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Verify we actually have valid utf8 metadata

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Before calling NewStringUTF, check that the metadata value is actually
valid utf-8, and replace the offending characters with "?" if it is not.
b/5534491

Change-Id: I43de4307e739ae0b7d4177937ed33aa1dfb90d98
This commit is contained in:
Marco Nelissen
2011-11-02 10:49:50 -07:00
parent c5ce130f65
commit f51f1bd9d4
1 changed files with 63 additions and 1 deletions
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64
media/jni/android_media_MediaScanner.cpp
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@@ -56,6 +56,53 @@ static status_t checkAndClearExceptionFromCallback(JNIEnv* env, const char* meth
return OK;
}
// stolen from dalvik/vm/checkJni.cpp
static bool isValidUtf8(const char* bytes) {
while (*bytes != '\0') {
unsigned char utf8 = *(bytes++);
// Switch on the high four bits.
switch (utf8 >> 4) {
case 0x00:
case 0x01:
case 0x02:
case 0x03:
case 0x04:
case 0x05:
case 0x06:
case 0x07:
// Bit pattern 0xxx. No need for any extra bytes.
break;
case 0x08:
case 0x09:
case 0x0a:
case 0x0b:
case 0x0f:
/*
* Bit pattern 10xx or 1111, which are illegal start bytes.
* Note: 1111 is valid for normal UTF-8, but not the
* modified UTF-8 used here.
*/
return false;
case 0x0e:
// Bit pattern 1110, so there are two additional bytes.
utf8 = *(bytes++);
if ((utf8 & 0xc0) != 0x80) {
return false;
}
// Fall through to take care of the final byte.
case 0x0c:
case 0x0d:
// Bit pattern 110x, so there is one additional byte.
utf8 = *(bytes++);
if ((utf8 & 0xc0) != 0x80) {
return false;
}
break;
}
}
return true;
}
class MyMediaScannerClient : public MediaScannerClient
{
public:
@@ -123,7 +170,22 @@ public:
mEnv->ExceptionClear();
return NO_MEMORY;
}
if ((valueStr = mEnv->NewStringUTF(value)) == NULL) {
char *cleaned = NULL;
if (!isValidUtf8(value)) {
cleaned = strdup(value);
char *chp = cleaned;
char ch;
while ((ch = *chp)) {
if (ch & 0x80) {
*chp = '?';
}
chp++;
}
value = cleaned;
}
valueStr = mEnv->NewStringUTF(value);
free(cleaned);
if (valueStr == NULL) {
mEnv->DeleteLocalRef(nameStr);
mEnv->ExceptionClear();
return NO_MEMORY;