# and die if the diskimage is not somewhere under the $ovf path
-	my $ovf_dir = realpath(dirname(File::Spec->rel2abs($ovf)));
-	my $backing_file_path = realpath(join ('/', $ovf_dir, $filepath));
-	if ($backing_file_path !~ /^\Q${ovf_dir}\E/) {
-	    die "error parsing $filepath, are you using a symlink ?\n";
-	}
+	my $ovf_dir = realpath(dirname(File::Spec->rel2abs($ovf)))
+	    or die "could not get absolute path of $ovf: $!\n";
+	my $backing_file_path = realpath(join ('/', $ovf_dir, $filepath))
+	    or die "could not get absolute path of $filepath: $!\n";
+
+	($backing_file_path) = $backing_file_path =~ m|^(/.*)|; # untaint
 
 	if (!-e $backing_file_path && !$isOva) {
 	    die "error parsing $filepath, file seems not to exist at $backing_file_path\n";
 	}
 
-	($backing_file_path) = $backing_file_path =~ m|^(/.*)|; # untaint
-	($filepath) = $filepath =~ m|^(${PVE::Storage::SAFE_CHAR_CLASS_RE}+)$|; # untaint & check no sub/parent dirs
-	die "invalid path\n" if !$filepath;
-
 	if (!$isOva) {
 	    my $size = PVE::Storage::file_size_info($backing_file_path);
 	    die "error parsing $backing_file_path, cannot determine file size\n"
-- 
2.39.2



_______________________________________________
pve-devel mailing list
pve-devel@lists.proxmox.com
https://lists.proxmox.com/cgi-bin/mailman/listinfo/pve-devel