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git-svn-id: svn://anonsvn.mit.edu/krb5/trunk@1826 dc483132-0cff-0310-8789-dd5450dbe970

diff --git a/src/lib/krb5/krb/gen_seqnum.c b/src/lib/krb5/krb/gen_seqnum.c
new file mode 100644 (file)
index 0000000..1a1e4b9
--- /dev/null
+++ b/src/lib/krb5/krb/gen_seqnum.c
@@ -0,0 +1,110 @@
+/*
+ * $Source$
+ * $Author$
+ *
+ * Copyright 1991 by the Massachusetts Institute of Technology.
+ * All Rights Reserved.
+ *
+ * For copying and distribution information, please see the file
+ * <krb5/copyright.h>.
+ *
+ * Routine to automatically generate a starting sequence number.
+ * We do this by getting a random key and encrypting something with it,
+ * then taking the output and slicing it up.
+ */
+
+#if !defined(lint) && !defined(SABER)
+static char rcsid_gen_seqnum_c[] =
+"$Id$";
+#endif /* !lint & !SABER */
+
+#include <krb5/krb5.h>
+#include <krb5/ext-proto.h>
+
+#ifndef MIN
+#define MIN(a,b) ((a) < (b) ? (a) : (b))
+#endif
+
+krb5_error_code
+krb5_generate_seq_number(key, seqno)
+const krb5_keyblock *key;
+krb5_int32 *seqno;
+{
+    krb5_pointer random_state;
+    krb5_encrypt_block eblock;
+    krb5_keyblock *subkey;
+    krb5_error_code retval;
+    struct tval {
+       krb5_int32 seconds;
+       krb5_int32 microseconds;
+    } timenow;
+    krb5_octet *intmp, *outtmp;
+    int esize;
+    char *outseqno;
+
+    if (!valid_keytype(key->keytype))
+       return KRB5_PROG_KEYTYPE_NOSUPP;
+
+    krb5_use_keytype(&eblock, key->keytype);
+
+    if (retval = krb5_init_random_key(&eblock, key, &random_state))
+       return(retval);
+       
+    if (retval = krb5_random_key(&eblock, random_state, &subkey)) {
+       (void) krb5_finish_random_key(&eblock, random_state);
+       return retval;
+    }  
+    /* ignore the error if any, since we've already gotten the key out */
+    if (retval = krb5_finish_random_key(&eblock, &random_state)) {
+       krb5_free_keyblock(subkey);
+       return retval;
+    }
+
+    esize = krb5_encrypt_size(sizeof(timenow), eblock.crypto_entry);
+    intmp = (krb5_octet *)malloc(esize);
+    if (!intmp) {
+       krb5_free_keyblock(subkey);
+       return ENOMEM;
+    }
+    outtmp = (krb5_octet *)malloc(esize);
+    if (!outtmp) {
+       xfree(intmp);
+       krb5_free_keyblock(subkey);
+       return ENOMEM;
+    }
+    if (retval = krb5_process_key(&eblock, subkey)) {
+       goto cleanup;
+    }
+    outseqno = (char *)seqno;
+
+    if (retval = krb5_us_timeofday(&timenow.seconds,
+                                  &timenow.microseconds)) {
+       goto cleanup;
+    }
+    memcpy((char *)intmp, (char *)&timenow, sizeof(timenow));
+
+    while (outseqno < (char *)(seqno+1)) {
+       memset((char *)intmp, 0, esize);
+
+       if (retval = krb5_encrypt((krb5_pointer)intmp,
+                                 (krb5_pointer)outtmp,
+                                 sizeof(timenow),
+                                 &eblock,
+                                 0)) {
+           (void) krb5_finish_key(&eblock);
+           goto cleanup;
+       }
+       memcpy(outseqno, (char *)outtmp, MIN((char *)(seqno+1)-outseqno,
+                                            esize));
+       outseqno += MIN((char *)(seqno+1)-outseqno, esize);
+       /* chain along */
+       memcpy(intmp,outtmp,esize);
+    }
+    (void) krb5_finish_key(&eblock);
+ cleanup:
+    krb5_free_keyblock(subkey);
+    xfree(intmp);
+    xfree(outtmp);
+    return retval;
+}
+