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-rw-r--r--src/openvpn/packet_id.c492
1 files changed, 0 insertions, 492 deletions
diff --git a/src/openvpn/packet_id.c b/src/openvpn/packet_id.c
deleted file mode 100644
index 6bc5b6b..0000000
--- a/src/openvpn/packet_id.c
+++ /dev/null
@@ -1,492 +0,0 @@
-/*
- * OpenVPN -- An application to securely tunnel IP networks
- * over a single TCP/UDP port, with support for SSL/TLS-based
- * session authentication and key exchange,
- * packet encryption, packet authentication, and
- * packet compression.
- *
- * Copyright (C) 2002-2005 OpenVPN Solutions LLC <info@openvpn.net>
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License version 2
- * as published by the Free Software Foundation.
- *
- * 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 included with this
- * distribution); if not, write to the Free Software Foundation, Inc.,
- * 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
- */
-
-/*
- * These routines are designed to catch replay attacks,
- * where a man-in-the-middle captures packets and then
- * attempts to replay them back later.
- *
- * We use the "sliding-window" algorithm, similar
- * to IPSec.
- */
-
-#ifdef WIN32
-#include "config-win32.h"
-#else
-#include "config.h"
-#endif
-
-#ifdef USE_CRYPTO
-
-#include "syshead.h"
-
-#include "packet_id.h"
-#include "misc.h"
-#include "integer.h"
-
-#include "memdbg.h"
-
-/*
- * Special time_t value that indicates that
- * sequence number has expired.
- */
-#define SEQ_UNSEEN ((time_t)0)
-#define SEQ_EXPIRED ((time_t)1)
-
-void
-packet_id_init (struct packet_id *p, int seq_backtrack, int time_backtrack)
-{
- dmsg (D_PID_DEBUG_LOW, "PID packet_id_init seq_backtrack=%d time_backtrack=%d",
- seq_backtrack,
- time_backtrack);
-
- ASSERT (p);
- CLEAR (*p);
-
- if (seq_backtrack)
- {
- ASSERT (MIN_SEQ_BACKTRACK <= seq_backtrack && seq_backtrack <= MAX_SEQ_BACKTRACK);
- ASSERT (MIN_TIME_BACKTRACK <= time_backtrack && time_backtrack <= MAX_TIME_BACKTRACK);
- CIRC_LIST_ALLOC (p->rec.seq_list, struct seq_list, seq_backtrack);
- p->rec.seq_backtrack = seq_backtrack;
- p->rec.time_backtrack = time_backtrack;
- }
- p->rec.initialized = true;
-}
-
-void
-packet_id_free (struct packet_id *p)
-{
- if (p)
- {
- dmsg (D_PID_DEBUG_LOW, "PID packet_id_free");
- if (p->rec.seq_list)
- free (p->rec.seq_list);
- CLEAR (*p);
- }
-}
-
-void
-packet_id_add (struct packet_id_rec *p, const struct packet_id_net *pin)
-{
- const time_t local_now = now;
- if (p->seq_list)
- {
- packet_id_type diff;
-
- /*
- * If time value increases, start a new
- * sequence number sequence.
- */
- if (!CIRC_LIST_SIZE (p->seq_list)
- || pin->time > p->time
- || (pin->id >= (packet_id_type)p->seq_backtrack
- && pin->id - (packet_id_type)p->seq_backtrack > p->id))
- {
- p->time = pin->time;
- p->id = 0;
- if (pin->id > (packet_id_type)p->seq_backtrack)
- p->id = pin->id - (packet_id_type)p->seq_backtrack;
- CIRC_LIST_RESET (p->seq_list);
- }
-
- while (p->id < pin->id)
- {
- CIRC_LIST_PUSH (p->seq_list, SEQ_UNSEEN);
- ++p->id;
- }
-
- diff = p->id - pin->id;
- if (diff < (packet_id_type) CIRC_LIST_SIZE (p->seq_list)
- && local_now > SEQ_EXPIRED)
- CIRC_LIST_ITEM (p->seq_list, diff) = local_now;
- }
- else
- {
- p->time = pin->time;
- p->id = pin->id;
- }
-}
-
-/*
- * Expire sequence numbers which can no longer
- * be accepted because they would violate
- * time_backtrack.
- */
-void
-packet_id_reap (struct packet_id_rec *p)
-{
- const time_t local_now = now;
- if (p->time_backtrack)
- {
- int i;
- bool expire = false;
- for (i = 0; i < CIRC_LIST_SIZE (p->seq_list); ++i)
- {
- const time_t t = CIRC_LIST_ITEM (p->seq_list, i);
- if (t == SEQ_EXPIRED)
- break;
- if (!expire && t && t + p->time_backtrack < local_now)
- expire = true;
- if (expire)
- CIRC_LIST_ITEM (p->seq_list, i) = SEQ_EXPIRED;
- }
- }
- p->last_reap = local_now;
-}
-
-/*
- * Return true if packet id is ok, or false if
- * it is a replay.
- */
-bool
-packet_id_test (const struct packet_id_rec *p,
- const struct packet_id_net *pin)
-{
- static int max_backtrack_stat;
- packet_id_type diff;
-
- dmsg (D_PID_DEBUG,
- "PID TEST " time_format ":" packet_id_format " " time_format ":" packet_id_format "",
- (time_type)p->time, (packet_id_print_type)p->id, (time_type)pin->time,
- (packet_id_print_type)pin->id);
-
- ASSERT (p->initialized);
-
- if (!pin->id)
- return false;
-
- if (p->seq_backtrack)
- {
- /*
- * In backtrack mode, we allow packet reordering subject
- * to the seq_backtrack and time_backtrack constraints.
- *
- * This mode is used with UDP.
- */
- if (pin->time == p->time)
- {
- /* is packet-id greater than any one we've seen yet? */
- if (pin->id > p->id)
- return true;
-
- /* check packet-id sliding window for original/replay status */
- diff = p->id - pin->id;
-
- /* keep track of maximum backtrack seen for debugging purposes */
- if ((int)diff > max_backtrack_stat)
- {
- max_backtrack_stat = (int)diff;
- msg (D_BACKTRACK, "Replay-window backtrack occurred [%d]", max_backtrack_stat);
- }
-
- if (diff >= (packet_id_type) CIRC_LIST_SIZE (p->seq_list))
- return false;
-
- return CIRC_LIST_ITEM (p->seq_list, diff) == 0;
- }
- else if (pin->time < p->time) /* if time goes back, reject */
- return false;
- else /* time moved forward */
- return true;
- }
- else
- {
- /*
- * In non-backtrack mode, all sequence number series must
- * begin at 1 and must increment linearly without gaps.
- *
- * This mode is used with TCP.
- */
- if (pin->time == p->time)
- return pin->id == p->id + 1;
- else if (pin->time < p->time) /* if time goes back, reject */
- return false;
- else /* time moved forward */
- return pin->id == 1;
- }
-}
-
-/*
- * Read/write a packet ID to/from the buffer. Short form is sequence number
- * only. Long form is sequence number and timestamp.
- */
-
-bool
-packet_id_read (struct packet_id_net *pin, struct buffer *buf, bool long_form)
-{
- packet_id_type net_id;
- net_time_t net_time;
-
- pin->id = 0;
- pin->time = 0;
-
- if (!buf_read (buf, &net_id, sizeof (net_id)))
- return false;
- pin->id = ntohpid (net_id);
- if (long_form)
- {
- if (!buf_read (buf, &net_time, sizeof (net_time)))
- return false;
- pin->time = ntohtime (net_time);
- }
- return true;
-}
-
-bool
-packet_id_write (const struct packet_id_net *pin, struct buffer *buf, bool long_form, bool prepend)
-{
- packet_id_type net_id = htonpid (pin->id);
- net_time_t net_time = htontime (pin->time);
-
- if (prepend)
- {
- if (long_form)
- {
- if (!buf_write_prepend (buf, &net_time, sizeof (net_time)))
- return false;
- }
- if (!buf_write_prepend (buf, &net_id, sizeof (net_id)))
- return false;
- }
- else
- {
- if (!buf_write (buf, &net_id, sizeof (net_id)))
- return false;
- if (long_form)
- {
- if (!buf_write (buf, &net_time, sizeof (net_time)))
- return false;
- }
- }
- return true;
-}
-
-const char *
-packet_id_net_print (const struct packet_id_net *pin, bool print_timestamp, struct gc_arena *gc)
-{
- struct buffer out = alloc_buf_gc (256, gc);
-
- buf_printf (&out, "[ #" packet_id_format, (packet_id_print_type)pin->id);
- if (print_timestamp && pin->time)
- buf_printf (&out, " / time = (" packet_id_format ") %s",
- (packet_id_print_type)pin->time,
- time_string (pin->time, 0, false, gc));
-
- buf_printf (&out, " ]");
- return BSTR (&out);
-}
-
-/* initialize the packet_id_persist structure in a disabled state */
-void
-packet_id_persist_init (struct packet_id_persist *p)
-{
- p->filename = NULL;
- p->fd = -1;
- p->time = p->time_last_written = 0;
- p->id = p->id_last_written = 0;
-}
-
-/* close the file descriptor if it is open, and switch to disabled state */
-void
-packet_id_persist_close (struct packet_id_persist *p)
-{
- if (packet_id_persist_enabled (p))
- {
- if (close (p->fd))
- msg (D_PID_PERSIST | M_ERRNO, "Close error on --replay-persist file %s", p->filename);
- packet_id_persist_init (p);
- }
-}
-
-/* load persisted rec packet_id (time and id) only once from file, and set state to enabled */
-void
-packet_id_persist_load (struct packet_id_persist *p, const char *filename)
-{
- struct gc_arena gc = gc_new ();
- if (!packet_id_persist_enabled (p))
- {
- /* open packet-id persist file for both read and write */
- p->fd = open (filename,
- O_CREAT | O_RDWR | O_BINARY,
- S_IRUSR | S_IWUSR);
- if (p->fd == -1)
- {
- msg (D_PID_PERSIST | M_ERRNO,
- "Cannot open --replay-persist file %s for read/write",
- filename);
- }
- else
- {
- struct packet_id_persist_file_image image;
- ssize_t n;
-
-#if defined(HAVE_FLOCK) && defined(LOCK_EX) && defined(LOCK_NB)
- if (flock (p->fd, LOCK_EX | LOCK_NB))
- msg (M_ERR, "Cannot obtain exclusive lock on --replay-persist file %s", filename);
-#endif
-
- p->filename = filename;
- n = read (p->fd, &image, sizeof(image));
- if (n == sizeof(image))
- {
- p->time = p->time_last_written = image.time;
- p->id = p->id_last_written = image.id;
- dmsg (D_PID_PERSIST_DEBUG, "PID Persist Read from %s: %s",
- p->filename, packet_id_persist_print (p, &gc));
- }
- else if (n == -1)
- {
- msg (D_PID_PERSIST | M_ERRNO,
- "Read error on --replay-persist file %s",
- p->filename);
- }
- }
- }
- gc_free (&gc);
-}
-
-/* save persisted rec packet_id (time and id) to file (only if enabled state) */
-void
-packet_id_persist_save (struct packet_id_persist *p)
-{
- if (packet_id_persist_enabled (p) && p->time && (p->time != p->time_last_written ||
- p->id != p->id_last_written))
- {
- struct packet_id_persist_file_image image;
- ssize_t n;
- off_t seek_ret;
- struct gc_arena gc = gc_new ();
-
- image.time = p->time;
- image.id = p->id;
- seek_ret = lseek(p->fd, (off_t)0, SEEK_SET);
- if (seek_ret == (off_t)0)
- {
- n = write(p->fd, &image, sizeof(image));
- if (n == sizeof(image))
- {
- p->time_last_written = p->time;
- p->id_last_written = p->id;
- dmsg (D_PID_PERSIST_DEBUG, "PID Persist Write to %s: %s",
- p->filename, packet_id_persist_print (p, &gc));
- }
- else
- {
- msg (D_PID_PERSIST | M_ERRNO,
- "Cannot write to --replay-persist file %s",
- p->filename);
- }
- }
- else
- {
- msg (D_PID_PERSIST | M_ERRNO,
- "Cannot seek to beginning of --replay-persist file %s",
- p->filename);
- }
- gc_free (&gc);
- }
-}
-
-/* transfer packet_id_persist -> packet_id */
-void
-packet_id_persist_load_obj (const struct packet_id_persist *p, struct packet_id *pid)
-{
- if (p && pid && packet_id_persist_enabled (p) && p->time)
- {
- pid->rec.time = p->time;
- pid->rec.id = p->id;
- }
-}
-
-const char *
-packet_id_persist_print (const struct packet_id_persist *p, struct gc_arena *gc)
-{
- struct buffer out = alloc_buf_gc (256, gc);
-
- buf_printf (&out, "[");
-
- if (packet_id_persist_enabled (p))
- {
- buf_printf (&out, " #" packet_id_format, (packet_id_print_type)p->id);
- if (p->time)
- buf_printf (&out, " / time = (" packet_id_format ") %s",
- (packet_id_print_type)p->time,
- time_string (p->time, 0, false, gc));
- }
-
- buf_printf (&out, " ]");
- return (char *)out.data;
-}
-
-#ifdef PID_TEST
-
-void
-packet_id_interactive_test ()
-{
- struct packet_id pid;
- struct packet_id_net pin;
- bool long_form;
- bool count = 0;
- bool test;
-
- const int seq_backtrack = 10;
- const int time_backtrack = 10;
-
- packet_id_init (&pid, seq_backtrack, time_backtrack);
-
- while (true) {
- char buf[80];
- if (!fgets(buf, sizeof(buf), stdin))
- break;
- update_time ();
- if (sscanf (buf, "%lu,%u", &pin.time, &pin.id) == 2)
- {
- packet_id_reap_test (&pid.rec);
- test = packet_id_test (&pid.rec, &pin);
- printf ("packet_id_test (" time_format ", " packet_id_format ") returned %d\n",
- (time_type)pin.time,
- (packet_id_print_type)pin.id,
- test);
- if (test)
- packet_id_add (&pid.rec, &pin);
- }
- else
- {
- long_form = (count < 20);
- packet_id_alloc_outgoing (&pid.send, &pin, long_form);
- printf ("(" time_format "(" packet_id_format "), %d)\n",
- (time_type)pin.time,
- (packet_id_print_type)pin.id,
- long_form);
- if (pid.send.id == 10)
- pid.send.id = 0xFFFFFFF8;
- ++count;
- }
- }
- packet_id_free (&pid);
-}
-#endif
-
-#endif /* USE_CRYPTO */
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