From e5bfea64c81ae34816479bb05d17cdffe45adddb Mon Sep 17 00:00:00 2001
From: Stanislav Malyshev <stas@php.net>
Date: Sun, 18 Nov 2018 17:10:43 -0800
Subject: Disable rsh/ssh functionality in imap by default (bug #77153)

---
 NEWS                         |  4 ++++
 UPGRADING                    |  7 +++++++
 ext/imap/php_imap.c          | 17 +++++++++++++++++
 ext/imap/php_imap.h          |  1 +
 ext/imap/tests/bug77153.phpt | 24 ++++++++++++++++++++++++
 5 files changed, 53 insertions(+)
 create mode 100644 ext/imap/tests/bug77153.phpt

diff --git a/NEWS b/NEWS
index 4144f59d15..536f48d028 100644
--- a/NEWS
+++ b/NEWS
@@ -2,6 +2,10 @@ PHP                                                                        NEWS
 |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
 ?? ??? 2018, PHP 5.6.39
 
+- IMAP:
+  . Fixed bug #77153 (imap_open allows to run arbitrary shell commands via
+    mailbox parameter). (Stas)
+
 13 Sep 2018, PHP 5.6.38
 
 - Apache2
diff --git a/UPGRADING b/UPGRADING
index 353ffa73ad..d0340868ed 100644
--- a/UPGRADING
+++ b/UPGRADING
@@ -64,6 +64,13 @@ PHP 5.6 UPGRADE NOTES
 - cURL:
   Uploads using the @file syntax are now unsupported by default.
 
+- IMAP:
+  Starting with 5.6.38, rsh/ssh logins are disabled by default. Use
+  imap.enable_insecure_rsh if you want to enable them. Note that the IMAP
+  library does not filter mailbox names before passing them to rsh/ssh
+  command, thus passing untrusted data to this function with rsh/ssh enabled
+  is insecure.
+
 ========================================
 2. New Features
 ========================================
diff --git a/ext/imap/php_imap.c b/ext/imap/php_imap.c
index 00eae89a96..f6feebe9f7 100644
--- a/ext/imap/php_imap.c
+++ b/ext/imap/php_imap.c
@@ -562,6 +562,15 @@ static const zend_module_dep imap_deps[] = {
 };
 /* }}} */
 
+
+/* {{{ PHP_INI
+ */
+PHP_INI_BEGIN()
+STD_PHP_INI_BOOLEAN("imap.enable_insecure_rsh", "0", PHP_INI_SYSTEM, OnUpdateBool, enable_rsh, zend_imap_globals, imap_globals)
+PHP_INI_END()
+/* }}} */
+
+
 /* {{{ imap_module_entry
  */
 zend_module_entry imap_module_entry = {
@@ -835,6 +844,8 @@ PHP_MINIT_FUNCTION(imap)
 {
 	unsigned long sa_all =	SA_MESSAGES | SA_RECENT | SA_UNSEEN | SA_UIDNEXT | SA_UIDVALIDITY;
 
+	REGISTER_INI_ENTRIES();
+
 #ifndef PHP_WIN32
 	mail_link(&unixdriver);		/* link in the unix driver */
 	mail_link(&mhdriver);		/* link in the mh driver */
@@ -1052,6 +1063,12 @@ PHP_MINIT_FUNCTION(imap)
 	GC_TEXTS               texts
 	*/
 
+	if (!IMAPG(enable_rsh)) {
+		/* disable SSH and RSH, see https://bugs.php.net/bug.php?id=77153 */
+		mail_parameters (NIL, SET_RSHTIMEOUT, 0);
+		mail_parameters (NIL, SET_SSHTIMEOUT, 0);
+	}
+
 	le_imap = zend_register_list_destructors_ex(mail_close_it, NULL, "imap", module_number);
 	return SUCCESS;
 }
diff --git a/ext/imap/php_imap.h b/ext/imap/php_imap.h
index 3a1d048cd3..0c3ce78d48 100644
--- a/ext/imap/php_imap.h
+++ b/ext/imap/php_imap.h
@@ -214,6 +214,7 @@ ZEND_BEGIN_MODULE_GLOBALS(imap)
 #endif
 	/* php_stream for php_mail_gets() */
 	php_stream *gets_stream;
+	zend_bool enable_rsh;
 ZEND_END_MODULE_GLOBALS(imap)
 
 #ifdef ZTS
diff --git a/ext/imap/tests/bug77153.phpt b/ext/imap/tests/bug77153.phpt
new file mode 100644
index 0000000000..63590aee1d
--- /dev/null
+++ b/ext/imap/tests/bug77153.phpt
@@ -0,0 +1,24 @@
+--TEST--                                 
+Bug #77153 (imap_open allows to run arbitrary shell commands via mailbox parameter)
+--SKIPIF--
+<?php
+        if (!extension_loaded("imap")) { 
+                die("skip imap extension not available");  
+        }
+?>
+--FILE--
+<?php
+$payload = "echo 'BUG'> " . __DIR__ . '/__bug';
+$payloadb64 = base64_encode($payload);
+$server = "x -oProxyCommand=echo\t$payloadb64|base64\t-d|sh}";
+@imap_open('{'.$server.':143/imap}INBOX', '', '');
+// clean
+imap_errors();
+var_dump(file_exists(__DIR__ . '/__bug'));
+?>
+--EXPECT--
+bool(false)
+--CLEAN--
+<?php
+if(file_exists(__DIR__ . '/__bug')) unlink(__DIR__ . '/__bug');
+?>
\ No newline at end of file
-- 
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