We had the password callback for ENGINEs pretty much wrong. And

passwords that were given to the key loading functions were completely
ignored, at least in the ncipher code, and then we made the assumption
that the callback wanted a prompt as user argument.

All that is now changed, and the application author is forced to give
a callback function of type pem_callback_cb and possibly an argument
for it, just as for all other functions that want to generate password
prompting.

NOTE: this change creates binary and source incompatibilities with
previous versions of OpenSSL [engine].  It's worth it this time, to
get it right (or at least better and with a chance that it'll work).

crypto/engine/engine.h

@@ -71,6 +71,7 @@
 #endif
 #include <openssl/rand.h>
 #include <openssl/evp.h>
+#include <openssl/pem.h>
 #include <openssl/symhacks.h>
 
 #ifdef  __cplusplus
@@ -262,7 +263,8 @@ typedef int (*ENGINE_GEN_INT_FUNC_PTR)(ENGINE *);
 /* Specific control function pointer */
 typedef int (*ENGINE_CTRL_FUNC_PTR)(ENGINE *, int, long, void *, void (*f)());
 /* Generic load_key function pointer */
-typedef EVP_PKEY * (*ENGINE_LOAD_KEY_PTR)(ENGINE *, const char *, const char *);
+typedef EVP_PKEY * (*ENGINE_LOAD_KEY_PTR)(ENGINE *, const char *,
+	pem_password_cb *callback, void *callback_data);
 
 /* STRUCTURE functions ... all of these functions deal with pointers to ENGINE
  * structures where the pointers have a "structural reference". This means that
@@ -417,9 +419,9 @@ int ENGINE_finish(ENGINE *e);
  * location, handled by the engine.  The storage may be on a card or
  * whatever. */
 EVP_PKEY *ENGINE_load_private_key(ENGINE *e, const char *key_id,
-	const char *passphrase);
+	pem_password_cb *callback, void *callback_data);
 EVP_PKEY *ENGINE_load_public_key(ENGINE *e, const char *key_id,
-	const char *passphrase);
+	pem_password_cb *callback, void *callback_data);
 
 /* This returns a pointer for the current ENGINE structure that
  * is (by default) performing any RSA operations. The value returned

crypto/engine/engine_lib.c

@@ -232,7 +232,7 @@ int ENGINE_finish(ENGINE *e)
 	}
 
 EVP_PKEY *ENGINE_load_private_key(ENGINE *e, const char *key_id,
-	const char *passphrase)
+	pem_password_cb *callback, void *callback_data)
 	{
 	EVP_PKEY *pkey;
 
@@ -257,7 +257,7 @@ EVP_PKEY *ENGINE_load_private_key(ENGINE *e, const char *key_id,
 			ENGINE_R_NO_LOAD_FUNCTION);
 		return 0;
 		}
-	pkey = e->load_privkey(e, key_id, passphrase);
+	pkey = e->load_privkey(e, key_id, callback, callback_data);
 	if (!pkey)
 		{
 		ENGINEerr(ENGINE_F_ENGINE_LOAD_PRIVATE_KEY,
@@ -268,7 +268,7 @@ EVP_PKEY *ENGINE_load_private_key(ENGINE *e, const char *key_id,
 	}
 
 EVP_PKEY *ENGINE_load_public_key(ENGINE *e, const char *key_id,
-	const char *passphrase)
+	pem_password_cb *callback, void *callback_data)
 	{
 	EVP_PKEY *pkey;
 
@@ -293,7 +293,7 @@ EVP_PKEY *ENGINE_load_public_key(ENGINE *e, const char *key_id,
 			ENGINE_R_NO_LOAD_FUNCTION);
 		return 0;
 		}
-	pkey = e->load_pubkey(e, key_id, passphrase);
+	pkey = e->load_pubkey(e, key_id, callback, callback_data);
 	if (!pkey)
 		{
 		ENGINEerr(ENGINE_F_ENGINE_LOAD_PUBLIC_KEY,

crypto/engine/hw_ncipher.c

@@ -58,6 +58,7 @@
  */
 
 #include <stdio.h>
+#include <string.h>
 #include <openssl/crypto.h>
 #include <openssl/pem.h>
 #include "cryptlib.h"
@@ -115,9 +116,9 @@ static int hwcrhk_rand_status(void);
 
 /* KM stuff */
 static EVP_PKEY *hwcrhk_load_privkey(ENGINE *eng, const char *key_id,
-	const char *passphrase);
+	pem_password_cb *callback, void *callback_data);
 static EVP_PKEY *hwcrhk_load_pubkey(ENGINE *eng, const char *key_id,
-	const char *passphrase);
+	pem_password_cb *callback, void *callback_data);
 static void hwcrhk_ex_free(void *obj, void *item, CRYPTO_EX_DATA *ad,
 	int ind,long argl, void *argp);
 
@@ -213,7 +214,8 @@ struct HWCryptoHook_MutexValue
    into HWCryptoHook_PassphraseContext */
 struct HWCryptoHook_PassphraseContextValue
 	{
-	void *any;
+	pem_password_cb *password_callback; /* If != NULL, will be called */
+	void *callback_data;
 	};
 
 /* hwcryptohook.h has some typedefs that turn
@@ -651,7 +653,7 @@ static int hwcrhk_ctrl(ENGINE *e, int cmd, long i, void *p, void (*f)())
 	}
 
 static EVP_PKEY *hwcrhk_load_privkey(ENGINE *eng, const char *key_id,
-	const char *passphrase)
+	pem_password_cb *callback, void *callback_data)
 	{
 #ifndef OPENSSL_NO_RSA
 	RSA *rtmp = NULL;
@@ -664,6 +666,7 @@ static EVP_PKEY *hwcrhk_load_privkey(ENGINE *eng, const char *key_id,
 #if !defined(OPENSSL_NO_RSA)
 	HWCryptoHook_ErrMsgBuf rmsg;
 #endif
+	HWCryptoHook_PassphraseContext ppctx;
 
 	if(!hwcrhk_context)
 		{
@@ -679,8 +682,10 @@ static EVP_PKEY *hwcrhk_load_privkey(ENGINE *eng, const char *key_id,
 			ERR_R_MALLOC_FAILURE);
 		goto err;
 		}
+	ppctx.password_callback = callback;
+	ppctx.callback_data = callback_data;
 	if (p_hwcrhk_RSALoadKey(hwcrhk_context, key_id, hptr,
-		&rmsg, NULL))
+		&rmsg, &ppctx))
 		{
 		ENGINEerr(ENGINE_F_HWCRHK_LOAD_PRIVKEY,
 			ENGINE_R_CHIL_ERROR);
@@ -747,12 +752,12 @@ static EVP_PKEY *hwcrhk_load_privkey(ENGINE *eng, const char *key_id,
 	}
 
 static EVP_PKEY *hwcrhk_load_pubkey(ENGINE *eng, const char *key_id,
-	const char *passphrase)
+	pem_password_cb *callback, void *callback_data)
 	{
 	EVP_PKEY *res = NULL;
 
 #ifndef OPENSSL_NO_RSA
-        res = hwcrhk_load_privkey(eng, key_id, passphrase);
+        res = hwcrhk_load_privkey(eng, key_id, callback, callback_data);
 #endif
 
 	if (res)
@@ -1079,38 +1084,23 @@ static int hwcrhk_get_pass(const char *prompt_info,
 	HWCryptoHook_PassphraseContext *ppctx,
 	HWCryptoHook_CallerContext *cactx)
 	{
-	int l = 0;
-	char prompt[1024];
+	pem_password_cb *callback = password_callback;
+	void *callback_data = NULL;
 
-	if (password_callback == NULL)
+	if (ppctx)
 		{
-		ENGINEerr(ENGINE_F_HWCRHK_GET_PASS,ENGINE_R_NO_CALLBACK);
-		return -1;
+		if (ppctx->password_callback)
+			callback = ppctx->password_callback;
+		if (ppctx->callback_data)
+			callback_data = ppctx->callback_data;
 		}
-	if (prompt_info)
+	if (callback == NULL)
 		{
-		strncpy(prompt, "Card: \"", sizeof(prompt));
-		l += 5;
-		strncpy(prompt + l, prompt_info, sizeof(prompt) - l);
-		l += strlen(prompt_info);
-		if (l + 2 < sizeof(prompt))
-			{
-			strncpy(prompt + l, "\"\n", sizeof(prompt) - l);
-			l += 2;
-			}
-		}
-	if (l < sizeof(prompt) - 1)
-		{
-		strncpy(prompt, "Enter Passphrase <enter to cancel>:",
-			sizeof(prompt) - l);
-		l += 35;
+		ENGINEerr(ENGINE_F_HWCRHK_GET_PASS,ENGINE_R_NO_CALLBACK);
+		return -1;
 		}
-	prompt[l] = '\0';
 
-	/* I know, passing on the prompt instead of the user data *is*
-	   a bad thing.  However, that's all we have right now.
-	   --  Richard Levitte */
-	*len_io = password_callback(buf, *len_io, 0, prompt);
+	*len_io = callback(buf, *len_io, 0, callback_data);
 	if(!*len_io)
 		return -1;
 	return 0;