not yet tested

git-svn-id: svn://anonsvn.mit.edu/krb5/trunk@471 dc483132-0cff-0310-8789-dd5450dbe970

diff --git a/src/lib/krb5/krb/rd_safe.c b/src/lib/krb5/krb/rd_safe.c
new file mode 100644 (file)
index 0000000..4864cc2
--- /dev/null
+++ b/src/lib/krb5/krb/rd_safe.c
@@ -0,0 +1,145 @@
+/*
+ * $Source$
+ * $Author$
+ *
+ * Copyright 1990 by the Massachusetts Institute of Technology.
+ *
+ * For copying and distribution information, please see the file
+ * <krb5/mit-copyright.h>.
+ *
+ * krb5_rd_safe()
+ */
+
+#if !defined(lint) && !defined(SABER)
+static char rcsid_rd_safe_c[] =
+"$Id$";
+#endif /* !lint & !SABER */
+
+#include <krb5/copyright.h>
+#include <krb5/krb5.h>
+#include <krb5/krb5_err.h>
+
+#include <krb5/asn1.h>
+#include <stdio.h>
+#include <krb5/libos-proto.h>
+#include <krb5/ext-proto.h>
+
+extern krb5_deltat krb5_clockskew;
+#define in_clock_skew(date) (abs((date)-currenttime) < krb5_clockskew)
+
+/*
+ parses a KRB_SAFE message from inbuf, placing the integrity-protected user
+ data in *outbuf.
+
+ key specifies the key to be used for decryption of the message.
+ 
+ sender_addr and recv_addr specify the full addresses (host and port) of
+ the sender and receiver.
+
+ outbuf points to allocated storage which the caller should free when finished.
+
+ returns system errors, integrity errors
+ */
+krb5_error_code
+krb5_rd_safe(inbuf, key, sender_addr, recv_addr, outbuf)
+krb5_data *inbuf;
+krb5_keyblock *key;
+krb5_fulladdr *sender_addr;
+krb5_fulladdr *recv_addr;
+krb5_data *outbuf;
+{
+    krb5_error_code retval;
+    krb5_safe *message;
+    krb5_ui_2 computed_direction;
+    krb5_checksum our_cksum, *his_cksum;
+    krb5_octet zero_octet = 0;
+    krb5_data *scratch;
+    krb5_timestamp currenttime;
+
+    if (retval = decode_krb5_safe(inbuf, &message))
+       return retval;
+
+#define cleanup() krb5_free_safe(message)
+
+    if (!valid_cksumtype(message->checksum->checksum_type))
+       return KRB5_PROG_SUMTYPE_NOSUPP;
+
+    /* length bounds check XXX ?? how */
+    
+    if (sender_addr && !krb5_address_search(sender_addr->address,
+                                           message->addresses)) {
+       cleanup();
+       return KRB5KRB_AP_ERR_BADADDR;
+    }
+
+    if (retval = krb5_timeofday(&currenttime)) {
+       cleanup();
+       return retval;
+    }
+    if (!in_clock_skew(message->timestamp)) {
+       cleanup();
+       return KRB5KRB_AP_ERR_SKEW;
+    }
+
+    /* replay detection goes here... XXX */
+    computed_direction = (krb5_fulladdr_order(sender_addr, recv_addr) > 0) ?
+                        MSEC_DIRBIT : 0; 
+    /* what if sender_addr == 0 ?????*/
+    if (computed_direction != message->msec & MSEC_DIRBIT) {
+       cleanup();
+       return KRB5KRB_AP_ERR_REPEAT;   /* XXX */
+    }
+
+    /* verify the checksum */
+    /* to do the checksum stuff, we need to re-encode the message with a
+       zero-length zero-type checksum, then checksum the encoding, and verify.
+     */
+    his_cksum = message->checksum;
+
+    our_cksum.checksum_type = 0;
+    our_cksum.length = 0;
+    our_cksum.contents = &zero_octet;
+
+    message->checksum = &our_cksum;
+
+    if (retval = encode_krb5_safe(&message, &scratch)) {
+       message->checksum = his_cksum;
+       cleanup();
+       return retval;
+    }
+                        
+    retval = (*(krb5_cksumarray[his_cksum->checksum_type]->
+               sum_func))(scratch->data,
+                          0, /* XXX? */
+                          (krb5_pointer) key->contents,
+                          scratch->length,
+                          key->length,
+                          &our_cksum);
+    (void) bzero((char *)scratch->data, scratch->length);
+    krb5_free_data(scratch);
+    
+    if (retval) {
+       cleanup();
+       return retval;
+    }
+
+#undef cleanup
+#define cleanup() {krb5_free_safe(message); xfree(our_cksum.contents);}
+
+    if (our_cksum.length != his_cksum->length ||
+       bcmp((char *)our_cksum.contents, (char *)his_cksum->contents,
+            our_cksum.length)) {
+       cleanup();
+       return KRB5KRB_AP_ERR_MODIFIED;
+    }
+
+    *outbuf = message->user_data;
+
+    xfree(our_cksum.contents);
+    if (message->addresses)
+       krb5_free_address(message->addresses);
+    krb5_free_checksum(his_cksum);
+    xfree(message);
+
+    return 0;
+}