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[Backport 7.85.x] fix(cws): read the Node.js record slot offset from the discovery struct #57447

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[Backport 7.85.x] fix(cws): read the Node.js record slot offset from the discovery struct #57447

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2 changes: 1 addition & 1 deletion pkg/security/ebpf/c/include/helpers/span_nodejs.h
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Original file line number Diff line number Diff line change
Expand Up @@ -162,7 +162,7 @@ static int __attribute__((always_inline)) otel_nodejs_record_ptr(
// holds the record pointer directly. Unlike the wrapper, the record is a
// byte buffer the writer allocates: nothing says it is aligned.
u64 record = 0;
if (otel_v8_read_word(otel_v8_untag(value) + v8->js_object_record_offset, &record)) {
if (otel_v8_read_word(otel_v8_untag(value) + nctx->record_slot_offset, &record)) {
return 0;
}
// Cleared when the isolate is torn down.
Expand Down
6 changes: 3 additions & 3 deletions pkg/security/ebpf/c/include/structs/span_context.h
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Expand Up @@ -126,8 +126,7 @@ struct otel_v8_layout_t {
u16 tagged_size; // width of a tagged word; only 8 is supported
u16 js_map_table_offset; // JSMap -> backing OrderedHashMap
u16 ordered_hash_map_header_size; // header before the OrderedHashMap fields
u16 js_object_record_offset; // JSObject -> internal field 0, the record pointer
u16 _pad[4];
u16 _pad[5];
};

// OTel TLS registration for a process, written once by user space after
Expand All @@ -148,7 +147,8 @@ struct otel_nodejs_ctx_t {
u64 cped_slot; // isolate slot holding the live AsyncContextFrame
u64 als_handle; // handle to the AsyncLocalStorage the frame is keyed by
u32 als_identity_hash; // its identity hash, which picks a single bucket
u32 _pad;
u8 record_slot_offset; // JSObject -> internal field 0, the record pointer
u8 _pad[3];
u64 undefined_addr; // this isolate's undefined, i.e. "no context here"
};

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5 changes: 1 addition & 4 deletions pkg/security/resolvers/process/otel_tls.go
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Expand Up @@ -68,7 +68,6 @@ type otelV8Layout struct {
taggedSize uint16
jsMapTableOffset uint16
orderedHashMapHeaderSize uint16
jsObjectRecordOffset uint16
}

// otelNodeJSSchemaVersion is one schema version the Node.js writer may
Expand All @@ -90,7 +89,6 @@ var otelNodeJSSchemaVersions = []otelNodeJSSchemaVersion{
taggedSize: otelSupportedTaggedSize,
jsMapTableOffset: 0x18,
orderedHashMapHeaderSize: 0x10,
jsObjectRecordOffset: 0x18,
},
},
}
Expand Down Expand Up @@ -165,8 +163,7 @@ func serializeOTelTLSValue(res otelTLSResolution) []byte {
binary.NativeEndian.PutUint16(buf[32:34], res.v8.taggedSize)
binary.NativeEndian.PutUint16(buf[34:36], res.v8.jsMapTableOffset)
binary.NativeEndian.PutUint16(buf[36:38], res.v8.orderedHashMapHeaderSize)
binary.NativeEndian.PutUint16(buf[38:40], res.v8.jsObjectRecordOffset)
// buf[40:48] is otel_v8_layout_t._pad, intentionally left zero.
// buf[38:48] is otel_v8_layout_t._pad, intentionally left zero.
return buf
}

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15 changes: 5 additions & 10 deletions pkg/security/tests/syscall_tester/c/otel_nodejs_common.h
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Expand Up @@ -30,10 +30,8 @@
#include "otel_process_ctx_common.h"
#include "otel_tls_common.h"

// --- V8 layout, as the writer publishes it in its process context ---
// --- V8 layout the nodejs_v1 schema implies ---

#define OTEL_NODEJS_TAGGED_SIZE 8
#define OTEL_NODEJS_JS_MAP_TABLE_OFFSET 0x18
#define OTEL_NODEJS_OHM_HEADER_SIZE 0x10
#define OTEL_NODEJS_JS_OBJECT_RECORD_OFFSET 24

Expand All @@ -58,7 +56,8 @@ struct otel_thread_ctx_nodejs {
uint64_t cped_slot;
uint64_t als_handle;
int32_t als_identity_hash;
int32_t _pad;
uint8_t record_slot_offset;
uint8_t _pad[3];
uint64_t undefined_addr;
};

Expand Down Expand Up @@ -168,6 +167,7 @@ static inline void otel_nodejs_build(struct otel_nodejs_graph *g, enum otel_node
g->discovery.cped_slot = (uint64_t)(uintptr_t)&g->cped;
g->discovery.als_handle = (uint64_t)(uintptr_t)&g->als_slot;
g->discovery.als_identity_hash = OTEL_NODEJS_ALS_HASH;
g->discovery.record_slot_offset = OTEL_NODEJS_JS_OBJECT_RECORD_OFFSET;
g->discovery.undefined_addr = g->undefined;
}

Expand All @@ -185,16 +185,11 @@ static const char *const otel_nodejs_attribute_keys[] = {
};

// otel_nodejs_encode_process_ctx writes the process context payload of a Node.js
// writer: the schema its records follow, the key names their attributes select,
// and the V8 layout the reader walks them with.
// writer: the schema its records follow and the key names their attributes select.
static inline size_t otel_nodejs_encode_process_ctx(uint8_t *out) {
size_t off = otel_pb_string_attribute(out, "threadlocal.schema_version", "nodejs_v1_dev");
off += otel_pb_string_array_attribute(out + off, "threadlocal.attribute_key_map", otel_nodejs_attribute_keys,
sizeof(otel_nodejs_attribute_keys) / sizeof(otel_nodejs_attribute_keys[0]));
off += otel_pb_int_attribute(out + off, "threadlocal.tagged_size", OTEL_NODEJS_TAGGED_SIZE);
off += otel_pb_int_attribute(out + off, "threadlocal.js_map_table_offset", OTEL_NODEJS_JS_MAP_TABLE_OFFSET);
off += otel_pb_int_attribute(out + off, "threadlocal.ordered_hash_map_header_size", OTEL_NODEJS_OHM_HEADER_SIZE);
off += otel_pb_int_attribute(out + off, "threadlocal.js_object_record_offset", OTEL_NODEJS_JS_OBJECT_RECORD_OFFSET);
return off;
}

Expand Down
13 changes: 0 additions & 13 deletions pkg/security/tests/syscall_tester/c/otel_process_ctx_common.h
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Expand Up @@ -45,11 +45,9 @@ struct otel_process_ctx_header {
#define OTEL_PB_KV_KEY 1
#define OTEL_PB_KV_VALUE 2
#define OTEL_PB_ANY_STRING 1
#define OTEL_PB_ANY_INT 3
#define OTEL_PB_ANY_ARRAY 5
#define OTEL_PB_ARRAY_VALUES 1

#define OTEL_PB_WIRE_VARINT 0
#define OTEL_PB_WIRE_BYTES 2

static inline size_t otel_pb_varint(uint8_t *out, uint64_t value) {
Expand Down Expand Up @@ -80,11 +78,6 @@ static inline size_t otel_pb_string_value(uint8_t *out, const char *value) {
return otel_pb_bytes(out, OTEL_PB_ANY_STRING, value, strlen(value));
}

static inline size_t otel_pb_int_value(uint8_t *out, int64_t value) {
size_t off = otel_pb_tag(out, OTEL_PB_ANY_INT, OTEL_PB_WIRE_VARINT);
return off + otel_pb_varint(out + off, (uint64_t)value);
}

// Appends one KeyValue of the extra attributes, its value already encoded as an
// AnyValue in `value`.
static inline size_t otel_pb_attribute(uint8_t *out, const char *key, const uint8_t *value, size_t value_len) {
Expand All @@ -100,12 +93,6 @@ static inline size_t otel_pb_string_attribute(uint8_t *out, const char *key, con
return otel_pb_attribute(out, key, any, any_len);
}

static inline size_t otel_pb_int_attribute(uint8_t *out, const char *key, int64_t value) {
uint8_t any[32];
size_t any_len = otel_pb_int_value(any, value);
return otel_pb_attribute(out, key, any, any_len);
}

static inline size_t otel_pb_string_array_attribute(uint8_t *out, const char *key, const char *const *values,
size_t count) {
uint8_t array[512];
Expand Down
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