| Message ID | 20191009160907.10981-3-christian.brauner@ubuntu.com |
|---|---|
| State | Changes Requested |
| Delegated to: | BPF Maintainers |
| Headers | show |
| Series | bpf: switch to new usercopy helpers | expand |
On 2019-10-09, Christian Brauner <christian.brauner@ubuntu.com> wrote: > 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") > Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com> Acked-by: Aleksa Sarai <cyphar@cyphar.com> > --- > kernel/bpf/syscall.c | 7 ++----- > 1 file changed, 2 insertions(+), 5 deletions(-) > > diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c > index 78790778f101..6f4f9097b1fe 100644 > --- a/kernel/bpf/syscall.c > +++ b/kernel/bpf/syscall.c > @@ -2312,13 +2312,10 @@ static int bpf_prog_get_info_by_fd(struct bpf_prog *prog, > u32 ulen; > int err; > > - err = bpf_check_uarg_tail_zero(uinfo, sizeof(info), info_len); > + info_len = min_t(u32, 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; > -- > 2.23.0
diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c index 78790778f101..6f4f9097b1fe 100644 --- a/kernel/bpf/syscall.c +++ b/kernel/bpf/syscall.c @@ -2312,13 +2312,10 @@ static int bpf_prog_get_info_by_fd(struct bpf_prog *prog, u32 ulen; int err; - err = bpf_check_uarg_tail_zero(uinfo, sizeof(info), info_len); + info_len = min_t(u32, 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;
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") Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com> --- kernel/bpf/syscall.c | 7 ++----- 1 file changed, 2 insertions(+), 5 deletions(-)