CVE-2022-24828 (published 2022-04-13T21:15Z)

Composer is a dependency manager for the PHP programming language. Integrators using Composer code to call `VcsDriver::getFileContent` can have a code injection vulnerability if the user can control the `$file` or `$identifier` argument. This leads to a vulnerability on packagist.org for example where the composer.json's `readme` field can be used as a vector for injecting parameters into hg/Mercurial via the `$file` argument, or git via the `$identifier` argument if you allow arbitrary data there (Packagist does not, but maybe other integrators do). Composer itself should not be affected by the vulnerability as it does not call `getFileContent` with arbitrary data into `$file`/`$identifier`. To the best of our knowledge this was not abused, and the vulnerability has been patched on packagist.org and Private Packagist within a day of the vulnerability report.

Severity: MEDIUM
CVSS v2 base score: 6.8 (AV:N/AC:M/Au:N/C:P/I:P/A:P)
CVSS v3 base score: 8.8, HIGH (CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H)

Weakness information:
cwe_id: CWE-88
cwe_name: Improper Neutralization of Argument Delimiters in a Command ('Argument Injection')
description: The product constructs a string for a command to be executed by a separate component
in another control sphere, but it does not properly delimit the
intended arguments, options, or switches within that command string.
extended_description: 
            When creating commands using interpolation into a string, developers may assume that only the arguments/options that they specify will be processed.  This assumption may be even stronger when the programmer has encoded the command in a way that prevents separate commands from being provided maliciously, e.g. in the case of shell metacharacters.  When constructing the command, the developer may use whitespace or other delimiters that are required to separate arguments when the command. However, if an attacker can provide an untrusted input that contains argument-separating delimiters, then the resulting command will have more arguments than intended by the developer.  The attacker may then be able to change the behavior of the command.  Depending on the functionality supported by the extraneous arguments, this may have security-relevant consequences.
         
         

Fix information:
repo_url: https://github.com/composer/composer
commit_details: repo_url: https://github.com/composer/composer
author: Stephan
author_date: 2022-04-13 14:54:58+01:00
msg: Merge pull request from GHSA-x7cr-6qr6-2hh6

* GitDriver: filter branch names starting with a - character

* GitDriver: getFileContent prevent identifiers starting with a -

* HgDriver: prevent invalid identifiers and prevent file from running commands

* HgDriver: filter branches starting with a - character
repository: repo_url: https://github.com/composer/composer
repo_name: composer/composer
description: Dependency Manager for PHP
repo_language: PHP
owner: composer
file_changes: filename: GitDriver.php
change_type: ModificationType.MODIFY
diff: @@ -138,6 +138,10 @@ public function getDist($identifier)
      */
     public function getFileContent($file, $identifier)
     {
+        if (isset($identifier[0]) && $identifier[0] === '-') {
+            throw new \RuntimeException('Invalid git identifier detected. Identifier must not start with a -, given: ' . $identifier);
+        }
+
         $resource = sprintf('%s:%s', ProcessExecutor::escape($identifier), ProcessExecutor::escape($file));
         $this->process->execute(sprintf('git show %s', $resource), $content, $this->repoDir);
 
@@ -191,7 +195,7 @@ public function getBranches()
             $this->process->execute('git branch --no-color --no-abbrev -v', $output, $this->repoDir);
             foreach ($this->process->splitLines($output) as $branch) {
                 if ($branch && !Preg::isMatch('{^ *[^/]+/HEAD }', $branch)) {
-                    if (Preg::isMatch('{^(?:\* )? *(\S+) *([a-f0-9]+)(?: .*)?$}', $branch, $match)) {
+                    if (Preg::isMatch('{^(?:\* )? *(\S+) *([a-f0-9]+)(?: .*)?$}', $branch, $match) && $match[1][0] !== '-') {
                         $branches[$match[1]] = $match[2];
                     }
                 }

programming_language: PHP
filename: HgDriver.php
change_type: ModificationType.MODIFY
diff: @@ -126,7 +126,11 @@ public function getDist($identifier)
      */
     public function getFileContent($file, $identifier)
     {
-        $resource = sprintf('hg cat -r %s %s', ProcessExecutor::escape($identifier), ProcessExecutor::escape($file));
+        if (isset($identifier[0]) && $identifier[0] === '-') {
+            throw new \RuntimeException('Invalid hg identifier detected. Identifier must not start with a -, given: ' . $identifier);
+        }
+
+        $resource = sprintf('hg cat -r %s -- %s', ProcessExecutor::escape($identifier), ProcessExecutor::escape($file));
         $this->process->execute($resource, $content, $this->repoDir);
 
         if (!trim($content)) {
@@ -186,14 +190,14 @@ public function getBranches()
 
             $this->process->execute('hg branches', $output, $this->repoDir);
             foreach ($this->process->splitLines($output) as $branch) {
-                if ($branch && Preg::isMatch('(^([^\s]+)\s+\d+:([a-f0-9]+))', $branch, $match)) {
+                if ($branch && Preg::isMatch('(^([^\s]+)\s+\d+:([a-f0-9]+))', $branch, $match) && $match[1][0] !== '-') {
                     $branches[$match[1]] = $match[2];
                 }
             }
 
             $this->process->execute('hg bookmarks', $output, $this->repoDir);
             foreach ($this->process->splitLines($output) as $branch) {
-                if ($branch && Preg::isMatch('(^(?:[\s*]*)([^\s]+)\s+\d+:(.*)$)', $branch, $match)) {
+                if ($branch && Preg::isMatch('(^(?:[\s*]*)([^\s]+)\s+\d+:(.*)$)', $branch, $match) && $match[1][0] !== '-') {
                     $bookmarks[$match[1]] = $match[2];
                 }
             }

programming_language: PHP
filename: GitDriverTest.php
change_type: ModificationType.ADD
diff: @@ -0,0 +1,81 @@
+<?php
+
+namespace Composer\Test\Repository\Vcs;
+
+use Composer\Config;
+use Composer\Repository\Vcs\GitDriver;
+use Composer\Test\Mock\ProcessExecutorMock;
+use Composer\Test\TestCase;
+
+class GitDriverTest extends TestCase
+{
+    /** @var Config */
+    private $config;
+    /** @var string */
+    private $home;
+
+    public function setUp()
+    {
+        $this->home = self::getUniqueTmpDirectory();
+        $this->config = new Config();
+        $this->config->merge(array(
+            'config' => array(
+                'home' => $this->home,
+            ),
+        ));
+    }
+
+    public function testGetBranchesFilterInvalidBranchNames()
+    {
+        $process = new ProcessExecutorMock;
+        $io = $this->getMockBuilder('Composer\IO\IOInterface')->getMock();
+
+        $driver = new GitDriver(array('url' => 'https://example.org/acme.git'), $io, $this->config, $this->getMockBuilder('Composer\Util\HttpDownloader')->disableOriginalConstructor()->getMock(), $process);
+        $this->setRepoDir($driver, $this->home);
+
+        // Branches starting with a - character are not valid git branches names
+        // Still assert that they get filtered to prevent issues later on
+        $stdout = <<<GIT
+* main 089681446ba44d6d9004350192486f2ceb4eaa06 commit
+  2.2  12681446ba44d6d9004350192486f2ceb4eaa06 commit
+  -h   089681446ba44d6d9004350192486f2ceb4eaa06 commit
+GIT;
+
+        $process
+            ->expects(array(array(
+                'cmd' => 'git branch --no-color --no-abbrev -v',
+                'stdout' => $stdout,
+            )));
+
+        $branches = $driver->getBranches();
+        $this->assertSame(array(
+            'main' => '089681446ba44d6d9004350192486f2ceb4eaa06',
+            '2.2' => '12681446ba44d6d9004350192486f2ceb4eaa06',
+        ), $branches);
+    }
+
+    public function testFileGetContentInvalidIdentifier()
+    {
+        $this->expectException('\RuntimeException');
+
+        $process = new ProcessExecutorMock;
+        $io = $this->getMockBuilder('Composer\IO\IOInterface')->getMock();
+        $driver = new GitDriver(array('url' => 'https://example.org/acme.git'), $io, $this->config, $this->getMockBuilder('Composer\Util\HttpDownloader')->disableOriginalConstructor()->getMock(), $process);
+
+        $this->assertNull($driver->getFileContent('file.txt', 'h'));
+
+        $driver->getFileContent('file.txt', '-h');
+    }
+
+    /**
+     * @param GitDriver $driver
+     * @param string $path
+     */
+    private function setRepoDir($driver, $path)
+    {
+        $reflectionClass = new \ReflectionClass($driver);
+        $reflectionProperty = $reflectionClass->getProperty('repoDir');
+        $reflectionProperty->setAccessible(true);
+        $reflectionProperty->setValue($driver, $path);
+    }
+}

programming_language: PHP
filename: HgDriverTest.php
change_type: ModificationType.MODIFY
diff: @@ -13,6 +13,7 @@
 namespace Composer\Test\Repository\Vcs;
 
 use Composer\Repository\Vcs\HgDriver;
+use Composer\Test\Mock\ProcessExecutorMock;
 use Composer\Test\TestCase;
 use Composer\Util\Filesystem;
 use Composer\Config;
@@ -66,4 +67,49 @@ public function supportsDataProvider()
             array('https://user@bitbucket.org/user/repo'),
         );
     }
+
+    public function testGetBranchesFilterInvalidBranchNames()
+    {
+        $process = new ProcessExecutorMock;
+
+        $driver = new HgDriver(array('url' => 'https://example.org/acme.git'), $this->io, $this->config, $this->getMockBuilder('Composer\Util\HttpDownloader')->disableOriginalConstructor()->getMock(), $process);
+
+        $stdout = <<<HG_BRANCHES
+default 1:dbf6c8acb640
+--help  1:dbf6c8acb640
+HG_BRANCHES;
+
+        $stdout1 = <<<HG_BOOKMARKS
+help    1:dbf6c8acb641
+--help  1:dbf6c8acb641
+
+HG_BOOKMARKS;
+
+        $process
+            ->expects(array(array(
+                'cmd' => 'hg branches',
+                'stdout' => $stdout,
+            ), array(
+                'cmd' => 'hg bookmarks',
+                'stdout' => $stdout1,
+            )));
+
+        $branches = $driver->getBranches();
+        $this->assertSame(array(
+            'help' => 'dbf6c8acb641',
+            'default' => 'dbf6c8acb640',
+        ), $branches);
+    }
+
+    public function testFileGetContentInvalidIdentifier()
+    {
+        $this->expectException('\RuntimeException');
+
+        $process = new ProcessExecutorMock;
+        $driver = new HgDriver(array('url' => 'https://example.org/acme.git'), $this->io, $this->config, $this->getMockBuilder('Composer\Util\HttpDownloader')->disableOriginalConstructor()->getMock(), $process);
+
+        $this->assertNull($driver->getFileContent('file.txt', 'h'));
+
+        $driver->getFileContent('file.txt', '-h');
+    }
 }

programming_language: PHP