This ommmit contains some security hardening measures for the Hugo build runtime.
There are some rarely used features in Hugo that would be good to have disabled by default. One example would be the "external helpers".
For `asciidoctor` and some others we use Go's `os/exec` package to start a new process.
These are a predefined set of binary names, all loaded from `PATH` and with a predefined set of arguments. Still, if you don't use `asciidoctor` in your project, you might as well have it turned off.
You can configure your own in the new `security` configuration section, but the defaults are configured to create a minimal amount of site breakage. And if that do happen, you will get clear instructions in the loa about what to do.
The default configuration is listed below. Note that almost all of these options are regular expression _whitelists_ (a string or a slice); the value `none` will block all.
```toml
[security]
enableInlineShortcodes = false
[security.exec]
allow = ['^dart-sass-embedded$', '^go$', '^npx$', '^postcss$']
osEnv = ['(?i)^(PATH|PATHEXT|APPDATA|TMP|TEMP|TERM)$']
[security.funcs]
getenv = ['^HUGO_']
[security.http]
methods = ['(?i)GET|POST']
urls = ['.*']
```
`go-toml/v2`'s unmarshaler does not specify zone name even if value has
offset explicitly.
To make time-formatting behaviour consistent, convert them into string
in hugo.
Close#8895
Unless the merge strategy is set up to do so.
For `disableKinds` the current workaround is to make sure the project config has an entry, even if is empty:
```
disableKinds = []
```
Note that this issue only touches root, non-map config-values that either is not set in project config or in Hugo's defaults.
Fixes#8866
We have been using `go-toml` for language files only. This commit makes it the only TOML library.
It's spec compliant and very fast.
A benchark building a site with 200 pages with TOML front matter:
```bash
name old time/op new time/op delta
SiteNew/Regular_TOML_front_matter-16 48.5ms ± 1% 47.1ms ± 1% -2.85% (p=0.029 n=4+4)
name old alloc/op new alloc/op delta
SiteNew/Regular_TOML_front_matter-16 16.9MB ± 0% 16.7MB ± 0% -1.56% (p=0.029 n=4+4)
name old allocs/op new allocs/op delta
SiteNew/Regular_TOML_front_matter-16 302k ± 0% 296k ± 0% -2.20% (p=0.029 n=4+4)
```
Note that the front matter unmarshaling is only a small part of building a site, so the above is very good.
Fixes#8801
