passhash9: Ensure that choose_pbkdf_prf returns a PRF if possible

1 files changed, 8 insertions, 2 deletions

diff --git a/src/constructs/passhash/passhash9.cpp b/src/constructs/passhash/passhash9.cpp
index 9e5ff3257..b869e2812 100644
--- a/src/constructs/passhash/passhash9.cpp
+++ b/src/constructs/passhash/passhash9.cpp
@@ -37,8 +37,14 @@ MessageAuthenticationCode* get_pbkdf_prf(byte alg_id)
 
 std::pair<byte, MessageAuthenticationCode*> choose_pbkdf_prf()
    {
-   byte alg_id = 0;
-   return std::make_pair(alg_id, get_pbkdf_prf(alg_id));
+   for(byte alg_id = 0; alg_id != 255; ++alg_id)
+      {
+      MessageAuthenticationCode* prf = get_pbkdf_prf(alg_id);
+      if(prf)
+         return std::make_pair(alg_id, prf);
+      }
+
+   throw Internal_Error("Passhash9: No PRF available");
    }
 
 }