netdev - [PATCH bpf] bpf: fix bpf_prog_get_info_by_fd to return 0 func

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Date:   Fri,  2 Nov 2018 11:35:46 +0100
From:   Daniel Borkmann <daniel@...earbox.net>
To:     ast@...nel.org
Cc:     netdev@...r.kernel.org, Daniel Borkmann <daniel@...earbox.net>,
        Sandipan Das <sandipan@...ux.vnet.ibm.com>,
        Song Liu <songliubraving@...com>
Subject: [PATCH bpf] bpf: fix bpf_prog_get_info_by_fd to return 0 func_lens for unpriv

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@...earbox.net>
Cc: Sandipan Das <sandipan@...ux.vnet.ibm.com>
Cc: Song Liu <songliubraving@...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