[pve-devel] [PATCH common] untaint df return values

[Thomas Lamprecht]

On 4/20/18 11:42 AM, Dominik Csapak wrote:
> since we sometimes use their length in a format string for printf
> 
> Signed-off-by: Dominik Csapak <d.csapak at proxmox.com>
> ---
>  src/PVE/Tools.pm | 11 ++++++++---
>  1 file changed, 8 insertions(+), 3 deletions(-)
> 
> diff --git a/src/PVE/Tools.pm b/src/PVE/Tools.pm
> index d5373a4..a366d47 100644
> --- a/src/PVE/Tools.pm
> +++ b/src/PVE/Tools.pm
> @@ -986,10 +986,15 @@ sub df {
>      my $res = eval { run_fork_with_timeout($timeout, $df) } // {};
>      warn $@ if $@;
>  
> +    #untaint the values
> +    my ($blocks) = $res->{blocks} =~ m/^(\d+)$/ if $res->{blocks};
> +    my ($used) = $res->{used} =~ m/^(\d+)$/ if $res->{used};
> +    my ($bavail) = $res->{bavail} =~ m/^(\d+)$/ if $res->{bavail};
> +
>      return {
> -	total => $res->{blocks} // 0,
> -	used => $res->{used} // 0,
> -	avail => $res->{bavail} // 0,
> +	total => $blocks // 0,
> +	used => $used // 0,
> +	avail => $bavail // 0,
>      };
>  }
>  
> 

Hmm, a bit much repetition... How about just doing:

----8<----
diff --git a/src/PVE/Tools.pm b/src/PVE/Tools.pm
index d5373a4..68f8215 100644
--- a/src/PVE/Tools.pm
+++ b/src/PVE/Tools.pm
@@ -986,10 +986,13 @@ sub df {
     my $res = eval { run_fork_with_timeout($timeout, $df) } // {};
     warn $@ if $@;

+    my ($blocks, $used, $bavail) = map { (/^(\d+)$/) // 0 }
+       $res->@{qw(blocks used bavail)};
+
     return {
-       total => $res->{blocks} // 0,
-       used => $res->{used} // 0,
-       avail => $res->{bavail} // 0,
+       total => $blocks,
+       used => $used,
+       avail => $bavail,
     };
 }