Specific return code for PK sig length mismatch
diff --git a/ChangeLog b/ChangeLog
index 7df0e7c..23e59dc 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -10,6 +10,8 @@
Changes
* x509_crt_info() now prints information about parsed extensions as well
+ * pk_verify() now returns a specific error code when the signature is valid
+ but shorter than the supplied length.
Security
* Avoid potential timing leak in ecdsa_sign() by blinding modular division.
diff --git a/include/polarssl/error.h b/include/polarssl/error.h
index 83102bd..d27b0e5 100644
--- a/include/polarssl/error.h
+++ b/include/polarssl/error.h
@@ -83,7 +83,7 @@
* PEM 1 9
* PKCS#12 1 4 (Started from top)
* X509 2 18
- * PK 2 13 (Started from top)
+ * PK 2 14 (Started from top, plus 0x2000)
* DHM 3 9
* PKCS5 3 4 (Started from top)
* RSA 4 9
diff --git a/include/polarssl/pk.h b/include/polarssl/pk.h
index b764d55..cebe057 100644
--- a/include/polarssl/pk.h
+++ b/include/polarssl/pk.h
@@ -57,6 +57,7 @@
#define POLARSSL_ERR_PK_INVALID_ALG -0x2A80 /**< The algorithm tag or value is invalid. */
#define POLARSSL_ERR_PK_UNKNOWN_NAMED_CURVE -0x2A00 /**< Elliptic curve is unsupported (only NIST curves are supported). */
#define POLARSSL_ERR_PK_FEATURE_UNAVAILABLE -0x2980 /**< Unavailable feature, e.g. RSA disabled for RSA key. */
+#define POLARSSL_ERR_PK_SIG_LEN_MISMATCH -0x2000 /**< The signature is valid but its length is less than expected. */
#if defined(POLARSSL_RSA_C)
@@ -288,6 +289,8 @@
* \param sig_len Signature length
*
* \return 0 on success (signature is valid),
+ * POLARSSL_ERR_PK_SIG_LEN_MISMATCH if the signature is
+ * valid but its actual length is less than sig_len,
* or a specific error code.
*
* \note If hash_len is 0, then the length associated with md_alg
diff --git a/library/error.c b/library/error.c
index 2e6bba6..b2e8346 100644
--- a/library/error.c
+++ b/library/error.c
@@ -308,6 +308,8 @@
snprintf( buf, buflen, "PK - Elliptic curve is unsupported (only NIST curves are supported)" );
if( use_ret == -(POLARSSL_ERR_PK_FEATURE_UNAVAILABLE) )
snprintf( buf, buflen, "PK - Unavailable feature, e.g. RSA disabled for RSA key" );
+ if( use_ret == -(POLARSSL_ERR_PK_SIG_LEN_MISMATCH) )
+ snprintf( buf, buflen, "PK - The signature is valid but its length is less than expected" );
#endif /* POLARSSL_PK_C */
#if defined(POLARSSL_PKCS12_C)
diff --git a/library/pk_wrap.c b/library/pk_wrap.c
index 61e78fe..2a4da03 100644
--- a/library/pk_wrap.c
+++ b/library/pk_wrap.c
@@ -64,11 +64,20 @@
const unsigned char *hash, size_t hash_len,
const unsigned char *sig, size_t sig_len )
{
- if( sig_len != ((rsa_context *) ctx)->len )
+ int ret;
+
+ if( sig_len < ((rsa_context *) ctx)->len )
return( POLARSSL_ERR_RSA_VERIFY_FAILED );
- return( rsa_pkcs1_verify( (rsa_context *) ctx, NULL, NULL,
- RSA_PUBLIC, md_alg, (unsigned int) hash_len, hash, sig ) );
+ if( ( ret = rsa_pkcs1_verify( (rsa_context *) ctx, NULL, NULL,
+ RSA_PUBLIC, md_alg,
+ (unsigned int) hash_len, hash, sig ) ) != 0 )
+ return( ret );
+
+ if( sig_len > ((rsa_context *) ctx)->len )
+ return( POLARSSL_ERR_PK_SIG_LEN_MISMATCH );
+
+ return( 0 );
}
static int rsa_sign_wrap( void *ctx, md_type_t md_alg,
@@ -292,10 +301,16 @@
const unsigned char *hash, size_t hash_len,
const unsigned char *sig, size_t sig_len )
{
+ int ret;
((void) md_alg);
- return( ecdsa_read_signature( (ecdsa_context *) ctx,
- hash, hash_len, sig, sig_len ) );
+ ret = ecdsa_read_signature( (ecdsa_context *) ctx,
+ hash, hash_len, sig, sig_len );
+
+ if( ret == POLARSSL_ERR_ECP_SIG_LEN_MISMATCH )
+ return( POLARSSL_ERR_PK_SIG_LEN_MISMATCH );
+
+ return( ret );
}
static int ecdsa_sign_wrap( void *ctx, md_type_t md_alg,
