[pve-devel] [PATCH v3 container] fix invalid device passthrough being added to config

[Filip Schauer]

Fix a bug that allows a device passthrough entry to be added to the
config despite the device path not pointing to a device. Previously,
adding an invalid device passthrough entry would throw an error, but the
entry would still be added to the config. This is fixed by moving the
respective checks from update_lxc_config to update_pct_config, which is
run before the entry is written to the config file.

Signed-off-by: Filip Schauer <f.schauer at proxmox.com>
---
Changes since v2:
* Rename get_device_stat to get_device_mode_and_rdev and move it from
  PVE::Tools to PVE::LXC::Tools.
* Cleanup formatting of post-ifs in get_device_mode_and_rdev

Changes since v1:
* Use "if" instead of "unless"
* Move device path validation and stat to seperate helper function

 src/PVE/LXC.pm        | 18 ++++--------------
 src/PVE/LXC/Config.pm | 11 ++++++++++-
 src/PVE/LXC/Tools.pm  | 15 +++++++++++++++
 3 files changed, 29 insertions(+), 15 deletions(-)

diff --git a/src/PVE/LXC.pm b/src/PVE/LXC.pm
index 9681d74..e688ea6 100644
--- a/src/PVE/LXC.pm
+++ b/src/PVE/LXC.pm
@@ -4,7 +4,7 @@ use strict;
 use warnings;
 
 use Cwd qw();
-use Errno qw(ELOOP ENOENT ENOTDIR EROFS ECONNREFUSED EEXIST);
+use Errno qw(ELOOP ENOTDIR EROFS ECONNREFUSED EEXIST);
 use Fcntl qw(O_RDONLY O_WRONLY O_NOFOLLOW O_DIRECTORY :mode);
 use File::Path;
 use File::Spec;
@@ -643,20 +643,10 @@ sub update_lxc_config {
     PVE::LXC::Config->foreach_passthrough_device($conf, sub {
 	my ($key, $device) = @_;
 
-	die "Path is not defined for passthrough device $key"
-	    unless (defined($device->{path}));
-
-	my $absolute_path = $device->{path};
-	my ($mode, $rdev) = (stat($absolute_path))[2, 6];
-
-	die "Device $absolute_path does not exist\n" if $! == ENOENT;
-
-	die "Error accessing device $absolute_path\n"
-	    if (!defined($mode) || !defined($rdev));
-
-	die "$absolute_path is not a device\n"
-	    if (!S_ISBLK($mode) && !S_ISCHR($mode));
+	die "Path is not defined for passthrough device $key\n"
+	    if !defined($device->{path});
 
+	my ($mode, $rdev) = PVE::LXC::Tools::get_device_mode_and_rdev($device->{path});
 	my $major = PVE::Tools::dev_t_major($rdev);
 	my $minor = PVE::Tools::dev_t_minor($rdev);
 	my $device_type_char = S_ISBLK($mode) ? 'b' : 'c';
diff --git a/src/PVE/LXC/Config.pm b/src/PVE/LXC/Config.pm
index 5ac1446..408140f 100644
--- a/src/PVE/LXC/Config.pm
+++ b/src/PVE/LXC/Config.pm
@@ -3,7 +3,8 @@ package PVE::LXC::Config;
 use strict;
 use warnings;
 
-use Fcntl qw(O_RDONLY);
+use Errno qw(ENOENT);
+use Fcntl qw(O_RDONLY :mode);
 
 use PVE::AbstractConfig;
 use PVE::Cluster qw(cfs_register_file);
@@ -1193,6 +1194,14 @@ sub update_pct_config {
 		die "$opt: MTU size '$mtu' is bigger than bridge MTU '$bridge_mtu'\n"
 		    if ($mtu > $bridge_mtu);
 	    }
+	} elsif ($opt =~ m/^dev(\d+)$/) {
+	    my $device = $class->parse_device($value);
+
+	    die "Path is not defined for passthrough device $opt"
+		if !defined($device->{path});
+
+            # Validate device
+            PVE::LXC::Tools::get_device_mode_and_rdev($device->{path});
 	}
 	$conf->{pending}->{$opt} = $value;
 	$class->remove_from_pending_delete($conf, $opt);
diff --git a/src/PVE/LXC/Tools.pm b/src/PVE/LXC/Tools.pm
index f96756d..7e3e530 100644
--- a/src/PVE/LXC/Tools.pm
+++ b/src/PVE/LXC/Tools.pm
@@ -4,6 +4,8 @@ package PVE::LXC::Tools;
 use strict;
 use warnings;
 
+use POSIX qw(ENOENT S_ISBLK S_ISCHR);
+
 use PVE::SafeSyslog;
 
 # LXC introduced an `lxc.hook.version` property which allows hooks to be executed in different
@@ -152,6 +154,19 @@ sub cgroup_do_write($$) {
     return 1;
 }
 
+sub get_device_mode_and_rdev($) {
+    my ($path) = @_;
+
+    die "Path is not defined\n" if !defined($path);
+
+    my ($mode, $rdev) = (stat($path))[2, 6];
+    die "Device $path does not exist\n" if $! == ENOENT;
+    die "Error accessing device $path\n" if !defined($mode) || !defined($rdev);
+    die "$path is not a device\n" if !S_ISBLK($mode) && !S_ISCHR($mode);
+
+    return ($mode, $rdev);
+}
+
 # Tries to the architecture of an executable file based on its ELF header.
 sub detect_elf_architecture {
     my ($elf_fn) = @_;
-- 
2.39.2