Relax checks on RSA mode for public key operations
diff --git a/include/polarssl/rsa.h b/include/polarssl/rsa.h
index 1c697fb..c57ff97 100644
--- a/include/polarssl/rsa.h
+++ b/include/polarssl/rsa.h
@@ -126,6 +126,17 @@
*
* \note The hash_id parameter is actually ignored
* when using RSA_PKCS_V15 padding.
+ *
+ * \note Choice of padding mode is strictly enforced for private key
+ * operations, since there might be security concerns in
+ * mixing padding modes. For public key operations it's merely
+ * a default value, which can be overriden by calling specific
+ * rsa_rsaes_xxx or rsa_rsassa_xxx functions.
+ *
+ * \note The chosen hash is always used for OEAP encryption.
+ * For PSS signatures, it's always used for making signatures,
+ * but can be overriden (and always is, if set to
+ * POLARSSL_MD_NONE) for verifying them.
*/
void rsa_init( rsa_context *ctx,
int padding,
@@ -133,16 +144,11 @@
/**
* \brief Set padding for an already initialized RSA context
- *
- * Note: Set padding to RSA_PKCS_V21 for the RSAES-OAEP
- * encryption scheme and the RSASSA-PSS signature scheme.
+ * See \c rsa_init() for details.
*
* \param ctx RSA context to be set
* \param padding RSA_PKCS_V15 or RSA_PKCS_V21
* \param hash_id RSA_PKCS_V21 hash identifier
- *
- * \note The hash_id parameter is actually ignored
- * when using RSA_PKCS_V15 padding.
*/
void rsa_set_padding( rsa_context *ctx, int padding, int hash_id);
@@ -405,11 +411,8 @@
* \note The "sig" buffer must be as large as the size
* of ctx->N (eg. 128 bytes if RSA-1024 is used).
*
- * \note In case of PKCS#1 v2.1 encoding keep in mind that
- * the hash_id in the RSA context is the one used for the
- * encoding. hash_id in the function call is the type of hash
- * that is encoded. According to RFC 3447 it is advised to
- * keep both hashes the same.
+ * \note In case of PKCS#1 v2.1 encoding, see comments on
+ * \note \c rsa_rsassa_pss_sign() for details on md_alg and hash_id.
*/
int rsa_pkcs1_sign( rsa_context *ctx,
int (*f_rng)(void *, unsigned char *, size_t),
@@ -466,9 +469,8 @@
* \note The "sig" buffer must be as large as the size
* of ctx->N (eg. 128 bytes if RSA-1024 is used).
*
- * \note In case of PKCS#1 v2.1 encoding keep in mind that
- * the hash_id in the RSA context is the one used for the
- * encoding. hash_id in the function call is the type of hash
+ * \note The hash_id in the RSA context is the one used for the
+ * encoding. md_alg in the function call is the type of hash
* that is encoded. According to RFC 3447 it is advised to
* keep both hashes the same.
*/
@@ -501,11 +503,8 @@
* \note The "sig" buffer must be as large as the size
* of ctx->N (eg. 128 bytes if RSA-1024 is used).
*
- * \note In case of PKCS#1 v2.1 encoding keep in mind that
- * the hash_id in the RSA context is the one used for the
- * verification. hash_id in the function call is the type of
- * hash that is verified. According to RFC 3447 it is advised to
- * keep both hashes the same.
+ * \note In case of PKCS#1 v2.1 encoding, see comments on
+ * \c rsa_rsassa_pss_verify() about md_alg and hash_id.
*/
int rsa_pkcs1_verify( rsa_context *ctx,
int (*f_rng)(void *, unsigned char *, size_t),
@@ -561,11 +560,11 @@
* \note The "sig" buffer must be as large as the size
* of ctx->N (eg. 128 bytes if RSA-1024 is used).
*
- * \note In case of PKCS#1 v2.1 encoding keep in mind that
- * the hash_id in the RSA context is the one used for the
- * verification. hash_id in the function call is the type of
+ * \note The hash_id in the RSA context is the one used for the
+ * verification. md_alg in the function call is the type of
* hash that is verified. According to RFC 3447 it is advised to
- * keep both hashes the same.
+ * keep both hashes the same. If hash_id in the RSA context is
+ * unset, the md_alg from the function call is used.
*/
int rsa_rsassa_pss_verify( rsa_context *ctx,
int (*f_rng)(void *, unsigned char *, size_t),
diff --git a/library/rsa.c b/library/rsa.c
index e3cac12..1e84d9f 100644
--- a/library/rsa.c
+++ b/library/rsa.c
@@ -505,7 +505,10 @@
const md_info_t *md_info;
md_context_t md_ctx;
- if( ctx->padding != RSA_PKCS_V21 || f_rng == NULL )
+ if( mode == RSA_PRIVATE && ctx->padding != RSA_PKCS_V21 )
+ return( POLARSSL_ERR_RSA_BAD_INPUT_DATA );
+
+ if( f_rng == NULL )
return( POLARSSL_ERR_RSA_BAD_INPUT_DATA );
md_info = md_info_from_type( ctx->hash_id );
@@ -515,7 +518,7 @@
olen = ctx->len;
hlen = md_get_size( md_info );
- if( olen < ilen + 2 * hlen + 2 || f_rng == NULL )
+ if( olen < ilen + 2 * hlen + 2 )
return( POLARSSL_ERR_RSA_BAD_INPUT_DATA );
memset( output, 0, olen );
@@ -572,7 +575,10 @@
int ret;
unsigned char *p = output;
- if( ctx->padding != RSA_PKCS_V15 || f_rng == NULL )
+ if( mode == RSA_PRIVATE && ctx->padding != RSA_PKCS_V15 )
+ return( POLARSSL_ERR_RSA_BAD_INPUT_DATA );
+
+ if( f_rng == NULL )
return( POLARSSL_ERR_RSA_BAD_INPUT_DATA );
olen = ctx->len;
@@ -675,7 +681,7 @@
/*
* Parameters sanity checks
*/
- if( ctx->padding != RSA_PKCS_V21 )
+ if( mode == RSA_PRIVATE && ctx->padding != RSA_PKCS_V21 )
return( POLARSSL_ERR_RSA_BAD_INPUT_DATA );
ilen = ctx->len;
@@ -780,7 +786,7 @@
unsigned char *p, bad, pad_done = 0;
unsigned char buf[POLARSSL_MPI_MAX_SIZE];
- if( ctx->padding != RSA_PKCS_V15 )
+ if( mode == RSA_PRIVATE && ctx->padding != RSA_PKCS_V15 )
return( POLARSSL_ERR_RSA_BAD_INPUT_DATA );
ilen = ctx->len;
@@ -901,7 +907,10 @@
const md_info_t *md_info;
md_context_t md_ctx;
- if( ctx->padding != RSA_PKCS_V21 || f_rng == NULL )
+ if( mode == RSA_PRIVATE && ctx->padding != RSA_PKCS_V21 )
+ return( POLARSSL_ERR_RSA_BAD_INPUT_DATA );
+
+ if( f_rng == NULL )
return( POLARSSL_ERR_RSA_BAD_INPUT_DATA );
olen = ctx->len;
@@ -995,7 +1004,7 @@
unsigned char *p = sig;
const char *oid;
- if( ctx->padding != RSA_PKCS_V15 )
+ if( mode == RSA_PRIVATE && ctx->padding != RSA_PKCS_V15 )
return( POLARSSL_ERR_RSA_BAD_INPUT_DATA );
olen = ctx->len;
@@ -1117,7 +1126,7 @@
const md_info_t *md_info;
md_context_t md_ctx;
- if( ctx->padding != RSA_PKCS_V21 )
+ if( mode == RSA_PRIVATE && ctx->padding != RSA_PKCS_V21 )
return( POLARSSL_ERR_RSA_BAD_INPUT_DATA );
siglen = ctx->len;
@@ -1148,7 +1157,8 @@
hashlen = md_get_size( md_info );
}
- md_info = md_info_from_type( ctx->hash_id );
+ md_info = md_info_from_type( ctx->hash_id != POLARSSL_MD_NONE ?
+ ctx->hash_id : md_alg );
if( md_info == NULL )
return( POLARSSL_ERR_RSA_BAD_INPUT_DATA );
@@ -1227,7 +1237,7 @@
const md_info_t *md_info;
asn1_buf oid;
- if( ctx->padding != RSA_PKCS_V15 )
+ if( mode == RSA_PRIVATE && ctx->padding != RSA_PKCS_V15 )
return( POLARSSL_ERR_RSA_BAD_INPUT_DATA );
siglen = ctx->len;