Fix null pointer dereference in the RSA module.

Introduced null pointer checks in mbedtls_rsa_rsaes_pkcs1_v15_encrypt

Author: yanesca

ChangeLog

@@ -10,6 +10,8 @@ Bugfix
    * Fix bug in mbedtls_x509_crt_parse that caused trailing extra data in the
      buffer after DER certificates to be included in the raw representation.
    * Fix issue that caused a hang when generating RSA keys of odd bitlength
+   * Fix bug in mbedtls_rsa_rsaes_pkcs1_v15_encrypt that made null pointer
+     dereference possible.
 
 Changes
    * On ARM platforms, when compiling with -O0 with GCC, Clang or armcc5,

library/rsa.c

@@ -590,7 +590,8 @@ int mbedtls_rsa_rsaes_pkcs1_v15_encrypt( mbedtls_rsa_context *ctx,
     if( mode == MBEDTLS_RSA_PRIVATE && ctx->padding != MBEDTLS_RSA_PKCS_V15 )
         return( MBEDTLS_ERR_RSA_BAD_INPUT_DATA );
 
-    if( f_rng == NULL )
+    // We don't check p_rng because it won't be dereferenced here
+    if( f_rng == NULL || input == NULL || output == NULL )
         return( MBEDTLS_ERR_RSA_BAD_INPUT_DATA );
 
     olen = ctx->len;