From: Fiona Ebner <f.ebner@proxmox.com>
To: pve-devel@lists.proxmox.com
Subject: [pve-devel] [PATCH v2 qemu-server] remote migration: fix online migration via API clients
Date: Tue, 13 Aug 2024 10:42:57 +0200 [thread overview]
Message-ID: <20240813084257.12720-1-f.ebner@proxmox.com> (raw)
As reported in the community forum [0], when a remote migration
request comes in via an API client, the -T flag for Perl is set, so an
insecure dependency in a call like unlink() in forward_unix_socket()
will fail with:
> failed to write forwarding command - Insecure dependency in unlink while running with -T switch
To fix it, untaint the problematic socket addresses coming from the
remote side. Require that all sockets are below '/run/qemu-server/'
and end with '.migrate'. This allows extensions in the future while
still being quite strict.
[0]: https://forum.proxmox.com/threads/123048/post-691958
Signed-off-by: Fiona Ebner <f.ebner@proxmox.com>
---
Changes in v2:
* rule out '../' in path
PVE/QemuMigrate.pm | 8 +++++++-
1 file changed, 7 insertions(+), 1 deletion(-)
diff --git a/PVE/QemuMigrate.pm b/PVE/QemuMigrate.pm
index e71face4..d31589e7 100644
--- a/PVE/QemuMigrate.pm
+++ b/PVE/QemuMigrate.pm
@@ -1095,7 +1095,10 @@ sub phase2 {
die "only UNIX sockets are supported for remote migration\n"
if $tunnel_info->{proto} ne 'unix';
- my $remote_socket = $tunnel_info->{addr};
+ # untaint
+ my ($remote_socket) =
+ $tunnel_info->{addr} =~ m|^(/run/qemu-server/(?:(?!\.\./).)+\.migrate)$|;
+ die "unexpected socket address '$tunnel_info->{addr}'\n" if !$remote_socket;
my $local_socket = $remote_socket;
$local_socket =~ s/$remote_vmid/$vmid/g;
$tunnel_info->{addr} = $local_socket;
@@ -1104,6 +1107,9 @@ sub phase2 {
PVE::Tunnel::forward_unix_socket($self->{tunnel}, $local_socket, $remote_socket);
foreach my $remote_socket (@{$tunnel_info->{unix_sockets}}) {
+ # untaint
+ ($remote_socket) = $remote_socket =~ m|^(/run/qemu-server/(?:(?!\.\./).)+\.migrate)$|
+ or die "unexpected socket address '$remote_socket'\n";
my $local_socket = $remote_socket;
$local_socket =~ s/$remote_vmid/$vmid/g;
next if $self->{tunnel}->{forwarded}->{$local_socket};
--
2.39.2
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next reply other threads:[~2024-08-13 8:43 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-08-13 8:42 Fiona Ebner [this message]
2024-09-03 9:37 ` Fabian Grünbichler
2024-09-04 11:14 ` Fiona Ebner
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