On 20/01/2022 21:31, Sergey Ponomarev wrote:
Package: coreutils
Currently the base64 util can't parse base64 url safe.
RFC 3548 Base 64 Encoding with URL and Filename Safe Alphabet
https://datatracker.ietf.org/doc/html/rfc3548#page-6
But basically this is the same encoding: just two symbols differ and
no padding. So it's easy and safe just to parse both forms.
The coreutils have a separate command `basenc --base64url` to parse
the b64u but actually there is no any sense to make it as a separate
command.
Having this as a separate command makes it unusable for small Linux
distros like OpenWrt where the device's disk is very small.
Note coreutils can be built like busybox to include multiple commands in a
single binary
Currently **many** shell scripts uses additional transformation like:
```sh
base64_padding()
{
local len=$(( ${#1} % 4 ))
local padded_b64=''
if [ ${len} = 2 ]; then
padded_b64="${1}=="
elif [ ${len} = 3 ]; then
padded_b64="${1}="
else
padded_b64="${1}"
fi
echo -n "$padded_b64"
}
base64url_to_b64()
{
base64_padding "${1}" | tr -- '-_' '+/'
}
```
I'm not sure about base64 accepting _either_ encoding without options.
There would be robustness issues with that.
Also blinding assuming padding may introduce robustness issues with truncated
data.
It might be useful to have a "--decode-relaxed" option or something
to support decoding any b64 variant and assume no padding,
though preprocessing isn't that onerous, so this is marginal.
But this over complicates everything, reduces performance and is error prone.
I created a similar ticked for OpenSSL base64
https://github.com/openssl/openssl/issues/17559
Also as an additional request: can we add the new param `-D` in upper
case which will be an alias to `-d`.
The issue is that on MacOS the small -d was used for debug and they
used the -D in upper case. This creates a lot of problems for scripts
that should work on both Linux and MacOS. So most people use the long
--decode. But many users just don't know about this interop problem
and once I faced a problem when my college gave me a script that
didn't work for me.
This will prevent unexpected compatibility problems.
macos using -D is unfortunate.
It's surprising they diverged from FreeBSD here.
The fact there is a cross platform --decode option,
suggests we don't need to add -D support,
as it doesn't help folks using -d on other systems.
cheers,
Pádraig
