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6539281: -Xcheck:jni should validate char* argument to ReleaseStringUTFChars

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Tag allocated memory with a magic value and verify when releasing.

Reviewed-by: phh, stefank
This commit is contained in:
Staffan Larsen 2010-12-07 03:15:45 -08:00
parent dd62e29b29
commit 1765b0fbf0
4 changed files with 65 additions and 17 deletions
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8
hotspot/src/share/vm/classfile/javaClasses.cpp
View file

@ -313,6 +313,14 @@ char* java_lang_String::as_utf8_string(oop java_string) {
return UNICODE::as_utf8(position, length);
}
char* java_lang_String::as_utf8_string(oop java_string, char* buf, int buflen) {
typeArrayOop value = java_lang_String::value(java_string);
int offset = java_lang_String::offset(java_string);
int length = java_lang_String::length(java_string);
jchar* position = (length == 0) ? NULL : value->char_at_addr(offset);
return UNICODE::as_utf8(position, length, buf, buflen);
}
char* java_lang_String::as_utf8_string(oop java_string, int start, int len) {
typeArrayOop value = java_lang_String::value(java_string);
int offset = java_lang_String::offset(java_string);

1
hotspot/src/share/vm/classfile/javaClasses.hpp
View file

@ -104,6 +104,7 @@ class java_lang_String : AllStatic {
// String converters
static char* as_utf8_string(oop java_string);
static char* as_utf8_string(oop java_string, char* buf, int buflen);
static char* as_utf8_string(oop java_string, int start, int len);
static char* as_platform_dependent_str(Handle java_string, TRAPS);
static jchar* as_unicode_string(oop java_string, int& length);

7
hotspot/src/share/vm/prims/jni.cpp
View file

@ -2113,11 +2113,10 @@ JNI_END
JNI_ENTRY(const char*, jni_GetStringUTFChars(JNIEnv *env, jstring string, jboolean *isCopy))
JNIWrapper("GetStringUTFChars");
DTRACE_PROBE3(hotspot_jni, GetStringUTFChars__entry, env, string, isCopy);
ResourceMark rm;
char* str = java_lang_String::as_utf8_string(JNIHandles::resolve_non_null(string));
int length = (int)strlen(str);
oop java_string = JNIHandles::resolve_non_null(string);
size_t length = java_lang_String::utf8_length(java_string);
char* result = AllocateHeap(length + 1, "GetStringUTFChars");
strcpy(result, str);
java_lang_String::as_utf8_string(java_string, result, (int) length + 1);
if (isCopy != NULL) *isCopy = JNI_TRUE;
DTRACE_PROBE1(hotspot_jni, GetStringUTFChars__return, result);
return result;

60
hotspot/src/share/vm/prims/jniCheck.cpp
View file

@ -1288,6 +1288,9 @@ JNI_ENTRY_CHECKED(jsize,
return result;
JNI_END
// Arbitrary (but well-known) tag
const jint STRING_TAG = 0x47114711;
JNI_ENTRY_CHECKED(const jchar *,
checked_jni_GetStringChars(JNIEnv *env,
jstring str,
@ -1297,8 +1300,19 @@ JNI_ENTRY_CHECKED(const jchar *,
checkString(thr, str);
)
const jchar *result = UNCHECKED()->GetStringChars(env,str,isCopy);
assert (isCopy == NULL || *isCopy == JNI_TRUE, "GetStringChars didn't return a copy as expected");
size_t len = UNCHECKED()->GetStringLength(env,str) + 1; // + 1 for NULL termination
jint* tagLocation = (jint*) AllocateHeap(len * sizeof(jchar) + sizeof(jint), "checked_jni_GetStringChars");
*tagLocation = STRING_TAG;
jchar* newResult = (jchar*) (tagLocation + 1);
memcpy(newResult, result, len * sizeof(jchar));
// Avoiding call to UNCHECKED()->ReleaseStringChars() since that will fire unexpected dtrace probes
// Note that the dtrace arguments for the allocated memory will not match up with this solution.
FreeHeap((char*)result);
functionExit(env);
return result;
return newResult;
JNI_END
JNI_ENTRY_CHECKED(void,
@ -1309,11 +1323,17 @@ JNI_ENTRY_CHECKED(void,
IN_VM(
checkString(thr, str);
)
/* cannot check validity of copy, unless every request is logged by
* checking code. Implementation of this check is deferred until a
* subsequent release.
*/
if (chars == NULL) {
// still do the unchecked call to allow dtrace probes
UNCHECKED()->ReleaseStringChars(env,str,chars);
}
else {
jint* tagLocation = ((jint*) chars) - 1;
if (*tagLocation != STRING_TAG) {
NativeReportJNIFatalError(thr, "ReleaseStringChars called on something not allocated by GetStringChars");
}
UNCHECKED()->ReleaseStringChars(env,str,(const jchar*)tagLocation);
}
functionExit(env);
JNI_END
@ -1338,6 +1358,9 @@ JNI_ENTRY_CHECKED(jsize,
return result;
JNI_END
// Arbitrary (but well-known) tag - different than GetStringChars
const jint STRING_UTF_TAG = 0x48124812;
JNI_ENTRY_CHECKED(const char *,
checked_jni_GetStringUTFChars(JNIEnv *env,
jstring str,
@ -1347,8 +1370,19 @@ JNI_ENTRY_CHECKED(const char *,
checkString(thr, str);
)
const char *result = UNCHECKED()->GetStringUTFChars(env,str,isCopy);
assert (isCopy == NULL || *isCopy == JNI_TRUE, "GetStringUTFChars didn't return a copy as expected");
size_t len = strlen(result) + 1; // + 1 for NULL termination
jint* tagLocation = (jint*) AllocateHeap(len + sizeof(jint), "checked_jni_GetStringUTFChars");
*tagLocation = STRING_UTF_TAG;
char* newResult = (char*) (tagLocation + 1);
strcpy(newResult, result);
// Avoiding call to UNCHECKED()->ReleaseStringUTFChars() since that will fire unexpected dtrace probes
// Note that the dtrace arguments for the allocated memory will not match up with this solution.
FreeHeap((char*)result);
functionExit(env);
return result;
return newResult;
JNI_END
JNI_ENTRY_CHECKED(void,
@ -1359,11 +1393,17 @@ JNI_ENTRY_CHECKED(void,
IN_VM(
checkString(thr, str);
)
/* cannot check validity of copy, unless every request is logged by
* checking code. Implementation of this check is deferred until a
* subsequent release.
*/
if (chars == NULL) {
// still do the unchecked call to allow dtrace probes
UNCHECKED()->ReleaseStringUTFChars(env,str,chars);
}
else {
jint* tagLocation = ((jint*) chars) - 1;
if (*tagLocation != STRING_UTF_TAG) {
NativeReportJNIFatalError(thr, "ReleaseStringUTFChars called on something not allocated by GetStringUTFChars");
}
UNCHECKED()->ReleaseStringUTFChars(env,str,(const char*)tagLocation);
}
functionExit(env);
JNI_END