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From e78b2696c7baf48e5d0898420368555ff4b99830 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Tim=20D=C3=BCsterhus?= <tim@bastelstu.be>
Date: Mon, 23 Jan 2023 21:15:24 +0100
Subject: [PATCH 1/8] crypt: Fix validation of malformed BCrypt hashes
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
PHP’s implementation of crypt_blowfish differs from the upstream Openwall
version by adding a “PHP Hack”, which allows one to cut short the BCrypt salt
by including a `$` character within the characters that represent the salt.
Hashes that are affected by the “PHP Hack” may erroneously validate any
password as valid when used with `password_verify` and when comparing the
return value of `crypt()` against the input.
The PHP Hack exists since the first version of PHP’s own crypt_blowfish
implementation that was added in 1e820eca02dcf322b41fd2fe4ed2a6b8309f8ab5.
No clear reason is given for the PHP Hack’s existence. This commit removes it,
because BCrypt hashes containing a `$` character in their salt are not valid
BCrypt hashes.
(cherry picked from commit c840f71524067aa474c00c3eacfb83bd860bfc8a)
(cherry picked from commit 7437aaae38cf4b3357e7580f9e22fd4a403b6c23)
---
ext/standard/crypt_blowfish.c | 8 --
.../tests/crypt/bcrypt_salt_dollar.phpt | 82 +++++++++++++++++++
2 files changed, 82 insertions(+), 8 deletions(-)
create mode 100644 ext/standard/tests/crypt/bcrypt_salt_dollar.phpt
diff --git a/ext/standard/crypt_blowfish.c b/ext/standard/crypt_blowfish.c
index c1f945f29e..aa7e1bc2e6 100644
--- a/ext/standard/crypt_blowfish.c
+++ b/ext/standard/crypt_blowfish.c
@@ -376,7 +376,6 @@ static unsigned char BF_atoi64[0x60] = {
#define BF_safe_atoi64(dst, src) \
{ \
tmp = (unsigned char)(src); \
- if (tmp == '$') break; /* PHP hack */ \
if ((unsigned int)(tmp -= 0x20) >= 0x60) return -1; \
tmp = BF_atoi64[tmp]; \
if (tmp > 63) return -1; \
@@ -404,13 +403,6 @@ static int BF_decode(BF_word *dst, const char *src, int size)
*dptr++ = ((c3 & 0x03) << 6) | c4;
} while (dptr < end);
- if (end - dptr == size) {
- return -1;
- }
-
- while (dptr < end) /* PHP hack */
- *dptr++ = 0;
-
return 0;
}
diff --git a/ext/standard/tests/crypt/bcrypt_salt_dollar.phpt b/ext/standard/tests/crypt/bcrypt_salt_dollar.phpt
new file mode 100644
index 0000000000..32e335f4b0
--- /dev/null
+++ b/ext/standard/tests/crypt/bcrypt_salt_dollar.phpt
@@ -0,0 +1,82 @@
+--TEST--
+bcrypt correctly rejects salts containing $
+--FILE--
+<?php
+for ($i = 0; $i < 23; $i++) {
+ $salt = '$2y$04$' . str_repeat('0', $i) . '$';
+ $result = crypt("foo", $salt);
+ var_dump($salt);
+ var_dump($result);
+ var_dump($result === $salt);
+}
+?>
+--EXPECT--
+string(8) "$2y$04$$"
+string(2) "*0"
+bool(false)
+string(9) "$2y$04$0$"
+string(2) "*0"
+bool(false)
+string(10) "$2y$04$00$"
+string(2) "*0"
+bool(false)
+string(11) "$2y$04$000$"
+string(2) "*0"
+bool(false)
+string(12) "$2y$04$0000$"
+string(2) "*0"
+bool(false)
+string(13) "$2y$04$00000$"
+string(2) "*0"
+bool(false)
+string(14) "$2y$04$000000$"
+string(2) "*0"
+bool(false)
+string(15) "$2y$04$0000000$"
+string(2) "*0"
+bool(false)
+string(16) "$2y$04$00000000$"
+string(2) "*0"
+bool(false)
+string(17) "$2y$04$000000000$"
+string(2) "*0"
+bool(false)
+string(18) "$2y$04$0000000000$"
+string(2) "*0"
+bool(false)
+string(19) "$2y$04$00000000000$"
+string(2) "*0"
+bool(false)
+string(20) "$2y$04$000000000000$"
+string(2) "*0"
+bool(false)
+string(21) "$2y$04$0000000000000$"
+string(2) "*0"
+bool(false)
+string(22) "$2y$04$00000000000000$"
+string(2) "*0"
+bool(false)
+string(23) "$2y$04$000000000000000$"
+string(2) "*0"
+bool(false)
+string(24) "$2y$04$0000000000000000$"
+string(2) "*0"
+bool(false)
+string(25) "$2y$04$00000000000000000$"
+string(2) "*0"
+bool(false)
+string(26) "$2y$04$000000000000000000$"
+string(2) "*0"
+bool(false)
+string(27) "$2y$04$0000000000000000000$"
+string(2) "*0"
+bool(false)
+string(28) "$2y$04$00000000000000000000$"
+string(2) "*0"
+bool(false)
+string(29) "$2y$04$000000000000000000000$"
+string(2) "*0"
+bool(false)
+string(30) "$2y$04$0000000000000000000000$"
+string(60) "$2y$04$000000000000000000000u2a2UpVexIt9k3FMJeAVr3c04F5tcI8K"
+bool(false)
--
2.39.1
From ae619b4ba0b325650d09447a48e18c578d52c681 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Tim=20D=C3=BCsterhus?= <tim@bastelstu.be>
Date: Mon, 23 Jan 2023 22:13:57 +0100
Subject: [PATCH 2/8] crypt: Fix possible buffer overread in php_crypt()
(cherry picked from commit a92acbad873a05470af1a47cb785a18eadd827b5)
(cherry picked from commit ed0281b588a6840cb95f3134a4e68847a3be5bb7)
---
ext/standard/crypt.c | 1 +
ext/standard/tests/password/password_bcrypt_short.phpt | 8 ++++++++
2 files changed, 9 insertions(+)
create mode 100644 ext/standard/tests/password/password_bcrypt_short.phpt
diff --git a/ext/standard/crypt.c b/ext/standard/crypt.c
index fec04ec584..9787b92f57 100644
--- a/ext/standard/crypt.c
+++ b/ext/standard/crypt.c
@@ -154,6 +154,7 @@ PHPAPI zend_string *php_crypt(const char *password, const int pass_len, const ch
} else if (
salt[0] == '$' &&
salt[1] == '2' &&
+ salt[2] != 0 &&
salt[3] == '$') {
char output[PHP_MAX_SALT_LEN + 1];
diff --git a/ext/standard/tests/password/password_bcrypt_short.phpt b/ext/standard/tests/password/password_bcrypt_short.phpt
new file mode 100644
index 0000000000..085bc8a239
--- /dev/null
+++ b/ext/standard/tests/password/password_bcrypt_short.phpt
@@ -0,0 +1,8 @@
+--TEST--
+Test that password_hash() does not overread buffers when a short hash is passed
+--FILE--
+<?php
+var_dump(password_verify("foo", '$2'));
+?>
+--EXPECT--
+bool(false)
--
2.39.1
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