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From: Andrii Nakryiko <andriin@fb.com>
To: <bpf@vger.kernel.org>, <netdev@vger.kernel.org>, <ast@fb.com>,
	<daniel@iogearbox.net>, <jonathan.lemon@gmail.com>
Cc: <andrii.nakryiko@gmail.com>, <kernel-team@fb.com>,
	Andrii Nakryiko <andriin@fb.com>
Subject: [PATCH bpf-next] libbpf: fix negative FD close() in xsk_setup_xdp_prog()
Date: Wed, 6 Nov 2019 21:40:59 -0800	[thread overview]
Message-ID: <20191107054059.313884-1-andriin@fb.com> (raw)

Fix issue reported by static analysis (Coverity). If bpf_prog_get_fd_by_id()
fails, xsk_lookup_bpf_maps() will fail as well and clean-up code will attempt
close() with fd=-1. Fix by checking bpf_prog_get_fd_by_id() return result and
exiting early.

Fixes: 10a13bb40e54 ("libbpf: remove qidconf and better support external bpf programs.")
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
---
 tools/lib/bpf/xsk.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/tools/lib/bpf/xsk.c b/tools/lib/bpf/xsk.c
index 74d84f36a5b2..86c1b61017f6 100644
--- a/tools/lib/bpf/xsk.c
+++ b/tools/lib/bpf/xsk.c
@@ -553,6 +553,8 @@ static int xsk_setup_xdp_prog(struct xsk_socket *xsk)
 		}
 	} else {
 		xsk->prog_fd = bpf_prog_get_fd_by_id(prog_id);
+		if (xsk->prog_fd < 0)
+			return -errno;
 		err = xsk_lookup_bpf_maps(xsk);
 		if (err) {
 			close(xsk->prog_fd);
-- 
2.17.1


             reply	other threads:[~2019-11-07  5:41 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-11-07  5:40 Andrii Nakryiko [this message]
2019-11-07 16:04 ` [PATCH bpf-next] libbpf: fix negative FD close() in xsk_setup_xdp_prog() Daniel Borkmann

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