Re: a problem with git describe

> On Mon, Apr 25, 2022 at 12:02:45AM -0700, Carlo Marcelo Arenas Belón wrote:
>> On Sun, Apr 24, 2022 at 11:39:27PM -0700, Junio C Hamano wrote:
>>> Carlo Marcelo Arenas Belón <carenas@gmail.com> writes:
>>>
>>>> At that point, though you might as well excempt root from this check
>>>
>>> But "root" or any higher-valued account is what needs this kind of
>>> protection the most, no?
>>
>> correct, and I didn't meant to excempt root from the protection, but
>> from the check that requires that the config file ownership matches.
>>
>> if the config file is owned by root, we already lost, regardless of what
>> uid git is running as.
> 
> apologies for my confusing english, hopefully this C is clearer
> 
> diff --git a/git-compat-util.h b/git-compat-util.h
> index 58fd813bd01..6a385be7d1d 100644
> --- a/git-compat-util.h
> +++ b/git-compat-util.h
> @@ -440,9 +440,19 @@ static inline int git_offset_1st_component(const char *path)
>   static inline int is_path_owned_by_current_uid(const char *path)
>   {
>   	struct stat st;
> +	uid_t euid;
> +
>   	if (lstat(path, &st))
>   		return 0;
> -	return st.st_uid == geteuid();
> +
> +	euid = geteuid();
> +	if (!euid && st.st_uid && isatty(0)) {
> +		struct stat ttyst;
> +		if (!stat(ttyname(0), &ttyst))
> +			euid = ttyst.st_uid;
> +	}
> +
> +	return st.st_uid == euid;
>   }
>   
>   #define is_path_owned_by_current_user is_path_owned_by_current_uid
> 
> it uses stdin instead not to fall in the issue that was raised by
> Gábor, but I am affraid that it might need to check all stdnandles for
> a valid tty to be safe, and it looking even more complex.
> 
> Carlo