From: Andrii Nakryiko <andriin@fb.com>
Date: Wed, 6 Nov 2019 21:40:59 -0800
Subject: libbpf: Fix negative FD close() in xsk_setup_xdp_prog()
Patch-mainline: Queued in subsystem maintainer repository
Git-repo: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
Git-commit: 9656b346b280c3e49c8a116c3a715f966633b161
References: bsc#1155518

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>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20191107054059.313884-1-andriin@fb.com
Acked-by: Gary Lin <glin@suse.com>
---
 tools/lib/bpf/xsk.c |    2 ++
 1 file changed, 2 insertions(+)

--- a/tools/lib/bpf/xsk.c
+++ b/tools/lib/bpf/xsk.c
@@ -531,6 +531,8 @@ static int xsk_setup_xdp_prog(struct 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);