[PATCH bpf] bpf: fix bpf_prog_get_info_by_fd to return 0 func_lens for unpriv

[Daniel Borkmann]

While dbecd7388476 ("bpf: get kernel symbol addresses via syscall")
zeroed info.nr_jited_ksyms in bpf_prog_get_info_by_fd() for queries
from unprivileged users, commit 815581c11cc2 ("bpf: get JITed image
lengths of functions via syscall") forgot about doing so and therefore
returns the #elems of the user set up buffer which is incorrect. It
also needs to indicate a info.nr_jited_func_lens of zero.

Fixes: 815581c11cc2 ("bpf: get JITed image lengths of functions via syscall")
Signed-off-by: Daniel Borkmann <dan...@iogearbox.net>
Cc: Sandipan Das <sandi...@linux.vnet.ibm.com>
Cc: Song Liu <songliubrav...@fb.com>
---
 kernel/bpf/syscall.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c
index ccb9327..1ea5ce1 100644
--- a/kernel/bpf/syscall.c
+++ b/kernel/bpf/syscall.c
@@ -2078,6 +2078,7 @@ static int bpf_prog_get_info_by_fd(struct bpf_prog *prog,
                info.jited_prog_len = 0;
                info.xlated_prog_len = 0;
                info.nr_jited_ksyms = 0;
+               info.nr_jited_func_lens = 0;
                goto done;
        }
 
-- 
2.9.5