Const-correctness in key-loading functions.

The passphrase parameter should be a const char *.

ssh.h

@@ -643,7 +643,7 @@ const char *dh_validate_f(void *handle, Bignum f);
 Bignum dh_find_K(void *, Bignum f);
 
 int loadrsakey(const Filename *filename, struct RSAKey *key,
-	       char *passphrase, const char **errorstr);
+	       const char *passphrase, const char **errorstr);
 int rsakey_encrypted(const Filename *filename, char **comment);
 int rsakey_pubblob(const Filename *filename, void **blob, int *bloblen,
 		   char **commentptr, const char **errorstr);
@@ -661,7 +661,8 @@ extern struct ssh2_userkey ssh2_wrong_passphrase;
 
 int ssh2_userkey_encrypted(const Filename *filename, char **comment);
 struct ssh2_userkey *ssh2_load_userkey(const Filename *filename,
-				       char *passphrase, const char **errorstr);
+				       const char *passphrase,
+                                       const char **errorstr);
 unsigned char *ssh2_userkey_loadpub(const Filename *filename, char **algorithm,
 				    int *pub_blob_len, char **commentptr,
 				    const char **errorstr);

sshpubk.c

@@ -22,7 +22,7 @@
                           (x)=='/' ? 63 : 0 )
 
 static int loadrsakey_main(FILE * fp, struct RSAKey *key, int pub_only,
-			   char **commentptr, char *passphrase,
+			   char **commentptr, const char *passphrase,
 			   const char **error)
 {
     unsigned char buf[16384];
@@ -155,8 +155,8 @@ static int loadrsakey_main(FILE * fp, struct RSAKey *key, int pub_only,
     return ret;
 }
 
-int loadrsakey(const Filename *filename, struct RSAKey *key, char *passphrase,
-	       const char **errorstr)
+int loadrsakey(const Filename *filename, struct RSAKey *key,
+               const char *passphrase, const char **errorstr)
 {
     FILE *fp;
     char buf[64];
@@ -581,7 +581,8 @@ const struct ssh_signkey *find_pubkey_alg(const char *name)
 }
 
 struct ssh2_userkey *ssh2_load_userkey(const Filename *filename,
-				       char *passphrase, const char **errorstr)
+				       const char *passphrase,
+                                       const char **errorstr)
 {
     FILE *fp;
     char header[40], *b, *encryption, *comment, *mac;