[PATCH AUTOSEL 4.19 15/73] bpf: fix bpf_prog_get_info_by_fd to return 0 func_lens for unpriv

Sasha Levin
2018-11-14T22:45:33Z

From: Daniel Borkmann <daniel@iogearbox.net>

[ Upstream commit 28c2fae726bf5003cd209b0d5910a642af98316f ]

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 <daniel@iogearbox.net>
Cc: Sandipan Das <sandipan@linux.vnet.ibm.com>
Cc: Song Liu <songliubraving@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
kernel/bpf/syscall.c | 1 +
1 file changed, 1 insertion(+)

diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c
index 8339d81cba1d..3002e3cdc033 100644
--- a/kernel/bpf/syscall.c
+++ b/kernel/bpf/syscall.c
@@ -1961,6 +1961,7 @@ 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;
}

--
2.17.1