[pbs-devel] [PATCH proxmox-backup] tape: mam: actually enforcing the length when writing attributes

[Thomas Lamprecht]

Am 23/05/2024 um 12:08 schrieb Dominik Csapak:
> we have to check against the length of the attribute, not the u16
> maximum value.
> 
> Signed-off-by: Dominik Csapak <d.csapak at proxmox.com>
> ---
>  pbs-tape/src/sg_tape/mam.rs | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/pbs-tape/src/sg_tape/mam.rs b/pbs-tape/src/sg_tape/mam.rs
> index 4e995d0b..dc5163a5 100644
> --- a/pbs-tape/src/sg_tape/mam.rs
> +++ b/pbs-tape/src/sg_tape/mam.rs
> @@ -169,7 +169,7 @@ pub fn write_mam_attribute<F: AsRawFd>(
>      attr_data.extend(data);
>      if !data.is_empty() && data.len() < attribute.len as usize {
>          attr_data.resize(attr_data.len() - data.len() + attribute.len as usize, 0);
> -    } else if data.len() > u16::MAX as usize {
> +    } else if data.len() > attribute.len as usize {
>          bail!("data to long");

Can we extend this error with the attribute name, the length we got and
the defined max length to have some more info for when a user runs into
this?

Something like:

bail!("attribute '{}' length {} is over the maximum allowed length {}", ...);

Or is this error already extended/concatenated with similar info somewhere
in the return chain (sorry, just doing a quick review directly in my MUA)