Implement support for HTTP digest authentication (RFC2617).

[pr0n] / perl / Sesse / pr0n / Common.pm

diff --git a/perl/Sesse/pr0n/Common.pm b/perl/Sesse/pr0n/Common.pm
index 14ae88b40664c29f8f39a2f0595580f950325962..4a552c4c7f9b5b793fdd59ad37ee6f0a76d8c200 100644 (file)
--- a/perl/Sesse/pr0n/Common.pm
+++ b/perl/Sesse/pr0n/Common.pm
@@ -18,7 +18,9 @@ use DBI;
 use DBD::Pg;
 use Image::Magick;
 use POSIX;
 use DBD::Pg;
 use Image::Magick;
 use POSIX;

+use Digest::MD5;

 use Digest::SHA1;
 use Digest::SHA1;

+use Digest::HMAC_SHA1;

 use MIME::Base64;
 use MIME::Types;
 use LWP::Simple;
 use MIME::Base64;
 use MIME::Types;
 use LWP::Simple;


@@ -317,41 +319,56 @@ sub check_access {
 
        my $auth = $r->headers_in->{'authorization'};
        if (!defined($auth)) {
 
        my $auth = $r->headers_in->{'authorization'};
        if (!defined($auth)) {

-               output_401($r);
+               output_401($r, 0);

                return undef;
                return undef;

-       }
+       } 
+       $r->log->warn("Auth: $auth");

        if ($auth =~ /^Basic ([a-zA-Z0-9+\/]+=*)$/) {
                return check_basic_auth($r, $1);
        if ($auth =~ /^Basic ([a-zA-Z0-9+\/]+=*)$/) {
                return check_basic_auth($r, $1);

+       }       
+       if ($auth =~ /^Digest (.*)$/) {
+               return check_digest_auth($r, $1);

        }
        }

-       output_401($r);
+       output_401($r, 0);

        return undef;
 }
 
 sub output_401 {
        return undef;
 }
 
 sub output_401 {

-       my $r = shift;
+       my ($r, %options) = @_;

        $r->content_type('text/plain; charset=utf-8');
        $r->status(401);
        $r->headers_out->{'www-authenticate'} = 'Basic realm="pr0n.sesse.net"';
        $r->content_type('text/plain; charset=utf-8');
        $r->status(401);
        $r->headers_out->{'www-authenticate'} = 'Basic realm="pr0n.sesse.net"';

+
+       if ($options{'DigestAuth'} // 1) {
+               # We make our nonce similar to the scheme of RFC2069 section 2.1.1,
+               # with some changes: We don't care about client IP (these have a nasty
+               # tendency to change from request to request when load-balancing
+               # proxies etc. are being used), and we use HMAC instead of simple
+               # hashing simply because that's a better signing method.
+               #
+               # NOTE: For some weird reason, Digest::HMAC_SHA1 doesn't like taking
+               # the output from time directly (it gives a different response), so we
+               # forcefully stringify the argument.
+               my $ts = time;
+               my $nonce = Digest::HMAC_SHA1->hmac_sha1_hex($ts . "", $Sesse::pr0n::Config::db_password);
+               my $stale_nonce_text = "";
+               $stale_nonce_text = ", stale=\"true\"" if ($options{'StaleNonce'} // 0);
+
+               $r->headers_out->{'www-authenticate'} =
+                       "Digest realm=\"pr0n.sesse.net\", " .
+                       "nonce=\"$nonce\", " .
+                       "opaque=\"$ts\", " .
+                       "qop=\"auth\"" . $stale_nonce_text;  # FIXME: support auth-int
+       }
+

        $r->print("Need authorization\n");
 }
 
 sub check_basic_auth {
        my ($r, $auth) = @_;    
 
        $r->print("Need authorization\n");
 }
 
 sub check_basic_auth {
        my ($r, $auth) = @_;    
 

-       my ($user, $pass) = split /:/, MIME::Base64::decode_base64($auth);
-
-       # WinXP is stupid :-)
-       if ($user =~ /^.*\\(.*)$/) {
-               $user = $1;
-       }
-
-       my $takenby;
-       if ($user =~ /^([a-zA-Z0-9^_-]+)\@([a-zA-Z0-9^_-]+)$/) {
-               $user = $1;
-               $takenby = $2;
-       } else {
-               ($takenby = $user) =~ s/^([a-zA-Z])/uc($1)/e;
-       }
+       my ($raw_user, $pass) = split /:/, MIME::Base64::decode_base64($auth);
+       my ($user, $takenby) = extract_takenby($raw_user);

        
        my $oldpass = $pass;
        $pass = Digest::SHA1::sha1_base64($pass);
        
        my $oldpass = $pass;
        $pass = Digest::SHA1::sha1_base64($pass);


@@ -368,6 +385,124 @@ sub check_basic_auth {
 
        return ($user, $takenby);
 }
 
        return ($user, $takenby);
 }

+
+sub check_digest_auth {
+       my ($r, $auth) = @_;    
+
+       # We're a bit more liberal than RFC2069 in the parsing here, allowing
+       # quoted strings everywhere.
+       my %auth = ();
+       while ($auth =~ s/^ ([a-zA-Z]+)                # key
+                        =                 
+                         (                            
+                           [^",]*                     # either something that doesn't contain comma or quotes
+                         |
+                           " ( [^"\\] | \\ . ) * "    # or a full quoted string
+                         )
+                         (?: (?: , \s* ) + | $ )      # delimiter(s), or end of string
+                        //x) {
+               my ($key, $value) = ($1, $2);
+               if ($value =~ /^"(.*)"$/) {
+                       $value = $1;
+                       $value =~ s/\\(.)/$1/g;
+               }
+               $auth{$key} = $value;
+       }
+       unless (exists($auth{'username'}) &&
+               exists($auth{'uri'}) &&
+               exists($auth{'nonce'}) &&
+               exists($auth{'opaque'}) &&
+               exists($auth{'response'})) {
+               output_401($r);
+               return undef;
+       }
+       if ($r->uri ne $auth{'uri'}) {  
+               output_401($r);
+               return undef;
+       }
+       
+       # Verify that the opaque data does indeed look like a timestamp, and that the nonce
+       # is indeed a signed version of it.
+       if ($auth{'opaque'} !~ /^\d+$/) {
+               output_401($r);
+               return undef;
+       }
+       my $compare_nonce = Digest::HMAC_SHA1->hmac_sha1_hex($auth{'opaque'}, $Sesse::pr0n::Config::db_password);
+       if ($auth{'nonce'} ne $compare_nonce) {
+               output_401($r);
+               return undef;
+       }
+
+       # Now look up the user's HA1 from the database, and calculate HA2.      
+       my ($user, $takenby) = extract_takenby($auth{'username'});
+       my $ref = $dbh->selectrow_hashref('SELECT digest_ha1_hex FROM users WHERE username=? AND vhost=?',
+               undef, $user, $r->get_server_name);
+       if (!defined($ref)) {
+               output_401($r);
+               return undef;
+       }
+       if (!defined($ref->{'digest_ha1_hex'}) || $ref->{'digest_ha1_hex'} !~ /^[0-9a-f]{32}$/) {
+               # A user that exists but has empty HA1 is a user that's not
+               # ready for digest auth, so we hack it and resend 401,
+               # only this time without digest auth.
+               output_401($r, DigestAuth => 0);
+               return undef;
+       }
+       my $ha1 = $ref->{'digest_ha1_hex'};
+       my $ha2 = Digest::MD5::md5_hex($r->method . ':' . $auth{'uri'});
+       my $response;
+       if (exists($auth{'qop'}) && $auth{'qop'} eq 'auth') {
+               unless (exists($auth{'nc'}) && exists($auth{'cnonce'})) {
+                       output_401($r);
+                       return undef;
+               }       
+
+               $response = $ha1;
+               $response .= ':' . $auth{'nonce'};
+               $response .= ':' . $auth{'nc'};
+               $response .= ':' . $auth{'cnonce'};
+               $response .= ':' . $auth{'qop'};
+               $response .= ':' . $ha2;
+       } else {
+               $response = $ha1;
+               $response .= ':' . $auth{'nonce'};
+               $response .= ':' . $ha2;
+       }
+       if ($auth{'response'} ne Digest::MD5::md5_hex($response)) {     
+               output_401($r);
+               return undef;
+       }
+
+       # OK, everything is good, and there's only one thing we need to check: That the nonce
+       # isn't too old. If it is, but everything else is ok, we tell the browser that and it
+       # will re-encrypt with the new nonce.
+       my $timediff = time - $auth{'opaque'};
+       if ($timediff < 0 || $timediff > 300) {
+               output_401($r, StaleNonce => 1);
+               return undef;
+       }
+
+       return ($user, $takenby);
+}
+
+sub extract_takenby {
+       my ($user) = shift;
+
+       # WinXP is stupid :-)
+       if ($user =~ /^.*\\(.*)$/) {
+               $user = $1;
+       }
+
+       my $takenby;
+       if ($user =~ /^([a-zA-Z0-9^_-]+)\@([a-zA-Z0-9^_-]+)$/) {
+               $user = $1;
+               $takenby = $2;
+       } else {
+               ($takenby = $user) =~ s/^([a-zA-Z])/uc($1)/e;
+       }
+
+       return ($user, $takenby);
+}

        
 sub stat_image {
        my ($r, $event, $filename) = (@_);
        
 sub stat_image {
        my ($r, $event, $filename) = (@_);