exo2: implement SmcPrepareEsDeviceUniqueKey, SmcPrepareEsCommonTitleKey, SmcLoadPreparedAesKey

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);
+    }
+
 }