Split cipher_set_iv() out of cipher_reset()
diff --git a/include/polarssl/cipher.h b/include/polarssl/cipher.h
index ef037be..e540c92 100644
--- a/include/polarssl/cipher.h
+++ b/include/polarssl/cipher.h
@@ -185,7 +185,8 @@
/** Name of the cipher */
const char * name;
- /** IV size, in bytes */
+ /** IV/NONCE size, in bytes, for ciphers with fixed-length IVs), or
+ * 0 for ciphers with variable-length IVs or not using IVs */
unsigned int iv_size;
/** block size, in bytes */
@@ -222,6 +223,9 @@
/** Current IV or NONCE_COUNTER for CTR-mode */
unsigned char iv[POLARSSL_MAX_IV_LENGTH];
+ /** IV size in bytes (for ciphers with variable-length IVs) */
+ size_t iv_size;
+
/** Cipher-specific context */
void *cipher_ctx;
} cipher_context_t;
@@ -315,18 +319,22 @@
}
/**
- * \brief Returns the size of the cipher's IV.
+ * \brief Returns the size of the cipher's IV/NONCE in bytes.
*
* \param ctx cipher's context. Must have been initialised.
*
- * \return size of the cipher's IV, or 0 if ctx has not been
- * initialised or accepts IV of various sizes.
+ * \return If IV has not been set yet: desired size for ciphers
+ * with fixed-size IVs, 0 for other ciphers.
+ * If IV has already been set: actual size.
*/
static inline int cipher_get_iv_size( const cipher_context_t *ctx )
{
if( NULL == ctx || NULL == ctx->cipher_info )
return 0;
+ if( ctx->iv_size != 0 )
+ return ctx->iv_size;
+
return ctx->cipher_info->iv_size;
}
@@ -428,12 +436,24 @@
int cipher_set_padding_mode( cipher_context_t *ctx, cipher_padding_t mode );
/**
+ * \brief Set the initialization vector (IV) or nonce
+ *
+ * \param iv IV to use (or NONCE_COUNTER for CTR-mode ciphers)
+ * \param iv_len IV length for ciphers with variable-size IV,
+ * Discarded by ciphers with fixed-size IV.
+ *
+ * \returns O on success, or POLARSSL_ERR_CIPHER_BAD_INPUT_DATA
+ *
+ * \note Some ciphers don't use IVs nor NONCE. For these
+ * ciphers, this function has no effect.
+ */
+int cipher_set_iv( cipher_context_t *ctx,
+ const unsigned char *iv, size_t iv_len );
+
+/**
* \brief Reset the given context, setting the IV to iv
*
* \param ctx generic cipher context
- * \param iv IV to use or NONCE_COUNTER in the case of a CTR-mode cipher
- * \param iv_len IV length for ciphers with variable-size IV,
- * Discared by ciphers with fixed-size IV.
* \param ad Additional data for AEAD ciphers, or discarded.
* May be NULL only if ad_len is 0.
* \param ad_len Length of ad for AEAD ciphers, or discarded.
@@ -442,7 +462,6 @@
* if parameter verification fails.
*/
int cipher_reset( cipher_context_t *ctx,
- const unsigned char *iv, size_t iv_len,
const unsigned char *ad, size_t ad_len );
/**
diff --git a/library/cipher.c b/library/cipher.c
index d7cac05..d90abe1 100644
--- a/library/cipher.c
+++ b/library/cipher.c
@@ -396,29 +396,42 @@
return POLARSSL_ERR_CIPHER_BAD_INPUT_DATA;
}
-int cipher_reset( cipher_context_t *ctx,
- const unsigned char *iv, size_t iv_len,
- const unsigned char *ad, size_t ad_len )
+int cipher_set_iv( cipher_context_t *ctx,
+ const unsigned char *iv, size_t iv_len )
{
+ size_t fixed_iv_size;
+
if( NULL == ctx || NULL == ctx->cipher_info || NULL == iv )
return POLARSSL_ERR_CIPHER_BAD_INPUT_DATA;
+ fixed_iv_size = cipher_get_iv_size( ctx );
+
+ /* 0 means variable size (or no IV): use given len */
+ if( fixed_iv_size == 0 )
+ fixed_iv_size = iv_len;
+
+ memcpy( ctx->iv, iv, fixed_iv_size );
+ ctx->iv_size = fixed_iv_size;
+
+ return 0;
+}
+
+int cipher_reset( cipher_context_t *ctx,
+ const unsigned char *ad, size_t ad_len )
+{
ctx->unprocessed_len = 0;
#if defined(POLARSSL_GCM_C)
if( POLARSSL_MODE_GCM == ctx->cipher_info->mode )
{
return gcm_starts( ctx->cipher_ctx, ctx->operation,
- iv, iv_len, ad, ad_len );
+ ctx->iv, ctx->iv_size, ad, ad_len );
}
#else
((void) ad);
((void) ad_len);
- ((void) iv_len);
#endif
- memcpy( ctx->iv, iv, cipher_get_iv_size( ctx ) );
-
return 0;
}
diff --git a/library/pkcs12.c b/library/pkcs12.c
index 9ccb60a..3634ce1 100644
--- a/library/pkcs12.c
+++ b/library/pkcs12.c
@@ -184,7 +184,10 @@
if( ( ret = cipher_setkey( &cipher_ctx, key, keylen, mode ) ) != 0 )
goto exit;
- if( ( ret = cipher_reset( &cipher_ctx, iv, 0, NULL, 0 ) ) != 0 )
+ if( ( ret = cipher_set_iv( &cipher_ctx, iv, 0 ) ) != 0 )
+ goto exit;
+
+ if( ( ret = cipher_reset( &cipher_ctx, iv, 0 ) ) != 0 )
goto exit;
if( ( ret = cipher_update( &cipher_ctx, data, len,
diff --git a/library/pkcs5.c b/library/pkcs5.c
index 2b6a75a..6582fd0 100644
--- a/library/pkcs5.c
+++ b/library/pkcs5.c
@@ -187,7 +187,10 @@
if( ( ret = cipher_setkey( &cipher_ctx, key, keylen, mode ) ) != 0 )
goto exit;
- if( ( ret = cipher_reset( &cipher_ctx, iv, 0, NULL, 0 ) ) != 0 )
+ if( ( ret = cipher_set_iv( &cipher_ctx, iv, 0 ) ) != 0 )
+ goto exit;
+
+ if( ( ret = cipher_reset( &cipher_ctx, NULL, 0 ) ) != 0 )
goto exit;
if( ( ret = cipher_update( &cipher_ctx, data, datalen,
diff --git a/programs/aes/crypt_and_hash.c b/programs/aes/crypt_and_hash.c
index a9b862e..8ffdb9f 100644
--- a/programs/aes/crypt_and_hash.c
+++ b/programs/aes/crypt_and_hash.c
@@ -306,7 +306,12 @@
fprintf( stderr, "cipher_setkey() returned error\n");
goto exit;
}
- if( cipher_reset( &cipher_ctx, IV, 16, NULL, 0 ) != 0 )
+ if( cipher_set_iv( &cipher_ctx, IV, 16 ) != 0 )
+ {
+ fprintf( stderr, "cipher_set_iv() returned error\n");
+ goto exit;
+ }
+ if( cipher_reset( &cipher_ctx, NULL, 0 ) != 0 )
{
fprintf( stderr, "cipher_reset() returned error\n");
goto exit;
@@ -424,7 +429,8 @@
cipher_setkey( &cipher_ctx, digest, cipher_info->key_length,
POLARSSL_DECRYPT );
- cipher_reset( &cipher_ctx, IV, 16, NULL, 0 );
+ cipher_set_iv( &cipher_ctx, IV, 16 );
+ cipher_reset( &cipher_ctx, NULL, 0 );
md_hmac_starts( &md_ctx, digest, 32 );
diff --git a/tests/suites/test_suite_cipher.function b/tests/suites/test_suite_cipher.function
index b1814fa..d247bab 100644
--- a/tests/suites/test_suite_cipher.function
+++ b/tests/suites/test_suite_cipher.function
@@ -58,8 +58,11 @@
TEST_ASSERT( 0 == cipher_set_padding_mode( &ctx_enc, pad_mode ) );
}
- TEST_ASSERT( 0 == cipher_reset( &ctx_dec, iv, 16, ad, 13 ) );
- TEST_ASSERT( 0 == cipher_reset( &ctx_enc, iv, 16, ad, 13 ) );
+ TEST_ASSERT( 0 == cipher_set_iv( &ctx_dec, iv, 16 ) );
+ TEST_ASSERT( 0 == cipher_set_iv( &ctx_enc, iv, 16 ) );
+
+ TEST_ASSERT( 0 == cipher_reset( &ctx_dec, ad, 13 ) );
+ TEST_ASSERT( 0 == cipher_reset( &ctx_enc, ad, 13 ) );
/* encode length number of bytes from inbuf */
TEST_ASSERT( 0 == cipher_update( &ctx_enc, inbuf, length, encbuf, &outlen ) );
@@ -133,7 +136,8 @@
TEST_ASSERT( 0 == cipher_init_ctx( &ctx, cipher_info ) );
TEST_ASSERT( 0 == cipher_setkey( &ctx, key, key_len, POLARSSL_ENCRYPT ) );
TEST_ASSERT( 0 == cipher_set_padding_mode( &ctx, pad_mode ) );
- TEST_ASSERT( 0 == cipher_reset( &ctx, iv, 16, NULL, 0 ) );
+ TEST_ASSERT( 0 == cipher_set_iv( &ctx, iv, 16 ) );
+ TEST_ASSERT( 0 == cipher_reset( &ctx, NULL, 0 ) );
/* encode length number of bytes from inbuf */
TEST_ASSERT( 0 == cipher_update( &ctx, inbuf, length, encbuf, &outlen ) );
@@ -166,7 +170,7 @@
memset( encbuf, 0, 64 );
memset( decbuf, 0, 64 );
- /* Initialise enc and dec contexts */
+ /* Initialise context */
cipher_info = cipher_info_from_type( POLARSSL_CIPHER_AES_128_CBC );
TEST_ASSERT( NULL != cipher_info);
@@ -174,7 +178,9 @@
TEST_ASSERT( 0 == cipher_setkey( &ctx_dec, key, 128, POLARSSL_DECRYPT ) );
- TEST_ASSERT( 0 == cipher_reset( &ctx_dec, iv, 16, NULL, 0 ) );
+ TEST_ASSERT( 0 == cipher_set_iv( &ctx_dec, iv, 16 ) );
+
+ TEST_ASSERT( 0 == cipher_reset( &ctx_dec, NULL, 0 ) );
/* decode 0-byte string */
TEST_ASSERT( 0 == cipher_update( &ctx_dec, encbuf, 0, decbuf, &outlen ) );
@@ -228,8 +234,11 @@
TEST_ASSERT( 0 == cipher_setkey( &ctx_dec, key, key_len, POLARSSL_DECRYPT ) );
TEST_ASSERT( 0 == cipher_setkey( &ctx_enc, key, key_len, POLARSSL_ENCRYPT ) );
- TEST_ASSERT( 0 == cipher_reset( &ctx_dec, iv, 16, NULL, 0 ) );
- TEST_ASSERT( 0 == cipher_reset( &ctx_enc, iv, 16, NULL, 0 ) );
+ TEST_ASSERT( 0 == cipher_set_iv( &ctx_dec, iv, 16 ) );
+ TEST_ASSERT( 0 == cipher_set_iv( &ctx_enc, iv, 16 ) );
+
+ TEST_ASSERT( 0 == cipher_reset( &ctx_dec, NULL, 0 ) );
+ TEST_ASSERT( 0 == cipher_reset( &ctx_enc, NULL, 0 ) );
/* encode length number of bytes from inbuf */
TEST_ASSERT( 0 == cipher_update( &ctx_enc, inbuf, first_length, encbuf, &outlen ) );
