netdev - [PATCH AUTOSEL 4.18 10/59] bpf: fix bpf_prog_get_info_by_fd to return 0 func

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Message-Id: <20181114222335.99339-10-sashal@kernel.org>
Date:   Wed, 14 Nov 2018 17:22:42 -0500
From:   Sasha Levin <sashal@...nel.org>
To:     stable@...r.kernel.org, linux-kernel@...r.kernel.org
Cc:     Daniel Borkmann <daniel@...earbox.net>,
        Sandipan Das <sandipan@...ux.vnet.ibm.com>,
        Song Liu <songliubraving@...com>,
        Alexei Starovoitov <ast@...nel.org>,
        Sasha Levin <sashal@...nel.org>, netdev@...r.kernel.org
Subject: [PATCH AUTOSEL 4.18 10/59] bpf: fix bpf_prog_get_info_by_fd to return 0 func_lens for unpriv

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

diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c
index a31a1ba0f8ea..482215292b0f 100644
--- a/kernel/bpf/syscall.c
+++ b/kernel/bpf/syscall.c
@@ -1896,6 +1896,7 @@ 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