GF_Err iSLT_Read(GF_Box *s, GF_BitStream *bs)
{
GF_ISMACrypSaltBox *ptr = (GF_ISMACrypSaltBox *)s;
if (ptr == NULL) return GF_BAD_PARAM;
ISOM_DECREASE_SIZE(ptr, 8);
ptr->salt = gf_bs_read_u64(bs);
return GF_OK;
}
GF_Err ohdr_Read(GF_Box *s, GF_BitStream *bs)
{
u16 cid_len, ri_len;
GF_Err e;
GF_OMADRMCommonHeaderBox *ptr = (GF_OMADRMCommonHeaderBox*)s;
if (ptr == NULL) return GF_BAD_PARAM;
e = gf_isom_full_box_read(s, bs);
if (e) return e;
ptr->EncryptionMethod = gf_bs_read_u8(bs);
ptr->PaddingScheme = gf_bs_read_u8(bs);
ptr->PlaintextLength = gf_bs_read_u64(bs);
cid_len = gf_bs_read_u16(bs);
ri_len = gf_bs_read_u16(bs);
ptr->TextualHeadersLen = gf_bs_read_u16(bs);
ptr->size -= 1+1+8+2+2+2;
if (ptr->size<cid_len+ri_len+ptr->TextualHeadersLen) return GF_ISOM_INVALID_FILE;
if (cid_len) {
ptr->ContentID = (char *)gf_malloc(sizeof(char)*(cid_len+1));
gf_bs_read_data(bs, ptr->ContentID, cid_len);
ptr->ContentID[cid_len]=0;
}
if (ri_len) {
ptr->RightsIssuerURL = (char *)gf_malloc(sizeof(char)*(ri_len+1));
gf_bs_read_data(bs, ptr->RightsIssuerURL, ri_len);
ptr->RightsIssuerURL[ri_len]=0;
}
if (ptr->TextualHeadersLen) {
ptr->TextualHeaders = (char *)gf_malloc(sizeof(char)*(ptr->TextualHeadersLen+1));
gf_bs_read_data(bs, ptr->TextualHeaders, ptr->TextualHeadersLen);
ptr->TextualHeaders[ptr->TextualHeadersLen] = 0;
}
ptr->size -= cid_len+ri_len+ptr->TextualHeadersLen;
return gf_isom_read_box_list(s, bs, ohdr_AddBox);
}
GF_Err ohdr_Read(GF_Box *s, GF_BitStream *bs)
{
u16 cid_len, ri_len;
GF_OMADRMCommonHeaderBox *ptr = (GF_OMADRMCommonHeaderBox*)s;
ptr->EncryptionMethod = gf_bs_read_u8(bs);
ptr->PaddingScheme = gf_bs_read_u8(bs);
ptr->PlaintextLength = gf_bs_read_u64(bs);
cid_len = gf_bs_read_u16(bs);
ri_len = gf_bs_read_u16(bs);
ptr->TextualHeadersLen = gf_bs_read_u16(bs);
ISOM_DECREASE_SIZE(ptr, (1+1+8+2+2+2) );
if (ptr->size<cid_len+ri_len+ptr->TextualHeadersLen) return GF_ISOM_INVALID_FILE;
if (cid_len) {
ptr->ContentID = (char *)gf_malloc(sizeof(char)*(cid_len+1));
gf_bs_read_data(bs, ptr->ContentID, cid_len);
ptr->ContentID[cid_len]=0;
}
if (ri_len) {
ptr->RightsIssuerURL = (char *)gf_malloc(sizeof(char)*(ri_len+1));
gf_bs_read_data(bs, ptr->RightsIssuerURL, ri_len);
ptr->RightsIssuerURL[ri_len]=0;
}
if (ptr->TextualHeadersLen) {
ptr->TextualHeaders = (char *)gf_malloc(sizeof(char)*(ptr->TextualHeadersLen+1));
gf_bs_read_data(bs, ptr->TextualHeaders, ptr->TextualHeadersLen);
ptr->TextualHeaders[ptr->TextualHeadersLen] = 0;
}
ISOM_DECREASE_SIZE(ptr, (cid_len+ri_len+ptr->TextualHeadersLen) );
return gf_isom_box_array_read(s, bs, ohdr_AddBox);
}
static GF_Err CENC_ProcessData(ISMAEAPriv *priv, GF_IPMPEvent *evt)
{
GF_Err e;
GF_BitStream *pleintext_bs, *cyphertext_bs, *sai_bs;
char IV[17];
bin128 KID;
char *buffer;
u32 max_size, i, subsample_count;
u64 BSO;
GF_CENCSampleAuxInfo *sai;
e = GF_OK;
pleintext_bs = cyphertext_bs = sai_bs = NULL;
buffer = NULL;
max_size = 4096;
if (!priv->crypt) return GF_SERVICE_ERROR;
if (!evt->is_encrypted || !evt->IV_size) return GF_OK;
cyphertext_bs = gf_bs_new(evt->data, evt->data_size, GF_BITSTREAM_READ);
sai_bs = gf_bs_new(evt->sai, evt->saiz, GF_BITSTREAM_READ);
pleintext_bs = gf_bs_new(NULL, 0, GF_BITSTREAM_WRITE);
buffer = (char*)gf_malloc(sizeof(char) * max_size);
sai = (GF_CENCSampleAuxInfo *)gf_malloc(sizeof(GF_CENCSampleAuxInfo));
if (!sai) {
e = GF_IO_ERR;
goto exit;
}
memset(sai, 0, sizeof(GF_CENCSampleAuxInfo));
sai->IV_size = evt->IV_size;
/*read sample auxiliary information from bitstream*/
gf_bs_read_data(sai_bs, (char *)KID, 16);
gf_bs_read_data(sai_bs, (char *)sai->IV, sai->IV_size);
sai->subsample_count = gf_bs_read_u16(sai_bs);
if (sai->subsample_count) {
sai->subsamples = (GF_CENCSubSampleEntry *)gf_malloc(sai->subsample_count*sizeof(GF_CENCSubSampleEntry));
for (i = 0; i < sai->subsample_count; i++) {
sai->subsamples[i].bytes_clear_data = gf_bs_read_u16(sai_bs);
sai->subsamples[i].bytes_encrypted_data = gf_bs_read_u32(sai_bs);
}
}
for (i = 0; i < priv->KID_count; i++) {
if (!strncmp((const char *)KID, (const char *)priv->KIDs[i], 16)) {
memmove(priv->key, priv->keys[i], 16);
break;
}
}
if (priv->first_crypted_samp) {
memmove(IV, sai->IV, sai->IV_size);
if (sai->IV_size == 8)
memset(IV+8, 0, sizeof(char)*8);
e = gf_crypt_init(priv->crypt, priv->key, 16, IV);
if (e) {
GF_LOG(GF_LOG_ERROR, GF_LOG_AUTHOR, ("[CENC] Cannot initialize AES-128 AES-128 %s (%s)\n", priv->is_cenc ? "CTR" : "CBC", gf_error_to_string(e)) );
e = GF_IO_ERR;
goto exit;
}
priv->first_crypted_samp = GF_FALSE;
} else {
if (priv->is_cenc) {
GF_BitStream *bs;
bs = gf_bs_new(IV, 17, GF_BITSTREAM_WRITE);
gf_bs_write_u8(bs, 0); /*begin of counter*/
gf_bs_write_data(bs,(char *)sai->IV, sai->IV_size);
if (sai->IV_size == 8)
gf_bs_write_u64(bs, 0); /*0-padded if IV_size == 8*/
gf_bs_del(bs);
gf_crypt_set_state(priv->crypt, IV, 17);
}
e = gf_crypt_set_key(priv->crypt, priv->key, 16, IV);
if (e) {
GF_LOG(GF_LOG_ERROR, GF_LOG_AUTHOR, ("[CENC] Cannot set key AES-128 %s (%s)\n", priv->is_cenc ? "CTR" : "CBC", gf_error_to_string(e)) );
e = GF_IO_ERR;
goto exit;
}
}
subsample_count = 0;
BSO = 0;
while (gf_bs_available(cyphertext_bs)) {
assert(subsample_count < sai->subsample_count);
/*read clear data and write it to pleintext bitstream*/
if (max_size < sai->subsamples[subsample_count].bytes_clear_data) {
buffer = (char*)gf_realloc(buffer, sizeof(char)*sai->subsamples[subsample_count].bytes_clear_data);
max_size = sai->subsamples[subsample_count].bytes_clear_data;
}
gf_bs_read_data(cyphertext_bs, buffer, sai->subsamples[subsample_count].bytes_clear_data);
gf_bs_write_data(pleintext_bs, buffer, sai->subsamples[subsample_count].bytes_clear_data);
/*now read encrypted data, decrypted it and write to pleintext bitstream*/
if (max_size < sai->subsamples[subsample_count].bytes_encrypted_data) {
buffer = (char*)gf_realloc(buffer, sizeof(char)*sai->subsamples[subsample_count].bytes_encrypted_data);
max_size = sai->subsamples[subsample_count].bytes_encrypted_data;
}
gf_bs_read_data(cyphertext_bs, buffer, sai->subsamples[subsample_count].bytes_encrypted_data);
gf_crypt_decrypt(priv->crypt, buffer, sai->subsamples[subsample_count].bytes_encrypted_data);
gf_bs_write_data(pleintext_bs, buffer, sai->subsamples[subsample_count].bytes_encrypted_data);
/*update IV for next subsample*/
if (priv->is_cenc) {
BSO += sai->subsamples[subsample_count].bytes_encrypted_data;
if (gf_bs_available(cyphertext_bs)) {
char next_IV[17];
u64 prev_block_count, salt_portion, block_count_portion;
u32 remain;
GF_BitStream *bs, *tmp;
prev_block_count = BSO / 16;
remain = BSO % 16;
tmp = gf_bs_new((const char *)sai->IV, 16, GF_BITSTREAM_READ);
bs = gf_bs_new(next_IV, 17, GF_BITSTREAM_WRITE);
gf_bs_write_u8(bs, 0); /*begin of counter*/
salt_portion = gf_bs_read_u64(tmp);
block_count_portion = gf_bs_read_u64(tmp);
/*reset the block counter to zero without affecting the other 64 bits of the IV*/
if (prev_block_count > 0xFFFFFFFFFFFFFFFFULL - block_count_portion)
block_count_portion = prev_block_count - (0xFFFFFFFFFFFFFFFFULL - block_count_portion) - 1;
else
block_count_portion += prev_block_count;
gf_bs_write_u64(bs, salt_portion);
gf_bs_write_u64(bs, block_count_portion);
gf_crypt_set_state(priv->crypt, next_IV, 17);
/*decrypt remain bytes*/
if (remain) {
char dummy[20];
gf_crypt_decrypt(priv->crypt, dummy, remain);
}
gf_bs_del(bs);
gf_bs_del(tmp);
}
}
subsample_count++;
}
if (buffer) gf_free(buffer);
gf_bs_get_content(pleintext_bs, &buffer, &evt->data_size);
memmove(evt->data, buffer, evt->data_size);
exit:
if (pleintext_bs) gf_bs_del(pleintext_bs);
if (sai_bs) gf_bs_del(sai_bs);
if (cyphertext_bs) gf_bs_del(cyphertext_bs);
if (buffer) gf_free(buffer);
if (sai && sai->subsamples) gf_free(sai->subsamples);
if (sai) gf_free(sai);
return e;
}
