[FFmpeg-devel] [PATCH 1/4] avformat/crypto: added encryption
Christian Suloway
csuloway at row44.com
Mon Dec 1 19:55:28 CET 2014
Signed-off-by: Christian Suloway <csuloway at globaleagleent.com>
---
libavformat/crypto.c | 166 ++++++++++++++++++++++++++++++++++++++++++++-------
1 file changed, 146 insertions(+), 20 deletions(-)
diff --git a/libavformat/crypto.c b/libavformat/crypto.c
index a9b6e47..f3a85c7 100644
--- a/libavformat/crypto.c
+++ b/libavformat/crypto.c
@@ -41,14 +41,32 @@ typedef struct {
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 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(CryptoContext *c, 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(c, AV_LOG_ERROR, "%s not set\n", desc);
+ return AVERROR(EINVAL);
+ } else if (default_buf_len != BLOCKSIZE) {
+ av_log(c, 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(c, 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_open2(URLContext *h, const char *uri, int flags, AVDictionary **options)
{
const char *nested_url;
@@ -72,28 +118,54 @@ static int crypto_open2(URLContext *h, const char *uri, int flags, AVDictionary
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(c, &c->decrypt_key, &c->decrypt_keylen,
+ c->key, c->keylen, "decryption key")) < 0)
+ goto err;
+ if ((ret = set_aes_arg(c, &c->decrypt_iv, &c->decrypt_ivlen,
+ c->key, c->keylen, "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(c, &c->encrypt_key, &c->encrypt_keylen,
+ c->key, c->keylen, "encryption key")) < 0)
+ if (ret < 0)
+ goto err;
+ if ((ret = set_aes_arg(c, &c->encrypt_iv, &c->encrypt_ivlen,
+ c->key, c->keylen, "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, options)) < 0) {
- av_log(h, AV_LOG_ERROR, "Unable to open input\n");
+ av_log(h, AV_LOG_ERROR, "Unable to open resource: %s\n", nested_url);
goto err;
}
- c->aes = av_aes_alloc();
- if (!c->aes) {
- ret = AVERROR(ENOMEM);
- goto err;
+
+ 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;
}
- av_aes_init(c->aes, c->key, 128, 1);
+ 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;
+ }
+
+ c->pad_len = 0;
h->is_streamed = 1;
@@ -131,8 +203,8 @@ 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;
@@ -150,12 +222,65 @@ retry:
goto retry;
}
+static int crypto_write(URLContext *h, const unsigned char *buf, int size)
+{
+ CryptoContext *c = h->priv_data;
+ int total_size, blocks, pad_len, out_size;
+ uint8_t *out_buf;
+ 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) {
+ out_buf = av_malloc(out_size);
+ if (!out_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, out_buf, c->pad, 1, c->encrypt_iv, 0);
+ blocks--;
+ }
+
+ av_aes_crypt(c->aes_encrypt, &out_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, out_buf, out_size);
+ av_free(out_buf);
+ 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;
+ uint8_t out_buf[BLOCKSIZE];
+ int ret, pad;
+
+ if (c->aes_encrypt) {
+ 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);
+ if ((ret = ffurl_write(c->hd, out_buf, BLOCKSIZE)) < 0)
+ return ret;
+ }
+
if (c->hd)
ffurl_close(c->hd);
- av_freep(&c->aes);
+ av_freep(&c->aes_decrypt);
+ av_freep(&c->aes_encrypt);
return 0;
}
@@ -163,6 +288,7 @@ URLProtocol ff_crypto_protocol = {
.name = "crypto",
.url_open2 = crypto_open2,
.url_read = crypto_read,
+ .url_write = crypto_write,
.url_close = crypto_close,
.priv_data_size = sizeof(CryptoContext),
.priv_data_class = &crypto_class,
--
1.9.3 (Apple Git-50)
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