.su objects to gitignore

[pam_pcsc_cr.git] / authobj.c

diff --git a/authobj.c b/authobj.c
index 78eb3f8682bb3811fed7837c42624ad972e860fb..b4a1f2be26e1f3e3a284a128a5a6ba49c2aac954 100644 (file)
--- a/authobj.c
+++ b/authobj.c
@@ -1,13 +1,36 @@
+/*
+Copyright (c) 2013 Eugene Crosser
+
+This software is provided 'as-is', without any express or implied
+warranty. In no event will the authors be held liable for any damages
+arising from the use of this software.
+
+Permission is granted to anyone to use this software for any purpose,
+including commercial applications, and to alter it and redistribute it
+freely, subject to the following restrictions:
+
+    1. The origin of this software must not be misrepresented; you must
+    not claim that you wrote the original software. If you use this
+    software in a product, an acknowledgment in the product documentation
+    would be appreciated but is not required.
+
+    2. Altered source versions must be plainly marked as such, and must
+    not be misrepresented as being the original software.
+
+    3. This notice may not be removed or altered from any source
+    distribution.
+*/
+
 #ifdef HAVE_CONFIG_H
 # include "config.h"
 #endif
 #include <stdio.h>
 #include <string.h>
+#include <stdlib.h>
 #include <alloca.h>
 #include "serial.h"
 #include "crypto.h"
 #include "authobj.h"
-#include "pcsc_cr.h"
 
 static struct _auth_chunk
 make_challenge(const char *uid, const char *pass, const char *nonce)
@@ -88,7 +111,7 @@ make_key(const char *userid, const char *password, const char *nonce,
 }
 
 static struct _auth_obj
-make_authobj(char *userid, char *password, char *nonce,
+make_authobj(const char *userid, const char *password, const char *nonce,
                const unsigned char *secret, const int secsize,
                const unsigned char *payload, const int paylsize)
 {
@@ -103,6 +126,15 @@ make_authobj(char *userid, char *password, char *nonce,
        datasize = ((secsize + paylsize + HASHSIZE + 4 * sizeof(short) - 1) /
                        CBLKSIZE + 1) * CBLKSIZE;
        data = alloca(datasize);
+       /* 
+          We allocate memory rounded up to CBLKSIZE on the stack, but do not
+          use the last bytes. Stack protectors, if enabled, fill this memory
+          with `canary` value. Later, when encryption function is called,
+          stack protector detects that it tries to access "uninitialized
+          memory". Which, while technically true, is not an error. Still,
+          let us make stack protector happy by initializing the whole area:
+        */
+       memset(data, 0, datasize);
        serial_init(&srl, data, datasize);
        if (serial_put(&srl, secret, secsize) != secsize) {
                ao.err = "authobj: serialization of secret failed";
@@ -146,7 +178,7 @@ make_authobj(char *userid, char *password, char *nonce,
 }
 
 static struct _auth_obj
-parse_authobj(char *userid, char *password, char *nonce,
+parse_authobj(const char *userid, const char *password, const char *nonce,
                const unsigned char *secret, const int secsize,
                const unsigned char *ablob, const int blobsize,
                struct _auth_chunk (*fetch_key)(const unsigned char *chal,
@@ -201,14 +233,18 @@ struct _auth_obj authobj(const char *userid, const char *password,
                struct _auth_chunk (*fetch_key)(const unsigned char *chal,
                                                const int csize))
 {
-       unsigned char *wsecret;
+       const unsigned char *wsecret;
        int wsecsize;
-       unsigned char *wpayload;
+       const unsigned char *wpayload;
        int wpaylsize;
        struct _auth_obj old_ao = {0};
        struct _auth_obj new_ao = {0};
 
        if (!secret || !secsize || !payload) {
+               if (!ablob || !blobsize) {
+                       new_ao.err = "authobj: previous data not supplied";
+                       return new_ao;
+               }
                old_ao = parse_authobj(userid, password, oldnonce,
                                        secret, secsize,
                                        ablob, blobsize, fetch_key);