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crypto: Add encryption support 

Signed-off-by: Christian Suloway <csuloway@globaleagleent.com>
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
Signed-off-by: Luca Barbato <lu_zero@gentoo.org>
This commit is contained in:
Christian Suloway 2014-12-01 12:55:28 -06:00 committed by Luca Barbato
parent 76167140a9
commit d860a3cc0a
1 changed files with 147 additions and 22 deletions
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169
libavformat/crypto.c
View File

@ -41,14 +41,32 @@ typedef struct CryptoContext {
int keylen;
uint8_t *iv;
int ivlen;
struct AVAES *aes;
uint8_t *decrypt_key;
int decrypt_keylen;
uint8_t *decrypt_iv;
int decrypt_ivlen;
uint8_t *encrypt_key;
int encrypt_keylen;
uint8_t *encrypt_iv;
int encrypt_ivlen;
struct AVAES *aes_decrypt;
struct AVAES *aes_encrypt;
uint8_t *write_buf;
unsigned int write_buf_size;
uint8_t pad[BLOCKSIZE];
int pad_len;
} CryptoContext;
#define OFFSET(x) offsetof(CryptoContext, x)
#define D AV_OPT_FLAG_DECODING_PARAM
#define E AV_OPT_FLAG_ENCODING_PARAM
static const AVOption options[] = {
{"key", "AES decryption key", OFFSET(key), AV_OPT_TYPE_BINARY, .flags = D },
{"iv", "AES decryption initialization vector", OFFSET(iv), AV_OPT_TYPE_BINARY, .flags = D },
{"key", "AES encryption/decryption key", OFFSET(key), AV_OPT_TYPE_BINARY, .flags = D|E },
{"iv", "AES encryption/decryption initialization vector", OFFSET(iv), AV_OPT_TYPE_BINARY, .flags = D|E },
{"decryption_key", "AES decryption key", OFFSET(decrypt_key), AV_OPT_TYPE_BINARY, .flags = D },
{"decryption_iv", "AES decryption initialization vector", OFFSET(decrypt_iv), AV_OPT_TYPE_BINARY, .flags = D },
{"encryption_key", "AES encryption key", OFFSET(encrypt_key), AV_OPT_TYPE_BINARY, .flags = E },
{"encryption_iv", "AES encryption initialization vector", OFFSET(encrypt_iv), AV_OPT_TYPE_BINARY, .flags = E },
{ NULL }
};
@ -59,6 +77,34 @@ static const AVClass crypto_class = {
.version = LIBAVUTIL_VERSION_INT,
};
static int set_aes_arg(URLContext *h, uint8_t **buf, int *buf_len,
uint8_t *default_buf, int default_buf_len,
const char *desc)
{
if (!*buf_len) {
if (!default_buf_len) {
av_log(h, AV_LOG_ERROR, "%s not set\n", desc);
return AVERROR(EINVAL);
} else if (default_buf_len != BLOCKSIZE) {
av_log(h, AV_LOG_ERROR,
"invalid %s size (%d bytes, block size is %d)\n",
desc, default_buf_len, BLOCKSIZE);
return AVERROR(EINVAL);
}
*buf = av_malloc(default_buf_len);
if (!*buf)
return AVERROR(ENOMEM);
memcpy(*buf, default_buf, default_buf_len);
*buf_len = default_buf_len;
} else if (*buf_len != BLOCKSIZE) {
av_log(h, AV_LOG_ERROR,
"invalid %s size (%d bytes, block size is %d)\n",
desc, *buf_len, BLOCKSIZE);
return AVERROR(EINVAL);
}
return 0;
}
static int crypto_open(URLContext *h, const char *uri, int flags)
{
const char *nested_url;
@ -72,28 +118,52 @@ static int crypto_open(URLContext *h, const char *uri, int flags)
goto err;
}
if (c->keylen < BLOCKSIZE || c->ivlen < BLOCKSIZE) {
av_log(h, AV_LOG_ERROR, "Key or IV not set\n");
ret = AVERROR(EINVAL);
goto err;
if (flags & AVIO_FLAG_READ) {
if ((ret = set_aes_arg(h, &c->decrypt_key, &c->decrypt_keylen,
c->key, c->keylen, "decryption key")) < 0)
goto err;
if ((ret = set_aes_arg(h, &c->decrypt_iv, &c->decrypt_ivlen,
c->iv, c->ivlen, "decryption IV")) < 0)
goto err;
}
if (flags & AVIO_FLAG_WRITE) {
av_log(h, AV_LOG_ERROR, "Only decryption is supported currently\n");
ret = AVERROR(ENOSYS);
goto err;
if ((ret = set_aes_arg(h, &c->encrypt_key, &c->encrypt_keylen,
c->key, c->keylen, "encryption key")) < 0)
if (ret < 0)
goto err;
if ((ret = set_aes_arg(h, &c->encrypt_iv, &c->encrypt_ivlen,
c->iv, c->ivlen, "encryption IV")) < 0)
goto err;
}
if ((ret = ffurl_open(&c->hd, nested_url, AVIO_FLAG_READ,
if ((ret = ffurl_open(&c->hd, nested_url, flags,
&h->interrupt_callback, NULL, h->protocols, h)) < 0) {
av_log(h, AV_LOG_ERROR, "Unable to open input\n");
goto err;
}
c->aes = av_aes_alloc();
if (!c->aes) {
ret = AVERROR(ENOMEM);
av_log(h, AV_LOG_ERROR, "Unable to open resource: %s\n", nested_url);
goto err;
}
av_aes_init(c->aes, c->key, 128, 1);
if (flags & AVIO_FLAG_READ) {
c->aes_decrypt = av_aes_alloc();
if (!c->aes_decrypt) {
ret = AVERROR(ENOMEM);
goto err;
}
ret = av_aes_init(c->aes_decrypt, c->decrypt_key, BLOCKSIZE * 8, 1);
if (ret < 0)
goto err;
}
if (flags & AVIO_FLAG_WRITE) {
c->aes_encrypt = av_aes_alloc();
if (!c->aes_encrypt) {
ret = AVERROR(ENOMEM);
goto err;
}
ret = av_aes_init(c->aes_encrypt, c->encrypt_key, BLOCKSIZE * 8, 0);
if (ret < 0)
goto err;
}
h->is_streamed = 1;
@ -131,8 +201,8 @@ retry:
return AVERROR_EOF;
if (!c->eof)
blocks--;
av_aes_crypt(c->aes, c->outbuffer, c->inbuffer + c->indata_used, blocks,
c->iv, 1);
av_aes_crypt(c->aes_decrypt, c->outbuffer, c->inbuffer + c->indata_used,
blocks, c->decrypt_iv, 1);
c->outdata = BLOCKSIZE * blocks;
c->outptr = c->outbuffer;
c->indata_used += BLOCKSIZE * blocks;
@ -150,19 +220,74 @@ retry:
goto retry;
}
static int crypto_write(URLContext *h, const uint8_t *buf, int size)
{
CryptoContext *c = h->priv_data;
int total_size, blocks, pad_len, out_size;
int ret = 0;
total_size = size + c->pad_len;
pad_len = total_size % BLOCKSIZE;
out_size = total_size - pad_len;
blocks = out_size / BLOCKSIZE;
if (out_size) {
av_fast_malloc(&c->write_buf, &c->write_buf_size, out_size);
if (!c->write_buf)
return AVERROR(ENOMEM);
if (c->pad_len) {
memcpy(&c->pad[c->pad_len], buf, BLOCKSIZE - c->pad_len);
av_aes_crypt(c->aes_encrypt, c->write_buf, c->pad, 1, c->encrypt_iv, 0);
blocks--;
}
av_aes_crypt(c->aes_encrypt,
&c->write_buf[c->pad_len ? BLOCKSIZE : 0],
&buf[c->pad_len ? BLOCKSIZE - c->pad_len : 0],
blocks, c->encrypt_iv, 0);
ret = ffurl_write(c->hd, c->write_buf, out_size);
if (ret < 0)
return ret;
memcpy(c->pad, &buf[size - pad_len], pad_len);
} else
memcpy(&c->pad[c->pad_len], buf, size);
c->pad_len = pad_len;
return size;
}
static int crypto_close(URLContext *h)
{
CryptoContext *c = h->priv_data;
int ret = 0;
if (c->aes_encrypt) {
uint8_t out_buf[BLOCKSIZE];
int pad = BLOCKSIZE - c->pad_len;
memset(&c->pad[c->pad_len], pad, pad);
av_aes_crypt(c->aes_encrypt, out_buf, c->pad, 1, c->encrypt_iv, 0);
ret = ffurl_write(c->hd, out_buf, BLOCKSIZE);
}
if (c->hd)
ffurl_close(c->hd);
av_freep(&c->aes);
return 0;
av_freep(&c->aes_decrypt);
av_freep(&c->aes_encrypt);
av_freep(&c->write_buf);
return ret;
}
const URLProtocol ff_crypto_protocol = {
.name = "crypto",
.url_open = crypto_open,
.url_read = crypto_read,
.url_write = crypto_write,
.url_close = crypto_close,
.priv_data_size = sizeof(CryptoContext),
.priv_data_class = &crypto_class,