Commit 69a0f9ec authored by Yonghong Song's avatar Yonghong Song Committed by Daniel Borkmann
Browse files

bpf, bpftool: fix a few ubsan warnings 

The issue is reported at https://github.com/libbpf/libbpf/issues/28

.

Basically, per C standard, for
  void *memcpy(void *dest, const void *src, size_t n)
if "dest" or "src" is NULL, regardless of whether "n" is 0 or not,
the result of memcpy is undefined. clang ubsan reported three such
instances in bpf.c with the following pattern:
  memcpy(dest, 0, 0).

Although in practice, no known compiler will cause issues when
copy size is 0. Let us still fix the issue to silence ubsan
warnings.

Signed-off-by: default avatarYonghong Song <yhs@fb.com>
Signed-off-by: default avatarDaniel Borkmann <daniel@iogearbox.net>
parent 6316f783

tools/lib/bpf/bpf.c

+9 −10
Original line number Original line Diff line number Diff line
@@ -79,7 +79,6 @@ static inline int sys_bpf_prog_load(union bpf_attr *attr, unsigned int size) 




int bpf_create_map_xattr(const struct bpf_create_map_attr *create_attr)

int bpf_create_map_xattr(const struct bpf_create_map_attr *create_attr)

{

{

	__u32 name_len = create_attr->name ? strlen(create_attr->name) : 0;

	union bpf_attr attr;

	union bpf_attr attr;





	memset(&attr, '\0', sizeof(attr));

	memset(&attr, '\0', sizeof(attr));
@@ -89,8 +88,9 @@ int bpf_create_map_xattr(const struct bpf_create_map_attr *create_attr) 
	attr.value_size = create_attr->value_size;

	attr.value_size = create_attr->value_size;

	attr.max_entries = create_attr->max_entries;

	attr.max_entries = create_attr->max_entries;

	attr.map_flags = create_attr->map_flags;

	attr.map_flags = create_attr->map_flags;

	if (create_attr->name)

		memcpy(attr.map_name, create_attr->name,

		memcpy(attr.map_name, create_attr->name,

	       min(name_len, BPF_OBJ_NAME_LEN - 1));

		       min(strlen(create_attr->name), BPF_OBJ_NAME_LEN - 1));

	attr.numa_node = create_attr->numa_node;

	attr.numa_node = create_attr->numa_node;

	attr.btf_fd = create_attr->btf_fd;

	attr.btf_fd = create_attr->btf_fd;

	attr.btf_key_type_id = create_attr->btf_key_type_id;

	attr.btf_key_type_id = create_attr->btf_key_type_id;
@@ -155,7 +155,6 @@ int bpf_create_map_in_map_node(enum bpf_map_type map_type, const char *name, 
			       int key_size, int inner_map_fd, int max_entries,

			       int key_size, int inner_map_fd, int max_entries,

			       __u32 map_flags, int node)

			       __u32 map_flags, int node)

{

{

	__u32 name_len = name ? strlen(name) : 0;

	union bpf_attr attr;

	union bpf_attr attr;





	memset(&attr, '\0', sizeof(attr));

	memset(&attr, '\0', sizeof(attr));
@@ -166,7 +165,9 @@ int bpf_create_map_in_map_node(enum bpf_map_type map_type, const char *name, 
	attr.inner_map_fd = inner_map_fd;

	attr.inner_map_fd = inner_map_fd;

	attr.max_entries = max_entries;

	attr.max_entries = max_entries;

	attr.map_flags = map_flags;

	attr.map_flags = map_flags;

	memcpy(attr.map_name, name, min(name_len, BPF_OBJ_NAME_LEN - 1));

	if (name)

		memcpy(attr.map_name, name,

		       min(strlen(name), BPF_OBJ_NAME_LEN - 1));





	if (node >= 0) {

	if (node >= 0) {

		attr.map_flags |= BPF_F_NUMA_NODE;

		attr.map_flags |= BPF_F_NUMA_NODE;
@@ -216,7 +217,6 @@ int bpf_load_program_xattr(const struct bpf_load_program_attr *load_attr, 
	void *finfo = NULL, *linfo = NULL;

	void *finfo = NULL, *linfo = NULL;

	union bpf_attr attr;

	union bpf_attr attr;

	__u32 log_level;

	__u32 log_level;

	__u32 name_len;

	int fd;

	int fd;





	if (!load_attr || !log_buf != !log_buf_sz)

	if (!load_attr || !log_buf != !log_buf_sz)
@@ -226,8 +226,6 @@ int bpf_load_program_xattr(const struct bpf_load_program_attr *load_attr, 
	if (log_level > (4 | 2 | 1) || (log_level && !log_buf))

	if (log_level > (4 | 2 | 1) || (log_level && !log_buf))

		return -EINVAL;

		return -EINVAL;





	name_len = load_attr->name ? strlen(load_attr->name) : 0;



	memset(&attr, 0, sizeof(attr));

	memset(&attr, 0, sizeof(attr));

	attr.prog_type = load_attr->prog_type;

	attr.prog_type = load_attr->prog_type;

	attr.expected_attach_type = load_attr->expected_attach_type;

	attr.expected_attach_type = load_attr->expected_attach_type;
@@ -253,8 +251,9 @@ int bpf_load_program_xattr(const struct bpf_load_program_attr *load_attr, 
	attr.line_info_rec_size = load_attr->line_info_rec_size;

	attr.line_info_rec_size = load_attr->line_info_rec_size;

	attr.line_info_cnt = load_attr->line_info_cnt;

	attr.line_info_cnt = load_attr->line_info_cnt;

	attr.line_info = ptr_to_u64(load_attr->line_info);

	attr.line_info = ptr_to_u64(load_attr->line_info);

	if (load_attr->name)

		memcpy(attr.prog_name, load_attr->name,

		memcpy(attr.prog_name, load_attr->name,

	       min(name_len, BPF_OBJ_NAME_LEN - 1));

		       min(strlen(load_attr->name), BPF_OBJ_NAME_LEN - 1));





	fd = sys_bpf_prog_load(&attr, sizeof(attr));

	fd = sys_bpf_prog_load(&attr, sizeof(attr));

	if (fd >= 0)

	if (fd >= 0)

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