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Fix unpickling error handling.

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This commit is contained in:
Denis Kasak 2021-07-06 12:36:39 +02:00 committed by Hubert Chathi
parent 34974551ab
commit bdd73c5c32
12 changed files with 121 additions and 81 deletions
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6
fuzzing/fuzzers/fuzz_unpickle_account.cpp
View file

@ -9,11 +9,7 @@ size_t fuzz_unpickle_account(
std::uint8_t * const pos = reinterpret_cast<std::uint8_t *>(pickled);
std::uint8_t * const end = pos + pickled_length;
/* On success unpickle will return (pos + raw_length). If unpickling
* terminates too soon then it will return a pointer before
* (pos + raw_length). On error unpickle will return (pos + raw_length + 1).
*/
if (end != unpickle(pos, end + 1, object)) {
if (!unpickle(pos, end, object)) {
if (object.last_error == OlmErrorCode::OLM_SUCCESS) {
object.last_error = OlmErrorCode::OLM_CORRUPTED_PICKLE;
}

21
include/olm/pickle.h
View file

@ -15,8 +15,25 @@
#ifndef OLM_PICKLE_H_
#define OLM_PICKLE_H_
#include <stddef.h>
#include <stdint.h>
/* Convenience macro for checking the return value of internal unpickling
* functions and returning early on failure. */
#ifndef UNPICKLE_OK
#define UNPICKLE_OK(x) do { if (!(x)) return NULL; } while(0)
#endif
/* Convenience macro for failing on corrupted pickles from public
* API unpickling functions. */
#define FAIL_ON_CORRUPTED_PICKLE(pos, session) \
do { \
if (!pos) { \
session->last_error = OLM_CORRUPTED_PICKLE; \
return (size_t)-1; \
} \
} while(0)
#ifdef __cplusplus
extern "C" {
#endif
@ -59,7 +76,7 @@ uint8_t * _olm_pickle_ed25519_public_key(
);
/** Unpickle the ed25519 public key. Returns a pointer to the next item in the
* buffer. */
* buffer on success, NULL on error. */
const uint8_t * _olm_unpickle_ed25519_public_key(
const uint8_t *pos, const uint8_t *end,
struct _olm_ed25519_public_key * value
@ -77,7 +94,7 @@ uint8_t * _olm_pickle_ed25519_key_pair(
);
/** Unpickle the ed25519 key pair. Returns a pointer to the next item in the
* buffer. */
* buffer on success, NULL on error. */
const uint8_t * _olm_unpickle_ed25519_key_pair(
const uint8_t *pos, const uint8_t *end,
struct _olm_ed25519_key_pair * value

16
include/olm/pickle.hh
View file

@ -21,6 +21,12 @@
#include <cstring>
#include <cstdint>
/* Convenience macro for checking the return value of internal unpickling
* functions and returning early on failure. */
#ifndef UNPICKLE_OK
#define UNPICKLE_OK(x) do { if (!(x)) return nullptr; } while(0)
#endif
namespace olm {
inline std::size_t pickle_length(
@ -88,11 +94,21 @@ std::uint8_t const * unpickle(
olm::List<T, max_size> & list
) {
std::uint32_t size;
pos = unpickle(pos, end, size);
if (!pos) {
return nullptr;
}
while (size-- && pos != end) {
T * value = list.insert(list.end());
pos = unpickle(pos, end, *value);
if (!pos) {
return nullptr;
}
}
return pos;
}

32
src/account.cpp
View file

@ -382,8 +382,8 @@ static std::uint8_t const * unpickle(
std::uint8_t const * pos, std::uint8_t const * end,
olm::IdentityKeys & value
) {
pos = _olm_unpickle_ed25519_key_pair(pos, end, &value.ed25519_key);
pos = olm::unpickle(pos, end, value.curve25519_key);
pos = _olm_unpickle_ed25519_key_pair(pos, end, &value.ed25519_key); UNPICKLE_OK(pos);
pos = olm::unpickle(pos, end, value.curve25519_key); UNPICKLE_OK(pos);
return pos;
}
@ -414,9 +414,9 @@ static std::uint8_t const * unpickle(
std::uint8_t const * pos, std::uint8_t const * end,
olm::OneTimeKey & value
) {
pos = olm::unpickle(pos, end, value.id);
pos = olm::unpickle(pos, end, value.published);
pos = olm::unpickle(pos, end, value.key);
pos = olm::unpickle(pos, end, value.id); UNPICKLE_OK(pos);
pos = olm::unpickle(pos, end, value.published); UNPICKLE_OK(pos);
pos = olm::unpickle(pos, end, value.key); UNPICKLE_OK(pos);
return pos;
}
@ -463,28 +463,34 @@ std::uint8_t const * olm::unpickle(
olm::Account & value
) {
uint32_t pickle_version;
pos = olm::unpickle(pos, end, pickle_version);
pos = olm::unpickle(pos, end, pickle_version); UNPICKLE_OK(pos);
switch (pickle_version) {
case ACCOUNT_PICKLE_VERSION:
case 2:
break;
case 1:
value.last_error = OlmErrorCode::OLM_BAD_LEGACY_ACCOUNT_PICKLE;
return end;
return nullptr;
default:
value.last_error = OlmErrorCode::OLM_UNKNOWN_PICKLE_VERSION;
return end;
return nullptr;
}
pos = olm::unpickle(pos, end, value.identity_keys);
pos = olm::unpickle(pos, end, value.one_time_keys);
pos = olm::unpickle(pos, end, value.identity_keys); UNPICKLE_OK(pos);
pos = olm::unpickle(pos, end, value.one_time_keys); UNPICKLE_OK(pos);
if (pickle_version == 2) {
// version 2 did not have fallback keys
value.current_fallback_key.published = false;
value.prev_fallback_key.published = false;
} else {
pos = olm::unpickle(pos, end, value.current_fallback_key);
pos = olm::unpickle(pos, end, value.prev_fallback_key);
pos = olm::unpickle(pos, end, value.current_fallback_key); UNPICKLE_OK(pos);
pos = olm::unpickle(pos, end, value.prev_fallback_key); UNPICKLE_OK(pos);
}
pos = olm::unpickle(pos, end, value.next_one_time_key_id);
pos = olm::unpickle(pos, end, value.next_one_time_key_id); UNPICKLE_OK(pos);
return pos;
}

15
src/inbound_group_session.c
View file

@ -246,14 +246,23 @@ size_t olm_unpickle_inbound_group_session(
pos = pickled;
end = pos + raw_length;
pos = _olm_unpickle_uint32(pos, end, &pickle_version);
FAIL_ON_CORRUPTED_PICKLE(pos, session);
if (pickle_version < 1 || pickle_version > PICKLE_VERSION) {
session->last_error = OLM_UNKNOWN_PICKLE_VERSION;
return (size_t)-1;
}
pos = megolm_unpickle(&session->initial_ratchet, pos, end);
FAIL_ON_CORRUPTED_PICKLE(pos, session);
pos = megolm_unpickle(&session->latest_ratchet, pos, end);
FAIL_ON_CORRUPTED_PICKLE(pos, session);
pos = _olm_unpickle_ed25519_public_key(pos, end, &session->signing_key);
FAIL_ON_CORRUPTED_PICKLE(pos, session);
if (pickle_version == 1) {
/* pickle v1 had no signing_key_verified field (all keyshares were
@ -263,11 +272,7 @@ size_t olm_unpickle_inbound_group_session(
pos = _olm_unpickle_bool(pos, end, &(session->signing_key_verified));
}
if (end != pos) {
/* We had the wrong number of bytes in the input. */
session->last_error = OLM_CORRUPTED_PICKLE;
return (size_t)-1;
}
FAIL_ON_CORRUPTED_PICKLE(pos, session);
return pickled_length;
}

4
src/megolm.c
View file

@ -73,7 +73,11 @@ const uint8_t * megolm_unpickle(Megolm *megolm, const uint8_t *pos,
const uint8_t *end) {
pos = _olm_unpickle_bytes(pos, end, (uint8_t *)(megolm->data),
MEGOLM_RATCHET_LENGTH);
UNPICKLE_OK(pos);
pos = _olm_unpickle_uint32(pos, end, &megolm->counter);
UNPICKLE_OK(pos);
return pos;
}

12
src/olm.cpp
View file

@ -290,11 +290,7 @@ size_t olm_unpickle_account(
return std::size_t(-1);
}
std::uint8_t * const end = pos + raw_length;
/* On success unpickle will return (pos + raw_length). If unpickling
* terminates too soon then it will return a pointer before
* (pos + raw_length). On error unpickle will return (pos + raw_length + 1).
*/
if (end != unpickle(pos, end + 1, object)) {
if (!unpickle(pos, end, object)) {
if (object.last_error == OlmErrorCode::OLM_SUCCESS) {
object.last_error = OlmErrorCode::OLM_CORRUPTED_PICKLE;
}
@ -319,11 +315,7 @@ size_t olm_unpickle_session(
}
std::uint8_t * const end = pos + raw_length;
/* On success unpickle will return (pos + raw_length). If unpickling
* terminates too soon then it will return a pointer before
* (pos + raw_length). On error unpickle will return (pos + raw_length + 1).
*/
if (end != unpickle(pos, end + 1, object)) {
if (!unpickle(pos, end, object)) {
if (object.last_error == OlmErrorCode::OLM_SUCCESS) {
object.last_error = OlmErrorCode::OLM_CORRUPTED_PICKLE;
}

15
src/outbound_group_session.c
View file

@ -143,19 +143,20 @@ size_t olm_unpickle_outbound_group_session(
pos = pickled;
end = pos + raw_length;
pos = _olm_unpickle_uint32(pos, end, &pickle_version);
FAIL_ON_CORRUPTED_PICKLE(pos, session);
if (pickle_version != PICKLE_VERSION) {
session->last_error = OLM_UNKNOWN_PICKLE_VERSION;
return (size_t)-1;
}
pos = megolm_unpickle(&(session->ratchet), pos, end);
pos = _olm_unpickle_ed25519_key_pair(pos, end, &(session->signing_key));
if (end != pos) {
/* We had the wrong number of bytes in the input. */
session->last_error = OLM_CORRUPTED_PICKLE;
return (size_t)-1;
}
pos = megolm_unpickle(&(session->ratchet), pos, end);
FAIL_ON_CORRUPTED_PICKLE(pos, session);
pos = _olm_unpickle_ed25519_key_pair(pos, end, &(session->signing_key));
FAIL_ON_CORRUPTED_PICKLE(pos, session);
return pickled_length;
}

24
src/pickle.cpp
View file

@ -30,7 +30,7 @@ std::uint8_t const * olm::unpickle(
std::uint32_t & value
) {
value = 0;
if (end < pos + 4) return end;
if (!pos || end <= pos + 4) return nullptr;
for (unsigned i = 4; i--;) { value <<= 8; value |= *(pos++); }
return pos;
}
@ -47,7 +47,7 @@ std::uint8_t const * olm::unpickle(
std::uint8_t const * pos, std::uint8_t const * end,
bool & value
) {
if (pos == end) return end;
if (!pos || pos == end) return nullptr;
value = *(pos++);
return pos;
}
@ -64,7 +64,7 @@ std::uint8_t const * olm::unpickle_bytes(
std::uint8_t const * pos, std::uint8_t const * end,
std::uint8_t * bytes, std::size_t bytes_length
) {
if (end < pos + bytes_length) return end;
if (!pos || end < pos + bytes_length) return nullptr;
std::memcpy(bytes, pos, bytes_length);
return pos + bytes_length;
}
@ -92,11 +92,9 @@ std::uint8_t const * olm::unpickle(
std::uint8_t const * pos, std::uint8_t const * end,
_olm_curve25519_public_key & value
) {
pos = olm::unpickle_bytes(
return olm::unpickle_bytes(
pos, end, value.public_key, sizeof(value.public_key)
);
return pos;
}
@ -132,10 +130,14 @@ std::uint8_t const * olm::unpickle(
pos, end, value.public_key.public_key,
sizeof(value.public_key.public_key)
);
if (!pos) return nullptr;
pos = olm::unpickle_bytes(
pos, end, value.private_key.private_key,
sizeof(value.private_key.private_key)
);
if (!pos) return nullptr;
return pos;
}
@ -152,10 +154,9 @@ std::uint8_t * _olm_pickle_ed25519_public_key(
std::uint8_t * pos,
const _olm_ed25519_public_key *value
) {
pos = olm::pickle_bytes(
return olm::pickle_bytes(
pos, value->public_key, sizeof(value->public_key)
);
return pos;
}
@ -163,10 +164,9 @@ std::uint8_t const * _olm_unpickle_ed25519_public_key(
std::uint8_t const * pos, std::uint8_t const * end,
_olm_ed25519_public_key * value
) {
pos = olm::unpickle_bytes(
return olm::unpickle_bytes(
pos, end, value->public_key, sizeof(value->public_key)
);
return pos;
}
@ -202,10 +202,14 @@ std::uint8_t const * _olm_unpickle_ed25519_key_pair(
pos, end, value->public_key.public_key,
sizeof(value->public_key.public_key)
);
if (!pos) return nullptr;
pos = olm::unpickle_bytes(
pos, end, value->private_key.private_key,
sizeof(value->private_key.private_key)
);
if (!pos) return nullptr;
return pos;
}

14
src/pk.cpp
View file

@ -274,7 +274,7 @@ namespace {
OlmPkDecryption & value
) {
uint32_t pickle_version;
pos = olm::unpickle(pos, end, pickle_version);
pos = olm::unpickle(pos, end, pickle_version); UNPICKLE_OK(pos);
switch (pickle_version) {
case 1:
@ -282,10 +282,11 @@ namespace {
default:
value.last_error = OlmErrorCode::OLM_UNKNOWN_PICKLE_VERSION;
return end;
return nullptr;
}
pos = olm::unpickle(pos, end, value.key_pair);
pos = olm::unpickle(pos, end, value.key_pair); UNPICKLE_OK(pos);
return pos;
}
}
@ -334,11 +335,8 @@ size_t olm_unpickle_pk_decryption(
return std::size_t(-1);
}
std::uint8_t * const end = pos + raw_length;
/* On success unpickle will return (pos + raw_length). If unpickling
* terminates too soon then it will return a pointer before
* (pos + raw_length). On error unpickle will return (pos + raw_length + 1).
*/
if (end != unpickle(pos, end + 1, object)) {
if (!unpickle(pos, end, object)) {
if (object.last_error == OlmErrorCode::OLM_SUCCESS) {
object.last_error = OlmErrorCode::OLM_CORRUPTED_PICKLE;
}

28
src/ratchet.cpp
View file

@ -280,9 +280,9 @@ static std::uint8_t const * unpickle(
std::uint8_t const * pos, std::uint8_t const * end,
olm::SenderChain & value
) {
pos = olm::unpickle(pos, end, value.ratchet_key);
pos = olm::unpickle(pos, end, value.chain_key.key);
pos = olm::unpickle(pos, end, value.chain_key.index);
pos = olm::unpickle(pos, end, value.ratchet_key); UNPICKLE_OK(pos);
pos = olm::unpickle(pos, end, value.chain_key.key); UNPICKLE_OK(pos);
pos = olm::unpickle(pos, end, value.chain_key.index); UNPICKLE_OK(pos);
return pos;
}
@ -312,9 +312,9 @@ static std::uint8_t const * unpickle(
std::uint8_t const * pos, std::uint8_t const * end,
olm::ReceiverChain & value
) {
pos = olm::unpickle(pos, end, value.ratchet_key);
pos = olm::unpickle(pos, end, value.chain_key.key);
pos = olm::unpickle(pos, end, value.chain_key.index);
pos = olm::unpickle(pos, end, value.ratchet_key); UNPICKLE_OK(pos);
pos = olm::unpickle(pos, end, value.chain_key.key); UNPICKLE_OK(pos);
pos = olm::unpickle(pos, end, value.chain_key.index); UNPICKLE_OK(pos);
return pos;
}
@ -345,9 +345,9 @@ static std::uint8_t const * unpickle(
std::uint8_t const * pos, std::uint8_t const * end,
olm::SkippedMessageKey & value
) {
pos = olm::unpickle(pos, end, value.ratchet_key);
pos = olm::unpickle(pos, end, value.message_key.key);
pos = olm::unpickle(pos, end, value.message_key.index);
pos = olm::unpickle(pos, end, value.ratchet_key); UNPICKLE_OK(pos);
pos = olm::unpickle(pos, end, value.message_key.key); UNPICKLE_OK(pos);
pos = olm::unpickle(pos, end, value.message_key.index); UNPICKLE_OK(pos);
return pos;
}
@ -383,15 +383,15 @@ std::uint8_t const * olm::unpickle(
olm::Ratchet & value,
bool includes_chain_index
) {
pos = unpickle(pos, end, value.root_key);
pos = unpickle(pos, end, value.sender_chain);
pos = unpickle(pos, end, value.receiver_chains);
pos = unpickle(pos, end, value.skipped_message_keys);
pos = unpickle(pos, end, value.root_key); UNPICKLE_OK(pos);
pos = unpickle(pos, end, value.sender_chain); UNPICKLE_OK(pos);
pos = unpickle(pos, end, value.receiver_chains); UNPICKLE_OK(pos);
pos = unpickle(pos, end, value.skipped_message_keys); UNPICKLE_OK(pos);
// pickle v 0x80000001 includes a chain index; pickle v1 does not.
if (includes_chain_index) {
std::uint32_t dummy;
pos = unpickle(pos, end, dummy);
pos = unpickle(pos, end, dummy); UNPICKLE_OK(pos);
}
return pos;
}

15
src/session.cpp
View file

@ -472,7 +472,7 @@ std::uint8_t const * olm::unpickle(
Session & value
) {
uint32_t pickle_version;
pos = olm::unpickle(pos, end, pickle_version);
pos = olm::unpickle(pos, end, pickle_version); UNPICKLE_OK(pos);
bool includes_chain_index;
switch (pickle_version) {
@ -486,13 +486,14 @@ std::uint8_t const * olm::unpickle(
default:
value.last_error = OlmErrorCode::OLM_UNKNOWN_PICKLE_VERSION;
return end;
return nullptr;
}
pos = olm::unpickle(pos, end, value.received_message);
pos = olm::unpickle(pos, end, value.alice_identity_key);
pos = olm::unpickle(pos, end, value.alice_base_key);
pos = olm::unpickle(pos, end, value.bob_one_time_key);
pos = olm::unpickle(pos, end, value.ratchet, includes_chain_index);
pos = olm::unpickle(pos, end, value.received_message); UNPICKLE_OK(pos);
pos = olm::unpickle(pos, end, value.alice_identity_key); UNPICKLE_OK(pos);
pos = olm::unpickle(pos, end, value.alice_base_key); UNPICKLE_OK(pos);
pos = olm::unpickle(pos, end, value.bob_one_time_key); UNPICKLE_OK(pos);
pos = olm::unpickle(pos, end, value.ratchet, includes_chain_index); UNPICKLE_OK(pos);
return pos;
}