From 076687f5f9e7e1fce24f33f498b4e03c4150108e Mon Sep 17 00:00:00 2001
From: Omair Majid <omajid@redhat.com>
Date: Fri, 2 Feb 2024 12:09:52 -0500
Subject: [PATCH] Revert "Disable implicit rejection for RSA PKCS#1 (#95218)"
This reverts commit e3500b8e8ad18e8bf067dc5250863b64bb8f0de0.
To quote Clemens Lang:
> [Disabling implcit rejection] re-enables a Bleichenbacher timing oracle
> attack against PKCS#1v1.5 decryption. See
> https://people.redhat.com/~hkario/marvin/ for details and
> https://github.com/dotnet/runtime/pull/95157#issuecomment-1842784399 for a
> comment by the researcher who published the vulnerability and proposed the
> change in OpenSSL.
For more details, see:
https://github.com/dotnet/runtime/pull/95216#issuecomment-1842799314
---
.../RSA/EncryptDecrypt.cs | 49 ++++---------------
.../opensslshim.h | 6 ---
.../pal_evp_pkey_rsa.c | 13 -----
3 files changed, 10 insertions(+), 58 deletions(-)
diff --git a/src/libraries/Common/tests/System/Security/Cryptography/AlgorithmImplementations/RSA/EncryptDecrypt.cs b/src/libraries/Common/tests/System/Security/Cryptography/AlgorithmImplementations/RSA/EncryptDecrypt.cs
index 55a044d62a6..e72d42e87d2 100644
--- a/src/libraries/Common/tests/System/Security/Cryptography/AlgorithmImplementations/RSA/EncryptDecrypt.cs
+++ b/src/libraries/Common/tests/System/Security/Cryptography/AlgorithmImplementations/RSA/EncryptDecrypt.cs
@@ -338,10 +338,19 @@ private void RsaCryptRoundtrip(RSAEncryptionPadding paddingMode, bool expectSucc
Assert.Equal(TestData.HelloBytes, output);
}
- [ConditionalFact(nameof(PlatformSupportsEmptyRSAEncryption))]
+ [ConditionalFact]
[SkipOnTargetFramework(TargetFrameworkMonikers.NetFramework)]
public void RoundtripEmptyArray()
{
+ if (OperatingSystem.IsIOS() && !OperatingSystem.IsIOSVersionAtLeast(13, 6))
+ {
+ throw new SkipTestException("iOS prior to 13.6 does not reliably support RSA encryption of empty data.");
+ }
+ if (OperatingSystem.IsTvOS() && !OperatingSystem.IsTvOSVersionAtLeast(14, 0))
+ {
+ throw new SkipTestException("tvOS prior to 14.0 does not reliably support RSA encryption of empty data.");
+ }
+
using (RSA rsa = RSAFactory.Create(TestData.RSA2048Params))
{
void RoundtripEmpty(RSAEncryptionPadding paddingMode)
@@ -692,26 +701,6 @@ public void NotSupportedValueMethods()
}
}
- [ConditionalTheory]
- [InlineData(new byte[] { 1, 2, 3, 4 })]
- [InlineData(new byte[0])]
- public void Decrypt_Pkcs1_ErrorsForInvalidPadding(byte[] data)
- {
- if (data.Length == 0 && !PlatformSupportsEmptyRSAEncryption)
- {
- throw new SkipTestException("Platform does not support RSA encryption of empty data.");
- }
-
- using (RSA rsa = RSAFactory.Create(TestData.RSA2048Params))
- {
- byte[] encrypted = Encrypt(rsa, data, RSAEncryptionPadding.Pkcs1);
- encrypted[1] ^= 0xFF;
-
- // PKCS#1, the data, and the key are all deterministic so this should always throw an exception.
- Assert.ThrowsAny<CryptographicException>(() => Decrypt(rsa, encrypted, RSAEncryptionPadding.Pkcs1));
- }
- }
-
[Fact]
public void Decrypt_Pkcs1_BadPadding()
{
@@ -726,23 +715,5 @@ public static IEnumerable<object[]> OaepPaddingModes
}
}
}
-
- public static bool PlatformSupportsEmptyRSAEncryption
- {
- get
- {
- if (OperatingSystem.IsIOS() && !OperatingSystem.IsIOSVersionAtLeast(13, 6))
- {
- return false;
- }
-
- if (OperatingSystem.IsTvOS() && !OperatingSystem.IsTvOSVersionAtLeast(14, 0))
- {
- return false;
- }
-
- return true;
- }
- }
}
}
diff --git a/src/libraries/Native/Unix/System.Security.Cryptography.Native/opensslshim.h b/src/libraries/Native/Unix/System.Security.Cryptography.Native/opensslshim.h
index 050df1193ff..dad18ebd9a1 100644
--- a/src/libraries/Native/Unix/System.Security.Cryptography.Native/opensslshim.h
+++ b/src/libraries/Native/Unix/System.Security.Cryptography.Native/opensslshim.h
@@ -272,10 +272,8 @@ const EVP_CIPHER* EVP_chacha20_poly1305(void);
REQUIRED_FUNCTION(ERR_peek_error) \
REQUIRED_FUNCTION(ERR_peek_error_line) \
REQUIRED_FUNCTION(ERR_peek_last_error) \
- REQUIRED_FUNCTION(ERR_pop_to_mark) \
FALLBACK_FUNCTION(ERR_put_error) \
REQUIRED_FUNCTION(ERR_reason_error_string) \
- REQUIRED_FUNCTION(ERR_set_mark) \
LIGHTUP_FUNCTION(ERR_set_debug) \
LIGHTUP_FUNCTION(ERR_set_error) \
REQUIRED_FUNCTION(EVP_aes_128_cbc) \
@@ -330,7 +328,6 @@ const EVP_CIPHER* EVP_chacha20_poly1305(void);
REQUIRED_FUNCTION(EVP_PKCS82PKEY) \
REQUIRED_FUNCTION(EVP_PKEY2PKCS8) \
REQUIRED_FUNCTION(EVP_PKEY_CTX_ctrl) \
- REQUIRED_FUNCTION(EVP_PKEY_CTX_ctrl_str) \
REQUIRED_FUNCTION(EVP_PKEY_CTX_free) \
REQUIRED_FUNCTION(EVP_PKEY_CTX_get0_pkey) \
REQUIRED_FUNCTION(EVP_PKEY_CTX_new) \
@@ -728,10 +725,8 @@ FOR_ALL_OPENSSL_FUNCTIONS
#define ERR_peek_error_line ERR_peek_error_line_ptr
#define ERR_peek_last_error ERR_peek_last_error_ptr
#define ERR_put_error ERR_put_error_ptr
-#define ERR_pop_to_mark ERR_pop_to_mark_ptr
#define ERR_reason_error_string ERR_reason_error_string_ptr
#define ERR_set_debug ERR_set_debug_ptr
-#define ERR_set_mark ERR_set_mark_ptr
#define ERR_set_error ERR_set_error_ptr
#define EVP_aes_128_cbc EVP_aes_128_cbc_ptr
#define EVP_aes_128_cfb8 EVP_aes_128_cfb8_ptr
@@ -785,7 +780,6 @@ FOR_ALL_OPENSSL_FUNCTIONS
#define EVP_PKCS82PKEY EVP_PKCS82PKEY_ptr
#define EVP_PKEY2PKCS8 EVP_PKEY2PKCS8_ptr
#define EVP_PKEY_CTX_ctrl EVP_PKEY_CTX_ctrl_ptr
-#define EVP_PKEY_CTX_ctrl_str EVP_PKEY_CTX_ctrl_str_ptr
#define EVP_PKEY_CTX_free EVP_PKEY_CTX_free_ptr
#define EVP_PKEY_CTX_get0_pkey EVP_PKEY_CTX_get0_pkey_ptr
#define EVP_PKEY_CTX_new EVP_PKEY_CTX_new_ptr
diff --git a/src/libraries/Native/Unix/System.Security.Cryptography.Native/pal_evp_pkey_rsa.c b/src/libraries/Native/Unix/System.Security.Cryptography.Native/pal_evp_pkey_rsa.c
index c3e491a868f..36924abb505 100644
--- a/src/libraries/Native/Unix/System.Security.Cryptography.Native/pal_evp_pkey_rsa.c
+++ b/src/libraries/Native/Unix/System.Security.Cryptography.Native/pal_evp_pkey_rsa.c
@@ -63,19 +63,6 @@ static bool ConfigureEncryption(EVP_PKEY_CTX* ctx, RsaPaddingMode padding, const
{
return false;
}
-
- // OpenSSL 3.2 introduced a change where PKCS#1 RSA decryption does not fail for invalid padding.
- // If the padding is invalid, the decryption operation returns random data.
- // See https://github.com/openssl/openssl/pull/13817 for background.
- // Some Linux distributions backported this change to previous versions of OpenSSL.
- // Here we do a best-effort to set a flag to revert the behavior to failing if the padding is invalid.
- ERR_set_mark();
-
- EVP_PKEY_CTX_ctrl_str(ctx, "rsa_pkcs1_implicit_rejection", "0");
-
- // Undo any changes to the error queue that may have occured while configuring implicit rejection if the
- // current version does not support implicit rejection.
- ERR_pop_to_mark();
}
else
{
--
2.43.0