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| 1 // Copyright 2016 The Chromium Authors. All rights reserved. |
| 2 // Use of this source code is governed by a BSD-style license that can be |
| 3 // found in the LICENSE file. |
| 4 |
| 5 #include "net/http2/decoder/http2_structure_decoder.h" |
| 6 |
| 7 #include <algorithm> |
| 8 |
| 9 #include "net/http2/tools/http2_bug_tracker.h" |
| 10 |
| 11 namespace net { |
| 12 |
| 13 // Below we have some defensive coding: if we somehow run off the end, don't |
| 14 // overwrite lots of memory. Note that most of this decoder is not defensive |
| 15 // against bugs in the decoder, only against malicious encoders, but since |
| 16 // we're copying memory into a buffer here, let's make sure we don't allow a |
| 17 // small mistake to grow larger. The decoder will get stuck if we hit the |
| 18 // HTTP2_BUG conditions, but shouldn't corrupt memory. |
| 19 |
| 20 uint32_t Http2StructureDecoder::IncompleteStart(DecodeBuffer* db, |
| 21 uint32_t target_size) { |
| 22 if (target_size > sizeof buffer_) { |
| 23 HTTP2_BUG << "target_size too large for buffer: " << target_size; |
| 24 return 0; |
| 25 } |
| 26 const uint32_t num_to_copy = db->MinLengthRemaining(target_size); |
| 27 memcpy(buffer_, db->cursor(), num_to_copy); |
| 28 offset_ = num_to_copy; |
| 29 db->AdvanceCursor(num_to_copy); |
| 30 return num_to_copy; |
| 31 } |
| 32 |
| 33 DecodeStatus Http2StructureDecoder::IncompleteStart(DecodeBuffer* db, |
| 34 uint32_t* remaining_payload, |
| 35 uint32_t target_size) { |
| 36 DVLOG(1) << "IncompleteStart@" << this |
| 37 << ": *remaining_payload=" << *remaining_payload |
| 38 << "; target_size=" << target_size |
| 39 << "; db->Remaining=" << db->Remaining(); |
| 40 *remaining_payload -= |
| 41 IncompleteStart(db, std::min(target_size, *remaining_payload)); |
| 42 if (*remaining_payload > 0 && db->Empty()) { |
| 43 return DecodeStatus::kDecodeInProgress; |
| 44 } |
| 45 DVLOG(1) << "IncompleteStart: kDecodeError"; |
| 46 return DecodeStatus::kDecodeError; |
| 47 } |
| 48 |
| 49 bool Http2StructureDecoder::ResumeFillingBuffer(DecodeBuffer* db, |
| 50 uint32_t target_size) { |
| 51 DVLOG(2) << "ResumeFillingBuffer@" << this << ": target_size=" << target_size |
| 52 << "; offset_=" << offset_ << "; db->Remaining=" << db->Remaining(); |
| 53 if (target_size < offset_) { |
| 54 HTTP2_BUG << "Already filled buffer_! target_size=" << target_size |
| 55 << " offset_=" << offset_; |
| 56 return false; |
| 57 } |
| 58 const uint32_t needed = target_size - offset_; |
| 59 const uint32_t num_to_copy = db->MinLengthRemaining(needed); |
| 60 DVLOG(2) << "ResumeFillingBuffer num_to_copy=" << num_to_copy; |
| 61 memcpy(&buffer_[offset_], db->cursor(), num_to_copy); |
| 62 db->AdvanceCursor(num_to_copy); |
| 63 offset_ += num_to_copy; |
| 64 return needed == num_to_copy; |
| 65 } |
| 66 |
| 67 bool Http2StructureDecoder::ResumeFillingBuffer(DecodeBuffer* db, |
| 68 uint32_t* remaining_payload, |
| 69 uint32_t target_size) { |
| 70 DVLOG(2) << "ResumeFillingBuffer@" << this << ": target_size=" << target_size |
| 71 << "; offset_=" << offset_ |
| 72 << "; *remaining_payload=" << *remaining_payload |
| 73 << "; db->Remaining=" << db->Remaining(); |
| 74 if (target_size < offset_) { |
| 75 HTTP2_BUG << "Already filled buffer_! target_size=" << target_size |
| 76 << " offset_=" << offset_; |
| 77 return false; |
| 78 } |
| 79 const uint32_t needed = target_size - offset_; |
| 80 const uint32_t num_to_copy = |
| 81 db->MinLengthRemaining(std::min(needed, *remaining_payload)); |
| 82 DVLOG(2) << "ResumeFillingBuffer num_to_copy=" << num_to_copy; |
| 83 memcpy(&buffer_[offset_], db->cursor(), num_to_copy); |
| 84 db->AdvanceCursor(num_to_copy); |
| 85 offset_ += num_to_copy; |
| 86 *remaining_payload -= num_to_copy; |
| 87 return needed == num_to_copy; |
| 88 } |
| 89 |
| 90 } // namespace net |
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