blob: 0569c984d0e81d5889630673fc7acf89840fad44 [file] [log] [blame]
// Copyright 2016 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "quiche/http2/decoder/http2_structure_decoder.h"
#include <algorithm>
#include <cstring>
#include "quiche/common/platform/api/quiche_bug_tracker.h"
namespace http2 {
// Below we have some defensive coding: if we somehow run off the end, don't
// overwrite lots of memory. Note that most of this decoder is not defensive
// against bugs in the decoder, only against malicious encoders, but since
// we're copying memory into a buffer here, let's make sure we don't allow a
// small mistake to grow larger. The decoder will get stuck if we hit the
// QUICHE_BUG conditions, but shouldn't corrupt memory.
uint32_t Http2StructureDecoder::IncompleteStart(DecodeBuffer* db,
uint32_t target_size) {
if (target_size > sizeof buffer_) {
QUICHE_BUG(http2_bug_154_1)
<< "target_size too large for buffer: " << target_size;
return 0;
}
const uint32_t num_to_copy = db->MinLengthRemaining(target_size);
memcpy(buffer_, db->cursor(), num_to_copy);
offset_ = num_to_copy;
db->AdvanceCursor(num_to_copy);
return num_to_copy;
}
DecodeStatus Http2StructureDecoder::IncompleteStart(DecodeBuffer* db,
uint32_t* remaining_payload,
uint32_t target_size) {
QUICHE_DVLOG(1) << "IncompleteStart@" << this
<< ": *remaining_payload=" << *remaining_payload
<< "; target_size=" << target_size
<< "; db->Remaining=" << db->Remaining();
*remaining_payload -=
IncompleteStart(db, std::min(target_size, *remaining_payload));
if (*remaining_payload > 0 && db->Empty()) {
return DecodeStatus::kDecodeInProgress;
}
QUICHE_DVLOG(1) << "IncompleteStart: kDecodeError";
return DecodeStatus::kDecodeError;
}
bool Http2StructureDecoder::ResumeFillingBuffer(DecodeBuffer* db,
uint32_t target_size) {
QUICHE_DVLOG(2) << "ResumeFillingBuffer@" << this
<< ": target_size=" << target_size << "; offset_=" << offset_
<< "; db->Remaining=" << db->Remaining();
if (target_size < offset_) {
QUICHE_BUG(http2_bug_154_2)
<< "Already filled buffer_! target_size=" << target_size
<< " offset_=" << offset_;
return false;
}
const uint32_t needed = target_size - offset_;
const uint32_t num_to_copy = db->MinLengthRemaining(needed);
QUICHE_DVLOG(2) << "ResumeFillingBuffer num_to_copy=" << num_to_copy;
memcpy(&buffer_[offset_], db->cursor(), num_to_copy);
db->AdvanceCursor(num_to_copy);
offset_ += num_to_copy;
return needed == num_to_copy;
}
bool Http2StructureDecoder::ResumeFillingBuffer(DecodeBuffer* db,
uint32_t* remaining_payload,
uint32_t target_size) {
QUICHE_DVLOG(2) << "ResumeFillingBuffer@" << this
<< ": target_size=" << target_size << "; offset_=" << offset_
<< "; *remaining_payload=" << *remaining_payload
<< "; db->Remaining=" << db->Remaining();
if (target_size < offset_) {
QUICHE_BUG(http2_bug_154_3)
<< "Already filled buffer_! target_size=" << target_size
<< " offset_=" << offset_;
return false;
}
const uint32_t needed = target_size - offset_;
const uint32_t num_to_copy =
db->MinLengthRemaining(std::min(needed, *remaining_payload));
QUICHE_DVLOG(2) << "ResumeFillingBuffer num_to_copy=" << num_to_copy;
memcpy(&buffer_[offset_], db->cursor(), num_to_copy);
db->AdvanceCursor(num_to_copy);
offset_ += num_to_copy;
*remaining_payload -= num_to_copy;
return needed == num_to_copy;
}
} // namespace http2