From: Wang Hai <wanghai38@xxxxxxxxxx> [ Upstream commit 85102ba58b4125ebad941d7555c3c248b23efd16 ] A Segmentation fault error is caused when the following command is executed. $ sudo ./samples/bpf/xdp_redirect lo Segmentation fault This command is missing a device <IFNAME|IFINDEX> as an argument, resulting in out-of-bounds access from argv. If the number of devices for the xdp_redirect parameter is not 2, we should report an error and exit. Fixes: 24251c264798 ("samples/bpf: add option for native and skb mode for redirect apps") Signed-off-by: Wang Hai <wanghai38@xxxxxxxxxx> Signed-off-by: Andrii Nakryiko <andrii@xxxxxxxxxx> Link: https://lore.kernel.org/bpf/20210616042324.314832-1-wanghai38@xxxxxxxxxx Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> --- samples/bpf/xdp_redirect_user.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/samples/bpf/xdp_redirect_user.c b/samples/bpf/xdp_redirect_user.c index 41d705c3a1f7..eb876629109a 100644 --- a/samples/bpf/xdp_redirect_user.c +++ b/samples/bpf/xdp_redirect_user.c @@ -130,7 +130,7 @@ int main(int argc, char **argv) if (!(xdp_flags & XDP_FLAGS_SKB_MODE)) xdp_flags |= XDP_FLAGS_DRV_MODE; - if (optind == argc) { + if (optind + 2 != argc) { printf("usage: %s <IFNAME|IFINDEX>_IN <IFNAME|IFINDEX>_OUT\n", argv[0]); return 1; } -- 2.30.2