Linux-libre 4.7.1-gnupck-4.7.1-gnu

1 files changed, 130 insertions, 7 deletions

diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c
index d0289414c..26f603da7 100644
--- a/kernel/trace/bpf_trace.c
+++ b/kernel/trace/bpf_trace.c
@@ -62,17 +62,21 @@ EXPORT_SYMBOL_GPL(trace_call_bpf);
 static u64 bpf_probe_read(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5)
 {
 	void *dst = (void *) (long) r1;
-	int size = (int) r2;
+	int ret, size = (int) r2;
 	void *unsafe_ptr = (void *) (long) r3;
 
-	return probe_kernel_read(dst, unsafe_ptr, size);
+	ret = probe_kernel_read(dst, unsafe_ptr, size);
+	if (unlikely(ret < 0))
+		memset(dst, 0, size);
+
+	return ret;
 }
 
 static const struct bpf_func_proto bpf_probe_read_proto = {
 	.func		= bpf_probe_read,
 	.gpl_only	= true,
 	.ret_type	= RET_INTEGER,
-	.arg1_type	= ARG_PTR_TO_STACK,
+	.arg1_type	= ARG_PTR_TO_RAW_STACK,
 	.arg2_type	= ARG_CONST_STACK_SIZE,
 	.arg3_type	= ARG_ANYTHING,
 };
@@ -205,6 +209,10 @@ static u64 bpf_perf_event_read(u64 r1, u64 index, u64 r3, u64 r4, u64 r5)
 	    event->pmu->count)
 		return -EINVAL;
 
+	if (unlikely(event->attr.type != PERF_TYPE_HARDWARE &&
+		     event->attr.type != PERF_TYPE_RAW))
+		return -EINVAL;
+
 	/*
 	 * we don't know if the function is run successfully by the
 	 * return value. It can be judged in other places, such as
@@ -221,11 +229,12 @@ static const struct bpf_func_proto bpf_perf_event_read_proto = {
 	.arg2_type	= ARG_ANYTHING,
 };
 
-static u64 bpf_perf_event_output(u64 r1, u64 r2, u64 index, u64 r4, u64 size)
+static u64 bpf_perf_event_output(u64 r1, u64 r2, u64 flags, u64 r4, u64 size)
 {
 	struct pt_regs *regs = (struct pt_regs *) (long) r1;
 	struct bpf_map *map = (struct bpf_map *) (long) r2;
 	struct bpf_array *array = container_of(map, struct bpf_array, map);
+	u64 index = flags & BPF_F_INDEX_MASK;
 	void *data = (void *) (long) r4;
 	struct perf_sample_data sample_data;
 	struct perf_event *event;
@@ -235,6 +244,10 @@ static u64 bpf_perf_event_output(u64 r1, u64 r2, u64 index, u64 r4, u64 size)
 		.data = data,
 	};
 
+	if (unlikely(flags & ~(BPF_F_INDEX_MASK)))
+		return -EINVAL;
+	if (index == BPF_F_CURRENT_CPU)
+		index = raw_smp_processor_id();
 	if (unlikely(index >= array->map.max_entries))
 		return -E2BIG;
 
@@ -268,7 +281,34 @@ static const struct bpf_func_proto bpf_perf_event_output_proto = {
 	.arg5_type	= ARG_CONST_STACK_SIZE,
 };
 
-static const struct bpf_func_proto *kprobe_prog_func_proto(enum bpf_func_id func_id)
+static DEFINE_PER_CPU(struct pt_regs, bpf_pt_regs);
+
+static u64 bpf_event_output(u64 r1, u64 r2, u64 flags, u64 r4, u64 size)
+{
+	struct pt_regs *regs = this_cpu_ptr(&bpf_pt_regs);
+
+	perf_fetch_caller_regs(regs);
+
+	return bpf_perf_event_output((long)regs, r2, flags, r4, size);
+}
+
+static const struct bpf_func_proto bpf_event_output_proto = {
+	.func		= bpf_event_output,
+	.gpl_only	= true,
+	.ret_type	= RET_INTEGER,
+	.arg1_type	= ARG_PTR_TO_CTX,
+	.arg2_type	= ARG_CONST_MAP_PTR,
+	.arg3_type	= ARG_ANYTHING,
+	.arg4_type	= ARG_PTR_TO_STACK,
+	.arg5_type	= ARG_CONST_STACK_SIZE,
+};
+
+const struct bpf_func_proto *bpf_get_event_output_proto(void)
+{
+	return &bpf_event_output_proto;
+}
+
+static const struct bpf_func_proto *tracing_func_proto(enum bpf_func_id func_id)
 {
 	switch (func_id) {
 	case BPF_FUNC_map_lookup_elem:
@@ -295,17 +335,26 @@ static const struct bpf_func_proto *kprobe_prog_func_proto(enum bpf_func_id func
 		return &bpf_get_smp_processor_id_proto;
 	case BPF_FUNC_perf_event_read:
 		return &bpf_perf_event_read_proto;
+	default:
+		return NULL;
+	}
+}
+
+static const struct bpf_func_proto *kprobe_prog_func_proto(enum bpf_func_id func_id)
+{
+	switch (func_id) {
 	case BPF_FUNC_perf_event_output:
 		return &bpf_perf_event_output_proto;
 	case BPF_FUNC_get_stackid:
 		return &bpf_get_stackid_proto;
 	default:
-		return NULL;
+		return tracing_func_proto(func_id);
 	}
 }
 
 /* bpf+kprobe programs can access fields of 'struct pt_regs' */
-static bool kprobe_prog_is_valid_access(int off, int size, enum bpf_access_type type)
+static bool kprobe_prog_is_valid_access(int off, int size, enum bpf_access_type type,
+					enum bpf_reg_type *reg_type)
 {
 	/* check bounds */
 	if (off < 0 || off >= sizeof(struct pt_regs))
@@ -332,9 +381,83 @@ static struct bpf_prog_type_list kprobe_tl = {
 	.type	= BPF_PROG_TYPE_KPROBE,
 };
 
+static u64 bpf_perf_event_output_tp(u64 r1, u64 r2, u64 index, u64 r4, u64 size)
+{
+	/*
+	 * r1 points to perf tracepoint buffer where first 8 bytes are hidden
+	 * from bpf program and contain a pointer to 'struct pt_regs'. Fetch it
+	 * from there and call the same bpf_perf_event_output() helper
+	 */
+	u64 ctx = *(long *)(uintptr_t)r1;
+
+	return bpf_perf_event_output(ctx, r2, index, r4, size);
+}
+
+static const struct bpf_func_proto bpf_perf_event_output_proto_tp = {
+	.func		= bpf_perf_event_output_tp,
+	.gpl_only	= true,
+	.ret_type	= RET_INTEGER,
+	.arg1_type	= ARG_PTR_TO_CTX,
+	.arg2_type	= ARG_CONST_MAP_PTR,
+	.arg3_type	= ARG_ANYTHING,
+	.arg4_type	= ARG_PTR_TO_STACK,
+	.arg5_type	= ARG_CONST_STACK_SIZE,
+};
+
+static u64 bpf_get_stackid_tp(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5)
+{
+	u64 ctx = *(long *)(uintptr_t)r1;
+
+	return bpf_get_stackid(ctx, r2, r3, r4, r5);
+}
+
+static const struct bpf_func_proto bpf_get_stackid_proto_tp = {
+	.func		= bpf_get_stackid_tp,
+	.gpl_only	= true,
+	.ret_type	= RET_INTEGER,
+	.arg1_type	= ARG_PTR_TO_CTX,
+	.arg2_type	= ARG_CONST_MAP_PTR,
+	.arg3_type	= ARG_ANYTHING,
+};
+
+static const struct bpf_func_proto *tp_prog_func_proto(enum bpf_func_id func_id)
+{
+	switch (func_id) {
+	case BPF_FUNC_perf_event_output:
+		return &bpf_perf_event_output_proto_tp;
+	case BPF_FUNC_get_stackid:
+		return &bpf_get_stackid_proto_tp;
+	default:
+		return tracing_func_proto(func_id);
+	}
+}
+
+static bool tp_prog_is_valid_access(int off, int size, enum bpf_access_type type,
+				    enum bpf_reg_type *reg_type)
+{
+	if (off < sizeof(void *) || off >= PERF_MAX_TRACE_SIZE)
+		return false;
+	if (type != BPF_READ)
+		return false;
+	if (off % size != 0)
+		return false;
+	return true;
+}
+
+static const struct bpf_verifier_ops tracepoint_prog_ops = {
+	.get_func_proto  = tp_prog_func_proto,
+	.is_valid_access = tp_prog_is_valid_access,
+};
+
+static struct bpf_prog_type_list tracepoint_tl = {
+	.ops	= &tracepoint_prog_ops,
+	.type	= BPF_PROG_TYPE_TRACEPOINT,
+};
+
 static int __init register_kprobe_prog_ops(void)
 {
 	bpf_register_prog_type(&kprobe_tl);
+	bpf_register_prog_type(&tracepoint_tl);
 	return 0;
 }
 late_initcall(register_kprobe_prog_ops);