From 73f3826ee6eb1c4e7300fa9e680f7affdbb8800c Mon Sep 17 00:00:00 2001
From: havoc <havoc@d7cf8633-e32d-0410-b094-e92efae38249>
Date: Thu, 16 Feb 2006 07:20:28 +0000
Subject: [PATCH] fixed bug that allowed accidental speed cheating with
cl_movement 1 mode (move->time was being cleared by ApplyClientMove, so when
ReadClientMove calculated how much to move since the last move, it always
thought the last move was at time == 0, and then it clamped this delta to 0.1
or less, which prevented it from being completely ridiculous, but still
horrible) added kicking of speed cheaters (if they echo a timestamp that has
not yet been issued by the server, they're clearly lying)
git-svn-id: svn://svn.icculus.org/twilight/trunk/darkplaces@5988 d7cf8633-e32d-0410-b094-e92efae38249
---
sv_user.c | 22 ++++++++++++++++++++--
1 file changed, 20 insertions(+), 2 deletions(-)
diff --git a/sv_user.c b/sv_user.c
index 6bdd8ba9..606d79aa 100644
--- a/sv_user.c
+++ b/sv_user.c
@@ -602,7 +602,7 @@ void SV_ClientThink(void)
SV_ReadClientMove
===================
*/
-void SV_ReadClientMove (void)
+qboolean SV_ReadClientMove (void)
{
int i;
double oldmovetime;
@@ -681,6 +681,17 @@ void SV_ReadClientMove (void)
if (!host_client->spawned)
memset(move, 0, sizeof(*move));
+ else if (move->time > sv.time + 0.01) // add a little fuzz factor due to float precision issues
+ {
+ Con_DPrintf("client move->time %f > sv.time %f, kicking\n", move->time, sv.time);
+ // if the client is lying about time, we have definitively detected a
+ // speed cheat attempt of the worst sort, and we can immediately kick
+ // the offending player off.
+ // this fixes the timestamp to prevent a speed cheat from working
+ move->time = sv.time;
+ // but we kick the player for good measure
+ return true;
+ }
else
{
// apply the latest accepted move to the entity fields
@@ -696,10 +707,12 @@ void SV_ReadClientMove (void)
prog->globals.server->frametime = oldframetime;
}
}
+ return false;
}
void SV_ApplyClientMove (void)
{
+ double movetime;
#ifdef NUM_PING_TIMES
int i;
float total;
@@ -750,7 +763,10 @@ void SV_ApplyClientMove (void)
if ((val = PRVM_GETEDICTFIELDVALUE(host_client->edict, eval_cursor_trace_ent))) val->edict = PRVM_EDICT_TO_PROG(PRVM_EDICT_NUM(move->cursor_entitynumber));
if ((val = PRVM_GETEDICTFIELDVALUE(host_client->edict, eval_ping))) val->_float = host_client->ping * 1000.0;
+ // don't clear move->time as it is used for applying cl_movement 1 moves
+ movetime = move->time;
memset(move, 0, sizeof(*move));
+ move->time = movetime;
}
void SV_FrameLost(int framenum)
@@ -854,7 +870,9 @@ void SV_ReadClientMessage(void)
return;
case clc_move:
- SV_ReadClientMove ();
+ // if ReadClientMove returns true, the client tried to speed cheat
+ if (SV_ReadClientMove ())
+ SV_DropClient (false);
break;
case clc_ackframe:
--
2.39.5