[PATCH] selftests/net/ipsec: Fix Null pointer dereference in rtattr_pack()

[liuye]

    Fix the following warning.

    tools/testing/selftests/net/ipsec.c:230:25: warning: Possible null pointer
    dereference: payload [nullPointer]
    memcpy(RTA_DATA(attr), payload, size);
                           ^
    tools/testing/selftests/net/ipsec.c:1618:54: note: Calling function 
'rtattr_pack',
    4th argument 'NULL' value is 0
    if (rtattr_pack(&req.nh, sizeof(req), XFRMA_IF_ID, NULL, 0)) {
                                                       ^
    tools/testing/selftests/net/ipsec.c:230:25: note: Null pointer dereference
    memcpy(RTA_DATA(attr), payload, size);
                           ^

Signed-off-by: liuye <li...@kylinos.cn>
---
 tools/testing/selftests/net/ipsec.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/tools/testing/selftests/net/ipsec.c 
b/tools/testing/selftests/net/ipsec.c
index be4a30a0d02a..725310ac26a9 100644
--- a/tools/testing/selftests/net/ipsec.c
+++ b/tools/testing/selftests/net/ipsec.c
@@ -227,7 +227,8 @@ static int rtattr_pack(struct nlmsghdr *nh, size_t req_sz,
 
        attr->rta_len = RTA_LENGTH(size);
        attr->rta_type = rta_type;
-       memcpy(RTA_DATA(attr), payload, size);
+       if (payload != NULL)
+               memcpy(RTA_DATA(attr), payload, size);
 
        return 0;
 }
-- 
2.25.1