Re: Add regular expression testing for user name mapping in the peer authentication TAP test

[Drouvot, Bertrand]

Hi,

On 10/15/22 5:11 AM, Michael Paquier wrote:
On Fri, Oct 14, 2022 at 06:31:15PM +0200, Drouvot, Bertrand wrote:
while working on [1], I thought it could also be useful to add regular
expression testing for user name mapping in the peer authentication TAP
test.

Good idea now that we have a bit more coverage in the authentication
tests.

Thanks for looking at it!

+# Test with regular expression in user name map.
+my $last_system_user_char = substr($system_user, -1);

This would attach to the regex the last character of the system user.

Right.

I would perhaps have used more characters than that (-3?), as substr()
with a negative number larger than the string given in input would
give the entire string.  That's a nit, though.

I don't have a strong opinion on this, so let's extract the last 3 
characters. This is what v2 attached does.


+# The regular expression does not match.
+reset_pg_ident($node, 'mypeermap', '/^$', 'testmapuser');

This matches only an empty string, my brain gets that right?

Right. Giving a second thought to the non matching case, I think I'd 
prefer to concatenate the system_user to the system_user instead. This 
is what v2 does.

Regards,

--
Bertrand Drouvot
PostgreSQL Contributors Team
RDS Open Source Databases
Amazon Web Services: https://aws.amazon.comdiff --git a/src/test/authentication/t/003_peer.pl 
b/src/test/authentication/t/003_peer.pl
index fc951dea06..e719b05d0f 100644
--- a/src/test/authentication/t/003_peer.pl
+++ b/src/test/authentication/t/003_peer.pl
@@ -23,18 +23,34 @@ sub reset_pg_hba
        return;
 }
 
+# Delete pg_ident.conf from the given node, add a new entry to it
+# and then execute a reload to refresh it.
+sub reset_pg_ident
+{
+       my $node        = shift;
+       my $map_name    = shift;
+       my $system_user = shift;
+       my $pg_user     = shift;
+
+       unlink($node->data_dir . '/pg_ident.conf');
+       $node->append_conf('pg_ident.conf', "$map_name $system_user $pg_user");
+       $node->reload;
+       return;
+}
+
 # Test access for a single role, useful to wrap all tests into one.
 sub test_role
 {
        local $Test::Builder::Level = $Test::Builder::Level + 1;
 
-       my ($node, $role, $method, $expected_res, %params) = @_;
+       my ($node, $role, $method, $expected_res, $test_details, %params) = @_;
        my $status_string = 'failed';
        $status_string = 'success' if ($expected_res eq 0);
 
        my $connstr = "user=$role";
        my $testname =
-         "authentication $status_string for method $method, role $role";
+         "authentication $status_string for method $method, role $role "
+         . $test_details;
 
        if ($expected_res eq 0)
        {
@@ -87,16 +103,50 @@ my $system_user =
 # Tests without the user name map.
 # Failure as connection is attempted with a database role not mapping
 # to an authorized system user.
-test_role($node, qq{testmapuser}, 'peer', 2,
+test_role(
+       $node, qq{testmapuser}, 'peer', 2,
+       'without user name map',
        log_like => [qr/Peer authentication failed for user "testmapuser"/]);
 
 # Tests with a user name map.
-$node->append_conf('pg_ident.conf', qq{mypeermap $system_user testmapuser});
+reset_pg_ident($node, 'mypeermap', $system_user, 'testmapuser');
 reset_pg_hba($node, 'peer map=mypeermap');
 
 # Success as the database role matches with the system user in the map.
-test_role($node, qq{testmapuser}, 'peer', 0,
+test_role($node, qq{testmapuser}, 'peer', 0, 'with user name map',
        log_like =>
          [qr/connection authenticated: identity="$system_user" method=peer/]);
 
+# Test with regular expression in user name map.
+# Extract the last 3 characters from the system_user
+# or the entire system_user (if its length is <= -3).
+my $regex_test_string = substr($system_user, -3);
+
+# The regular expression matches.
+reset_pg_ident($node, 'mypeermap', qq{/^.*$regex_test_string\$},
+       'testmapuser');
+test_role(
+       $node,
+       qq{testmapuser},
+       'peer',
+       0,
+       'with regular expression in user name map',
+       log_like =>
+         [qr/connection authenticated: identity="$system_user" method=peer/]);
+
+
+# Concatenate system_user to system_user.
+$regex_test_string = $system_user . $system_user;
+
+# The regular expression does not match.
+reset_pg_ident($node, 'mypeermap', qq{/^.*$regex_test_string\$},
+       'testmapuser');
+test_role(
+       $node,
+       qq{testmapuser},
+       'peer',
+       2,
+       'with regular expression in user name map',
+       log_like => [qr/no match in usermap "mypeermap" for user 
"testmapuser"/]);
+
 done_testing();