mirror of
https://github.com/Atmosphere-NX/Atmosphere
synced 2024-12-26 22:51:12 +00:00
120 lines
4.4 KiB
C++
120 lines
4.4 KiB
C++
/*
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* Copyright (c) 2018-2020 Atmosphère-NX
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*
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* This program is free software; you can redistribute it and/or modify it
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* under the terms and conditions of the GNU General Public License,
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* version 2, as published by the Free Software Foundation.
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*
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* This program is distributed in the hope it will be useful, but WITHOUT
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
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* more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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#include "fsmitm_boot0storage.hpp"
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namespace ams::mitm::fs {
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using namespace ams::fs;
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namespace {
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os::Mutex g_boot0_access_mutex(false);
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u8 g_boot0_bct_buffer[Boot0Storage::BctEndOffset];
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}
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bool Boot0Storage::CanModifyBctPublicKey() {
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if (exosphere::IsRcmBugPatched()) {
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/* RCM bug patched. */
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/* Only allow NS to update the BCT pubks. */
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/* AutoRCM on a patched unit will cause a brick, so homebrew should NOT be allowed to write. */
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return this->client_info.program_id == ncm::SystemProgramId::Ns;
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} else {
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/* RCM bug unpatched. */
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/* Allow homebrew but not NS to update the BCT pubks. */
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return this->client_info.override_status.IsHbl();
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}
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}
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Result Boot0Storage::Read(s64 offset, void *_buffer, size_t size) {
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std::scoped_lock lk{g_boot0_access_mutex};
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/* Check if we have nothing to do. */
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if (size == 0) {
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return ResultSuccess();
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}
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return Base::Read(offset, _buffer, size);
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}
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Result Boot0Storage::Write(s64 offset, const void *_buffer, size_t size) {
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std::scoped_lock lk{g_boot0_access_mutex};
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const u8 *buffer = static_cast<const u8 *>(_buffer);
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/* Check if we have nothing to do. */
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if (size == 0) {
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return ResultSuccess();
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}
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/* Protect the EKS region from writes. */
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if (offset <= EksStart) {
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if (offset + size < EksStart) {
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/* Fall through, no need to do anything here. */
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} else {
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if (offset + size > EksEnd) {
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/* Perform portion of write falling past end of keyblobs. */
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const s64 diff = EksEnd - offset;
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R_TRY(Base::Write(EksEnd, buffer + diff, size - diff));
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}
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/* Adjust size to avoid writing end of data. */
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size = EksStart - offset;
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}
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} else if (offset < EksEnd) {
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if (offset + size <= EksEnd) {
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/* Ignore writes falling strictly within the region. */
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return ResultSuccess();
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} else {
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/* Only write past the end of the region. */
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const s64 diff = EksEnd - offset;
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buffer += diff;
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size -= diff;
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offset = EksEnd;
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}
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}
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/* If we have nothing to write, succeed immediately. */
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if (size == 0) {
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return ResultSuccess();
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}
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/* We want to protect AutoRCM from NS on ipatched units. If we can modify bct pubks or we're not touching any of them, proceed. */
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if (this->CanModifyBctPublicKey() || offset >= BctEndOffset || (util::AlignUp(offset, BctSize) >= BctEndOffset && (offset % BctSize) >= BctPubkEnd)) {
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return Base::Write(offset, buffer, size);
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}
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/* Handle any data written past the end of the pubk region. */
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if (offset + size > BctEndOffset) {
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const u64 diff = BctEndOffset - offset;
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R_TRY(Base::Write(BctEndOffset, buffer + diff, size - diff));
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size = diff;
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}
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/* Read in the current BCT region. */
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R_TRY(Base::Read(0, g_boot0_bct_buffer, BctEndOffset));
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/* Update the bct buffer. */
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for (u64 cur_offset = offset; cur_offset < BctEndOffset && cur_offset < offset + size; cur_offset++) {
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const u64 cur_bct_relative_ofs = cur_offset % BctSize;
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if (cur_bct_relative_ofs < BctPubkStart || BctPubkEnd <= cur_bct_relative_ofs) {
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g_boot0_bct_buffer[cur_offset] = buffer[cur_offset - offset];
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}
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}
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return Base::Write(0, g_boot0_bct_buffer, BctEndOffset);
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}
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}
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