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Avoid potential infinite loop for rdpUpdate. #193

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Merged
merged 1 commit into from
May 26, 2021
Merged

Avoid potential infinite loop for rdpUpdate. #193

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21 changes: 15 additions & 6 deletions module/rdpClientCon.c
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Original file line number Diff line number Diff line change
Expand Up @@ -33,6 +33,7 @@ Client connection to xrdp
#include <sys/types.h>
#include <sys/ipc.h>
#include <sys/shm.h>
#include <limits.h>

/* this should be before all X11 .h files */
#include <xorg-server.h>
Expand Down Expand Up @@ -212,6 +213,7 @@ rdpClientConGotConnection(ScreenPtr pScreen, rdpPtr dev)
LLOGLN(0, ("rdpClientConGotConnection:"));
clientCon = g_new0(rdpClientCon, 1);
clientCon->shmemstatus = SHM_UNINITIALIZED;
clientCon->updateRetries = 0;
clientCon->dev = dev;
dev->last_event_time_ms = GetTimeInMillis();
dev->do_dirty_ons = 1;
Expand Down Expand Up @@ -2069,7 +2071,7 @@ rdpClientConAddOsBitmap(rdpPtr dev, rdpClientCon *clientCon,
return -1;
}

oldest = 0x7fffffff;
oldest = INT_MAX;
oldest_index = -1;
rv = -1;
index = 0;
Expand Down Expand Up @@ -2137,7 +2139,7 @@ rdpClientConAddOsBitmap(rdpPtr dev, rdpClientCon *clientCon,
"clientCon->osBitmapNumUsed %d",
clientCon->osBitmapNumUsed));
/* find oldest */
oldest = 0x7fffffff;
oldest = INT_MAX;
oldest_index = -1;
index = 0;
while (index < clientCon->maxOsBitmaps)
Expand Down Expand Up @@ -2479,10 +2481,8 @@ rdpDeferredUpdateCallback(OsTimerPtr timer, CARD32 now, pointer arg)
rdpScheduleDeferredUpdate(clientCon);
return 0;
}
else
{
LLOGLN(10, ("rdpDeferredUpdateCallback: sending"));
}
LLOGLN(10, ("rdpDeferredUpdateCallback: sending"));
clientCon->updateRetries = 0;
rdpClientConGetScreenImageRect(clientCon->dev, clientCon, &id);
LLOGLN(10, ("rdpDeferredUpdateCallback: rdp_width %d rdp_height %d "
"rdp_Bpp %d screen width %d screen height %d",
Expand Down Expand Up @@ -2578,13 +2578,21 @@ rdpDeferredUpdateCallback(OsTimerPtr timer, CARD32 now, pointer arg)
/******************************************************************************/
#define MIN_MS_BETWEEN_FRAMES 40
#define MIN_MS_TO_WAIT_FOR_MORE_UPDATES 4
#define UPDATE_RETRY_TIMEOUT 200 // After this number of retries, give up and perform the capture anyway. This prevents an infinite loop.
static void
rdpScheduleDeferredUpdate(rdpClientCon *clientCon)
{
uint32_t curTime;
uint32_t msToWait;
uint32_t minNextUpdateTime;

if (clientCon->updateRetries > UPDATE_RETRY_TIMEOUT) {
LLOGLN(10, ("rdpScheduleDeferredUpdate: clientCon->updateRetries is %d"
" and has exceeded the timeout of %d retries."
" Overriding rect_id_ack to INT_MAX.", clientCon->updateRetries, UPDATE_RETRY_TIMEOUT));
clientCon->rect_id_ack = INT_MAX;
}

curTime = (uint32_t) GetTimeInMillis();
/* use two separate delays in order to limit the update rate and wait a bit
for more changes before sending an update. Always waiting the longer
Expand All @@ -2604,6 +2612,7 @@ rdpScheduleDeferredUpdate(rdpClientCon *clientCon)
rdpDeferredUpdateCallback,
clientCon);
clientCon->updateScheduled = TRUE;
++clientCon->updateRetries;
}

/******************************************************************************/
Expand Down
1 change: 1 addition & 0 deletions module/rdpClientCon.h
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Original file line number Diff line number Diff line change
Expand Up @@ -116,6 +116,7 @@ struct _rdpClientCon
OsTimerPtr updateTimer;
CARD32 lastUpdateTime; /* millisecond timestamp */
int updateScheduled; /* boolean */
int updateRetries;

RegionPtr dirtyRegion;

Expand Down