src/jdk.management.agent/windows/native/libmanagement_agent/FileSystemImpl.c
changeset 47216 71c04702a3d5
parent 43511 bbd181840d2d
child 47613 af241e3e5a13
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/jdk.management.agent/windows/native/libmanagement_agent/FileSystemImpl.c	Tue Sep 12 19:03:39 2017 +0200
@@ -0,0 +1,326 @@
+/*
+ * Copyright (c) 2004, 2011, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.  Oracle designates this
+ * particular file as subject to the "Classpath" exception as provided
+ * by Oracle in the LICENSE file that accompanied this code.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+
+#include <windows.h>
+#include <malloc.h>
+#include <string.h>
+
+#include "jni.h"
+#include "jni_util.h"
+#include "jdk_internal_agent_FileSystemImpl.h"
+
+JNIEXPORT jint JNICALL DEF_JNI_OnLoad(JavaVM *vm, void *reserved)
+{
+    JNIEnv* env;
+
+    if ((*vm)->GetEnv(vm, (void**) &env, JNI_VERSION_1_2) != JNI_OK) {
+        return JNI_EVERSION; /* JNI version not supported */
+    }
+
+    return JNI_VERSION_9;
+}
+
+
+/*
+ * Access mask to represent any file access
+ */
+#define ANY_ACCESS (FILE_GENERIC_READ | FILE_GENERIC_WRITE | FILE_GENERIC_EXECUTE)
+
+/*
+ * Returns JNI_TRUE if the specified file is on a file system that supports
+ * persistent ACLs (On NTFS file systems returns true, on FAT32 file systems
+ * returns false).
+ */
+static jboolean isSecuritySupported(JNIEnv* env, const char* path) {
+    char* root;
+    char* p;
+    BOOL res;
+    DWORD dwMaxComponentLength;
+    DWORD dwFlags;
+    char fsName[128];
+    DWORD fsNameLength;
+
+    /*
+     * Get root directory. Assume that files are absolute paths. For UNCs
+     * the slash after the share name is required.
+     */
+    root = strdup(path);
+    if (*root == '\\') {
+        /*
+         * \\server\share\file ==> \\server\share\
+         */
+        int slashskip = 3;
+        p = root;
+        while ((*p == '\\') && (slashskip > 0)) {
+            char* p2;
+            p++;
+            p2 = strchr(p, '\\');
+            if ((p2 == NULL) || (*p2 != '\\')) {
+                free(root);
+                JNU_ThrowIOException(env, "Malformed UNC");
+                return JNI_FALSE;
+            }
+            p = p2;
+            slashskip--;
+        }
+        if (slashskip != 0) {
+            free(root);
+            JNU_ThrowIOException(env, "Malformed UNC");
+            return JNI_FALSE;
+        }
+        p++;
+        *p = '\0';
+
+    } else {
+        p = strchr(root, '\\');
+        if (p == NULL) {
+            free(root);
+            JNU_ThrowIOException(env, "Absolute filename not specified");
+            return JNI_FALSE;
+        }
+        p++;
+        *p = '\0';
+    }
+
+
+    /*
+     * Get the volume information - this gives us the file system file and
+     * also tells us if the file system supports persistent ACLs.
+     */
+    fsNameLength = sizeof(fsName)-1;
+    res = GetVolumeInformation(root,
+                               NULL,        // address of name of the volume, can be NULL
+                               0,           // length of volume name
+                               NULL,        // address of volume serial number, can be NULL
+                               &dwMaxComponentLength,
+                               &dwFlags,
+                               fsName,
+                               fsNameLength);
+    if (res == 0) {
+        free(root);
+        JNU_ThrowIOExceptionWithLastError(env, "GetVolumeInformation failed");
+        return JNI_FALSE;
+    }
+
+    free(root);
+    return (dwFlags & FS_PERSISTENT_ACLS) ? JNI_TRUE : JNI_FALSE;
+}
+
+
+/*
+ * Returns the security descriptor for a file.
+ */
+static SECURITY_DESCRIPTOR* getFileSecurityDescriptor(JNIEnv* env, const char* path) {
+    SECURITY_DESCRIPTOR* sd;
+    DWORD len = 0;
+    SECURITY_INFORMATION info =
+        OWNER_SECURITY_INFORMATION | DACL_SECURITY_INFORMATION;
+
+    GetFileSecurityA(path, info , 0, 0, &len);
+    if (GetLastError() != ERROR_INSUFFICIENT_BUFFER) {
+        JNU_ThrowIOExceptionWithLastError(env, "GetFileSecurity failed");
+        return NULL;
+    }
+    sd = (SECURITY_DESCRIPTOR *)malloc(len);
+    if (sd == NULL) {
+        JNU_ThrowOutOfMemoryError(env, 0);
+    } else {
+        if (!(*GetFileSecurityA)(path, info, sd, len, &len)) {
+            JNU_ThrowIOExceptionWithLastError(env, "GetFileSecurity failed");
+            free(sd);
+            return NULL;
+        }
+    }
+    return sd;
+}
+
+/*
+ * Returns pointer to the SID identifying the owner of the specified
+ * file.
+ */
+static SID* getFileOwner(JNIEnv* env, SECURITY_DESCRIPTOR* sd) {
+    SID* owner;
+    BOOL defaulted;
+
+    if (!GetSecurityDescriptorOwner(sd, &owner, &defaulted)) {
+        JNU_ThrowIOExceptionWithLastError(env, "GetSecurityDescriptorOwner failed");
+        return NULL;
+    }
+    return owner;
+}
+
+/*
+ * Returns pointer discretionary access-control list (ACL) from the security
+ * descriptor of the specified file.
+ */
+static ACL* getFileDACL(JNIEnv* env, SECURITY_DESCRIPTOR* sd) {
+    ACL *acl;
+    int defaulted, present;
+
+    if (!GetSecurityDescriptorDacl(sd, &present, &acl, &defaulted)) {
+        JNU_ThrowIOExceptionWithLastError(env, "GetSecurityDescriptorDacl failed");
+        return NULL;
+    }
+    if (!present) {
+        JNU_ThrowInternalError(env, "Security descriptor does not contain a DACL");
+        return NULL;
+    }
+    return acl;
+}
+
+/*
+ * Returns JNI_TRUE if the specified owner is the only SID will access
+ * to the file.
+ */
+static jboolean isAccessUserOnly(JNIEnv* env, SID* owner, ACL* acl) {
+    ACL_SIZE_INFORMATION acl_size_info;
+    DWORD i;
+
+    /*
+     * If there's no DACL then there's no access to the file
+     */
+    if (acl == NULL) {
+        return JNI_TRUE;
+    }
+
+    /*
+     * Get the ACE count
+     */
+    if (!GetAclInformation(acl, (void *) &acl_size_info, sizeof(acl_size_info),
+                           AclSizeInformation)) {
+        JNU_ThrowIOExceptionWithLastError(env, "GetAclInformation failed");
+        return JNI_FALSE;
+    }
+
+    /*
+     * Iterate over the ACEs. For each "allow" type check that the SID
+     * matches the owner, and check that the access is read only.
+     */
+    for (i = 0; i < acl_size_info.AceCount; i++) {
+        void* ace;
+        ACCESS_ALLOWED_ACE *access;
+        SID* sid;
+
+        if (!GetAce(acl, i, &ace)) {
+            JNU_ThrowIOExceptionWithLastError(env, "GetAce failed");
+            return -1;
+        }
+        if (((ACCESS_ALLOWED_ACE *)ace)->Header.AceType != ACCESS_ALLOWED_ACE_TYPE) {
+            continue;
+        }
+        access = (ACCESS_ALLOWED_ACE *)ace;
+        sid = (SID *) &access->SidStart;
+        if (!EqualSid(owner, sid)) {
+            /*
+             * If the ACE allows any access then the file is not secure.
+             */
+            if (access->Mask & ANY_ACCESS) {
+                return JNI_FALSE;
+            }
+        }
+    }
+    return JNI_TRUE;
+}
+
+
+/*
+ * Class:     jdk_internal_agent_FileSystemImpl
+ * Method:    init0
+ * Signature: ()V
+ */
+JNIEXPORT void JNICALL Java_jdk_internal_agent_FileSystemImpl_init0
+  (JNIEnv *env, jclass ignored)
+{
+        /* nothing to do */
+}
+
+/*
+ * Class:     jdk_internal_agent_FileSystemImpl
+ * Method:    isSecuritySupported0
+ * Signature: (Ljava/lang/String;)Z
+ */
+JNIEXPORT jboolean JNICALL Java_jdk_internal_agent_FileSystemImpl_isSecuritySupported0
+  (JNIEnv *env, jclass ignored, jstring str)
+{
+    jboolean res;
+    jboolean isCopy;
+    const char* path;
+
+    path = JNU_GetStringPlatformChars(env, str, &isCopy);
+    if (path != NULL) {
+        res = isSecuritySupported(env, path);
+        if (isCopy) {
+            JNU_ReleaseStringPlatformChars(env, str, path);
+        }
+        return res;
+    } else {
+        /* exception thrown - doesn't matter what we return */
+        return JNI_TRUE;
+    }
+}
+
+
+/*
+ * Class:     jdk_internal_agent_FileSystemImpl
+ * Method:    isAccessUserOnly0
+ * Signature: (Ljava/lang/String;)Z
+ */
+JNIEXPORT jboolean JNICALL Java_jdk_internal_agent_FileSystemImpl_isAccessUserOnly0
+  (JNIEnv *env, jclass ignored, jstring str)
+{
+    jboolean res = JNI_FALSE;
+    jboolean isCopy;
+    const char* path;
+
+    path = JNU_GetStringPlatformChars(env, str, &isCopy);
+    if (path != NULL) {
+        /*
+         * From the security descriptor get the file owner and
+         * DACL. Then check if anybody but the owner has access
+         * to the file.
+         */
+        SECURITY_DESCRIPTOR* sd = getFileSecurityDescriptor(env, path);
+        if (sd != NULL) {
+            SID *owner = getFileOwner(env, sd);
+            if (owner != NULL) {
+                ACL* acl = getFileDACL(env, sd);
+                if (acl != NULL) {
+                    res = isAccessUserOnly(env, owner, acl);
+                } else {
+                    /*
+                     * If acl is NULL it means that an exception was thrown
+                     * or there is "all acess" to the file.
+                     */
+                    res = JNI_FALSE;
+                }
+            }
+            free(sd);
+        }
+        if (isCopy) {
+            JNU_ReleaseStringPlatformChars(env, str, path);
+        }
+    }
+    return res;
+}