[HDFS-4132] when libwebhdfs is not enabled, nativeMiniDfsClient frees uninitialized memory

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 2.0.3-alpha
• Fix Version/s: 2.0.3-alpha
• Component/s: libhdfs
• Target Version/s: 2.0.3-alpha
• Hadoop Flags: Reviewed
• Assignee: Colin McCabe
• Reporter: Colin McCabe
• Created: 31/Oct/12 22:51
• Updated: 03/Sep/14 23:09
• Resolved: 02/Nov/12 20:36

Description

When libwebhdfs is not enabled, nativeMiniDfsClient frees uninitialized memory.

Details: jconfStr is declared uninitialized...

struct NativeMiniDfsCluster* nmdCreate(struct NativeMiniDfsConf *conf)
{
    struct NativeMiniDfsCluster* cl = NULL;
    jobject bld = NULL, bld2 = NULL, cobj = NULL;
    jvalue  val;
    JNIEnv *env = getJNIEnv();
    jthrowable jthr;
    jstring jconfStr;

and only initialized later if conf->webhdfsEnabled:

    ...
    if (conf->webhdfsEnabled) {
        jthr = newJavaStr(env, DFS_WEBHDFS_ENABLED_KEY, &jconfStr);
        if (jthr) {
            printExceptionAndFree(env, jthr, PRINT_EXC_ALL,
    ...

Then we try to free this uninitialized memory at the end, usually resulting in a crash.

    (*env)->DeleteLocalRef(env, jconfStr);
    return cl;

Issue Links

• duplicates: HDFS-4136 libhdfs segfaults after recent changes