On 2019-10-09, Christian Brauner <christian.brau...@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.brau...@ubuntu.com>Acked-by: Aleksa Sarai <cyp...@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 -- Aleksa Sarai Senior Software Engineer (Containers) SUSE Linux GmbH <https://www.cyphar.com/>
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