Return an error for IV lengths other than 12 with ChaCha20
The implementation was silently overwriting the IV length to 12
even though the caller passed a different value.
Change the behavior to signal that a different length is not supported.
Signed-off-by: Andrzej Kurek <andrzej.kurek@arm.com>
diff --git a/library/cipher.c b/library/cipher.c
index 03e84c6..39c105c 100644
--- a/library/cipher.c
+++ b/library/cipher.c
@@ -386,6 +386,12 @@
#if defined(MBEDTLS_CHACHA20_C)
if ( ctx->cipher_info->type == MBEDTLS_CIPHER_CHACHA20 )
{
+ /* Even though the actual_iv_size is overwritten with a correct value
+ * of 12 from the cipher info, return an error to indicate that
+ * the input iv_len is wrong. */
+ if( iv_len != 12 )
+ return( MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA );
+
if ( 0 != mbedtls_chacha20_starts( (mbedtls_chacha20_context*)ctx->cipher_ctx,
iv,
0U ) ) /* Initial counter value */
diff --git a/tests/suites/test_suite_cipher.chacha20.data b/tests/suites/test_suite_cipher.chacha20.data
index 11de103..117fce3 100644
--- a/tests/suites/test_suite_cipher.chacha20.data
+++ b/tests/suites/test_suite_cipher.chacha20.data
@@ -109,3 +109,23 @@
ChaCha20 Encrypt and decrypt 32 bytes in multiple parts
depends_on:MBEDTLS_CHACHA20_C
enc_dec_buf_multipart:MBEDTLS_CIPHER_CHACHA20:256:16:16:-1:16:16:16:16
+
+ChaCha20 IV Length 0
+depends_on:MBEDTLS_CHACHA20_C
+check_iv:MBEDTLS_CIPHER_CHACHA20:"CHACHA20":0:MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA
+
+ChaCha20 IV Length 11
+depends_on:MBEDTLS_CHACHA20_C
+check_iv:MBEDTLS_CIPHER_CHACHA20:"CHACHA20":11:MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA
+
+ChaCha20 IV Length 12
+depends_on:MBEDTLS_CHACHA20_C
+check_iv:MBEDTLS_CIPHER_CHACHA20:"CHACHA20":12:0
+
+ChaCha20 IV Length 13
+depends_on:MBEDTLS_CHACHA20_C
+check_iv:MBEDTLS_CIPHER_CHACHA20:"CHACHA20":13:MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA
+
+ChaCha20 IV Length 16
+depends_on:MBEDTLS_CHACHA20_C
+check_iv:MBEDTLS_CIPHER_CHACHA20:"CHACHA20":16:MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA
diff --git a/tests/suites/test_suite_cipher.function b/tests/suites/test_suite_cipher.function
index fd2985b..c837a69 100644
--- a/tests/suites/test_suite_cipher.function
+++ b/tests/suites/test_suite_cipher.function
@@ -442,6 +442,8 @@
if( NULL != strstr( cipher_info->name, "CCM*-NO-TAG") )
iv_len = 13; /* For CCM, IV length is expected to be between 7 and 13 bytes.
* For CCM*-NO-TAG, IV length must be exactly 13 bytes long. */
+ else if( cipher_info->type == MBEDTLS_CIPHER_CHACHA20 )
+ iv_len = 12;
else
iv_len = sizeof(iv);
@@ -689,6 +691,8 @@
if( NULL != strstr( cipher_info->name, "CCM*-NO-TAG") )
iv_len = 13; /* For CCM, IV length is expected to be between 7 and 13 bytes.
* For CCM*-NO-TAG, IV length must be exactly 13 bytes long. */
+ else if( cipher_info->type == MBEDTLS_CIPHER_CHACHA20 )
+ iv_len = 12;
else
iv_len = sizeof(iv);
@@ -1130,3 +1134,40 @@
TEST_ASSERT( dlen == (size_t) dlen_check );
}
/* END_CASE */
+
+/* BEGIN_CASE */
+void check_iv( int cipher_id, char * cipher_string,
+ int iv_len_val, int ret )
+{
+ size_t iv_len = iv_len_val;
+ unsigned char iv[16];
+
+ const mbedtls_cipher_info_t *cipher_info;
+ mbedtls_cipher_context_t ctx_dec;
+ mbedtls_cipher_context_t ctx_enc;
+
+ /*
+ * Prepare contexts
+ */
+ mbedtls_cipher_init( &ctx_dec );
+ mbedtls_cipher_init( &ctx_enc );
+
+ /* Check and get info structures */
+ cipher_info = mbedtls_cipher_info_from_type( cipher_id );
+ TEST_ASSERT( NULL != cipher_info );
+ TEST_ASSERT( mbedtls_cipher_info_from_string( cipher_string ) == cipher_info );
+ TEST_ASSERT( strcmp( mbedtls_cipher_info_get_name( cipher_info ),
+ cipher_string ) == 0 );
+
+ /* Initialise enc and dec contexts */
+ TEST_ASSERT( 0 == mbedtls_cipher_setup( &ctx_dec, cipher_info ) );
+ TEST_ASSERT( 0 == mbedtls_cipher_setup( &ctx_enc, cipher_info ) );
+
+ TEST_ASSERT( ret == mbedtls_cipher_set_iv( &ctx_dec, iv, iv_len ) );
+ TEST_ASSERT( ret == mbedtls_cipher_set_iv( &ctx_enc, iv, iv_len ) );
+
+exit:
+ mbedtls_cipher_free( &ctx_dec );
+ mbedtls_cipher_free( &ctx_enc );
+}
+/* END_CASE */