commit 442d9e5cb4a526c91498af36a9beadfddb4f5f59
author Jian Zhang <zhangjian.3032@bytedance.com> Thu Oct 20 22:11:14 2022 +0800
committer William A. Kennington III <wak@google.com> Wed Nov 09 20:32:36 2022 +0000
tree f980b8b842be37d35c7c47a0f2feec428cb3f2f0
parent 85dc57a57c5e8c9394bad5c787d6f837eae76178

util: Add data ptr check to avoid crash

When the eth device is down, the data ptr is NULL,
so we should add a check to avoid crash.

Tested:
1. Let ncsi device down
`~# ip link set eth0 down`

2. Send a oem command to ncsi device, no crash.
```
ncsi-netlink -x 3 -p 0 -c 0 --oem-payload 00
Send OEM Command, CHANNEL : 0, PACKAGE : 0, IFINDEX: 3
Payload : 00
Response: No data
Failed to receive the message , RC : -1
```

Signed-off-by: Jian Zhang <zhangjian.3032@bytedance.com>
Change-Id: I1e1119f7891732a87b56a345dad8ec3549868bf7

src/ncsi_util.cpp

diff --git a/src/ncsi_util.cpp b/src/ncsi_util.cpp
index 06eb254..aa31a18 100644
--- a/src/ncsi_util.cpp
+++ b/src/ncsi_util.cpp
@@ -227,6 +227,12 @@
         return ret;
     }
 
+    if (tb[NCSI_ATTR_DATA] == nullptr)
+    {
+        std::cerr << "Response: No data" << std::endl;
+        return -1;
+    }
+
     auto data_len = nla_len(tb[NCSI_ATTR_DATA]) - sizeof(NCSIPacketHeader);
     unsigned char* data =
         (unsigned char*)nla_data(tb[NCSI_ATTR_DATA]) + sizeof(NCSIPacketHeader);