fix(nix-compat/narinfo): don't panic trying to parse signatures r/7074

BASE64.decode_mut panics if we're passing data that has the wrong size.
Do the size check first and error out there.

Also update the error, and talk about b64-encoded sizes.

Change-Id: I290f80a37d48526a30bf1df9d1d9fe34865008eb
Reviewed-on: https://cl.tvl.fyi/c/depot/+/10146
Tested-by: BuildkiteCI
Reviewed-by: edef <edef@edef.eu>
Autosubmit: flokli <flokli@flokli.de>

0 files changed, 0 insertions, 0 deletions