bpf: Make btf_load command to be bpfptr_t compatible.

Similar to prog_load make btf_load command to be availble to
bpf_prog_type_syscall program.
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20210514003623.28033-7-alexei.starovoitov@gmail.com

include/linux/btf.h

@@ -21,7 +21,7 @@ extern const struct file_operations btf_fops;
 
 void btf_get(struct btf *btf);
 void btf_put(struct btf *btf);
-int btf_new_fd(const union bpf_attr *attr);
+int btf_new_fd(const union bpf_attr *attr, bpfptr_t uattr);
 struct btf *btf_get_by_fd(int fd);
 int btf_get_info_by_fd(const struct btf *btf,
 		       const union bpf_attr *attr,

kernel/bpf/btf.c

@@ -4257,7 +4257,7 @@ static int btf_parse_hdr(struct btf_verifier_env *env)
 	return 0;
 }
 
-static struct btf *btf_parse(void __user *btf_data, u32 btf_data_size,
+static struct btf *btf_parse(bpfptr_t btf_data, u32 btf_data_size,
 			     u32 log_level, char __user *log_ubuf, u32 log_size)
 {
 	struct btf_verifier_env *env = NULL;
@@ -4306,7 +4306,7 @@ static struct btf *btf_parse(void __user *btf_data, u32 btf_data_size,
 	btf->data = data;
 	btf->data_size = btf_data_size;
 
-	if (copy_from_user(data, btf_data, btf_data_size)) {
+	if (copy_from_bpfptr(data, btf_data, btf_data_size)) {
 		err = -EFAULT;
 		goto errout;
 	}
@@ -5780,12 +5780,12 @@ static int __btf_new_fd(struct btf *btf)
 	return anon_inode_getfd("btf", &btf_fops, btf, O_RDONLY | O_CLOEXEC);
 }
 
-int btf_new_fd(const union bpf_attr *attr)
+int btf_new_fd(const union bpf_attr *attr, bpfptr_t uattr)
 {
 	struct btf *btf;
 	int ret;
 
-	btf = btf_parse(u64_to_user_ptr(attr->btf),
+	btf = btf_parse(make_bpfptr(attr->btf, uattr.is_kernel),
 			attr->btf_size, attr->btf_log_level,
 			u64_to_user_ptr(attr->btf_log_buf),
 			attr->btf_log_size);

kernel/bpf/syscall.c

@@ -3842,7 +3842,7 @@ static int bpf_obj_get_info_by_fd(const union bpf_attr *attr,
 
 #define BPF_BTF_LOAD_LAST_FIELD btf_log_level
 
-static int bpf_btf_load(const union bpf_attr *attr)
+static int bpf_btf_load(const union bpf_attr *attr, bpfptr_t uattr)
 {
 	if (CHECK_ATTR(BPF_BTF_LOAD))
 		return -EINVAL;
@@ -3850,7 +3850,7 @@ static int bpf_btf_load(const union bpf_attr *attr)
 	if (!bpf_capable())
 		return -EPERM;
 
-	return btf_new_fd(attr);
+	return btf_new_fd(attr, uattr);
 }
 
 #define BPF_BTF_GET_FD_BY_ID_LAST_FIELD btf_id
@@ -4471,7 +4471,7 @@ static int __sys_bpf(int cmd, bpfptr_t uattr, unsigned int size)
 		err = bpf_raw_tracepoint_open(&attr);
 		break;
 	case BPF_BTF_LOAD:
-		err = bpf_btf_load(&attr);
+		err = bpf_btf_load(&attr, uattr);
 		break;
 	case BPF_BTF_GET_FD_BY_ID:
 		err = bpf_btf_get_fd_by_id(&attr);
@@ -4552,6 +4552,7 @@ BPF_CALL_3(bpf_sys_bpf, int, cmd, void *, attr, u32, attr_size)
 	case BPF_MAP_UPDATE_ELEM:
 	case BPF_MAP_FREEZE:
 	case BPF_PROG_LOAD:
+	case BPF_BTF_LOAD:
 		break;
 	/* case BPF_PROG_TEST_RUN:
 	 * is not part of this list to prevent recursive test_run