[bpf-next,v3,2/7] bpf: Abstract out functions to check sleepable helpers

Commit Message

Yonghong Song Nov. 9, 2022, 9:19 p.m. UTC

Abstract out two functions to check whether a particular helper
is sleepable or not for bpf_lsm and bpf_trace. These two
functions will be used later to check whether a helper is
sleepable or not in verifier. There is no functionality
change.

Signed-off-by: Yonghong Song <[e-mail]>
---
 include/linux/bpf_lsm.h      |  6 ++++++
 include/linux/trace_events.h |  8 ++++++++
 kernel/bpf/bpf_lsm.c         | 20 ++++++++++++++++----
 kernel/trace/bpf_trace.c     | 22 ++++++++++++++++++----
 4 files changed, 48 insertions(+), 8 deletions(-)

Patch

diff --git a/include/linux/bpf_lsm.h b/include/linux/bpf_lsm.h
index 4bcf76a9bb06..d99b1caf118e 100644
--- a/include/linux/bpf_lsm.h
+++ b/include/linux/bpf_lsm.h
@@ -28,6 +28,7 @@  int bpf_lsm_verify_prog(struct bpf_verifier_log *vlog,
 			const struct bpf_prog *prog);
 
 bool bpf_lsm_is_sleepable_hook(u32 btf_id);
+const struct bpf_func_proto *bpf_lsm_sleepable_func_proto(enum bpf_func_id func_id);
 
 static inline struct bpf_storage_blob *bpf_inode(
 	const struct inode *inode)
@@ -50,6 +51,11 @@  static inline bool bpf_lsm_is_sleepable_hook(u32 btf_id)
 {
 	return false;
 }
+static inline const struct bpf_func_proto *
+bpf_lsm_sleepable_func_proto(enum bpf_func_id func_id)
+{
+	return NULL;
+}
 
 static inline int bpf_lsm_verify_prog(struct bpf_verifier_log *vlog,
 				      const struct bpf_prog *prog)
diff --git a/include/linux/trace_events.h b/include/linux/trace_events.h
index 20749bd9db71..c3eb4fb78ea5 100644
--- a/include/linux/trace_events.h
+++ b/include/linux/trace_events.h
@@ -9,6 +9,7 @@ 
 #include <linux/hardirq.h>
 #include <linux/perf_event.h>
 #include <linux/tracepoint.h>
+#include <uapi/linux/bpf.h>
 
 struct trace_array;
 struct array_buffer;
@@ -16,6 +17,7 @@  struct tracer;
 struct dentry;
 struct bpf_prog;
 union bpf_attr;
+struct bpf_func_proto;
 
 const char *trace_print_flags_seq(struct trace_seq *p, const char *delim,
 				  unsigned long flags,
@@ -748,6 +750,7 @@  int bpf_get_perf_event_info(const struct perf_event *event, u32 *prog_id,
 			    u32 *fd_type, const char **buf,
 			    u64 *probe_offset, u64 *probe_addr);
 int bpf_kprobe_multi_link_attach(const union bpf_attr *attr, struct bpf_prog *prog);
+const struct bpf_func_proto *bpf_tracing_sleepable_func_proto(enum bpf_func_id func_id);
 #else
 static inline unsigned int trace_call_bpf(struct trace_event_call *call, void *ctx)
 {
@@ -794,6 +797,11 @@  bpf_kprobe_multi_link_attach(const union bpf_attr *attr, struct bpf_prog *prog)
 {
 	return -EOPNOTSUPP;
 }
+static inline const struct bpf_func_proto *
+bpf_tracing_sleepable_func_proto(enum bpf_func_id func_id)
+{
+	return NULL;
+}
 #endif
 
 enum {
diff --git a/kernel/bpf/bpf_lsm.c b/kernel/bpf/bpf_lsm.c
index d6c9b3705f24..2f993a003389 100644
--- a/kernel/bpf/bpf_lsm.c
+++ b/kernel/bpf/bpf_lsm.c
@@ -192,6 +192,18 @@  static const struct bpf_func_proto bpf_get_attach_cookie_proto = {
 	.arg1_type	= ARG_PTR_TO_CTX,
 };
 
+const struct bpf_func_proto *bpf_lsm_sleepable_func_proto(enum bpf_func_id func_id)
+{
+	switch (func_id) {
+	case BPF_FUNC_ima_inode_hash:
+		return &bpf_ima_inode_hash_proto;
+	case BPF_FUNC_ima_file_hash:
+		return &bpf_ima_file_hash_proto;
+	default:
+		return NULL;
+	}
+}
+
 static const struct bpf_func_proto *
 bpf_lsm_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog)
 {
@@ -203,6 +215,10 @@  bpf_lsm_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog)
 			return func_proto;
 	}
 
+	func_proto = bpf_lsm_sleepable_func_proto(func_id);
+	if (func_proto)
+		return prog->aux->sleepable ? func_proto : NULL;
+
 	switch (func_id) {
 	case BPF_FUNC_inode_storage_get:
 		return &bpf_inode_storage_get_proto;
@@ -220,10 +236,6 @@  bpf_lsm_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog)
 		return &bpf_spin_unlock_proto;
 	case BPF_FUNC_bprm_opts_set:
 		return &bpf_bprm_opts_set_proto;
-	case BPF_FUNC_ima_inode_hash:
-		return prog->aux->sleepable ? &bpf_ima_inode_hash_proto : NULL;
-	case BPF_FUNC_ima_file_hash:
-		return prog->aux->sleepable ? &bpf_ima_file_hash_proto : NULL;
 	case BPF_FUNC_get_attach_cookie:
 		return bpf_prog_has_trampoline(prog) ? &bpf_get_attach_cookie_proto : NULL;
 #ifdef CONFIG_NET
diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c
index f2d8d070d024..7804fa71d3f1 100644
--- a/kernel/trace/bpf_trace.c
+++ b/kernel/trace/bpf_trace.c
@@ -1383,9 +1383,27 @@  static int __init bpf_key_sig_kfuncs_init(void)
 late_initcall(bpf_key_sig_kfuncs_init);
 #endif /* CONFIG_KEYS */
 
+const struct bpf_func_proto *bpf_tracing_sleepable_func_proto(enum bpf_func_id func_id)
+{
+	switch (func_id) {
+	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;
+	default:
+		return NULL;
+	}
+}
+
 static const struct bpf_func_proto *
 bpf_tracing_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog)
 {
+	const struct bpf_func_proto *func_proto;
+
+	func_proto = bpf_tracing_sleepable_func_proto(func_id);
+	if (func_proto)
+		return prog->aux->sleepable ? func_proto : NULL;
+
 	switch (func_id) {
 	case BPF_FUNC_map_lookup_elem:
 		return &bpf_map_lookup_elem_proto;
@@ -1484,10 +1502,6 @@  bpf_tracing_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog)
 		return &bpf_jiffies64_proto;
 	case BPF_FUNC_get_task_stack:
 		return &bpf_get_task_stack_proto;
-	case BPF_FUNC_copy_from_user:
-		return prog->aux->sleepable ? &bpf_copy_from_user_proto : NULL;
-	case BPF_FUNC_copy_from_user_task:
-		return prog->aux->sleepable ? &bpf_copy_from_user_task_proto : NULL;
 	case BPF_FUNC_snprintf_btf:
 		return &bpf_snprintf_btf_proto;
 	case BPF_FUNC_per_cpu_ptr: