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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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64
hotspot/src/share/vm/prims/jniCheck.cpp
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@ -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.
*/
UNCHECKED()->ReleaseStringChars(env,str,chars);
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.
*/
UNCHECKED()->ReleaseStringUTFChars(env,str,chars);
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