Re: [PATCH bpf] bpf: link: refuse non-zero file_flags in BPF_OBJ_GET

2021-03-26 Thread Lorenz Bauer
On Fri, 26 Mar 2021 at 04:43, Andrii Nakryiko wrote: > > Makes sense, but see below about details. > > Also, should we do the same for BPF programs as well? I guess they > don't have a "write operation", once loaded, but still... I asked myself the same question, I don't have a good answer. Right

Re: [PATCH bpf] bpf: link: refuse non-zero file_flags in BPF_OBJ_GET

2021-03-25 Thread Andrii Nakryiko
On Thu, Mar 25, 2021 at 8:22 AM Lorenz Bauer wrote: > > Invoking BPF_OBJ_GET on a pinned bpf_link checks the path access > permissions based on file_flags, but the returned fd ignores flags. > This means that any user can acquire a "read-write" fd for a pinned > link with mode 0664 by invoking BPF