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Group cryptography: Group trial decryption implemented. (#13709)
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* Group cryptography: Group trial decryption implemented.

* Group cryptography: Code review comments implemented.

* Group cryptography: Code review comments implemented.

* Group cryptography: Code review comments implemented.
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rcasallas-silabs authored and pull[bot] committed Nov 1, 2023
1 parent bea63ce commit 7043cec
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Showing 9 changed files with 1,047 additions and 305 deletions.
Original file line number Diff line number Diff line change
Expand Up @@ -351,14 +351,16 @@ bool emberAfGroupKeyManagementClusterKeySetReadCallback(
return true;
}

// In KeySetReadResponse, EpochKey0, EpochKey1 and EpochKey2 key contents shall be null
GroupKeyManagement::Commands::KeySetReadResponse::Type response;
response.groupKeySet.groupKeySetID = keyset.keyset_id;
response.groupKeySet.securityPolicy = keyset.policy;

// Keyset 0
if (keyset.num_keys_used > 0)
{
response.groupKeySet.epochStartTime0 = keyset.epoch_keys[0].start_time;
response.groupKeySet.epochKey0 = chip::ByteSpan(keyset.epoch_keys[0].key, GroupDataProvider::EpochKey::kLengthBytes);
response.groupKeySet.epochKey0 = chip::ByteSpan(nullptr, 0);
}
else
{
Expand All @@ -369,7 +371,7 @@ bool emberAfGroupKeyManagementClusterKeySetReadCallback(
if (keyset.num_keys_used > 1)
{
response.groupKeySet.epochStartTime1 = keyset.epoch_keys[1].start_time;
response.groupKeySet.epochKey1 = chip::ByteSpan(keyset.epoch_keys[1].key, GroupDataProvider::EpochKey::kLengthBytes);
response.groupKeySet.epochKey1 = chip::ByteSpan(nullptr, 0);
}
else
{
Expand All @@ -380,7 +382,7 @@ bool emberAfGroupKeyManagementClusterKeySetReadCallback(
if (keyset.num_keys_used > 2)
{
response.groupKeySet.epochStartTime2 = keyset.epoch_keys[2].start_time;
response.groupKeySet.epochKey2 = chip::ByteSpan(keyset.epoch_keys[2].key, GroupDataProvider::EpochKey::kLengthBytes);
response.groupKeySet.epochKey2 = chip::ByteSpan(nullptr, 0);
}
else
{
Expand Down
118 changes: 75 additions & 43 deletions src/credentials/GroupDataProvider.h
Original file line number Diff line number Diff line change
Expand Up @@ -24,7 +24,6 @@
#include <app/util/basic-types.h>
#include <crypto/CHIPCryptoPAL.h>
#include <lib/core/CHIPError.h>
#include <transport/raw/MessageHeader.h>

namespace chip {
namespace Credentials {
Expand All @@ -37,15 +36,15 @@ class GroupDataProvider
static constexpr size_t kGroupNameMax = CHIP_CONFIG_MAX_GROUP_NAME_LENGTH;

// Identifies group within the scope of the given Fabric
chip::GroupId group_id = kUndefinedGroupId;
GroupId group_id = kUndefinedGroupId;
// Lastest group name written for a given GroupId on any Endpoint via the Groups cluster
char name[kGroupNameMax + 1] = { 0 };

GroupInfo() { SetName(nullptr); }
GroupInfo(const char * groupName) { SetName(groupName); }
GroupInfo(const CharSpan & groupName) { SetName(groupName); }
GroupInfo(chip::GroupId id, const char * groupName) : group_id(id) { SetName(groupName); }
GroupInfo(chip::GroupId id, const CharSpan & groupName) : group_id(id) { SetName(groupName); }
GroupInfo(GroupId id, const char * groupName) : group_id(id) { SetName(groupName); }
GroupInfo(GroupId id, const CharSpan & groupName) : group_id(id) { SetName(groupName); }
void SetName(const char * groupName)
{
if (nullptr == groupName)
Expand Down Expand Up @@ -81,29 +80,37 @@ class GroupDataProvider
struct GroupKey
{
GroupKey() = default;
GroupKey(chip::GroupId group, chip::KeysetId keyset) : group_id(group), keyset_id(keyset) {}
GroupKey(GroupId group, KeysetId keyset) : group_id(group), keyset_id(keyset) {}
// Identifies group within the scope of the given Fabric
chip::GroupId group_id = kUndefinedGroupId;
GroupId group_id = kUndefinedGroupId;
// Set of group keys that generate operational group keys for use with this group
chip::KeysetId keyset_id = 0;
KeysetId keyset_id = 0;
bool operator==(const GroupKey & other) { return this->group_id == other.group_id && this->keyset_id == other.keyset_id; }
};

struct GroupEndpoint
{
GroupEndpoint() = default;
GroupEndpoint(chip::GroupId group, chip::EndpointId endpoint) : group_id(group), endpoint_id(endpoint) {}
GroupEndpoint(GroupId group, EndpointId endpoint) : group_id(group), endpoint_id(endpoint) {}
// Identifies group within the scope of the given Fabric
chip::GroupId group_id = kUndefinedGroupId;
GroupId group_id = kUndefinedGroupId;
// Endpoint on the Node to which messages to this group may be forwarded
chip::EndpointId endpoint_id = kInvalidEndpointId;
EndpointId endpoint_id = kInvalidEndpointId;

bool operator==(const GroupEndpoint & other)
{
return this->group_id == other.group_id && this->endpoint_id == other.endpoint_id;
}
};

struct GroupSession
{
GroupSession() = default;
GroupId group_id = kUndefinedGroupId;
FabricIndex fabric_index;
Crypto::SymmetricKeyContext * key = nullptr;
};

// An EpochKey is a single key usable to determine an operational group key
struct EpochKey
{
Expand All @@ -118,14 +125,15 @@ class GroupDataProvider
// A operational group key set, usable by many GroupState mappings
struct KeySet
{
using SecurityPolicy = chip::app::Clusters::GroupKeyManagement::GroupKeySecurityPolicy;
static constexpr size_t kEpochKeysMax = 3;
using SecurityPolicy = app::Clusters::GroupKeyManagement::GroupKeySecurityPolicy;

KeySet() = default;
KeySet(uint16_t id, SecurityPolicy policy_id, uint8_t num_keys) : keyset_id(id), policy(policy_id), num_keys_used(num_keys)
{}

// The actual keys for the group key set
EpochKey epoch_keys[3];
EpochKey epoch_keys[kEpochKeysMax];
// Logical id provided by the Administrator that configured the entry
uint16_t keyset_id = 0;
// Security policy to use for groups that use this keyset
Expand All @@ -138,6 +146,22 @@ class GroupDataProvider
VerifyOrReturnError(this->policy == other.policy && this->num_keys_used == other.num_keys_used, false);
return !memcmp(this->epoch_keys, other.epoch_keys, this->num_keys_used * sizeof(EpochKey));
}

ByteSpan GetCurrentKey()
{
// An epoch key update SHALL order the keys from oldest to newest,
// the current epoch key having the second newest time
switch (this->num_keys_used)
{
case 1:
case 2:
return ByteSpan(epoch_keys[0].key, EpochKey::kLengthBytes);
case 3:
return ByteSpan(epoch_keys[1].key, EpochKey::kLengthBytes);
default:
return ByteSpan(nullptr, 0);
}
}
};

/**
Expand All @@ -152,13 +176,13 @@ class GroupDataProvider
*
* @param[in] new_group GroupInfo structure of the new group.
*/
virtual void OnGroupAdded(chip::FabricIndex fabric_index, const GroupInfo & new_group) = 0;
virtual void OnGroupAdded(FabricIndex fabric_index, const GroupInfo & new_group) = 0;
/**
* Callback invoked when an existing group is removed.
*
* @param[in] removed_state GroupInfo structure of the removed group.
*/
virtual void OnGroupRemoved(chip::FabricIndex fabric_index, const GroupInfo & old_group) = 0;
virtual void OnGroupRemoved(FabricIndex fabric_index, const GroupInfo & old_group) = 0;
};

/**
Expand Down Expand Up @@ -189,10 +213,11 @@ class GroupDataProvider
Iterator() = default;
};

using GroupInfoIterator = Iterator<GroupInfo>;
using GroupKeyIterator = Iterator<GroupKey>;
using EndpointIterator = Iterator<GroupEndpoint>;
using KeySetIterator = Iterator<KeySet>;
using GroupInfoIterator = Iterator<GroupInfo>;
using GroupKeyIterator = Iterator<GroupKey>;
using EndpointIterator = Iterator<GroupEndpoint>;
using KeySetIterator = Iterator<KeySet>;
using GroupSessionIterator = Iterator<GroupSession>;

GroupDataProvider(uint16_t maxGroupsPerFabric = CHIP_CONFIG_MAX_GROUPS_PER_FABRIC,
uint16_t maxGroupKeysPerFabric = CHIP_CONFIG_MAX_GROUP_KEYS_PER_FABRIC) :
Expand Down Expand Up @@ -224,18 +249,18 @@ class GroupDataProvider
//

// By id
virtual CHIP_ERROR SetGroupInfo(chip::FabricIndex fabric_index, const GroupInfo & info) = 0;
virtual CHIP_ERROR GetGroupInfo(chip::FabricIndex fabric_index, chip::GroupId group_id, GroupInfo & info) = 0;
virtual CHIP_ERROR RemoveGroupInfo(chip::FabricIndex fabric_index, chip::GroupId group_id) = 0;
virtual CHIP_ERROR SetGroupInfo(FabricIndex fabric_index, const GroupInfo & info) = 0;
virtual CHIP_ERROR GetGroupInfo(FabricIndex fabric_index, GroupId group_id, GroupInfo & info) = 0;
virtual CHIP_ERROR RemoveGroupInfo(FabricIndex fabric_index, GroupId group_id) = 0;
// By index
virtual CHIP_ERROR SetGroupInfoAt(chip::FabricIndex fabric_index, size_t index, const GroupInfo & info) = 0;
virtual CHIP_ERROR GetGroupInfoAt(chip::FabricIndex fabric_index, size_t index, GroupInfo & info) = 0;
virtual CHIP_ERROR RemoveGroupInfoAt(chip::FabricIndex fabric_index, size_t index) = 0;
virtual CHIP_ERROR SetGroupInfoAt(FabricIndex fabric_index, size_t index, const GroupInfo & info) = 0;
virtual CHIP_ERROR GetGroupInfoAt(FabricIndex fabric_index, size_t index, GroupInfo & info) = 0;
virtual CHIP_ERROR RemoveGroupInfoAt(FabricIndex fabric_index, size_t index) = 0;
// Endpoints
virtual bool HasEndpoint(chip::FabricIndex fabric_index, chip::GroupId group_id, chip::EndpointId endpoint_id) = 0;
virtual CHIP_ERROR AddEndpoint(chip::FabricIndex fabric_index, chip::GroupId group_id, chip::EndpointId endpoint_id) = 0;
virtual CHIP_ERROR RemoveEndpoint(chip::FabricIndex fabric_index, chip::GroupId group_id, chip::EndpointId endpoint_id) = 0;
virtual CHIP_ERROR RemoveEndpoint(chip::FabricIndex fabric_index, chip::EndpointId endpoint_id) = 0;
virtual bool HasEndpoint(FabricIndex fabric_index, GroupId group_id, EndpointId endpoint_id) = 0;
virtual CHIP_ERROR AddEndpoint(FabricIndex fabric_index, GroupId group_id, EndpointId endpoint_id) = 0;
virtual CHIP_ERROR RemoveEndpoint(FabricIndex fabric_index, GroupId group_id, EndpointId endpoint_id) = 0;
virtual CHIP_ERROR RemoveEndpoint(FabricIndex fabric_index, EndpointId endpoint_id) = 0;
// Iterators
/**
* Creates an iterator that may be used to obtain the list of groups associated with the given fabric.
Expand All @@ -244,24 +269,24 @@ class GroupDataProvider
* @retval An instance of EndpointIterator on success
* @retval nullptr if no iterator instances are available.
*/
virtual GroupInfoIterator * IterateGroupInfo(chip::FabricIndex fabric_index) = 0;
virtual GroupInfoIterator * IterateGroupInfo(FabricIndex fabric_index) = 0;
/**
* Creates an iterator that may be used to obtain the list of (group, endpoint) pairs associated with the given fabric.
* In order to release the allocated memory, the Release() method must be called after the iteration is finished.
* Modifying the group table during the iteration is currently not supported, and may yield unexpected behaviour.
* @retval An instance of EndpointIterator on success
* @retval nullptr if no iterator instances are available.
*/
virtual EndpointIterator * IterateEndpoints(chip::FabricIndex fabric_index) = 0;
virtual EndpointIterator * IterateEndpoints(FabricIndex fabric_index) = 0;

//
// Group-Key map
//

virtual CHIP_ERROR SetGroupKeyAt(chip::FabricIndex fabric_index, size_t index, const GroupKey & info) = 0;
virtual CHIP_ERROR GetGroupKeyAt(chip::FabricIndex fabric_index, size_t index, GroupKey & info) = 0;
virtual CHIP_ERROR RemoveGroupKeyAt(chip::FabricIndex fabric_index, size_t index) = 0;
virtual CHIP_ERROR RemoveGroupKeys(chip::FabricIndex fabric_index) = 0;
virtual CHIP_ERROR SetGroupKeyAt(FabricIndex fabric_index, size_t index, const GroupKey & info) = 0;
virtual CHIP_ERROR GetGroupKeyAt(FabricIndex fabric_index, size_t index, GroupKey & info) = 0;
virtual CHIP_ERROR RemoveGroupKeyAt(FabricIndex fabric_index, size_t index) = 0;
virtual CHIP_ERROR RemoveGroupKeys(FabricIndex fabric_index) = 0;

/**
* Creates an iterator that may be used to obtain the list of (group, keyset) pairs associated with the given fabric.
Expand All @@ -270,42 +295,49 @@ class GroupDataProvider
* @retval An instance of GroupKeyIterator on success
* @retval nullptr if no iterator instances are available.
*/
virtual GroupKeyIterator * IterateGroupKeys(chip::FabricIndex fabric_index) = 0;
virtual GroupKeyIterator * IterateGroupKeys(FabricIndex fabric_index) = 0;

//
// Key Sets
//

virtual CHIP_ERROR SetKeySet(chip::FabricIndex fabric_index, const KeySet & keys) = 0;
virtual CHIP_ERROR GetKeySet(chip::FabricIndex fabric_index, chip::KeysetId keyset_id, KeySet & keys) = 0;
virtual CHIP_ERROR RemoveKeySet(chip::FabricIndex fabric_index, chip::KeysetId keyset_id) = 0;
virtual CHIP_ERROR SetKeySet(FabricIndex fabric_index, const KeySet & keys) = 0;
virtual CHIP_ERROR GetKeySet(FabricIndex fabric_index, KeysetId keyset_id, KeySet & keys) = 0;
virtual CHIP_ERROR RemoveKeySet(FabricIndex fabric_index, KeysetId keyset_id) = 0;
/**
* Creates an iterator that may be used to obtain the list of key sets associated with the given fabric.
* In order to release the allocated memory, the Release() method must be called after the iteration is finished.
* Modifying the key sets table during the iteration is currently not supported, and may yield unexpected behaviour.
* @retval An instance of KeySetIterator on success
* @retval nullptr if no iterator instances are available.
*/
virtual KeySetIterator * IterateKeySets(chip::FabricIndex fabric_index) = 0;
virtual KeySetIterator * IterateKeySets(FabricIndex fabric_index) = 0;

// Fabrics
virtual CHIP_ERROR RemoveFabric(chip::FabricIndex fabric_index) = 0;
virtual CHIP_ERROR RemoveFabric(FabricIndex fabric_index) = 0;

// General
virtual CHIP_ERROR Decrypt(PacketHeader packetHeader, PayloadHeader & payloadHeader, System::PacketBufferHandle & msg) = 0;
// Decryption
virtual GroupSessionIterator * IterateGroupSessions(uint16_t session_id) = 0;

// Listener
void SetListener(GroupListener * listener) { mListener = listener; };
void RemoveListener() { mListener = nullptr; };

protected:
void GroupAdded(chip::FabricIndex fabric_index, const GroupInfo & new_group)
void GroupAdded(FabricIndex fabric_index, const GroupInfo & new_group)
{
if (mListener)
{
mListener->OnGroupAdded(fabric_index, new_group);
}
}
void GroupRemoved(FabricIndex fabric_index, const GroupInfo & old_group)
{
if (mListener)
{
mListener->OnGroupRemoved(fabric_index, old_group);
}
}
const uint16_t mMaxGroupsPerFabric;
const uint16_t mMaxGroupKeysPerFabric;
GroupListener * mListener = nullptr;
Expand Down
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