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From: "Ævar Arnfjörð Bjarmason" <avarab@gmail.com>
To: git@vger.kernel.org
Cc: "Junio C Hamano" <gitster@pobox.com>,
	"Matthieu Moy" <git@matthieu-moy.fr>,
	"Johannes Schindelin" <Johannes.Schindelin@gmx.de>,
	"Antoine Beaupré" <anarcat@debian.org>,
	"Đoàn Trần Công Danh" <congdanhqx@gmail.com>,
	"imon Legner" <Simon.Legner@gmail.com>,
	"Eric Sunshine" <sunshine@sunshineco.com>,
	"Jeff King" <peff@peff.net>,
	"Ævar Arnfjörð Bjarmason" <avarab@gmail.com>
Subject: [PATCH v2 18/18] remote-mediawiki: use "sh" to eliminate unquoted commands
Date: Mon, 21 Sep 2020 12:40:00 +0200
Message-ID: <20200921104000.2304-19-avarab@gmail.com> (raw)
In-Reply-To: <20200916102918.29805-1-avarab@gmail.com>

Remove the use of run_git_unquoted() completely with a use of "sh -c"
suggested by Jeff King, i.e.:

    sh -c '"$@" 2>/dev/null' -- echo sneaky 'argument;id'

I don't think this is needed now for any potential RCE issue. The
$remotename argument is ultimately picked by the local user (and
similarly, the $local variable comes from a user-supplied
refspec).

But completely eliminating the use of unquoted shell arguments has a
value in and of itself, by making the code easier to review. As noted
in an earlier commit I think the use of IPC::Open3 would be too
verbose here, but this "sh -c" trick strikes the right balance between
readability and semantic sanity.

Suggested-by: Jeff King <peff@peff.net>
Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
---
 contrib/mw-to-git/git-remote-mediawiki.perl | 24 +++++++--------------
 1 file changed, 8 insertions(+), 16 deletions(-)

diff --git a/contrib/mw-to-git/git-remote-mediawiki.perl b/contrib/mw-to-git/git-remote-mediawiki.perl
index d21c18df7b..a5624413dc 100755
--- a/contrib/mw-to-git/git-remote-mediawiki.perl
+++ b/contrib/mw-to-git/git-remote-mediawiki.perl
@@ -371,8 +371,8 @@ sub get_mw_pages {
 
 # usage: $out = run_git_quoted(["command", "args", ...]);
 #        $out = run_git_quoted(["command", "args", ...], "raw"); # don't interpret output as UTF-8.
-#        $out = run_git_unquoted(["command args"); # don't quote arguments
-#        $out = run_git_unquoted(["command args", "raw"); # ditto but raw instead of UTF-8 as above
+#        $out = run_git_quoted_nostderr(["command", "args", ...]); # discard stderr
+#        $out = run_git_quoted_nostderr(["command", "args", ...], "raw"); # ditto but raw instead of UTF-8 as above
 sub _run_git {
 	my $args = shift;
 	my $encoding = (shift || 'encoding(UTF-8)');
@@ -391,8 +391,8 @@ sub run_git_quoted {
     _run_git(["git", @{$_[0]}], $_[1]);
 }
 
-sub run_git_unquoted {
-    _run_git(["git $_[0]"], $_[1]);
+sub run_git_quoted_nostderr {
+    _run_git(['sh', '-c', 'git "$@" 2>/dev/null', '--', @{$_[0]}], $_[1]);
 }
 
 sub get_all_mediafiles {
@@ -521,10 +521,8 @@ sub download_mw_mediafile {
 
 sub get_last_local_revision {
 	# Get note regarding last mediawiki revision.
-	#
-	# It's OK to use run_git_unquoted() here because $remotename is
-	# supplied by the local git itself.
-	my $note = run_git_unquoted("notes --ref=${remotename}/mediawiki show refs/mediawiki/${remotename}/master 2>/dev/null");
+	my $note = run_git_quoted_nostderr(["notes", "--ref=${remotename}/mediawiki",
+					    "show", "refs/mediawiki/${remotename}/master"]);
 	my @note_info = split(/ /, $note);
 
 	my $lastrevision_number;
@@ -1189,16 +1187,10 @@ sub mw_push_revision {
 	my $mw_revision = $last_remote_revid;
 
 	# Get sha1 of commit pointed by local HEAD
-	#
-	# It's OK to use run_git_unquoted() because $local is supplied
-	# by the local git itself.
-	my $HEAD_sha1 = run_git_unquoted("rev-parse ${local} 2>/dev/null");
+	my $HEAD_sha1 = run_git_quoted_nostderr(["rev-parse", $local]);
 	chomp($HEAD_sha1);
 	# Get sha1 of commit pointed by remotes/$remotename/master
-	#
-	# It's OK to use run_git_unquoted() here because $remotename is
-	# supplied by the local git itself.
-	my $remoteorigin_sha1 = run_git_unquoted("rev-parse refs/remotes/${remotename}/master 2>/dev/null");
+	my $remoteorigin_sha1 = run_git_quoted_nostderr(["rev-parse", "refs/remotes/${remotename}/master"]);
 	chomp($remoteorigin_sha1);
 
 	if ($last_local_revid > 0 &&
-- 
2.28.0.297.g1956fa8f8d


      parent reply	other threads:[~2020-09-21 10:40 UTC|newest]

Thread overview: 54+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-09-16 10:29 [PATCH 00/15] remote-mediawiki: various fixes to make tests pass Ævar Arnfjörð Bjarmason
2020-09-16 10:29 ` [PATCH 01/15] remote-mediawiki doc: correct link to GitHub project Ævar Arnfjörð Bjarmason
2020-09-16 10:29 ` [PATCH 02/15] remote-mediawiki doc: link to MediaWiki's current version Ævar Arnfjörð Bjarmason
2020-09-16 10:29 ` [PATCH 03/15] remote-mediawiki doc: bump recommended PHP version to 7.3 Ævar Arnfjörð Bjarmason
2020-09-16 13:47   ` Đoàn Trần Công Danh
2020-09-16 20:41     ` Junio C Hamano
2020-09-16 10:29 ` [PATCH 04/15] remote-mediawiki tests: use the login/password variables Ævar Arnfjörð Bjarmason
2020-09-16 10:29 ` [PATCH 05/15] remote-mediawiki tests: use a 10 character password Ævar Arnfjörð Bjarmason
2020-09-16 10:29 ` [PATCH 06/15] remote-mediawiki tests: use test_cmp in tests Ævar Arnfjörð Bjarmason
2020-09-16 18:38   ` Jeff King
2020-09-16 10:29 ` [PATCH 07/15] remote-mediawiki tests: guard test_cmp with test_path_is_file Ævar Arnfjörð Bjarmason
2020-09-16 14:04   ` Đoàn Trần Công Danh
2020-09-16 16:53   ` Eric Sunshine
2020-09-16 21:13     ` Junio C Hamano
2020-10-03  7:04       ` [PATCH] test_cmp: diagnose incorrect arguments more precisely Eric Sunshine
2020-10-03 17:22         ` Junio C Hamano
2020-09-21  8:54     ` [PATCH 07/15] remote-mediawiki tests: guard test_cmp with test_path_is_file Ævar Arnfjörð Bjarmason
2020-09-21 10:42       ` Ævar Arnfjörð Bjarmason
2020-09-16 18:41   ` Jeff King
2020-09-16 10:29 ` [PATCH 08/15] remote-mediawiki tests: change `[]` to `test` Ævar Arnfjörð Bjarmason
2020-09-16 10:29 ` [PATCH 09/15] remote-mediawiki tests: use "$dir/" instead of "$dir." Ævar Arnfjörð Bjarmason
2020-09-16 18:43   ` Jeff King
2020-09-16 21:15   ` Junio C Hamano
2020-09-16 10:29 ` [PATCH 10/15] remote-mediawiki tests: use a more idiomatic dispatch table Ævar Arnfjörð Bjarmason
2020-09-16 10:29 ` [PATCH 11/15] remote-mediawiki tests: replace deprecated Perl construct Ævar Arnfjörð Bjarmason
2020-09-16 18:49   ` Jeff King
2020-09-16 10:29 ` [PATCH 12/15] remote-mediawiki tests: use inline PerlIO for readability Ævar Arnfjörð Bjarmason
2020-09-16 10:29 ` [PATCH 13/15] remote-mediawiki tests: use CLI installer Ævar Arnfjörð Bjarmason
2020-09-16 10:29 ` [PATCH 14/15] remote-mediawiki: fix duplicate revisions being imported Ævar Arnfjörð Bjarmason
2020-09-16 10:29 ` [PATCH 15/15] remote-mediawiki tests: annotate failing tests Ævar Arnfjörð Bjarmason
2020-09-16 18:57 ` [PATCH 00/15] remote-mediawiki: various fixes to make tests pass Jeff King
2020-09-17 22:28   ` Junio C Hamano
2020-09-16 19:46 ` Johannes Schindelin
2020-09-21 10:15   ` Ævar Arnfjörð Bjarmason
2020-09-21 10:39 ` [PATCH v2 00/18] remote-mediawiki: fix RCE issue, and the tests Ævar Arnfjörð Bjarmason
2020-09-25  6:50   ` Jeff King
2020-09-21 10:39 ` [PATCH v2 01/18] remote-mediawiki doc: correct link to GitHub project Ævar Arnfjörð Bjarmason
2020-09-21 10:39 ` [PATCH v2 02/18] remote-mediawiki doc: link to MediaWiki's current version Ævar Arnfjörð Bjarmason
2020-09-21 10:39 ` [PATCH v2 03/18] remote-mediawiki doc: don't hardcode Debian PHP versions Ævar Arnfjörð Bjarmason
2020-09-21 10:39 ` [PATCH v2 04/18] remote-mediawiki tests: use the login/password variables Ævar Arnfjörð Bjarmason
2020-09-21 10:39 ` [PATCH v2 05/18] remote-mediawiki tests: use a 10 character password Ævar Arnfjörð Bjarmason
2020-09-21 10:39 ` [PATCH v2 06/18] remote-mediawiki tests: use test_cmp in tests Ævar Arnfjörð Bjarmason
2020-09-21 10:39 ` [PATCH v2 07/18] remote-mediawiki tests: change `[]` to `test` Ævar Arnfjörð Bjarmason
2020-09-21 10:39 ` [PATCH v2 08/18] remote-mediawiki tests: use "$dir/" instead of "$dir." Ævar Arnfjörð Bjarmason
2020-09-21 10:39 ` [PATCH v2 09/18] remote-mediawiki tests: use a more idiomatic dispatch table Ævar Arnfjörð Bjarmason
2020-09-21 10:39 ` [PATCH v2 10/18] remote-mediawiki tests: replace deprecated Perl construct Ævar Arnfjörð Bjarmason
2020-09-21 10:39 ` [PATCH v2 11/18] remote-mediawiki tests: use inline PerlIO for readability Ævar Arnfjörð Bjarmason
2020-09-21 10:39 ` [PATCH v2 12/18] remote-mediawiki tests: use CLI installer Ævar Arnfjörð Bjarmason
2020-09-21 10:39 ` [PATCH v2 13/18] remote-mediawiki: fix duplicate revisions being imported Ævar Arnfjörð Bjarmason
2020-09-21 10:39 ` [PATCH v2 14/18] remote-mediawiki tests: annotate failing tests Ævar Arnfjörð Bjarmason
2020-09-21 10:39 ` [PATCH v2 15/18] remote-mediawiki: provide a list form of run_git() Ævar Arnfjörð Bjarmason
2020-09-21 10:39 ` [PATCH v2 16/18] remote-mediawiki: convert to quoted run_git() invocation Ævar Arnfjörð Bjarmason
2020-09-21 10:39 ` [PATCH v2 17/18] remote-mediawiki: annotate unquoted uses of run_git() Ævar Arnfjörð Bjarmason
2020-09-21 10:40 ` Ævar Arnfjörð Bjarmason [this message]

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