bpf: Allow some trace helpers for all prog types

kknjh · Kernel Patches Daemon · commit e75ef2f6f771 · 2025-04-25T01:06:38.000-07:00
if it works under NMI and doesn't use any context-dependent things, should be fine for any program type. The detailed discussion is in [1]. [1] https://lore.kernel.org/all/CAEf4Bza6gK3dsrTosk6k3oZgtHesNDSrDd8sdeQ-GiS6oJixQg@mail.gmail.com/ Suggested-by: Andrii Nakryiko <andrii.nakryiko@gmail.com> Signed-off-by: Feng Yang <yangfeng@kylinos.cn>
diff --git a/kernel/bpf/cgroup.c b/kernel/bpf/cgroup.c
@@ -2607,16 +2607,10 @@ const struct bpf_func_proto *
 cgroup_current_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog)
 {
 	switch (func_id) {
-	case BPF_FUNC_get_current_uid_gid:
-		return &bpf_get_current_uid_gid_proto;
-	case BPF_FUNC_get_current_comm:
-		return &bpf_get_current_comm_proto;
 #ifdef CONFIG_CGROUP_NET_CLASSID
 	case BPF_FUNC_get_cgroup_classid:
 		return &bpf_get_cgroup_classid_curr_proto;
 #endif
-	case BPF_FUNC_current_task_under_cgroup:
-		return &bpf_current_task_under_cgroup_proto;
 	default:
 		return NULL;
 	}
diff --git a/kernel/bpf/helpers.c b/kernel/bpf/helpers.c
@@ -23,6 +23,7 @@
 #include <linux/btf_ids.h>
 #include <linux/bpf_mem_alloc.h>
 #include <linux/kasan.h>
+#include <linux/bpf_verifier.h>
 
 #include "../../lib/kstrtox.h"
 
@@ -1907,11 +1908,21 @@ static const struct bpf_func_proto bpf_dynptr_data_proto = {
 
 const struct bpf_func_proto bpf_get_current_task_proto __weak;
 const struct bpf_func_proto bpf_get_current_task_btf_proto __weak;
+#ifdef CONFIG_ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE
+const struct bpf_func_proto bpf_probe_read_compat_proto __weak;
+const struct bpf_func_proto bpf_probe_read_compat_str_proto __weak;
+#endif
 const struct bpf_func_proto bpf_probe_read_user_proto __weak;
 const struct bpf_func_proto bpf_probe_read_user_str_proto __weak;
 const struct bpf_func_proto bpf_probe_read_kernel_proto __weak;
 const struct bpf_func_proto bpf_probe_read_kernel_str_proto __weak;
 const struct bpf_func_proto bpf_task_pt_regs_proto __weak;
+const struct bpf_func_proto bpf_perf_event_read_proto __weak;
+const struct bpf_func_proto bpf_send_signal_proto __weak;
+const struct bpf_func_proto bpf_send_signal_thread_proto __weak;
+const struct bpf_func_proto bpf_get_task_stack_sleepable_proto __weak;
+const struct bpf_func_proto bpf_get_task_stack_proto __weak;
+const struct bpf_func_proto bpf_get_branch_snapshot_proto __weak;
 
 const struct bpf_func_proto *
 bpf_base_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog)
@@ -1965,6 +1976,8 @@ bpf_base_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog)
 		return &bpf_get_current_pid_tgid_proto;
 	case BPF_FUNC_get_ns_current_pid_tgid:
 		return &bpf_get_ns_current_pid_tgid_proto;
+	case BPF_FUNC_get_current_uid_gid:
+		return &bpf_get_current_uid_gid_proto;
 	default:
 		break;
 	}
@@ -2022,6 +2035,8 @@ bpf_base_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog)
 		return &bpf_get_current_cgroup_id_proto;
 	case BPF_FUNC_get_current_ancestor_cgroup_id:
 		return &bpf_get_current_ancestor_cgroup_id_proto;
+	case BPF_FUNC_current_task_under_cgroup:
+		return &bpf_current_task_under_cgroup_proto;
 #endif
 	default:
 		break;
@@ -2037,6 +2052,16 @@ bpf_base_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog)
 		return &bpf_get_current_task_proto;
 	case BPF_FUNC_get_current_task_btf:
 		return &bpf_get_current_task_btf_proto;
+	case BPF_FUNC_get_current_comm:
+		return &bpf_get_current_comm_proto;
+#ifdef CONFIG_ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE
+	case BPF_FUNC_probe_read:
+		return security_locked_down(LOCKDOWN_BPF_READ_KERNEL) < 0 ?
+		       NULL : &bpf_probe_read_compat_proto;
+	case BPF_FUNC_probe_read_str:
+		return security_locked_down(LOCKDOWN_BPF_READ_KERNEL) < 0 ?
+		       NULL : &bpf_probe_read_compat_str_proto;
+#endif
 	case BPF_FUNC_probe_read_user:
 		return &bpf_probe_read_user_proto;
 	case BPF_FUNC_probe_read_kernel:
@@ -2057,6 +2082,31 @@ bpf_base_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog)
 		return bpf_get_trace_vprintk_proto();
 	case BPF_FUNC_perf_event_read_value:
 		return bpf_get_perf_event_read_value_proto();
+	case BPF_FUNC_perf_event_read:
+		return &bpf_perf_event_read_proto;
+	case BPF_FUNC_send_signal:
+		return &bpf_send_signal_proto;
+	case BPF_FUNC_send_signal_thread:
+		return &bpf_send_signal_thread_proto;
+	case BPF_FUNC_get_task_stack:
+		return prog->sleepable ? &bpf_get_task_stack_sleepable_proto
+				       : &bpf_get_task_stack_proto;
+	case BPF_FUNC_copy_from_user:
+		return prog->sleepable ? &bpf_copy_from_user_proto : NULL;
+	case BPF_FUNC_copy_from_user_task:
+		return prog->sleepable ? &bpf_copy_from_user_task_proto : NULL;
+	case BPF_FUNC_task_storage_get:
+		if (bpf_prog_check_recur(prog))
+			return &bpf_task_storage_get_recur_proto;
+		return &bpf_task_storage_get_proto;
+	case BPF_FUNC_task_storage_delete:
+		if (bpf_prog_check_recur(prog))
+			return &bpf_task_storage_delete_recur_proto;
+		return &bpf_task_storage_delete_proto;
+	case BPF_FUNC_get_branch_snapshot:
+		return &bpf_get_branch_snapshot_proto;
+	case BPF_FUNC_find_vma:
+		return &bpf_find_vma_proto;
 	default:
 		return NULL;
 	}
diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c
@@ -294,7 +294,7 @@ BPF_CALL_3(bpf_probe_read_compat, void *, dst, u32, size,
 	return bpf_probe_read_kernel_common(dst, size, unsafe_ptr);
 }
 
-static const struct bpf_func_proto bpf_probe_read_compat_proto = {
+const struct bpf_func_proto bpf_probe_read_compat_proto = {
 	.func		= bpf_probe_read_compat,
 	.gpl_only	= true,
 	.ret_type	= RET_INTEGER,
@@ -313,7 +313,7 @@ BPF_CALL_3(bpf_probe_read_compat_str, void *, dst, u32, size,
 	return bpf_probe_read_kernel_str_common(dst, size, unsafe_ptr);
 }
 
-static const struct bpf_func_proto bpf_probe_read_compat_str_proto = {
+const struct bpf_func_proto bpf_probe_read_compat_str_proto = {
 	.func		= bpf_probe_read_compat_str,
 	.gpl_only	= true,
 	.ret_type	= RET_INTEGER,
@@ -572,7 +572,7 @@ BPF_CALL_2(bpf_perf_event_read, struct bpf_map *, map, u64, flags)
 	return value;
 }
 
-static const struct bpf_func_proto bpf_perf_event_read_proto = {
+const struct bpf_func_proto bpf_perf_event_read_proto = {
 	.func		= bpf_perf_event_read,
 	.gpl_only	= true,
 	.ret_type	= RET_INTEGER,
@@ -882,7 +882,7 @@ BPF_CALL_1(bpf_send_signal, u32, sig)
 	return bpf_send_signal_common(sig, PIDTYPE_TGID, NULL, 0);
 }
 
-static const struct bpf_func_proto bpf_send_signal_proto = {
+const struct bpf_func_proto bpf_send_signal_proto = {
 	.func		= bpf_send_signal,
 	.gpl_only	= false,
 	.ret_type	= RET_INTEGER,
@@ -894,7 +894,7 @@ BPF_CALL_1(bpf_send_signal_thread, u32, sig)
 	return bpf_send_signal_common(sig, PIDTYPE_PID, NULL, 0);
 }
 
-static const struct bpf_func_proto bpf_send_signal_thread_proto = {
+const struct bpf_func_proto bpf_send_signal_thread_proto = {
 	.func		= bpf_send_signal_thread,
 	.gpl_only	= false,
 	.ret_type	= RET_INTEGER,
@@ -1185,7 +1185,7 @@ BPF_CALL_3(bpf_get_branch_snapshot, void *, buf, u32, size, u64, flags)
 	return entry_cnt * br_entry_size;
 }
 
-static const struct bpf_func_proto bpf_get_branch_snapshot_proto = {
+const struct bpf_func_proto bpf_get_branch_snapshot_proto = {
 	.func		= bpf_get_branch_snapshot,
 	.gpl_only	= true,
 	.ret_type	= RET_INTEGER,
@@ -1430,51 +1430,10 @@ bpf_tracing_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog)
 	const struct bpf_func_proto *func_proto;
 
 	switch (func_id) {
-	case BPF_FUNC_get_current_uid_gid:
-		return &bpf_get_current_uid_gid_proto;
-	case BPF_FUNC_get_current_comm:
-		return &bpf_get_current_comm_proto;
 	case BPF_FUNC_get_smp_processor_id:
 		return &bpf_get_smp_processor_id_proto;
-	case BPF_FUNC_perf_event_read:
-		return &bpf_perf_event_read_proto;
-#ifdef CONFIG_ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE
-	case BPF_FUNC_probe_read:
-		return security_locked_down(LOCKDOWN_BPF_READ_KERNEL) < 0 ?
-		       NULL : &bpf_probe_read_compat_proto;
-	case BPF_FUNC_probe_read_str:
-		return security_locked_down(LOCKDOWN_BPF_READ_KERNEL) < 0 ?
-		       NULL : &bpf_probe_read_compat_str_proto;
-#endif
-#ifdef CONFIG_CGROUPS
-	case BPF_FUNC_current_task_under_cgroup:
-		return &bpf_current_task_under_cgroup_proto;
-#endif
-	case BPF_FUNC_send_signal:
-		return &bpf_send_signal_proto;
-	case BPF_FUNC_send_signal_thread:
-		return &bpf_send_signal_thread_proto;
-	case BPF_FUNC_get_task_stack:
-		return prog->sleepable ? &bpf_get_task_stack_sleepable_proto
-				       : &bpf_get_task_stack_proto;
-	case BPF_FUNC_copy_from_user:
-		return &bpf_copy_from_user_proto;
-	case BPF_FUNC_copy_from_user_task:
-		return &bpf_copy_from_user_task_proto;
-	case BPF_FUNC_task_storage_get:
-		if (bpf_prog_check_recur(prog))
-			return &bpf_task_storage_get_recur_proto;
-		return &bpf_task_storage_get_proto;
-	case BPF_FUNC_task_storage_delete:
-		if (bpf_prog_check_recur(prog))
-			return &bpf_task_storage_delete_recur_proto;
-		return &bpf_task_storage_delete_proto;
 	case BPF_FUNC_get_func_ip:
 		return &bpf_get_func_ip_proto_tracing;
-	case BPF_FUNC_get_branch_snapshot:
-		return &bpf_get_branch_snapshot_proto;
-	case BPF_FUNC_find_vma:
-		return &bpf_find_vma_proto;
 	default:
 		break;
 	}
diff --git a/net/core/filter.c b/net/core/filter.c
@@ -8488,8 +8488,6 @@ sk_msg_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog)
 		return &bpf_msg_pop_data_proto;
 	case BPF_FUNC_perf_event_output:
 		return &bpf_event_output_data_proto;
-	case BPF_FUNC_get_current_uid_gid:
-		return &bpf_get_current_uid_gid_proto;
 	case BPF_FUNC_sk_storage_get:
 		return &bpf_sk_storage_get_proto;
 	case BPF_FUNC_sk_storage_delete:
