static int decrypt_init(AVFormatContext *s, ID3v2ExtraMeta *em, uint8_t *header) { OMAContext *oc = s->priv_data; ID3v2ExtraMetaGEOB *geob = NULL; uint8_t *gdata; oc->encrypted = 1; av_log(s, AV_LOG_INFO, "File is encrypted\n"); /* find GEOB metadata */ while (em) { if (!strcmp(em->tag, "GEOB") && (geob = em->data) && (!strcmp(geob->description, "OMG_LSI") || !strcmp(geob->description, "OMG_BKLSI"))) { break; } em = em->next; } if (!em) { av_log(s, AV_LOG_ERROR, "No encryption header found\n"); return AVERROR_INVALIDDATA; } if (geob->datasize < 64) { av_log(s, AV_LOG_ERROR, "Invalid GEOB data size: %u\n", geob->datasize); return AVERROR_INVALIDDATA; } gdata = geob->data; if (AV_RB16(gdata) != 1) av_log(s, AV_LOG_WARNING, "Unknown version in encryption header\n"); oc->k_size = AV_RB16(&gdata[2]); oc->e_size = AV_RB16(&gdata[4]); oc->i_size = AV_RB16(&gdata[6]); oc->s_size = AV_RB16(&gdata[8]); if (memcmp(&gdata[OMA_ENC_HEADER_SIZE], "KEYRING ", 12)) { av_log(s, AV_LOG_ERROR, "Invalid encryption header\n"); return AVERROR_INVALIDDATA; } oc->rid = AV_RB32(&gdata[OMA_ENC_HEADER_SIZE + 28]); av_log(s, AV_LOG_DEBUG, "RID: %.8x\n", oc->rid); memcpy(oc->iv, &header[0x58], 8); hex_log(s, AV_LOG_DEBUG, "IV", oc->iv, 8); hex_log(s, AV_LOG_DEBUG, "CBC-MAC", &gdata[OMA_ENC_HEADER_SIZE + oc->k_size + oc->e_size + oc->i_size], 8); if (s->keylen > 0) { kset(s, s->key, s->key, s->keylen); } if (!memcmp(oc->r_val, (const uint8_t[8]){0}, 8) || rprobe(s, gdata, oc->r_val) < 0 && nprobe(s, gdata, geob->datasize, oc->n_val) < 0) { int i; for (i = 0; i < FF_ARRAY_ELEMS(leaf_table); i += 2) { uint8_t buf[16]; AV_WL64(buf, leaf_table[i]); AV_WL64(&buf[8], leaf_table[i + 1]); kset(s, buf, buf, 16); if (!rprobe(s, gdata, oc->r_val) || !nprobe(s, gdata, geob->datasize, oc->n_val)) break; } if (i >= sizeof(leaf_table)) { av_log(s, AV_LOG_ERROR, "Invalid key\n"); return AVERROR_INVALIDDATA; } } /* e_val */ av_des_init(&oc->av_des, oc->m_val, 64, 0); av_des_crypt(&oc->av_des, oc->e_val, &gdata[OMA_ENC_HEADER_SIZE + 40], 1, NULL, 0); hex_log(s, AV_LOG_DEBUG, "EK", oc->e_val, 8); /* init e_val */ av_des_init(&oc->av_des, oc->e_val, 64, 1); return 0; }