NIF for Unix crypt

msantos · Jan 14, 2010 · b9247fa · b9247fa
commit b9247fa
Show file tree

Hide file tree

Showing 6 changed files with 300 additions and 0 deletions.
diff --git a/Emakefile b/Emakefile
@@ -0,0 +1,6 @@
+{["src/*"],
+ [{i, "include"},
+  {outdir, "ebin"},
+  debug_info]
+}.
+
diff --git a/Makefile b/Makefile
@@ -0,0 +1,36 @@
+
+ERL=erl
+APP=crypt
+
+CC=gcc
+
+#Mac OS X: use "-m64" for a 64-bit erlang
+#ARCH=-m32
+#FLAGS=$(ARCH) -O3 -fPIC -bundle -flat_namespace -undefined suppress -fno-common -lcrypt
+
+# Linux
+FLAGS=-fPIC -shared -lcrypt
+
+#ERL_ROOT=/usr/local/lib/erlang
+ERL_ROOT=/media/opt/local/lib/erlang
+CFLAGS=-g -Wall
+
+
+all: dir erl nif 
+
+dir:
+	-@mkdir -p priv ebin
+
+erl:
+	@$(ERL) -noinput +B \
+		-eval 'case make:all() of up_to_date -> halt(0); error -> halt(1) end.'
+
+nif:
+	(cd c_src && \
+	$(CC) -g -Wall $(FLAGS) -o ../priv/$(APP).so \
+		$(APP).c -I $(ERL_ROOT)/usr/include/ )
+
+clean:  
+	@rm -fv ebin/*.beam priv/$(APP).so c_src/*.a c_src/*.o
+
+
diff --git a/README b/README
@@ -0,0 +1,25 @@
+
+Erlang R13B03 (erts-5.7.4) [source] [rq:1] [async-threads:0] [hipe] [kernel-poll:false]
+
+Eshell V5.7.4  (abort with ^G)
+1> crypt:crypt("test","aa").
+"aaqPiZY5xR5l."
+2> crypt:crypt("test","$1$aaaaaaaa").
+"$1$aaaaaaaa$lWxWtPmiNjS/cwJnGm6fe0"
+3> crypt:crypt("test","$6$aaaaaaaa").
+"$6$aaaaaaaa$HREHv6TuSmUS/7spCDO5Js3ssSZ6.iwVkUoVtatJUhJDKVmERrRKBTolrPMub2s5dX6IEjZg6d6wZzFRlidV41"
+4> 
+
+
+TODO
+
+1. What is the maximum password and salt length?
+
+There doesn't appear to be a limit. DES has an 8 character limit and
+MD5 has a 255 character limit, but for the other types, no idea.
+
+sysconf(_SC_PASS_MAX) seems to return the limit on Solaris, but isn't
+available on Ubuntu.
+
+2. Provide an erlang version of the crypt() interface.
+
diff --git a/c_src/crypt.c b/c_src/crypt.c
@@ -0,0 +1,140 @@
+/* Copyright (c) 2010, Michael Santos <michael.santos@gmail.com>
+ * All rights reserved.
+ * 
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 
+ * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ * 
+ * Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the distribution.
+ * 
+ * Neither the name of the author nor the names of its contributors
+ * may be used to endorse or promote products derived from this software
+ * without specific prior written permission.
+ * 
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+ * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
+ * COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
+ * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+ * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
+ * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ */
+#include "erl_nif.h"
+#include "crypt.h"
+
+static int my_enif_get_string(ErlNifEnv *env, ERL_NIF_TERM list, char *buf, size_t buflen);
+static ERL_NIF_TERM error_message(ErlNifEnv *env, char *atom, char *err, char *msg);
+
+
+    static int
+load(ErlNifEnv *env, void **priv, ERL_NIF_TERM load_info)
+{
+    return (0);
+}   
+
+
+    static int
+reload(ErlNifEnv *env, void **priv, ERL_NIF_TERM load_info)
+{
+    return load(env, priv, load_info);
+}
+
+
+    static ERL_NIF_TERM
+nif_crypt(ErlNifEnv *env, ERL_NIF_TERM _key, ERL_NIF_TERM _salt)
+{
+    char key[MAXBUFLEN];
+    char salt[MAXBUFLEN];
+    char *result = NULL;
+    int rerrno = 0;
+
+    (void)memset(&key, '\0', sizeof(key));
+    (void)memset(&salt, '\0', sizeof(salt));
+
+    if (!my_enif_get_string(env, _key, key, sizeof(key)))
+        return enif_make_badarg(env);
+
+    if (!my_enif_get_string(env, _salt, salt, sizeof(salt)))
+        return enif_make_badarg(env);
+
+    errno = 0;
+    result = crypt(key, salt);
+    rerrno = errno;
+
+    (void)memset(&key, '\0', sizeof(key));
+    (void)memset(&salt, '\0', sizeof(salt));
+
+    if (result == NULL)
+        return error_message(env, "error", "crypt", strerror(rerrno));
+
+    return enif_make_string(env, result);
+}
+
+
+    static ERL_NIF_TERM
+error_message(ErlNifEnv *env, char *atom, char *err, char *msg)
+{
+    return enif_make_tuple(env, 2,
+            enif_make_atom(env, atom),
+            enif_make_tuple(env, 2,
+            enif_make_atom(env, err),
+            enif_make_string(env, msg)));
+}
+
+
+/* from:
+ * http://d.hatena.ne.jp/vostok92/20091201/1259680319
+ *
+ * Copies at most one less than buflen from buf and null
+ * terminates the string.
+ *
+ * Should probably indicate that a truncation has taken place, but
+ * the convention of the enif_get_* interfaces seems to be to return
+ * true/false.
+ *
+ * The alternative is to return failure if a string is too large
+ * for the buffer. This seems to allow for more predictable 
+ * behaviour.
+ *
+ */
+    static int
+my_enif_get_string(ErlNifEnv *env, ERL_NIF_TERM list, char *buf, size_t buflen)
+{
+    ERL_NIF_TERM head, tail;
+    int val;
+    int n = 1;
+
+
+    while (enif_get_list_cell(env, list, &head, &tail)) {
+        if (!enif_get_int(env, head, &val))
+            return (0);
+
+        if (n++ >= buflen)
+            return (0);
+
+        *buf = (char)val;
+        buf++;
+        list = tail; 
+    }
+    *buf = '\0';
+
+    return (1);
+}
+
+static ErlNifFunc nif_funcs[] = {
+    {"crypt", 2, nif_crypt}
+};
+
+ERL_NIF_INIT(crypt, nif_funcs, load, reload, NULL, NULL)
+
+
diff --git a/c_src/crypt.h b/c_src/crypt.h
@@ -0,0 +1,48 @@
+/*
+ * Copyright (c) 2010, Michael Santos <michael.santos@gmail.com>
+ * All rights reserved.
+ * 
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 
+ * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ * 
+ * Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the distribution.
+ * 
+ * Neither the name of the author nor the names of its contributors
+ * may be used to endorse or promote products derived from this software
+ * without specific prior written permission.
+ * 
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+ * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
+ * COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
+ * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+ * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
+ * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ */
+#define _XOPEN_SOURCE
+#define __USE_XOPEN
+
+#include <unistd.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <err.h>
+
+#include <sys/errno.h>
+
+
+#define CRYPT_VERSION   "0.01"
+#define MAXBUFLEN       1024    /* XXX appropriate maximum values for passwd length and salt? */
+
+
diff --git a/src/crypt.erl b/src/crypt.erl
@@ -0,0 +1,45 @@
+%% Copyright (c) 2010, Michael Santos <michael.santos@gmail.com>
+%% All rights reserved.
+%% 
+%% Redistribution and use in source and binary forms, with or without
+%% modification, are permitted provided that the following conditions
+%% are met:
+%% 
+%% Redistributions of source code must retain the above copyright
+%% notice, this list of conditions and the following disclaimer.
+%% 
+%% Redistributions in binary form must reproduce the above copyright
+%% notice, this list of conditions and the following disclaimer in the
+%% documentation and/or other materials provided with the distribution.
+%% 
+%% Neither the name of the author nor the names of its contributors
+%% may be used to endorse or promote products derived from this software
+%% without specific prior written permission.
+%% 
+%% THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+%% "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+%% LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+%% FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
+%% COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+%% INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
+%% BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+%% LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+%% CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+%% LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
+%% ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+%% POSSIBILITY OF SUCH DAMAGE.
+-module(crypt).
+
+-export([crypt/2]).
+
+-define(NIF, "priv/crypt").
+
+-on_load(on_load/0).
+
+on_load() ->
+    ok = erlang:load_nif(?NIF, []),
+    true.
+
+crypt(_,_) ->
+    erlang:error(not_implemented).
+