Re: [PATCH] gitweb: Improve repository verification

> Bring repository verification in check_export_ok() to standards of
> is_git_directory function from setup.c (core git), and validate_headref()
> to standards of the same function in path.c,... and a bit more.
>
> validate_headref() replaces check_head_link(); note that the former
> requires path to HEAD file, while the late latter path to repository.
>
> Issues of note:
> * is_git_directory() in gitweb is a bit stricter: it checks that
>   "/objects" and "/refs" are directories, and not only 'executable'
>   permission,
> * validate_headref() in gitweb is a bit stricter: it checks that
>   reference symlink or symref points to starts with "refs/heads/",
>   and not only with "refs/",
> * calls to check_head_link(), all of which were meant to check if
>   given directory can be a git repository, were replaced by newly
>   introduced is_git_directory().
>
> This change is preparation for removing "Last change" column from list
> of projects, which is currently used also for validating repository.
>
> Suggested-by: Kacper Kornet <draenog@pld-linux.org>
> Signed-off-by: Jakub Narebski <jnareb@gmail.com>
> ---
> Here is how such first step could look like...

>  gitweb/gitweb.perl |   52 ++++++++++++++++++++++++++++++++++++++++++----------
>  1 files changed, 42 insertions(+), 10 deletions(-)
>
> diff --git a/gitweb/gitweb.perl b/gitweb/gitweb.perl
> index 098e527..767d7a5 100755
> --- a/gitweb/gitweb.perl
> +++ b/gitweb/gitweb.perl
> @@ -621,19 +621,51 @@ sub feature_avatar {
>  	return @val ? @val : @_;
>  }
>  
> -# checking HEAD file with -e is fragile if the repository was
> -# initialized long time ago (i.e. symlink HEAD) and was pack-ref'ed
> -# and then pruned.
> -sub check_head_link {
> -	my ($dir) = @_;
> -	my $headfile = "$dir/HEAD";
> -	return ((-e $headfile) ||
> -		(-l $headfile && readlink($headfile) =~ /^refs\/heads\//));
> +# Test if it looks like we're at a git directory.
> +# We want to see:
> +#
> +#  - an objects/ directory,
> +#  - a refs/ directory,
> +#  - either a HEAD symlink or a HEAD file that is formatted as
> +#    a proper "ref:", or a regular file HEAD that has a properly
> +#    formatted sha1 object name.
> +#
> +# See is_git_directory() in setup.c
> +sub is_git_directory {
> +	my $dir = shift;
> +	return
> +		-x "$dir/objects" && -d _ &&
> +		-x "$dir/refs"    && -d _ &&
> +		validate_headref("$dir/HEAD");
> +}
> +
> +# Check HEAD file, that it is either
> +#
> +#  - a "refs/heads/.." symlink, or
> +#  - a symbolic ref to "refs/heads/..", or
> +#  - a detached HEAD.
> +#
> +# See validate_headref() in path.c
> +sub validate_headref {
> +	my $headfile = shift;
> +	if (-l $headfile) {
> +		return readlink($headfile) =~ m!^refs/heads/!;
> +
> +	} elsif (-e _) {
> +		open my $fh, '<', $headfile or return;
> +		my $line = <$fh>;
> +		close $fh or return;
> +
> +		return
> +			$line =~ m!^ref:\s*refs/heads/! ||  # symref
> +			$line =~ m!^[0-9a-z]{40}$!i;        # detached HEAD
> +	}
> +	return;
>  }
>  
>  sub check_export_ok {
>  	my ($dir) = @_;
> -	return (check_head_link($dir) &&
> +	return (is_git_directory($dir) &&
>  		(!$export_ok || -e "$dir/$export_ok") &&
>  		(!$export_auth_hook || $export_auth_hook->($dir)));
>  }
> @@ -842,7 +874,7 @@ sub evaluate_path_info {
>  	# find which part of PATH_INFO is project
>  	my $project = $path_info;
>  	$project =~ s,/+$,,;
> -	while ($project && !check_head_link("$projectroot/$project")) {
> +	while ($project && !is_git_directory("$projectroot/$project")) {
>  		$project =~ s,/*[^/]*$,,;
>  	}
>  	return unless $project;