The verifier should invalidate all packet pointers after a packet data changing kfunc is called. So, similar to commit 3f23ee5590d9 ("selftests/bpf: test for changing packet data from global functions"), test changing packet data from global functions to make sure packet pointers are indeed invalidated. Signed-off-by: Amery Hung --- .../selftests/bpf/progs/verifier_sock.c | 30 ++++++++++++++++++- 1 file changed, 29 insertions(+), 1 deletion(-) diff --git a/tools/testing/selftests/bpf/progs/verifier_sock.c b/tools/testing/selftests/bpf/progs/verifier_sock.c index bf88c644eb30..0bed5715c9e1 100644 --- a/tools/testing/selftests/bpf/progs/verifier_sock.c +++ b/tools/testing/selftests/bpf/progs/verifier_sock.c @@ -1,7 +1,7 @@ // SPDX-License-Identifier: GPL-2.0 /* Converted from tools/testing/selftests/bpf/verifier/sock.c */ -#include +#include "vmlinux.h" #include #include "bpf_misc.h" @@ -1068,6 +1068,34 @@ int invalidate_pkt_pointers_from_global_func(struct __sk_buff *sk) return TCX_PASS; } +__noinline +long xdp_pull_data2(struct xdp_md *x, __u32 len) +{ + return bpf_xdp_pull_data(x, len); +} + +__noinline +long xdp_pull_data1(struct xdp_md *x, __u32 len) +{ + return xdp_pull_data2(x, len); +} + +/* global function calls bpf_xdp_pull_data(), which invalidates packet + * pointers established before global function call. + */ +SEC("xdp") +__failure __msg("invalid mem access") +int invalidate_xdp_pkt_pointers_from_global_func(struct xdp_md *x) +{ + int *p = (void *)(long)x->data; + + if ((void *)(p + 1) > (void *)(long)x->data_end) + return TCX_DROP; + xdp_pull_data1(x, 0); + *p = 42; /* this is unsafe */ + return TCX_PASS; +} + __noinline int tail_call(struct __sk_buff *sk) { -- 2.47.3