Merge branch 'bpf_func_info-improvements'

Martin KaFai Lau says:

====================
The patchset has a few improvements on bpf_func_info:
1. Improvements on the behaviors of info.func_info, info.func_info_cnt
   and info.func_info_rec_size.
2. Name change: s/insn_offset/insn_off/

Please see individual patch for details.
====================

Signed-off-by: Alexei Starovoitov <ast@kernel.org>

3 files changed, 30 insertions, 36 deletions

diff --git a/kernel/bpf/core.c b/kernel/bpf/core.c
index 86817ab204e8..628b3970a49b 100644
--- a/kernel/bpf/core.c
+++ b/kernel/bpf/core.c
@@ -410,7 +410,7 @@ static void bpf_get_prog_name(const struct bpf_prog *prog, char *sym)
 	sym  = bin2hex(sym, prog->tag, sizeof(prog->tag));
 
 	/* prog->aux->name will be ignored if full btf name is available */
-	if (prog->aux->btf) {
+	if (prog->aux->func_info_cnt) {
 		type = btf_type_by_id(prog->aux->btf,
 				      prog->aux->func_info[prog->aux->func_idx].type_id);
 		func_name = btf_name_by_offset(prog->aux->btf, type->name_off);
diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c
index 4445d0d084d8..aa05aa38f4a8 100644
--- a/kernel/bpf/syscall.c
+++ b/kernel/bpf/syscall.c
@@ -2083,6 +2083,12 @@ static int bpf_prog_get_info_by_fd(struct bpf_prog *prog,
 				return -EFAULT;
 	}
 
+	if ((info.func_info_cnt || info.func_info_rec_size) &&
+	    info.func_info_rec_size != sizeof(struct bpf_func_info))
+		return -EINVAL;
+
+	info.func_info_rec_size = sizeof(struct bpf_func_info);
+
 	if (!capable(CAP_SYS_ADMIN)) {
 		info.jited_prog_len = 0;
 		info.xlated_prog_len = 0;
@@ -2226,35 +2232,23 @@ static int bpf_prog_get_info_by_fd(struct bpf_prog *prog,
 		}
 	}
 
-	if (prog->aux->btf) {
-		u32 krec_size = sizeof(struct bpf_func_info);
-		u32 ucnt, urec_size;
-
+	if (prog->aux->btf)
 		info.btf_id = btf_id(prog->aux->btf);
 
-		ucnt = info.func_info_cnt;
-		info.func_info_cnt = prog->aux->func_info_cnt;
-		urec_size = info.func_info_rec_size;
-		info.func_info_rec_size = krec_size;
-		if (ucnt) {
-			/* expect passed-in urec_size is what the kernel expects */
-			if (urec_size != info.func_info_rec_size)
-				return -EINVAL;
-
-			if (bpf_dump_raw_ok()) {
-				char __user *user_finfo;
-
-				user_finfo = u64_to_user_ptr(info.func_info);
-				ucnt = min_t(u32, info.func_info_cnt, ucnt);
-				if (copy_to_user(user_finfo, prog->aux->func_info,
-						 krec_size * ucnt))
-					return -EFAULT;
-			} else {
-				info.func_info_cnt = 0;
-			}
+	ulen = info.func_info_cnt;
+	info.func_info_cnt = prog->aux->func_info_cnt;
+	if (info.func_info_cnt && ulen) {
+		if (bpf_dump_raw_ok()) {
+			char __user *user_finfo;
+
+			user_finfo = u64_to_user_ptr(info.func_info);
+			ulen = min_t(u32, info.func_info_cnt, ulen);
+			if (copy_to_user(user_finfo, prog->aux->func_info,
+					 info.func_info_rec_size * ulen))
+				return -EFAULT;
+		} else {
+			info.func_info = 0;
 		}
-	} else {
-		info.func_info_cnt = 0;
 	}
 
 done:
diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index 71988337ac14..7658c61c1a88 100644
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -4707,24 +4707,24 @@ static int check_btf_func(struct bpf_prog *prog, struct bpf_verifier_env *env,
 			goto free_btf;
 		}
 
-		/* check insn_offset */
+		/* check insn_off */
 		if (i == 0) {
-			if (krecord[i].insn_offset) {
+			if (krecord[i].insn_off) {
 				verbose(env,
-					"nonzero insn_offset %u for the first func info record",
-					krecord[i].insn_offset);
+					"nonzero insn_off %u for the first func info record",
+					krecord[i].insn_off);
 				ret = -EINVAL;
 				goto free_btf;
 			}
-		} else if (krecord[i].insn_offset <= prev_offset) {
+		} else if (krecord[i].insn_off <= prev_offset) {
 			verbose(env,
 				"same or smaller insn offset (%u) than previous func info record (%u)",
-				krecord[i].insn_offset, prev_offset);
+				krecord[i].insn_off, prev_offset);
 			ret = -EINVAL;
 			goto free_btf;
 		}
 
-		if (env->subprog_info[i].start != krecord[i].insn_offset) {
+		if (env->subprog_info[i].start != krecord[i].insn_off) {
 			verbose(env, "func_info BTF section doesn't match subprog layout in BPF program\n");
 			ret = -EINVAL;
 			goto free_btf;
@@ -4739,7 +4739,7 @@ static int check_btf_func(struct bpf_prog *prog, struct bpf_verifier_env *env,
 			goto free_btf;
 		}
 
-		prev_offset = krecord[i].insn_offset;
+		prev_offset = krecord[i].insn_off;
 		urecord += urec_size;
 	}
 
@@ -4762,7 +4762,7 @@ static void adjust_btf_func(struct bpf_verifier_env *env)
 		return;
 
 	for (i = 0; i < env->subprog_cnt; i++)
-		env->prog->aux->func_info[i].insn_offset = env->subprog_info[i].start;
+		env->prog->aux->func_info[i].insn_off = env->subprog_info[i].start;
 }
 
 /* check %cur's range satisfies %old's */