Index: net/quic/crypto/strike_register.h |
diff --git a/net/quic/crypto/strike_register.h b/net/quic/crypto/strike_register.h |
deleted file mode 100644 |
index 9d7431bfd058cbbd2a8f8366e5444c0d22616a4b..0000000000000000000000000000000000000000 |
--- a/net/quic/crypto/strike_register.h |
+++ /dev/null |
@@ -1,223 +0,0 @@ |
-// Copyright (c) 2013 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. |
- |
-#ifndef NET_QUIC_CRYPTO_STRIKE_REGISTER_H_ |
-#define NET_QUIC_CRYPTO_STRIKE_REGISTER_H_ |
- |
-#include <stdint.h> |
- |
-#include <memory> |
-#include <set> |
-#include <utility> |
-#include <vector> |
- |
-#include "base/macros.h" |
-#include "net/base/net_export.h" |
- |
-namespace net { |
- |
-// InsertStatus enum values cannot be changed, they need to be stable. |
-enum InsertStatus { |
- NONCE_OK = 0, |
- // The default error value for nonce verification failures from strike |
- // register (covers old strike registers and unknown failures). |
- NONCE_UNKNOWN_FAILURE = 1, |
- // Decrypted nonce had incorrect length. |
- NONCE_INVALID_FAILURE = 2, |
- // Nonce is not unique. |
- NONCE_NOT_UNIQUE_FAILURE = 3, |
- // Nonce's orbit is invalid or incorrect. |
- NONCE_INVALID_ORBIT_FAILURE = 4, |
- // Nonce's timestamp is not in the strike register's valid time range. |
- NONCE_INVALID_TIME_FAILURE = 5, |
- // Strike register's RPC call timed out, nonce couldn't be verified. |
- STRIKE_REGISTER_TIMEOUT = 6, |
- // Strike register is down, nonce couldn't be verified. |
- STRIKE_REGISTER_FAILURE = 7, |
-}; |
- |
-// A StrikeRegister is critbit tree which stores a set of observed nonces. |
-// We use a critbit tree because: |
-// 1) It's immune to algorithmic complexity attacks. If we had used a hash |
-// tree, an attacker could send us a series of values which stretch out one |
-// of the hash chains, causing us to do much more work than normal. |
-// 2) We can write it to use a fixed block of memory: avoiding fragmentation |
-// issues and so forth. (We might be able to do that with the STL |
-// algorithms and a custom allocator, but I don't want to go there.) |
-// 3) It's simple (compared to balanced binary trees) and doesn't involve |
-// bouncing nearly as many cache lines around. |
-// 4) It allows us to query for the oldest element in log(n) time. |
-// |
-// This code is based on djb's public domain critbit tree from qhasm. |
-// |
-// A critbit tree has external and internal nodes. External nodes are just the |
-// nonce values (which are stored with internal times, see below, and without |
-// the orbit values included). Internal nodes contain the bit number at which |
-// the tree is branching and exactly two children. The critical bit is stored |
-// as a byte number and a byte (|otherbits|) which has all the bits set |
-// /except/ the one in question. |
-// |
-// Internal nodes have exactly two children: an internal node with only a |
-// single child would be useless. |
-// |
-// The branching bit number (considering the MSB to be the 1st bit) is |
-// monotonically increasing as you go down the tree. |
-// |
-// There are two distinct time representations used. External times are those |
-// which are exposed to the users of this class. They are expected to be a |
-// count of the number of seconds since the UNIX epoch. Internal times are a |
-// count of the number of seconds since a point in time a couple of years |
-// before the creation time given to the constructor. (See |
-// |ExternalTimeToInternal|) This avoids having to worry about overflow since |
-// we assume that no process will run for 130 years. |
-class NET_EXPORT_PRIVATE StrikeRegister { |
- public: |
- enum StartupType { |
- // DENY_REQUESTS_AT_STARTUP is the typical mode for a strike register. |
- // Because servers can crash and the strike-register memory-based, the |
- // state of the strike-register may be lost at any time. Thus the previous |
- // instance of the server may have accepted an nonce with time |
- // now+window_secs, which was forgotten in the crash. Therefore |
- // DENY_REQUESTS_AT_STARTUP causes the strike-register to reject all |
- // requests timestampped before window_secs + the creation time (the |
- // quiescent period). |
- DENY_REQUESTS_AT_STARTUP, |
- // NO_STARTUP_PERIOD_NEEDED indicates that no quiescent period is required. |
- // This may be because the strike-register is using an orbit randomly |
- // generated at startup and therefore nonces accepted by the previous |
- // instance of the strike-register are invalid for that reason. |
- NO_STARTUP_PERIOD_NEEDED, |
- }; |
- |
- // An external node takes 24 bytes as we don't record the orbit. |
- static const uint32_t kExternalNodeSize; |
- |
- // We address the nodes by their index in the array. This means that 0 is a |
- // valid index. Therefore this is our invalid index. It also has a one bit |
- // in the LSB position because we tend to store indexes shifted up 8 bits |
- // and this distinguishes kNil from (kExternalFlag | 0) << 8. |
- static const uint32_t kNil; |
- |
- // Our pointers from internal nodes can either point to an internal or |
- // external node. We flag the 24th bit to mark a pointer as external. |
- static const uint32_t kExternalFlag; |
- |
- // Allows early validation before a strike register is created. |
- static void ValidateStrikeRegisterConfig(unsigned max_entries); |
- |
- // Construct a new set which can hold, at most, |max_entries| (which must be |
- // less than 2**23). See the comments around StartupType about initial |
- // behaviour. Otherwise, all nonces that are outside +/- |window_secs| from |
- // the current time will be rejected. Additionally, all nonces that have an |
- // orbit value other than |orbit| will be rejected. |
- // |
- // (Note that this code is independent of the actual units of time used, but |
- // you should use seconds.) |
- StrikeRegister(unsigned max_entries, |
- uint32_t current_time_external, |
- uint32_t window_secs, |
- const uint8_t orbit[8], |
- StartupType startup); |
- |
- ~StrikeRegister(); |
- |
- void Reset(); |
- |
- // |Insert| queries to see if |nonce| is |
- // a) for the wrong orbit |
- // b) before the current horizon |
- // c) outside of the valid time window |
- // d) already in the set of observed nonces |
- // and returns the failure reason if any of these are true. It is also free to |
- // return failure reason for other reasons as it's always safe to reject an |
- // nonce. |
- // |
- // nonces are: |
- // 4 bytes of timestamp (UNIX epoch seconds) |
- // 8 bytes of orbit value (a cluster id) |
- // 20 bytes of random data |
- // |
- // Otherwise, it inserts |nonce| into the observed set and returns NONCE_OK. |
- InsertStatus Insert(const uint8_t nonce[32], uint32_t current_time); |
- |
- // orbit returns a pointer to the 8-byte orbit value for this |
- // strike-register. |
- const uint8_t* orbit() const; |
- |
- // Time window for which the strike register has complete information. |
- uint32_t GetCurrentValidWindowSecs(uint32_t current_time_external) const; |
- |
- // This is a debugging aid which checks the tree for sanity. |
- void Validate(); |
- |
- private: |
- class InternalNode; |
- |
- // TimeFromBytes returns a big-endian uint32_t from |d|. |
- static uint32_t TimeFromBytes(const uint8_t d[4]); |
- |
- // Range of internal times for which the strike register has |
- // complete information. A nonce is within the valid range of the |
- // strike register if: |
- // valid_range.first <= nonce_time_internal <= valid_range.second |
- std::pair<uint32_t, uint32_t> GetValidRange( |
- uint32_t current_time_internal) const; |
- |
- // ExternalTimeToInternal converts an external time value into an internal |
- // time value using |internal_epoch_|. |
- uint32_t ExternalTimeToInternal(uint32_t external_time) const; |
- |
- // BestMatch returns either kNil, or an external node index which could |
- // possibly match |v|. |
- uint32_t BestMatch(const uint8_t v[24]) const; |
- |
- // external_node_next_ptr returns the 'next' pointer embedded in external |
- // node |i|. This is used to thread a free list through the external nodes. |
- uint32_t& external_node_next_ptr(unsigned i); |
- |
- uint8_t* external_node(unsigned i); |
- |
- uint32_t GetFreeExternalNode(); |
- |
- uint32_t GetFreeInternalNode(); |
- |
- // DropOldestNode removes the oldest node in the tree and updates |horizon_| |
- // accordingly. |
- void DropOldestNode(); |
- |
- void FreeExternalNode(uint32_t index); |
- |
- void FreeInternalNode(uint32_t index); |
- |
- void ValidateTree(uint32_t internal_node, |
- int last_bit, |
- const std::vector<std::pair<unsigned, bool>>& bits, |
- const std::set<uint32_t>& free_internal_nodes, |
- const std::set<uint32_t>& free_external_nodes, |
- std::set<uint32_t>* used_internal_nodes, |
- std::set<uint32_t>* used_external_nodes); |
- |
- const uint32_t max_entries_; |
- const uint32_t window_secs_; |
- // internal_epoch_ contains the external time value of the start of internal |
- // time. |
- const uint32_t internal_epoch_; |
- uint8_t orbit_[8]; |
- // The strike register will reject nonces with internal times < |horizon_| . |
- uint32_t horizon_; |
- |
- uint32_t internal_node_free_head_; |
- uint32_t external_node_free_head_; |
- uint32_t internal_node_head_; |
- // internal_nodes_ can't be a scoped_ptr because the type isn't defined in |
- // this header. |
- InternalNode* internal_nodes_; |
- std::unique_ptr<uint8_t[]> external_nodes_; |
- |
- DISALLOW_COPY_AND_ASSIGN(StrikeRegister); |
-}; |
- |
-} // namespace net |
- |
-#endif // NET_QUIC_CRYPTO_STRIKE_REGISTER_H_ |