Commit 991e555e authored by Amery Hung's avatar Amery Hung Committed by Martin KaFai Lau
Browse files

selftests/bpf: Test changing packet data from kfunc 



bpf_xdp_pull_data() is the first kfunc that changes packet data. Make
sure the verifier clear all packet pointers after calling packet data
changing kfunc.

Signed-off-by: default avatarAmery Hung <ameryhung@gmail.com>
Signed-off-by: default avatarMartin KaFai Lau <martin.lau@kernel.org>
Link: https://patch.msgid.link/20250926164142.1850176-1-ameryhung@gmail.com
parent d43029ff

tools/testing/selftests/bpf/progs/verifier_sock.c

+14 −0
Original line number Diff line number Diff line
@@ -1096,6 +1096,20 @@ int invalidate_xdp_pkt_pointers_from_global_func(struct xdp_md *x) 
	return XDP_PASS;

}



/* XDP packet changing kfunc calls invalidate packet pointers */

SEC("xdp")

__failure __msg("invalid mem access")

int invalidate_xdp_pkt_pointers(struct xdp_md *x)

{

	int *p = (void *)(long)x->data;



	if ((void *)(p + 1) > (void *)(long)x->data_end)

		return XDP_DROP;

	bpf_xdp_pull_data(x, 0);

	*p = 42; /* this is unsafe */

	return XDP_PASS;

}



__noinline

int tail_call(struct __sk_buff *sk)

{