Re: [PATCH v3 4/9] bugreport: add config values from whitelist

[Johannes Schindelin <Johannes.Schindelin@gmx.de>]

Hi Emily,

On Thu, 24 Oct 2019, Emily Shaffer wrote:

> Teach bugreport to gather the values of config options which are present
> in 'git-bugreport-config-whitelist'.
>
> Many config options are sensitive, and many Git add-ons use config
> options which git-core does not know about; it is better only to gather
> config options which we know to be safe, rather than excluding options
> which we know to be unsafe.

Should we still have the `// bugreport-exclude` comments, then?

>
> Reading the whitelist into memory and sorting it saves us time -
> since git_config_bugreport() is called for every option the user has
> configured, limiting the file IO to one open/read/close and performing
> option lookup in sublinear time is a useful optimization.

Maybe we even want a hashmap? That would reduce the time complexity even
further.

> diff --git a/bugreport.c b/bugreport.c
> index ada54fe583..afa4836ab1 100644
> --- a/bugreport.c
> +++ b/bugreport.c
> @@ -1,10 +1,24 @@
>  #include "cache.h"
>
>  #include "bugreport.h"
> +#include "config.h"
> +#include "exec-cmd.h"
>  #include "help.h"
>  #include "run-command.h"
>  #include "version.h"
>
> +/**
> + * A sorted list of config options which we will add to the bugreport. Managed
> + * by 'gather_whitelist(...)'.
> + */
> +struct string_list whitelist = STRING_LIST_INIT_DUP;
> +struct strbuf configs_and_values = STRBUF_INIT;
> +
> +// git version --build-options
> +// uname -a
> +// curl-config --version
> +// ldd --version
> +// echo $SHELL

These comments probably want to move to a single, C style comment, and
they probably want to be introduced together with `get_system_info()`.

I also have to admit that I might have missed where `$SHELL` was added
to the output...

>  void get_system_info(struct strbuf *sys_info)
>  {
>  	struct child_process cp = CHILD_PROCESS_INIT;
> @@ -53,3 +67,39 @@ void get_system_info(struct strbuf *sys_info)
>  	argv_array_clear(&cp.args);
>  	strbuf_reset(&std_out);
>  }
> +
> +void gather_whitelist(struct strbuf *path)
> +{
> +	struct strbuf tmp = STRBUF_INIT;
> +	strbuf_read_file(&tmp, path->buf, 0);
> +	string_list_init(&whitelist, 1);
> +	string_list_split(&whitelist, tmp.buf, '\n', -1);
> +	string_list_sort(&whitelist);
> +}
> +
> +int git_config_bugreport(const char *var, const char *value, void *cb)
> +{
> +	if (string_list_has_string(&whitelist, var)) {
> +		strbuf_addf(&configs_and_values,
> +			    "%s : %s\n",
> +			    var, value);

A quite useful piece of information would be the config source. Not sure
whether we can do that outside of `config.c` yet...

> +	}
> +
> +	return 0;
> +}
> +
> +void get_whitelisted_config(struct strbuf *config_info)
> +{
> +	struct strbuf path = STRBUF_INIT;
> +
> +	strbuf_addstr(&path, git_exec_path());
> +	strbuf_addstr(&path, "/git-bugreport-config-whitelist");

Hmm. I would have expected this patch to come directly after the patch
2/9 that generates that white-list, and I would also have expected that
to be pre-sorted, and compiled in.

Do you want users to _edit_ the file in the exec path? In general, that
path will be write-protected, though. A better alternative would
probably be to compile in a hard-coded list, and to allow including more
values e.g. by offering command-line options to specify config setting
patterns. But if we allow patterns, we might actually want to have those
exclusions to prevent sensitive data from being included.

> +
> +	gather_whitelist(&path);
> +	strbuf_init(&configs_and_values, whitelist.nr);
> +
> +	git_config(git_config_bugreport, NULL);
> +
> +	strbuf_reset(config_info);
> +	strbuf_addbuf(config_info, &configs_and_values);
> +}
> diff --git a/bugreport.h b/bugreport.h
> index ba216acf3f..7413e7e1be 100644
> --- a/bugreport.h
> +++ b/bugreport.h
> @@ -5,3 +5,10 @@
>   * The previous contents of sys_info will be discarded.
>   */
>  void get_system_info(struct strbuf *sys_info);
> +
> +/**

I also frequently use JavaDoc-style `/**`, but I am not sure that this
is actually desired in Git's source code ;-)

> + * Adds the values of the config items listed in
> + * 'git-bugreport-config-whitelist' to config_info. The previous contents of
> + * config_info will be discarded.
> + */
> +void get_whitelisted_config(struct strbuf *sys_info);
> diff --git a/builtin/bugreport.c b/builtin/bugreport.c
> index 7232d31be7..70fe0d2b85 100644
> --- a/builtin/bugreport.c
> +++ b/builtin/bugreport.c
> @@ -56,6 +56,10 @@ int cmd_bugreport(int argc, const char **argv, const char *prefix)
>  	get_system_info(&buffer);
>  	strbuf_write(&buffer, report);
>
> +	add_header(report, "Whitelisted Config");

Quite honestly, I would like to avoid the term "whitelist" for good. How
about "Selected config settings" instead?

Thanks,
Dscho

> +	get_whitelisted_config(&buffer);
> +	strbuf_write(&buffer, report);
> +
>  	fclose(report);
>
>  	launch_editor(report_path.buf, NULL, NULL);
> --
> 2.24.0.rc0.303.g954a862665-goog
>
>