exo2: implement SmcPrepareEsDeviceUniqueKey, SmcPrepareEsCommonTitleKey, SmcLoadPreparedAesKey

exosphere2/program/source/smc/secmon_smc_aes.cpp

@@ -155,6 +155,15 @@ namespace ams::secmon::smc {
             0xE2, 0xD6, 0xB8, 0x7A, 0x11, 0x9C, 0xB8, 0x80, 0xE8, 0x22, 0x88, 0x8A, 0x46, 0xFB, 0xA1, 0x95
         };
 
+        constexpr const u8 EsCommonKeySources[EsCommonKeyType_Count][AesKeySize] = {
+            [EsCommonKeyType_TitleKey]   = { 0x1E, 0xDC, 0x7B, 0x3B, 0x60, 0xE6, 0xB4, 0xD8, 0x78, 0xB8, 0x17, 0x15, 0x98, 0x5E, 0x62, 0x9B },
+            [EsCommonKeyType_ArchiveKey] = { 0x3B, 0x78, 0xF2, 0x61, 0x0F, 0x9D, 0x5A, 0xE2, 0x7B, 0x4E, 0x45, 0xAF, 0xCB, 0x0B, 0x67, 0x4D },
+        };
+
+        constexpr const u8 EsSealKeySource[AesKeySize] = {
+            0xCB, 0xB7, 0x6E, 0x38, 0xA1, 0xCB, 0x77, 0x0F, 0xB2, 0xA5, 0xB2, 0x9D, 0xD8, 0x56, 0x9F, 0x76
+        };
+
         constexpr const u8 SecureDataSource[AesKeySize] = {
             0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00
         };
@@ -463,6 +472,51 @@ namespace ams::secmon::smc {
             return SmcResult::Success;
         }
 
+        SmcResult LoadPreparedAesKeyImpl(SmcArguments &args) {
+            /* Decode arguments. */
+            u8 access_key[AesKeySize];
+
+            const int slot = args.r[1];
+            std::memcpy(access_key, std::addressof(args.r[2]), sizeof(access_key));
+
+            /* Validate arguments. */
+            SMC_R_UNLESS(pkg1::IsUserAesKeySlot(slot), InvalidArgument);
+
+            /* Derive the seal key. */
+            se::SetEncryptedAesKey128(pkg1::AesKeySlot_Smc, pkg1::AesKeySlot_RandomForUserWrap, EsSealKeySource, sizeof(EsSealKeySource));
+
+            /* Unseal the key. */
+            se::SetEncryptedAesKey128(slot, pkg1::AesKeySlot_Smc, access_key, sizeof(access_key));
+
+            return SmcResult::Success;
+        }
+
+        SmcResult PrepareEsCommonTitleKeyImpl(SmcArguments &args) {
+            /* Declare variables. */
+            u8 key_source[se::AesBlockSize];
+            u8 key[se::AesBlockSize];
+            u8 access_key[se::AesBlockSize];
+
+            /* Decode arguments. */
+            std::memcpy(key_source, std::addressof(args.r[1]), sizeof(key_source));
+            const int generation = GetTargetFirmware() >= TargetFirmware_3_0_0 ? std::max(0, static_cast<int>(args.r[3]) - 1) : 0;
+
+            /* Validate arguments. */
+            SMC_R_UNLESS(pkg1::IsValidKeyGeneration(generation), InvalidArgument);
+            SMC_R_UNLESS(generation <= GetKeyGeneration(),       InvalidArgument);
+
+            /* Derive the key. */
+            DecryptWithEsCommonKey(key, sizeof(key), key_source, sizeof(key_source), EsCommonKeyType_TitleKey, generation);
+
+            /* Prepare the aes key. */
+            PrepareEsAesKey(access_key, sizeof(access_key), key, sizeof(key));
+
+            /* Copy the access key to output. */
+            std::memcpy(std::addressof(args.r[1]), access_key, sizeof(access_key));
+
+            return SmcResult::Success;
+        }
+
         SmcResult DecryptDeviceUniqueDataImpl(SmcArguments &args) {
             /* Decode arguments. */
             u8 access_key[se::AesBlockSize];
@@ -530,6 +584,7 @@ namespace ams::secmon::smc {
                     case DeviceUniqueData_ImportEsClientCertKey:
                         ImportRsaKeyExponent(ConvertToImportRsaKey(mode), work_buffer, se::RsaSize);
                         ImportRsaKeyModulusProvisionally(ConvertToImportRsaKey(mode), work_buffer + se::RsaSize, se::RsaSize);
+                        CommitRsaKeyModulus(ConvertToImportRsaKey(mode));
                         break;
                     AMS_UNREACHABLE_DEFAULT_CASE();
                 }
@@ -579,8 +634,11 @@ namespace ams::secmon::smc {
     }
 
     SmcResult SmcLoadPreparedAesKey(SmcArguments &args) {
-        /* TODO */
+        return LockSecurityEngineAndInvoke(args, LoadPreparedAesKeyImpl);
-        return SmcResult::NotImplemented;
+    }
+
+    SmcResult SmcPrepareEsCommonTitleKey(SmcArguments &args) {
+        return LockSecurityEngineAndInvoke(args, PrepareEsCommonTitleKeyImpl);
     }
 
     /* Device unique data functionality. */
@@ -604,6 +662,35 @@ namespace ams::secmon::smc {
         return SmcResult::NotImplemented;
     }
 
+    /* Es encryption utilities. */
+    void DecryptWithEsCommonKey(void *dst, size_t dst_size, const void *src, size_t src_size, EsCommonKeyType type, int generation) {
+        /* Validate pre-conditions. */
+        AMS_ABORT_UNLESS(dst_size == AesKeySize);
+        AMS_ABORT_UNLESS(src_size == AesKeySize);
+        AMS_ABORT_UNLESS(0 <= type && type < EsCommonKeyType_Count);
+
+        /* Prepare the master key for the generation. */
+        const int slot = PrepareMasterKey(generation);
+
+        /* Derive the es common key. */
+        se::SetEncryptedAesKey128(pkg1::AesKeySlot_Smc, slot, EsCommonKeySources[type], AesKeySize);
+
+        /* Decrypt the input using the common key. */
+        se::DecryptAes128(dst, dst_size, pkg1::AesKeySlot_Smc, src, src_size);
+    }
+
+    void PrepareEsAesKey(void *dst, size_t dst_size, const void *src, size_t src_size) {
+        /* Validate pre-conditions. */
+        AMS_ABORT_UNLESS(dst_size == AesKeySize);
+        AMS_ABORT_UNLESS(src_size == AesKeySize);
+
+        /* Derive the seal key. */
+        se::SetEncryptedAesKey128(pkg1::AesKeySlot_Smc, pkg1::AesKeySlot_RandomForUserWrap, EsSealKeySource, sizeof(EsSealKeySource));
+
+        /* Seal the key. */
+        se::EncryptAes128(dst, dst_size, pkg1::AesKeySlot_Smc, src, src_size);
+    }
+
     /* 'Tis the last rose of summer, / Left blooming alone;    */
     /* Oh! who would inhabit         / This bleak world alone? */
     SmcResult SmcGetSecureData(SmcArguments &args) {

exosphere2/program/source/smc/secmon_smc_aes.hpp

@@ -19,6 +19,13 @@
 
 namespace ams::secmon::smc {
 
+    enum EsCommonKeyType {
+        EsCommonKeyType_TitleKey   = 0,
+        EsCommonKeyType_ArchiveKey = 1,
+
+        EsCommonKeyType_Count,
+    };
+
     /* General Aes functionality. */
     SmcResult SmcGenerateAesKek(SmcArguments &args);
     SmcResult SmcLoadAesKey(SmcArguments &args);
@@ -26,6 +33,7 @@ namespace ams::secmon::smc {
     SmcResult SmcGenerateSpecificAesKey(SmcArguments &args);
     SmcResult SmcComputeCmac(SmcArguments &args);
     SmcResult SmcLoadPreparedAesKey(SmcArguments &args);
+    SmcResult SmcPrepareEsCommonTitleKey(SmcArguments &args);
 
     /* Device unique data functionality. */
     SmcResult SmcDecryptDeviceUniqueData(SmcArguments &args);
@@ -35,6 +43,10 @@ namespace ams::secmon::smc {
     SmcResult SmcDecryptAndImportEsDeviceKey(SmcArguments &args);
     SmcResult SmcDecryptAndImportLotusKey(SmcArguments &args);
 
+    /* Es encryption utilities. */
+    void DecryptWithEsCommonKey(void *dst, size_t dst_size, const void *src, size_t src_size, EsCommonKeyType type, int generation);
+    void PrepareEsAesKey(void *dst, size_t dst_size, const void *src, size_t src_size);
+
     /* The last rose of summer. */
     SmcResult SmcGetSecureData(SmcArguments &args);
 

exosphere2/program/source/smc/secmon_smc_es.cpp

@@ -1,32 +0,0 @@
-/*
- * Copyright (c) 2018-2020 Atmosphère-NX
- *
- * This program is free software; you can redistribute it and/or modify it
- * under the terms and conditions of the GNU General Public License,
- * version 2, as published by the Free Software Foundation.
- *
- * This program is distributed in the hope it will be useful, but WITHOUT
- * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
- * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
- * more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program.  If not, see <http://www.gnu.org/licenses/>.
- */
-#include <exosphere.hpp>
-#include "../secmon_error.hpp"
-#include "secmon_smc_es.hpp"
-
-namespace ams::secmon::smc {
-
-    SmcResult SmcPrepareEsDeviceUniqueKey(SmcArguments &args) {
-        /* TODO */
-        return SmcResult::NotImplemented;
-    }
-
-    SmcResult SmcPrepareEsCommonKey(SmcArguments &args) {
-        /* TODO */
-        return SmcResult::NotImplemented;
-    }
-
-}

exosphere2/program/source/smc/secmon_smc_handler.cpp

@@ -22,7 +22,6 @@
 #include "secmon_smc_carveout.hpp"
 #include "secmon_smc_device_unique_data.hpp"
 #include "secmon_smc_error.hpp"
-#include "secmon_smc_es.hpp"
 #include "secmon_smc_info.hpp"
 #include "secmon_smc_memory_access.hpp"
 #include "secmon_smc_power_management.hpp"
@@ -120,7 +119,7 @@ namespace ams::secmon::smc {
             { 0xC300060F, Restriction_DeviceUniqueDataNotAllowed, SmcModularExponentiateByStorageKey },
             { 0xC3000610, Restriction_SafeModeNotAllowed,         SmcPrepareEsDeviceUniqueKey        },
             { 0xC3000011, Restriction_SafeModeNotAllowed,         SmcLoadPreparedAesKey              },
-            { 0xC3000012, Restriction_SafeModeNotAllowed,         SmcPrepareEsCommonKey              }
+            { 0xC3000012, Restriction_SafeModeNotAllowed,         SmcPrepareEsCommonTitleKey         }
         };
 
         constinit HandlerInfo g_kern_handlers[] = {
@@ -233,8 +232,8 @@ namespace ams::secmon::smc {
 
         constinit std::atomic<int> g_logged = 0;
 
-        constexpr int LogMin = 0x4000;
+        constexpr int LogMin = 0x1000000;
-        constexpr int LogMax = 0x4200;
+        constexpr int LogMax = 0x1000000;
 
         constexpr size_t LogBufSize = 0x5000;
 

exosphere2/program/source/smc/secmon_smc_rsa.cpp

@@ -15,10 +15,158 @@
  */
 #include <exosphere.hpp>
 #include "../secmon_error.hpp"
+#include "../secmon_key_storage.hpp"
+#include "secmon_smc_aes.hpp"
 #include "secmon_smc_rsa.hpp"
+#include "secmon_smc_se_lock.hpp"
+#include "secmon_page_mapper.hpp"
 
 namespace ams::secmon::smc {
 
+    namespace {
+
+        struct PrepareEsDeviceUniqueKeyOption {
+            using KeyGeneration = util::BitPack32::Field<0,  6, int>;
+            using Type          = util::BitPack32::Field<6,  1, EsCommonKeyType>;
+            using Reserved      = util::BitPack32::Field<7, 25, u32>;
+        };
+
+        class PrepareEsDeviceUniqueKeyAsyncArguments {
+            private:
+                int generation;
+                EsCommonKeyType type;
+                u8 label_digest[crypto::Sha256Generator::HashSize];
+            public:
+                void Set(int gen, EsCommonKeyType t, const u8 ld[crypto::Sha256Generator::HashSize]) {
+                    this->generation = gen;
+                    this->type       = t;
+                    std::memcpy(this->label_digest, ld, sizeof(this->label_digest));
+                }
+
+                int GetKeyGeneration() const { return this->generation; }
+                EsCommonKeyType GetCommonKeyType() const { return this->type; }
+                void GetLabelDigest(u8 dst[crypto::Sha256Generator::HashSize]) const { std::memcpy(dst, this->label_digest, sizeof(this->label_digest)); }
+        };
+
+        class ModularExponentiateByStorageKeyAsyncArguments {
+            private:
+                u8 msg[se::RsaSize];
+            public:
+                void Set(const void *m, size_t m_size) {
+                    std::memcpy(this->msg, m, sizeof(this->msg));
+                }
+
+                void GetMessage(void *dst, size_t dst_size) const { std::memcpy(dst, this->msg, sizeof(this->msg)); }
+        };
+
+        constinit bool g_exp_mod_completed = false;
+
+        constinit union {
+            ModularExponentiateByStorageKeyAsyncArguments modular_exponentiate_by_storage_key;
+            PrepareEsDeviceUniqueKeyAsyncArguments prepare_es_device_unique_key;
+        } g_async_arguments;
+
+        ALWAYS_INLINE ModularExponentiateByStorageKeyAsyncArguments &GetModularExponentiateByStorageKeyAsyncArguments() {
+            return g_async_arguments.modular_exponentiate_by_storage_key;
+        }
+
+        ALWAYS_INLINE PrepareEsDeviceUniqueKeyAsyncArguments &GetPrepareEsDeviceUniqueKeyAsyncArguments() {
+            return g_async_arguments.prepare_es_device_unique_key;
+        }
+
+        void SecurityEngineDoneHandler() {
+            /* End the asynchronous operation. */
+            g_exp_mod_completed = true;
+            EndAsyncOperation();
+        }
+
+        SmcResult PrepareEsDeviceUniqueKeyImpl(SmcArguments &args) {
+            /* Decode arguments. */
+            u8 label_digest[crypto::Sha256Generator::HashSize];
+
+            const uintptr_t msg_address = args.r[1];
+            const uintptr_t mod_address = args.r[2];
+            std::memcpy(label_digest, std::addressof(args.r[3]), sizeof(label_digest));
+            const util::BitPack32 option = { static_cast<u32>(args.r[7]) };
+
+            const auto generation = GetTargetFirmware() >= TargetFirmware_3_0_0 ? std::max(0, option.Get<PrepareEsDeviceUniqueKeyOption::KeyGeneration>() - 1) : 0;
+            const auto type       = option.Get<PrepareEsDeviceUniqueKeyOption::Type>();
+            const auto reserved   = option.Get<PrepareEsDeviceUniqueKeyOption::Reserved>();
+
+            /* Validate arguments. */
+            SMC_R_UNLESS(reserved == 0,                          InvalidArgument);
+            SMC_R_UNLESS(pkg1::IsValidKeyGeneration(generation), InvalidArgument);
+            SMC_R_UNLESS(generation <= GetKeyGeneration(),       InvalidArgument);
+            SMC_R_UNLESS(type < EsCommonKeyType_Count,           InvalidArgument);
+
+            /* Copy the message and modulus from the user. */
+            alignas(8) u8 msg[se::RsaSize];
+            alignas(8) u8 mod[se::RsaSize];
+            {
+                UserPageMapper mapper(msg_address);
+                SMC_R_UNLESS(mapper.Map(),                                       InvalidArgument);
+                SMC_R_UNLESS(mapper.CopyFromUser(msg, msg_address, sizeof(msg)), InvalidArgument);
+                SMC_R_UNLESS(mapper.CopyFromUser(mod, mod_address, sizeof(mod)), InvalidArgument);
+            }
+
+            /* We're performing an operation, so the operation is not completed. */
+            g_exp_mod_completed = false;
+
+            /* Set the async arguments. */
+            GetPrepareEsDeviceUniqueKeyAsyncArguments().Set(generation, type, label_digest);
+
+            /* Load the es drm key into the security engine. */
+            SMC_R_UNLESS(LoadRsaKey(pkg1::RsaKeySlot_Temporary, ImportRsaKey_EsDrmCert), NotInitialized);
+
+            /* Trigger the asynchronous modular exponentiation. */
+            se::ModularExponentiateAsync(pkg1::RsaKeySlot_Temporary, msg, sizeof(msg), SecurityEngineDoneHandler);
+
+            return SmcResult::Success;
+        }
+
+        SmcResult GetPrepareEsDeviceUniqueKeyResult(void *dst, size_t dst_size) {
+            /* Declare variables. */
+            u8 key_source[se::AesBlockSize];
+            u8 key[se::AesBlockSize];
+            u8 access_key[se::AesBlockSize];
+
+            /* Validate state. */
+            SMC_R_UNLESS(g_exp_mod_completed,                       Busy);
+            SMC_R_UNLESS(dst_size == sizeof(access_key), InvalidArgument);
+
+            /* We want to relinquish our security engine lock at the end of scope. */
+            ON_SCOPE_EXIT { UnlockSecurityEngine(); };
+
+            /* Get the async args. */
+            const auto &async_args = GetPrepareEsDeviceUniqueKeyAsyncArguments();
+
+            /* Get the exponentiation output. */
+            alignas(8) u8 msg[se::RsaSize];
+            se::GetRsaResult(msg, sizeof(msg));
+
+            /* Decode the key. */
+            {
+                /* Get the label digest. */
+                u8 label_digest[crypto::Sha256Generator::HashSize];
+                async_args.GetLabelDigest(label_digest);
+
+                /* Decode the key source. */
+                const size_t key_source_size = se::DecodeRsaOaepSha256(key_source, sizeof(key_source), msg, sizeof(msg), label_digest, sizeof(label_digest));
+                SMC_R_UNLESS(key_source_size == sizeof(key_source), InvalidArgument);
+            }
+
+            /* Decrypt the key. */
+            DecryptWithEsCommonKey(key, sizeof(key), key_source, sizeof(key_source), async_args.GetCommonKeyType(), async_args.GetKeyGeneration());
+            PrepareEsAesKey(access_key, sizeof(access_key), key, sizeof(key));
+
+            /* Copy the access key to output. */
+            std::memcpy(dst, access_key, sizeof(access_key));
+
+            return SmcResult::Success;
+        }
+
+    }
+
     SmcResult SmcModularExponentiate(SmcArguments &args) {
         /* TODO */
         return SmcResult::NotImplemented;
@@ -29,4 +177,8 @@ namespace ams::secmon::smc {
         return SmcResult::NotImplemented;
     }
 
+    SmcResult SmcPrepareEsDeviceUniqueKey(SmcArguments &args) {
+        return LockSecurityEngineAndInvokeAsync(args, PrepareEsDeviceUniqueKeyImpl, GetPrepareEsDeviceUniqueKeyResult);
+    }
+
 }

exosphere2/program/source/smc/secmon_smc_rsa.hpp

@@ -22,4 +22,6 @@ namespace ams::secmon::smc {
     SmcResult SmcModularExponentiate(SmcArguments &args);
     SmcResult SmcModularExponentiateByStorageKey(SmcArguments &args);
 
+    SmcResult SmcPrepareEsDeviceUniqueKey(SmcArguments &args);
+
 }

libraries/libexosphere/include/exosphere/se.hpp

@@ -20,6 +20,7 @@
 #include <exosphere/se/se_management.hpp>
 #include <exosphere/se/se_aes.hpp>
 #include <exosphere/se/se_hash.hpp>
+#include <exosphere/se/se_oaep.hpp>
 #include <exosphere/se/se_rsa.hpp>
 #include <exosphere/se/se_rng.hpp>
 #include <exosphere/se/se_suspend.hpp>

libraries/libexosphere/include/exosphere/se/se_oaep.hpp

@@ -14,19 +14,10 @@
  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  */
 #pragma once
-#include <exosphere.hpp>
+#include <vapours.hpp>
-#include "secmon_smc_common.hpp"
 
-namespace ams::secmon::smc {
+namespace ams::se {
 
-    enum EsKeyType {
+    size_t DecodeRsaOaepSha256(void *dst, size_t dst_size, void *src, size_t src_size, const void *label_digest, size_t label_digest_size);
-        EsKeyType_TitleKey   = 0,
-        EsKeyType_ArchiveKey = 1,
-
-        EsKeyType_Count      = 2,
-    };
-
-    SmcResult SmcPrepareEsDeviceUniqueKey(SmcArguments &args);
-    SmcResult SmcPrepareEsCommonKey(SmcArguments &args);
 
 }

libraries/libexosphere/include/exosphere/se/se_rsa.hpp

@@ -15,6 +15,7 @@
  */
 #pragma once
 #include <vapours.hpp>
+#include <exosphere/se/se_common.hpp>
 
 namespace ams::se {
 
@@ -27,5 +28,8 @@ namespace ams::se {
     void SetRsaKey(int slot, const void *mod, size_t mod_size, const void *exp, size_t exp_size);
 
     void ModularExponentiate(void *dst, size_t dst_size, int slot, const void *src, size_t src_size);
+    void ModularExponentiateAsync(int slot, const void *src, size_t src_size, DoneHandler handler);
+
+    void GetRsaResult(void *dst, size_t dst_size);
 
 }

libraries/libexosphere/source/se/se_execute.cpp

@@ -131,6 +131,25 @@ namespace ams::se {
         std::memcpy(dst, aligned, dst_size);
     }
 
+    void StartInputOperation(volatile SecurityEngineRegisters *SE, const void *src, size_t src_size) {
+        /* Set the linked list entry. */
+        LinkedListEntry src_entry;
+        SetLinkedListEntry(std::addressof(src_entry), src, src_size);
+
+        /* Ensure the linked list entry data is seen correctly. */
+        hw::FlushDataCache(std::addressof(src_entry), sizeof(src_entry));
+        hw::DataSynchronizationBarrierInnerShareable();
+
+        /* Configure the linked list addresses. */
+        reg::Write(SE->SE_IN_LL_ADDR,  static_cast<u32>(GetPhysicalAddress(std::addressof(src_entry))));
+
+        /* Start the operation. */
+        StartOperation(SE, SE_OPERATION_OP_START);
+
+        /* Ensure the operation is started. */
+        EnsureOperationStarted(SE);
+    }
+
     void StartOperationRaw(volatile SecurityEngineRegisters *SE, SE_OPERATION_OP op, u32 out_ll_address, u32 in_ll_address) {
         /* Configure the linked list addresses. */
         reg::Write(SE->SE_IN_LL_ADDR,  in_ll_address);

libraries/libexosphere/source/se/se_execute.hpp

@@ -23,6 +23,7 @@ namespace ams::se {
     void ExecuteOperation(volatile SecurityEngineRegisters *SE, SE_OPERATION_OP op, void *dst, size_t dst_size, const void *src, size_t src_size);
     void ExecuteOperationSingleBlock(volatile SecurityEngineRegisters *SE, void *dst, size_t dst_size, const void *src, size_t src_size);
 
+    void StartInputOperation(volatile SecurityEngineRegisters *SE, const void *src, size_t src_size);
     void StartOperationRaw(volatile SecurityEngineRegisters *SE, SE_OPERATION_OP op, u32 out_ll_address, u32 in_ll_address);
     void SetDoneHandler(volatile SecurityEngineRegisters *SE, DoneHandler handler);
 

libraries/libexosphere/source/se/se_oaep.cpp

@@ -0,0 +1,122 @@
+/*
+ * Copyright (c) 2018-2020 Atmosphère-NX
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
+ * more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+#include <exosphere.hpp>
+#include "se_execute.hpp"
+
+namespace ams::se {
+
+    /* NOTE: This implementation is mostly copy/pasted from crypto::impl::RsaOaepImpl. */
+
+    namespace {
+
+        constexpr inline size_t HashSize = sizeof(Sha256Hash);
+
+        constexpr inline u8 HeadMagic = 0x00;
+
+        void ApplyMGF1(u8 *dst, size_t dst_size, const void *src, size_t src_size) {
+            /* Check our pre-conditions. */
+            AMS_ABORT_UNLESS(src_size <= RsaSize - (1 + HashSize));
+
+            /* Create a buffer. */
+            util::AlignedBuffer<hw::DataCacheLineSize, RsaSize - (1 + HashSize) + sizeof(u32)> buf;
+            u32 counter = 0;
+
+            while (dst_size > 0) {
+                /* Setup the current hash buffer. */
+                const size_t cur_size = std::min(HashSize, dst_size);
+                std::memcpy(static_cast<u8 *>(buf), src, src_size);
+                {
+                    u32 counter_be;
+                    util::StoreBigEndian(std::addressof(counter_be), counter++);
+                    std::memcpy(static_cast<u8 *>(buf) + src_size, std::addressof(counter_be), sizeof(counter_be));
+                }
+
+                /* Ensure se sees correct data. */
+                hw::FlushDataCache(buf, src_size + sizeof(u32));
+                hw::DataSynchronizationBarrierInnerShareable();
+
+                /* Calculate the hash. */
+                Sha256Hash hash;
+                se::CalculateSha256(std::addressof(hash), buf, src_size + sizeof(u32));
+
+                /* Mask the current output. */
+                const u8 *mask = hash.bytes;
+                for (size_t i = 0; i < cur_size; ++i) {
+                    *(dst++) ^= *(mask++);
+                }
+
+                /* Advance. */
+                dst_size -= cur_size;
+            }
+        }
+
+    }
+
+    size_t DecodeRsaOaepSha256(void *dst, size_t dst_size, void *src, size_t src_size, const void *label_digest, size_t label_digest_size) {
+        /* Check our preconditions. */
+        AMS_ABORT_UNLESS(src_size == RsaSize);
+        AMS_ABORT_UNLESS(label_digest_size == HashSize);
+
+        /* Get a byte-readable copy of the input. */
+        u8 *buf = static_cast<u8 *>(src);
+
+        /* Validate sanity byte. */
+        bool is_valid = buf[0] == HeadMagic;
+
+        /* Decrypt seed and masked db. */
+        size_t db_len = src_size - HashSize - 1;
+        u8 *seed = buf + 1;
+        u8 *db   = seed + HashSize;
+        ApplyMGF1(seed, HashSize, db, db_len);
+        ApplyMGF1(db, db_len, seed, HashSize);
+
+        /* Check the label digest. */
+        is_valid &= crypto::IsSameBytes(label_digest, db, HashSize);
+
+        /* Skip past the label digest. */
+        db     += HashSize;
+        db_len -= HashSize;
+
+        /* Verify that DB is of the form 0000...0001 < message > */
+        s32 msg_ofs = 0;
+        {
+            int looking_for_one = 1;
+            int invalid_db_padding = 0;
+            int is_zero;
+            int is_one;
+            for (size_t i = 0; i < db_len; /* ... */) {
+                is_zero = (db[i] == 0);
+                is_one  = (db[i] == 1);
+                msg_ofs += (looking_for_one & is_one) * (static_cast<s32>(++i));
+                looking_for_one &= ~is_one;
+                invalid_db_padding |= (looking_for_one & ~is_zero);
+            }
+
+            is_valid &= (invalid_db_padding == 0);
+        }
+
+        /* If we're invalid, return zero size. */
+        const size_t valid_msg_size = db_len - msg_ofs;
+        const size_t msg_size       = std::min(dst_size, static_cast<size_t>(is_valid) * valid_msg_size);
+
+        /* Copy to output. */
+        std::memcpy(dst, db + msg_ofs, msg_size);
+
+        /* Return copied size. */
+        return msg_size;
+    }
+
+}

libraries/libexosphere/source/se/se_rsa.cpp

@@ -67,6 +67,10 @@ namespace ams::se {
             }
         }
 
+        void WaitForInputReadComplete(volatile SecurityEngineRegisters *SE) {
+            while (reg::HasValue(SE->SE_INT_STATUS, SE_REG_BITS_ENUM(INT_STATUS_IN_DONE, CLEAR))) { /* ... */ }
+        }
+
     }
 
     void ClearRsaKeySlot(int slot) {
@@ -174,4 +178,53 @@ namespace ams::se {
         GetRsaResult(SE, dst, dst_size);
     }
 
+    void ModularExponentiateAsync(int slot, const void *src, size_t src_size, DoneHandler handler) {
+        /* Validate the slot and size. */
+        AMS_ABORT_UNLESS(0 <= slot && slot < RsaKeySlotCount);
+        AMS_ABORT_UNLESS(src_size <= RsaSize);
+
+        /* Get the engine. */
+        auto *SE = GetRegisters();
+
+        /* Create a work buffer. */
+        u8 work[RsaSize];
+        util::ClearMemory(work, sizeof(work));
+
+        /* Copy the input into the work buffer (reversing endianness). */
+        const u8 *src_u8 = static_cast<const u8 *>(src);
+        for (size_t i = 0; i < src_size; ++i) {
+            work[src_size - 1 - i] = src_u8[i];
+        }
+
+        /* Flush the work buffer to ensure the SE sees correct results. */
+        hw::FlushDataCache(work, sizeof(work));
+        hw::DataSynchronizationBarrierInnerShareable();
+
+        /* Configure the engine to perform RSA encryption. */
+        reg::Write(SE->SE_CONFIG, SE_REG_BITS_ENUM(CONFIG_ENC_MODE, AESMODE_KEY128),
+                                  SE_REG_BITS_ENUM(CONFIG_DEC_MODE, AESMODE_KEY128),
+                                  SE_REG_BITS_ENUM(CONFIG_ENC_ALG,             RSA),
+                                  SE_REG_BITS_ENUM(CONFIG_DEC_ALG,             NOP),
+                                  SE_REG_BITS_ENUM(CONFIG_DST,             RSA_REG));
+
+        /* Configure the engine to use the keyslot and correct modulus/exp sizes. */
+        const auto &info = g_rsa_key_infos[slot];
+        reg::Write(SE->SE_RSA_CONFIG, SE_REG_BITS_VALUE(RSA_CONFIG_KEY_SLOT, slot));
+        reg::Write(SE->SE_RSA_KEY_SIZE, info.modulus_size_val);
+        reg::Write(SE->SE_RSA_EXP_SIZE, info.exponent_size_val);
+
+        /* Set the done handler. */
+        SetDoneHandler(SE, handler);
+
+        /* Trigger the input operation. */
+        StartInputOperation(SE, work, src_size);
+
+        /* Wait for input to be read by the se. */
+        WaitForInputReadComplete(SE);
+    }
+
+    void GetRsaResult(void *dst, size_t dst_size) {
+        GetRsaResult(GetRegisters(), dst, dst_size);
+    }
+
 }