When migrating from the bpf.h's to the vmlinux.h's definition of struct
bps_sock, an interesting LLVM behavior happened. LLVM started producing
two fetches of ctx->sk in the sockops program this means that the
verifier could not keep track of the NULL-check on ctx->sk. Therefore,
we need to extract ctx->sk in a variable before checking and
dereferencing it.
Acked-by: KP Singh <kpsingh@xxxxxxxxxx>
Signed-off-by: Florent Revest <revest@xxxxxxxxxxxx>
---
.../testing/selftests/bpf/progs/socket_cookie_prog.c | 11 ++++++-----
1 file changed, 6 insertions(+), 5 deletions(-)
diff --git a/tools/testing/selftests/bpf/progs/socket_cookie_prog.c b/tools/testing/selftests/bpf/progs/socket_cookie_prog.c
index 81e84be6f86d..fbd5eaf39720 100644
--- a/tools/testing/selftests/bpf/progs/socket_cookie_prog.c
+++ b/tools/testing/selftests/bpf/progs/socket_cookie_prog.c
@@ -1,12 +1,13 @@
// SPDX-License-Identifier: GPL-2.0
// Copyright (c) 2018 Facebook
-#include <linux/bpf.h>
-#include <sys/socket.h>
+#include "vmlinux.h"
#include <bpf/bpf_helpers.h>
#include <bpf/bpf_endian.h>
+#define AF_INET6 10
+
struct socket_cookie {
__u64 cookie_key;
__u32 cookie_value;
@@ -41,7 +42,7 @@ int set_cookie(struct bpf_sock_addr *ctx)
SEC("sockops")
int update_cookie(struct bpf_sock_ops *ctx)
{
- struct bpf_sock *sk;
+ struct bpf_sock *sk = ctx->sk;
struct socket_cookie *p;
if (ctx->family != AF_INET6)
@@ -50,10 +51,10 @@ int update_cookie(struct bpf_sock_ops *ctx)
if (ctx->op != BPF_SOCK_OPS_TCP_CONNECT_CB)
return 1;
- if (!ctx->sk)
+ if (!sk)
return 1;
- p = bpf_sk_storage_get(&socket_cookies, ctx->sk, 0, 0);
+ p = bpf_sk_storage_get(&socket_cookies, sk, 0, 0);
if (!p)
return 1;
--
2.30.0.280.ga3ce27912f-goog
