/*
* 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 "ldr_capabilities.hpp"
#include "ldr_content_management.hpp"
#include "ldr_development_manager.hpp"
#include "ldr_meta.hpp"
namespace ams::ldr {
namespace {
/* Convenience definitions. */
constexpr size_t MetaCacheBufferSize = 0x8000;
constexpr inline const char AtmosphereMetaPath[] = ENCODE_ATMOSPHERE_CODE_PATH("/main.npdm");
constexpr inline const char SdOrBaseMetaPath[] = ENCODE_SD_OR_CODE_PATH("/main.npdm");
constexpr inline const char BaseMetaPath[] = ENCODE_CODE_PATH("/main.npdm");
/* Types. */
struct MetaCache {
Meta meta;
u8 buffer[MetaCacheBufferSize];
};
/* Global storage. */
ncm::ProgramId g_cached_program_id;
cfg::OverrideStatus g_cached_override_status;
MetaCache g_meta_cache;
MetaCache g_original_meta_cache;
/* Helpers. */
Result ValidateSubregion(size_t allowed_start, size_t allowed_end, size_t start, size_t size, size_t min_size = 0) {
R_UNLESS(size >= min_size, ResultInvalidMeta());
R_UNLESS(allowed_start <= start, ResultInvalidMeta());
R_UNLESS(start <= allowed_end, ResultInvalidMeta());
R_UNLESS(start + size <= allowed_end, ResultInvalidMeta());
return ResultSuccess();
}
Result ValidateNpdm(const Npdm *npdm, size_t size) {
/* Validate magic. */
R_UNLESS(npdm->magic == Npdm::Magic, ResultInvalidMeta());
/* Validate flags. */
u32 mask = ~0x1F;
if (hos::GetVersion() < hos::Version_7_0_0) {
/* 7.0.0 added 0x10 as a valid bit to NPDM flags, so before that we only check 0xF. */
mask = ~0xF;
}
R_UNLESS(!(npdm->flags & mask), ResultInvalidMeta());
/* Validate Acid extents. */
R_TRY(ValidateSubregion(sizeof(Npdm), size, npdm->acid_offset, npdm->acid_size, sizeof(Acid)));
/* Validate Aci extends. */
R_TRY(ValidateSubregion(sizeof(Npdm), size, npdm->aci_offset, npdm->aci_size, sizeof(Aci)));
return ResultSuccess();
}
Result ValidateAcid(const Acid *acid, size_t size) {
/* Validate magic. */
R_UNLESS(acid->magic == Acid::Magic, ResultInvalidMeta());
/* Validate that the acid is for production if not development. */
if (!IsDevelopmentForAcidProductionCheck()) {
R_UNLESS((acid->flags & Acid::AcidFlag_Production) != 0, ResultInvalidMeta());
}
/* Validate Fac, Sac, Kac. */
R_TRY(ValidateSubregion(sizeof(Acid), size, acid->fac_offset, acid->fac_size));
R_TRY(ValidateSubregion(sizeof(Acid), size, acid->sac_offset, acid->sac_size));
R_TRY(ValidateSubregion(sizeof(Acid), size, acid->kac_offset, acid->kac_size));
return ResultSuccess();
}
Result ValidateAci(const Aci *aci, size_t size) {
/* Validate magic. */
R_UNLESS(aci->magic == Aci::Magic, ResultInvalidMeta());
/* Validate Fah, Sac, Kac. */
R_TRY(ValidateSubregion(sizeof(Aci), size, aci->fah_offset, aci->fah_size));
R_TRY(ValidateSubregion(sizeof(Aci), size, aci->sac_offset, aci->sac_size));
R_TRY(ValidateSubregion(sizeof(Aci), size, aci->kac_offset, aci->kac_size));
return ResultSuccess();
}
const u8 *GetAcidSignatureModulus(u32 key_generation) {
AMS_ASSERT(key_generation <= fssystem::AcidSignatureKeyGenerationMax);
const u32 used_keygen = (key_generation % (fssystem::AcidSignatureKeyGenerationMax + 1));
if (IsDevelopmentForAcidSignatureCheck()) {
return fssystem::AcidSignatureKeyModulusDev[used_keygen];
} else {
return fssystem::AcidSignatureKeyModulusProd[used_keygen];
}
}
Result ValidateAcidSignature(Meta *meta) {
/* Loader did not check signatures prior to 10.0.0. */
if (hos::GetVersion() < hos::Version_10_0_0) {
meta->is_signed = false;
return ResultSuccess();
}
/* Verify the signature. */
const u8 *sig = meta->acid->signature;
const size_t sig_size = sizeof(meta->acid->signature);
const u8 *mod = GetAcidSignatureModulus(meta->npdm->signature_key_generation);
const size_t mod_size = fssystem::AcidSignatureKeyModulusSize;
const u8 *exp = fssystem::AcidSignatureKeyExponent;
const size_t exp_size = fssystem::AcidSignatureKeyExponentSize;
const u8 *msg = meta->acid->modulus;
const size_t msg_size = meta->acid->size;
const bool is_signature_valid = crypto::VerifyRsa2048PssSha256(sig, sig_size, mod, mod_size, exp, exp_size, msg, msg_size);
R_UNLESS(is_signature_valid || !IsEnabledProgramVerification(), ResultInvalidAcidSignature());
meta->is_signed = is_signature_valid;
return ResultSuccess();
}
Result LoadMetaFromFile(fs::FileHandle file, MetaCache *cache) {
/* Reset cache. */
cache->meta = {};
/* Read from file. */
s64 npdm_size = 0;
{
/* Get file size. */
R_TRY(fs::GetFileSize(std::addressof(npdm_size), file));
/* Read data into cache buffer. */
R_UNLESS(npdm_size <= static_cast<s64>(MetaCacheBufferSize), ResultTooLargeMeta());
R_TRY(fs::ReadFile(file, 0, cache->buffer, npdm_size));
}
/* Ensure size is big enough. */
R_UNLESS(npdm_size >= static_cast<s64>(sizeof(Npdm)), ResultInvalidMeta());
/* Validate the meta. */
{
Meta *meta = &cache->meta;
Npdm *npdm = reinterpret_cast<Npdm *>(cache->buffer);
R_TRY(ValidateNpdm(npdm, npdm_size));
Acid *acid = reinterpret_cast<Acid *>(cache->buffer + npdm->acid_offset);
Aci *aci = reinterpret_cast<Aci *>(cache->buffer + npdm->aci_offset);
R_TRY(ValidateAcid(acid, npdm->acid_size));
R_TRY(ValidateAci(aci, npdm->aci_size));
/* Set Meta members. */
meta->npdm = npdm;
meta->acid = acid;
meta->aci = aci;
meta->acid_fac = reinterpret_cast<u8 *>(acid) + acid->fac_offset;
meta->acid_sac = reinterpret_cast<u8 *>(acid) + acid->sac_offset;
meta->acid_kac = reinterpret_cast<u8 *>(acid) + acid->kac_offset;
meta->aci_fah = reinterpret_cast<u8 *>(aci) + aci->fah_offset;
meta->aci_sac = reinterpret_cast<u8 *>(aci) + aci->sac_offset;
meta->aci_kac = reinterpret_cast<u8 *>(aci) + aci->kac_offset;
meta->modulus = acid->modulus;
}
return ResultSuccess();
}
}
/* API. */
Result LoadMeta(Meta *out_meta, const ncm::ProgramLocation &loc, const cfg::OverrideStatus &status) {
/* Try to load meta from file. */
fs::FileHandle file;
R_TRY(fs::OpenFile(std::addressof(file), AtmosphereMetaPath, fs::OpenMode_Read));
{
ON_SCOPE_EXIT { fs::CloseFile(file); };
R_TRY(LoadMetaFromFile(file, &g_meta_cache));
}
/* Patch meta. Start by setting all program ids to the current program id. */
Meta *meta = &g_meta_cache.meta;
meta->acid->program_id_min = loc.program_id;
meta->acid->program_id_max = loc.program_id;
meta->aci->program_id = loc.program_id;
/* For HBL, we need to copy some information from the base meta. */
if (status.IsHbl()) {
if (R_SUCCEEDED(fs::OpenFile(std::addressof(file), SdOrBaseMetaPath, fs::OpenMode_Read))) {
ON_SCOPE_EXIT { fs::CloseFile(file); };
if (R_SUCCEEDED(LoadMetaFromFile(file, &g_original_meta_cache))) {
Meta *o_meta = &g_original_meta_cache.meta;
/* Fix pool partition. */
if (hos::GetVersion() >= hos::Version_5_0_0) {
meta->acid->flags = (meta->acid->flags & 0xFFFFFFC3) | (o_meta->acid->flags & 0x0000003C);
}
/* Fix flags. */
const u16 program_info_flags = caps::GetProgramInfoFlags(o_meta->aci_kac, o_meta->aci->kac_size);
caps::SetProgramInfoFlags(program_info_flags, meta->acid_kac, meta->acid->kac_size);
caps::SetProgramInfoFlags(program_info_flags, meta->aci_kac, meta->aci->kac_size);
}
}
} else if (hos::GetVersion() >= hos::Version_10_0_0) {
/* If storage id is none, there is no base code filesystem, and thus it is impossible for us to validate. */
if (static_cast<ncm::StorageId>(loc.storage_id) != ncm::StorageId::None) {
R_TRY(fs::OpenFile(std::addressof(file), BaseMetaPath, fs::OpenMode_Read));
ON_SCOPE_EXIT { fs::CloseFile(file); };
R_TRY(LoadMetaFromFile(file, &g_original_meta_cache));
R_TRY(ValidateAcidSignature(&g_original_meta_cache.meta));
meta->modulus = g_original_meta_cache.meta.modulus;
meta->is_signed = g_original_meta_cache.meta.is_signed;
}
}
/* Set output. */
g_cached_program_id = loc.program_id;
g_cached_override_status = status;
*out_meta = *meta;
return ResultSuccess();
}
Result LoadMetaFromCache(Meta *out_meta, const ncm::ProgramLocation &loc, const cfg::OverrideStatus &status) {
if (g_cached_program_id != loc.program_id || g_cached_override_status != status) {
return LoadMeta(out_meta, loc, status);
}
*out_meta = g_meta_cache.meta;
return ResultSuccess();
}
void InvalidateMetaCache() {
/* Set the cached program id back to zero. */
g_cached_program_id = {};
}
}