Thread (15 messages) 15 messages, 5 authors, 2021-04-08

Re: [PATCH v3] gitweb: redacted e-mail addresses feature.

From: Ævar Arnfjörð Bjarmason <hidden>
Date: 2021-03-21 18:32:14

On Sun, Mar 21 2021, Georgios Kontaxis via GitGitGadget wrote:
quoted hunk ↗ jump to hunk
From: Georgios Kontaxis <redacted>

Gitweb extracts content from the Git log and makes it accessible
over HTTP. As a result, e-mail addresses found in commits are
exposed to web crawlers and they may not respect robots.txt.
This may result in unsolicited messages.
This is a feature for redacting e-mail addresses
from the generated HTML, etc. content.

This feature does not prevent someone from downloading the
unredacted commit log, e.g., by cloning the repository, and
extracting information from it.
It aims to hinder the low-effort bulk collection of e-mail
addresses by web crawlers.

Changes since v1:
- Turned off the feature by default.
- Removed duplicate code.
- Added note about Gitweb consumers receiving redacted logs.

Changes since v2:
- The feature can be set on a per-project basis. ('override' => 1)

Signed-off-by: Georgios Kontaxis <redacted>
---
    gitweb: Redacted e-mail addresses feature.
    
    Gitweb extracts content from the Git log and makes it accessible over
    HTTP. As a result, e-mail addresses found in commits are exposed to web
    crawlers. This may result in unsolicited messages. This is a feature for
    redacting e-mail addresses from the generated HTML content.
    
    This feature does not prevent someone from downloading the unredacted
    commit log and extracting information from it. It aims to hinder the
    low-effort bulk collection of e-mail addresses by web crawlers.
    
    Signed-off-by: Georgios Kontaxis geko1702+commits@99rst.org

Published-As: https://github.com/gitgitgadget/git/releases/tag/pr-910%2Fkontaxis%2Fkontaxis%2Femail_privacy-v3
Fetch-It-Via: git fetch https://github.com/gitgitgadget/git pr-910/kontaxis/kontaxis/email_privacy-v3
Pull-Request: https://github.com/gitgitgadget/git/pull/910

Range-diff vs v2:

 1:  74af11ca8bf2 ! 1:  930cdefe7ee0 gitweb: redacted e-mail addresses feature.
     @@ Commit message
          - Removed duplicate code.
          - Added note about Gitweb consumers receiving redacted logs.
      
     +    Changes since v2:
     +    - The feature can be set on a per-project basis. ('override' => 1)
     +
          Signed-off-by: Georgios Kontaxis [off-list ref]
      
       ## Documentation/gitweb.conf.txt ##
     @@ gitweb/gitweb.perl: sub evaluate_uri {
      +	# $feature{'email_privacy'}{'default'} = [1];
      +	'email_privacy' => {
      +		'sub' => sub { feature_bool('email_privacy', @_) },
     -+		'override' => 0,
     ++		'override' => 1,
      +		'default' => [0]},
       );
       


 Documentation/gitweb.conf.txt | 16 +++++++++++++
 gitweb/gitweb.perl            | 42 ++++++++++++++++++++++++++++++++---
 2 files changed, 55 insertions(+), 3 deletions(-)
diff --git a/Documentation/gitweb.conf.txt b/Documentation/gitweb.conf.txt
index 7963a79ba98b..b7af3240177d 100644
--- a/Documentation/gitweb.conf.txt
+++ b/Documentation/gitweb.conf.txt
@@ -896,6 +896,22 @@ same as of the snippet above:
 It is an error to specify a ref that does not pass "git check-ref-format"
 scrutiny. Duplicated values are filtered.
 
+email_privacy::
+    Redact e-mail addresses from the generated HTML, etc. content.
+    This hides e-mail addresses found in the commit log from web crawlers.
+    Disabled by default.
++
+It is highly recommended to enable this feature unless web crawlers are
+hindered in some other way. Note that crawlers intent on harvesting e-mail
+addresses may disregard robots.txt. You can enable this feature like so:
++
+---------------------------------------------------------------------------
+$feature{'email_privacy'}{'default'} = [1];
+---------------------------------------------------------------------------
++
+Note that if Gitweb is not the final step in a workflow then subsequent
+steps may misbehave because of the redacted information they receive.
+
 
 EXAMPLES
 --------
diff --git a/gitweb/gitweb.perl b/gitweb/gitweb.perl
index 0959a782eccb..174cc566d97d 100755
--- a/gitweb/gitweb.perl
+++ b/gitweb/gitweb.perl
@@ -569,6 +569,15 @@ sub evaluate_uri {
 		'sub' => \&feature_extra_branch_refs,
 		'override' => 0,
 		'default' => []},
+
+	# Redact e-mail addresses.
+
+	# To enable system wide have in $GITWEB_CONFIG
+	# $feature{'email_privacy'}{'default'} = [1];
+	'email_privacy' => {
+		'sub' => sub { feature_bool('email_privacy', @_) },
+		'override' => 1,
+		'default' => [0]},
 );
 
 sub gitweb_get_feature {
@@ -3449,6 +3458,19 @@ sub parse_date {
 	return %date;
 }
 
[snip]
So in the v1 feedback I suggested:

BEGIN QUOTE
    sub maybe_hide_email {
        my $email = shift;
        return $email unless gitweb_check_feature('email_privacy');
        return hide_email($email);
    }

then:

    $tag{author_email} = maybe_hide_email($2);
END QUOTE

But:
quoted hunk ↗ jump to hunk
 sub parse_tag {
 	my $tag_id = shift;
 	my %tag;
@@ -3471,6 +3493,10 @@ sub parse_tag {
 			if ($tag{'author'} =~ m/^([^<]+) <([^>]*)>/) {
 				$tag{'author_name'}  = $1;
 				$tag{'author_email'} = $2;
+				if (gitweb_check_feature('email_privacy')) {
+					$tag{'author_email'} = "private";
+					$tag{'author'} = hide_mailaddr($tag{'author'});
+				}
This code seems quite awkward, we've already done the regex match, but
this code:
[snip]
+sub hide_mailaddr_if_private {
+	my $line = shift;
+	return $line unless (gitweb_check_feature('email_privacy') &&
+						$line =~ m/^([^<]+) <([^>]*)>/);
+	return hide_mailaddr($line)
+}
+
+sub hide_mailaddr {
+	my $mailaddr = shift;
+	$mailaddr =~ s/<([^>]*)>/<private>/;
+	return $mailaddr;
+}
Is going to do it again incrementally, and then just act on a
search-replacement if we've got the feature enabled.

It seems much simpler to just turn your:
+				if (gitweb_check_feature('email_privacy')) {
+					$tag{'author_email'} = "private";
+					$tag{'author'} = hide_mailaddr($tag{'author'});
+				}
Into:

    $tag{'author'} = maybe_hide_mailaddr($tag{author}, \$tag{author_email});

Using:

    sub maybe_hide_email {
        my ($email, $ref) = shift;
        return $email unless gitweb_check_feature('email_privacy');
        $$ref = "private" if $ref;
        return hide_email($email);
    }

Which also works for the case where you don't have a "private" hash key
to assign to. But maybe it overcomplicates things...
quoted hunk ↗ jump to hunk
 			} else {
 				$tag{'author_name'} = $tag{'author'};
 			}
@@ -3519,6 +3545,10 @@ sub parse_commit_text {
 			if ($co{'author'} =~ m/^([^<]+) <([^>]*)>/) {
 				$co{'author_name'}  = $1;
 				$co{'author_email'} = $2;
+				if (gitweb_check_feature('email_privacy')) {
+					$co{'author_email'} = "private";
+					$co{'author'} = hide_mailaddr($co{'author'});
+				}
 			} else {
 				$co{'author_name'} = $co{'author'};
 			}
@@ -3529,6 +3559,10 @@ sub parse_commit_text {
 			if ($co{'committer'} =~ m/^([^<]+) <([^>]*)>/) {
 				$co{'committer_name'}  = $1;
 				$co{'committer_email'} = $2;
+				if (gitweb_check_feature('email_privacy')) {
+					$co{'committer_email'} = "private";
+					$co{'committer'} = hide_mailaddr($co{'committer'});
+				}
[...]
 			} else {
 				$co{'committer_name'} = $co{'committer'};
 			}
@@ -3568,9 +3602,10 @@ sub parse_commit_text {
 	if (! defined $co{'title'} || $co{'title'} eq "") {
 		$co{'title'} = $co{'title_short'} = '(no commit message)';
 	}
-	# remove added spaces
+	# remove added spaces, redact e-mail addresses if applicable.
 	foreach my $line (@commit_lines) {
 		$line =~ s/^    //;
+		$line = hide_mailaddr_if_private($line);
 	}
 	$co{'comment'} = \@commit_lines;
 
@@ -8060,8 +8095,9 @@ sub git_commitdiff {
 		close $fd
 			or print "Reading git-diff-tree failed\n";
 	} elsif ($format eq 'patch') {
-		local $/ = undef;
-		print <$fd>;
+		while (my $line = <$fd>) {
+			print hide_mailaddr_if_private($line);
+		}
Urm, have you tested this? How does a while loop over a <$fd> make sense
when $/ is undef, the readline() operator will always return just one
record, so having a while loop doesn't make sense.

I'm not sure of the input here, but given that if you're expecting to
replace all e-mail addresses on all lines with this function that's not
how it'll work, the s/// doesn't have a /g, so it'll stop at the first
replacement.
 		close $fd
 			or print "Reading git-format-patch failed\n";
 	}

base-commit: a5828ae6b52137b913b978e16cd2334482eb4c1f
  
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