[reactos] 01/01: [NSLOOKUP] Fix crash in case of no network connectivity (#1354)

[Julian Kirsch]

https://git.reactos.org/?p=reactos.git;a=commitdiff;h=42515190c53d45e282a8d…

commit 42515190c53d45e282a8d6eea4dfa917bfc1f170
Author:     Julian Kirsch <kirschju(a)sec.in.tum.de>
AuthorDate: Wed Feb 13 13:12:52 2019 +0100
Commit:     Hermès BÉLUSCA - MAÏTO <hermes.belusca-maito(a)reactos.org>
CommitDate: Wed Feb 13 13:12:52 2019 +0100

    [NSLOOKUP] Fix crash in case of no network connectivity (#1354)
    
    Prevent nslookup.exe from crashing when executed in a ROS VM with no network
    interfaces. This is due to a NULL pointer dereference occurring if
    `GetNetworkParams` in `main` fails with an error other than
    `ERROR_BUFFER_OVERFLOW`. In this case, `pNetInfo` remains initialized to
    NULL, causing `strncpy` to crash.
---
 base/applications/network/nslookup/nslookup.c | 35 +++++++++++++++------------
 1 file changed, 20 insertions(+), 15 deletions(-)

diff --git a/base/applications/network/nslookup/nslookup.c
b/base/applications/network/nslookup/nslookup.c
index 6f80dfae1e..d86803eb3a 100644
--- a/base/applications/network/nslookup/nslookup.c
+++ b/base/applications/network/nslookup/nslookup.c
@@ -792,26 +792,31 @@ int main( int argc, char* argv[] )
     /* We don't know how long of a buffer it will want to return. So we'll
        pass an empty one now and let it fail only once, instead of guessing. */
     Status = GetNetworkParams( pNetInfo, &NetBufLen );
-    if( Status == ERROR_BUFFER_OVERFLOW )
+
+    if( Status != ERROR_BUFFER_OVERFLOW )
     {
-        pNetInfo = (PFIXED_INFO)HeapAlloc( ProcessHeap, 0, NetBufLen );
-        if( pNetInfo == NULL )
-        {
-            _tprintf( _T("ERROR: Out of memory\n") );
+        _tprintf( _T("Error in GetNetworkParams call\n") );
 
-            return -1;
-        }
+        return -2;
+    }
 
-        /* For real this time. */
-        Status = GetNetworkParams( pNetInfo, &NetBufLen );
-        if( Status != NO_ERROR )
-        {
-            _tprintf( _T("Error in GetNetworkParams call\n") );
+    pNetInfo = (PFIXED_INFO)HeapAlloc( ProcessHeap, 0, NetBufLen );
+    if( pNetInfo == NULL )
+    {
+        _tprintf( _T("ERROR: Out of memory\n") );
 
-            HeapFree( ProcessHeap, 0, pNetInfo );
+        return -1;
+    }
 
-            return -2;
-        }
+    /* For real this time. */
+    Status = GetNetworkParams( pNetInfo, &NetBufLen );
+    if( Status != NO_ERROR )
+    {
+        _tprintf( _T("Error in GetNetworkParams call\n") );
+
+        HeapFree( ProcessHeap, 0, pNetInfo );
+
+        return -2;
     }
 
     strncpy( State.domain, pNetInfo->DomainName, 255 );