Ommit AEAD functions if GCM not defined
diff --git a/include/polarssl/cipher.h b/include/polarssl/cipher.h
index dc5a41c..b7d4492 100644
--- a/include/polarssl/cipher.h
+++ b/include/polarssl/cipher.h
@@ -30,6 +30,12 @@
#ifndef POLARSSL_CIPHER_H
#define POLARSSL_CIPHER_H
+#include "config.h"
+
+#if defined(POLARSSL_GCM_C)
+#define POLARSSL_CIPHER_MODE_AEAD
+#endif
+
#include <string.h>
#if defined(_MSC_VER) && !defined(inline)
@@ -457,15 +463,13 @@
* \brief Finish preparation of the given context
*
* \param ctx generic cipher context
- * \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.
*
* \returns 0 on success, POLARSSL_ERR_CIPHER_BAD_INPUT_DATA
* if parameter verification fails.
*/
int cipher_reset( cipher_context_t *ctx );
+#if defined(POLARSSL_CIPHER_MODE_AEAD)
/**
* \brief Add additional data (for AEAD ciphers).
* This function has no effect for non-AEAD ciphers.
@@ -483,6 +487,7 @@
*/
int cipher_update_ad( cipher_context_t *ctx,
const unsigned char *ad, size_t ad_len );
+#endif /* POLARSSL_CIPHER_MODE_AEAD */
/**
* \brief Generic cipher update function. Encrypts/decrypts
@@ -530,6 +535,7 @@
int cipher_finish( cipher_context_t *ctx,
unsigned char *output, size_t *olen );
+#if defined(POLARSSL_CIPHER_MODE_AEAD)
/**
* \brief Write tag for AEAD ciphers.
* No effect for other ciphers.
@@ -556,6 +562,7 @@
*/
int cipher_check_tag( cipher_context_t *ctx,
const unsigned char *tag, size_t tag_len );
+#endif /* POLARSSL_CIPHER_MODE_AEAD */
/**
* \brief Checkup routine
diff --git a/library/cipher.c b/library/cipher.c
index a90e2dc..160f4bc 100644
--- a/library/cipher.c
+++ b/library/cipher.c
@@ -425,6 +425,7 @@
return 0;
}
+#if defined(POLARSSL_CIPHER_MODE_AEAD)
int cipher_update_ad( cipher_context_t *ctx,
const unsigned char *ad, size_t ad_len )
{
@@ -444,13 +445,11 @@
return gcm_starts( ctx->cipher_ctx, ctx->operation,
ctx->iv, ctx->iv_size, ad, ad_len );
}
-#else
- ((void) ad);
- ((void) ad_len);
#endif
return 0;
}
+#endif /* POLARSSL_CIPHER_MODE_AEAD */
int cipher_update( cipher_context_t *ctx, const unsigned char *input, size_t ilen,
unsigned char *output, size_t *olen )
@@ -904,50 +903,62 @@
return 0;
}
+#if defined(POLARSSL_CIPHER_MODE_AEAD)
int cipher_write_tag( cipher_context_t *ctx,
unsigned char *tag, size_t tag_len )
{
if( NULL == ctx || NULL == ctx->cipher_info || NULL == tag )
return POLARSSL_ERR_CIPHER_BAD_INPUT_DATA;
- if( POLARSSL_MODE_GCM != ctx->cipher_info->mode )
- return( 0 );
-
if( POLARSSL_ENCRYPT != ctx->operation )
return POLARSSL_ERR_CIPHER_BAD_INPUT_DATA;
- return gcm_finish( ctx->cipher_ctx, tag, tag_len );
+#if defined(POLARSSL_GCM_C)
+ if( POLARSSL_MODE_GCM == ctx->cipher_info->mode )
+ return gcm_finish( ctx->cipher_ctx, tag, tag_len );
+#endif
+
+ return 0;
}
int cipher_check_tag( cipher_context_t *ctx,
const unsigned char *tag, size_t tag_len )
{
int ret;
- unsigned char check_tag[16];
- size_t i;
- int diff;
- if( NULL == ctx || NULL == ctx->cipher_info )
+ if( NULL == ctx || NULL == ctx->cipher_info ||
+ POLARSSL_DECRYPT != ctx->operation )
+ {
return POLARSSL_ERR_CIPHER_BAD_INPUT_DATA;
+ }
- if( POLARSSL_MODE_GCM != ctx->cipher_info->mode )
+#if defined(POLARSSL_GCM_C)
+ if( POLARSSL_MODE_GCM == ctx->cipher_info->mode )
+ {
+ unsigned char check_tag[16];
+ size_t i;
+ int diff;
+
+ if( tag_len > sizeof( check_tag ) )
+ return POLARSSL_ERR_CIPHER_BAD_INPUT_DATA;
+
+ if( 0 != ( ret = gcm_finish( ctx->cipher_ctx, check_tag, tag_len ) ) )
+ return( ret );
+
+ /* Check the tag in "constant-time" */
+ for( diff = 0, i = 0; i < tag_len; i++ )
+ diff |= tag[i] ^ check_tag[i];
+
+ if( diff != 0 )
+ return( POLARSSL_ERR_GCM_AUTH_FAILED );
+
return( 0 );
-
- if( POLARSSL_DECRYPT != ctx->operation || tag_len > sizeof( check_tag ) )
- return POLARSSL_ERR_CIPHER_BAD_INPUT_DATA;
-
- if( 0 != ( ret = gcm_finish( ctx->cipher_ctx, check_tag, tag_len ) ) )
- return( ret );
-
- /* On decryption, check the tag (in "constant-time") */
- for( diff = 0, i = 0; i < tag_len; i++ )
- diff |= tag[i] ^ check_tag[i];
-
- if( diff != 0 )
- return( POLARSSL_ERR_GCM_AUTH_FAILED );
+ }
+#endif
return( 0 );
}
+#endif /* POLARSSL_CIPHER_MODE_AEAD */
#if defined(POLARSSL_SELF_TEST)
diff --git a/tests/suites/test_suite_cipher.function b/tests/suites/test_suite_cipher.function
index 5d32bc3..63de2db 100644
--- a/tests/suites/test_suite_cipher.function
+++ b/tests/suites/test_suite_cipher.function
@@ -64,8 +64,10 @@
TEST_ASSERT( 0 == cipher_reset( &ctx_dec ) );
TEST_ASSERT( 0 == cipher_reset( &ctx_enc ) );
+#if defined(POLARSSL_CIPHER_MODE_AEAD)
TEST_ASSERT( 0 == cipher_update_ad( &ctx_dec, ad, 13 ) );
TEST_ASSERT( 0 == cipher_update_ad( &ctx_enc, ad, 13 ) );
+#endif /* POLARSSL_CIPHER_MODE_AEAD */
/* encode length number of bytes from inbuf */
TEST_ASSERT( 0 == cipher_update( &ctx_enc, inbuf, length, encbuf, &outlen ) );
@@ -79,7 +81,9 @@
TEST_ASSERT( 0 == cipher_finish( &ctx_enc, encbuf + outlen, &outlen ) );
total_len += outlen;
+#if defined(POLARSSL_CIPHER_MODE_AEAD)
TEST_ASSERT( 0 == cipher_write_tag( &ctx_enc, tag, 16 ) );
+#endif /* POLARSSL_CIPHER_MODE_AEAD */
TEST_ASSERT( total_len == length ||
( total_len % cipher_get_block_size( &ctx_enc ) == 0 &&
@@ -98,7 +102,9 @@
TEST_ASSERT( 0 == cipher_finish( &ctx_dec, decbuf + outlen, &outlen ) );
total_len += outlen;
+#if defined(POLARSSL_CIPHER_MODE_AEAD)
TEST_ASSERT( 0 == cipher_check_tag( &ctx_dec, tag, 16 ) );
+#endif /* POLARSSL_CIPHER_MODE_AEAD */
TEST_ASSERT( total_len == length );
@@ -143,7 +149,9 @@
TEST_ASSERT( 0 == cipher_set_padding_mode( &ctx, pad_mode ) );
TEST_ASSERT( 0 == cipher_set_iv( &ctx, iv, 16 ) );
TEST_ASSERT( 0 == cipher_reset( &ctx ) );
+#if defined(POLARSSL_CIPHER_MODE_AEAD)
TEST_ASSERT( 0 == cipher_update_ad( &ctx, NULL, 0 ) );
+#endif /* POLARSSL_CIPHER_MODE_AEAD */
/* encode length number of bytes from inbuf */
TEST_ASSERT( 0 == cipher_update( &ctx, inbuf, length, encbuf, &outlen ) );
@@ -188,7 +196,9 @@
TEST_ASSERT( 0 == cipher_reset( &ctx_dec ) );
+#if defined(POLARSSL_CIPHER_MODE_AEAD)
TEST_ASSERT( 0 == cipher_update_ad( &ctx_dec, NULL, 0 ) );
+#endif /* POLARSSL_CIPHER_MODE_AEAD */
/* decode 0-byte string */
TEST_ASSERT( 0 == cipher_update( &ctx_dec, encbuf, 0, decbuf, &outlen ) );
@@ -248,8 +258,10 @@
TEST_ASSERT( 0 == cipher_reset( &ctx_dec ) );
TEST_ASSERT( 0 == cipher_reset( &ctx_enc ) );
+#if defined(POLARSSL_CIPHER_MODE_AEAD)
TEST_ASSERT( 0 == cipher_update_ad( &ctx_dec, NULL, 0 ) );
TEST_ASSERT( 0 == cipher_update_ad( &ctx_enc, NULL, 0 ) );
+#endif /* POLARSSL_CIPHER_MODE_AEAD */
/* encode length number of bytes from inbuf */
TEST_ASSERT( 0 == cipher_update( &ctx_enc, inbuf, first_length, encbuf, &outlen ) );