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fix(ebpf): kernel data filter combine bitmap #4468

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merged 2 commits into from
Jan 8, 2025
Merged

fix(ebpf): kernel data filter combine bitmap #4468

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d66134b
fix(ebpf): kernel data filter combine bitmap
rscampos Jan 6, 2025
22fa7ba
test(filters): kernel data filter
rscampos Jan 7, 2025
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8 changes: 7 additions & 1 deletion pkg/ebpf/c/common/filtering.h
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Original file line number Diff line number Diff line change
Expand Up @@ -357,6 +357,9 @@ statfunc u64 match_data_filters(program_data_t *p, u8 index)
u64 explicit_disable_policies = 0;
u64 explicit_enable_policies = 0;
u64 default_enable_policies = 0;
// Determine policies that do not use any type of string filter (exact, prefix, suffix)
u64 mask_no_str_filter_policies =
~str_filter->exact_enabled & ~str_filter->prefix_enabled & ~str_filter->suffix_enabled;
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void *filter_map = NULL;

// event ID
Expand Down Expand Up @@ -434,8 +437,11 @@ statfunc u64 match_data_filters(program_data_t *p, u8 index)
// 2. Default Enabled Policies: Policies that are enabled by default (default_enable_policies)
// remain enabled only if they are not explicitly disabled (explicit_disable_policies).
res = explicit_enable_policies | (default_enable_policies & ~explicit_disable_policies);
// Combine policies that use string filters with those that do not
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res |= mask_no_str_filter_policies;

return res;
// Make sure only enabled policies are set in the bitmap (other bits are invalid)
return res & policies_cfg->enabled_policies;
}

statfunc bool evaluate_scope_filters(program_data_t *p)
Expand Down
136 changes: 136 additions & 0 deletions tests/integration/event_filters_test.go
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Expand Up @@ -1950,6 +1950,142 @@ func Test_EventFilters(t *testing.T) {
coolDown: 0,
test: ExpectAtLeastOneForEach,
},
{
name: "comm: event: data: trace event security_file_open set in multiple policies (with and without in-kernel filter)",
policyFiles: []testutils.PolicyFileWithID{
{
Id: 1,
PolicyFile: v1beta1.PolicyFile{
Metadata: v1beta1.Metadata{
Name: "sfo-pol-1",
},
Spec: k8s.PolicySpec{
Scope: []string{
"comm=more",
},
DefaultActions: []string{"log"},
Rules: []k8s.Rule{
{
Event: "security_file_open",
Filters: []string{
"data.syscall_pathname=/sys/class/dmi/id*",
},
},
},
},
},
},
{
Id: 2,
PolicyFile: v1beta1.PolicyFile{
Metadata: v1beta1.Metadata{
Name: "sfo-pol-2",
},
Spec: k8s.PolicySpec{
Scope: []string{
"comm=more",
},
DefaultActions: []string{"log"},
Rules: []k8s.Rule{
{
Event: "security_file_open",
Filters: []string{
"data.pathname=/etc/pam.d/*",
},
},
},
},
},
},
},
cmdEvents: []cmdEvents{
newCmdEvents(
"more /sys/class/dmi/id/bios_date",
0,
1*time.Second,
[]trace.Event{
expectEvent(anyHost, "more", testutils.CPUForTests, anyPID, 0, events.SecurityFileOpen, orPolNames("sfo-pol-1"), orPolIDs(1), expectArg("syscall_pathname", "/sys/class/dmi/id/bios_date")),
},
[]string{},
),
newCmdEvents(
"more /etc/pam.d/other",
0,
1*time.Second,
[]trace.Event{
expectEvent(anyHost, "more", testutils.CPUForTests, anyPID, 0, events.SecurityFileOpen, orPolNames("sfo-pol-2"), orPolIDs(2), expectArg("pathname", "/etc/pam.d/other")),
},
[]string{},
),
},
useSyscaller: false,
coolDown: 0,
test: ExpectAtLeastOneForEach,
},
{
name: "comm: event: data: trace event security_file_open set in multiple policies (with and without in-kernel filter) mixed in same policy",
policyFiles: []testutils.PolicyFileWithID{
{
Id: 1,
PolicyFile: v1beta1.PolicyFile{
Metadata: v1beta1.Metadata{
Name: "sfo-pol-1",
},
Spec: k8s.PolicySpec{
Scope: []string{
"comm=more",
},
DefaultActions: []string{"log"},
Rules: []k8s.Rule{
{
Event: "security_file_open",
Filters: []string{
"data.pathname=/sys/devices/virtual/dmi/id*",
"data.syscall_pathname=/sys/class/dmi/id*",
},
},
},
},
},
},
{
Id: 2,
PolicyFile: v1beta1.PolicyFile{
Metadata: v1beta1.Metadata{
Name: "sfo-pol-2",
},
Spec: k8s.PolicySpec{
Scope: []string{
"comm=more",
},
DefaultActions: []string{"log"},
Rules: []k8s.Rule{
{
Event: "security_file_open",
Filters: []string{
"data.pathname=/etc/pam.d/*",
},
},
},
},
},
},
},
cmdEvents: []cmdEvents{
newCmdEvents(
"more /sys/class/dmi/id/bios_date",
0,
1*time.Second,
[]trace.Event{
expectEvent(anyHost, "more", testutils.CPUForTests, anyPID, 0, events.SecurityFileOpen, orPolNames("sfo-pol-1"), orPolIDs(1), expectArg("pathname", "/sys/devices/virtual/dmi/id/bios_date")),
},
[]string{},
),
},
useSyscaller: false,
coolDown: 0,
test: ExpectAtLeastOneForEach,
},
{
name: "comm: event: data: trace event security_mmap_file using multiple filter types",
policyFiles: []testutils.PolicyFileWithID{
Expand Down
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