Initial import of libpam-tacplus (1.4.3-cl3u4)

1 files changed, 114 insertions, 0 deletions

diff --git a/libtac/lib/crypt.c b/libtac/lib/crypt.c
new file mode 100644
index 0000000..49a071c
--- /dev/null
+++ b/libtac/lib/crypt.c
@@ -0,0 +1,114 @@
+/* crypt.c - TACACS+ encryption related functions
+ *
+ * Copyright (C) 2010, Pawel Krawczyk <pawel.krawczyk@hush.com> and
+ * Jeroen Nijhof <jeroen@jeroennijhof.nl>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program - see the file COPYING.
+ *
+ * See `CHANGES' file for revision history.
+ */
+
+#include "libtac.h"
+#include "xalloc.h"
+
+#ifdef HAVE_CONFIG_H
+  #include "config.h"
+#endif
+
+#if defined(HAVE_OPENSSL_MD5_H) && defined(HAVE_LIBCRYPTO)
+# include <openssl/md5.h>
+#else
+# include "md5.h"
+# ifndef MD5_LBLOCK /*  should be always, since it's in openssl */
+#  define MD5_LBLOCK MD5_LEN
+# endif
+#endif
+
+/* Produce MD5 pseudo-random pad for TACACS+ encryption.
+   Use data from packet header and secret, which
+   should be a global variable */
+u_char *_tac_md5_pad(int len, HDR *hdr)  {
+    int n, i, bufsize;
+    int bp = 0; /* buffer pointer */
+    int pp = 0; /* pad pointer */
+    u_char *pad;
+    u_char *buf;
+    MD5_CTX mdcontext;
+
+    /* make pseudo pad */
+    n = (int)(len/16)+1;  /* number of MD5 runs */
+    bufsize = sizeof(hdr->session_id) + strlen(tac_secret) + sizeof(hdr->version)
+        + sizeof(hdr->seq_no) + MD5_LBLOCK + 10;
+    buf = (u_char *) tac_xcalloc(1, bufsize);
+    pad = (u_char *) tac_xcalloc(n, MD5_LBLOCK);
+
+    for (i=0; i<n; i++) {
+        /* MD5_1 = MD5{session_id, secret, version, seq_no}
+           MD5_2 = MD5{session_id, secret, version, seq_no, MD5_1} */
+
+        /* place session_id, key, version and seq_no in buffer */
+        bp = 0;
+        bcopy(&hdr->session_id, buf, sizeof(session_id));
+        bp += sizeof(session_id);
+        bcopy(tac_secret, buf+bp, strlen(tac_secret));
+        bp += strlen(tac_secret);
+        bcopy(&hdr->version, buf+bp, sizeof(hdr->version));
+        bp += sizeof(hdr->version);
+        bcopy(&hdr->seq_no, buf+bp, sizeof(hdr->seq_no));
+        bp += sizeof(hdr->seq_no);
+
+        /* append previous pad if this is not the first run */
+        if (i) {
+            bcopy(pad+((i-1)*MD5_LBLOCK), buf+bp, MD5_LBLOCK);
+            bp+=MD5_LBLOCK;
+        }
+
+#if defined(HAVE_OPENSSL_MD5_H) && defined(HAVE_LIBCRYPTO)
+        MD5_Init(&mdcontext);
+        MD5_Update(&mdcontext, buf, bp);
+        MD5_Final(pad+pp, &mdcontext);
+#else
+        MD5Init(&mdcontext);
+        MD5Update(&mdcontext, buf, bp);
+        MD5Final(pad+pp, &mdcontext);
+#endif
+
+        pp += MD5_LBLOCK;
+    }
+
+    free(buf);
+    return pad;
+
+}    /* _tac_md5_pad */
+
+/* Perform encryption/decryption on buffer. This means simply XORing
+   each byte from buffer with according byte from pseudo-random
+   pad. */
+void _tac_crypt(u_char *buf, HDR *th, int length) {
+    int i;
+    u_char *pad;
+
+    /* null operation if no encryption requested */
+    if((tac_secret != NULL) && (th->encryption == TAC_PLUS_ENCRYPTED_FLAG)) {
+        pad = _tac_md5_pad(length, th);
+
+        for (i=0; i<length; i++) {
+            *(buf+i) ^= pad[i];
+        }
+
+        free(pad);
+    } else {
+        TACSYSLOG((LOG_WARNING, "%s: using no TACACS+ encryption", __func__))
+    }
+}    /* _tac_crypt */