@@ -2304,21 +2304,18 @@ static int bpf_prog_get_info_by_fd(struct bpf_prog *prog,
union bpf_attr __user *uattr)
{
struct bpf_prog_info __user *uinfo = u64_to_user_ptr(attr->info.info);
- struct bpf_prog_info info = {};
+ struct bpf_prog_info info;
u32 info_len = attr->info.info_len;
struct bpf_prog_stats stats;
char __user *uinsns;
u32 ulen;
int err;
- err = bpf_check_uarg_tail_zero(uinfo, sizeof(info), info_len);
+ err = copy_struct_from_user(&info, sizeof(info), uinfo, info_len);
if (err)
return err;
info_len = min_t(u32, sizeof(info), info_len);
- if (copy_from_user(&info, uinfo, info_len))
- return -EFAULT;
-
info.type = prog->type;
info.id = prog->aux->id;
info.load_time = prog->aux->load_time;
In v5.4-rc2 we added a new helper (cf. [1]) copy_struct_from_user(). This helper is intended for all codepaths that copy structs from userspace that are versioned by size. bpf_prog_get_info_by_fd() does exactly what copy_struct_from_user() is doing. Note that copy_struct_from_user() is calling min() already. So technically, the min_t() call could go. But the info_len is used further below so leave it. [1]: f5a1a536fa14 ("lib: introduce copy_struct_from_user() helper") Cc: Alexei Starovoitov <ast@kernel.org> Cc: Daniel Borkmann <daniel@iogearbox.net> Cc: Aleksa Sarai <cyphar@cyphar.com> Cc: bpf@vger.kernel.org Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com> --- /* v1 */ Link: https://lore.kernel.org/r/20191009160907.10981-3-christian.brauner@ubuntu.com /* v2 */ Link: https://lore.kernel.org/r/20191016004138.24845-3-christian.brauner@ubuntu.com - Alexei Starovoitov <ast@kernel.org>: - remove unneeded initialization /* v3 */ Link: https://lore.kernel.org/r/20191016034432.4418-3-christian.brauner@ubuntu.com unchanged /* v4 */ - Alexei Starovoitov <ast@kernel.org>: - move misplaced min after copy_struct_from_user() --- kernel/bpf/syscall.c | 7 ++----- 1 file changed, 2 insertions(+), 5 deletions(-)