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Commit f51f1bd9 authored by Marco Nelissen's avatar Marco Nelissen
Browse files

Verify we actually have valid utf8 metadata 

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
parent c5ce130f

media/jni/android_media_MediaScanner.cpp

+63 −1
Original line number Diff line number Diff line
@@ -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;