bpf: Change bpf_obj_name_cpy() to better ensure map's name is init by 0
During get_info_by_fd, the prog/map name is memcpy-ed. It depends
on the prog->aux->name and map->name to be zero initialized.
bpf_prog_aux is easy to guarantee that aux->name is zero init.
The name in bpf_map may be harder to be guaranteed in the future when
new map type is added.
Hence, this patch makes bpf_obj_name_cpy() to always zero init
the prog/map name.
Suggested-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: Martin KaFai Lau <kafai@fb.com>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c
index 0048cb2..d124e70 100644
--- a/kernel/bpf/syscall.c
+++ b/kernel/bpf/syscall.c
@@ -322,6 +322,8 @@ static int bpf_obj_name_cpy(char *dst, const char *src)
{
const char *end = src + BPF_OBJ_NAME_LEN;
+ memset(dst, 0, BPF_OBJ_NAME_LEN);
+
/* Copy all isalnum() and '_' char */
while (src < end && *src) {
if (!isalnum(*src) && *src != '_')
@@ -333,9 +335,6 @@ static int bpf_obj_name_cpy(char *dst, const char *src)
if (src == end)
return -EINVAL;
- /* '\0' terminates dst */
- *dst = 0;
-
return 0;
}
