From 28821d7a29e4babcdc508f254c1ebc69e5916baf Mon Sep 17 00:00:00 2001
From: James Muehlner <jmuehlner@keepersecurity.com>
Date: Wed, 2 Aug 2023 21:48:00 +0000
Subject: [PATCH] GUACAMOLE-1841: Always close event handles.

---
 src/guacd/connection.c       |  8 +++++++-
 src/libguac/handle-helpers.c | 25 ++++++++++++++++++++-----
 src/libguac/wait-handle.c    | 19 ++++++++++++++-----
 3 files changed, 41 insertions(+), 11 deletions(-)

diff --git a/src/guacd/connection.c b/src/guacd/connection.c
index f0ecf9772..1e8baacc1 100644
--- a/src/guacd/connection.c
+++ b/src/guacd/connection.c
@@ -373,8 +373,14 @@ static int guacd_add_user(guacd_proc* proc, guac_parser* parser, guac_socket* so
         return 1;
     }
 
-    /* Wait for the other end of the pipe to connect before attempting IO */
+    /* Create an event to monitor for pipe connection */
     HANDLE event = CreateEvent(NULL, FALSE, FALSE, NULL);
+    if (event == NULL) {
+        guacd_log(GUAC_LOG_ERROR, "Event creation failed.");
+        return 1;
+    }
+
+    /* Wait for the other end of the pipe to connect before attempting IO */
     OVERLAPPED overlapped = { 0 };
     overlapped.hEvent = event;
     ConnectNamedPipe(pipe_handle, &overlapped);
diff --git a/src/libguac/handle-helpers.c b/src/libguac/handle-helpers.c
index 6c878336f..3c48dc795 100755
--- a/src/libguac/handle-helpers.c
+++ b/src/libguac/handle-helpers.c
@@ -39,6 +39,8 @@ int guac_read_from_handle(
      */
     OVERLAPPED overlapped = { 0 };
     overlapped.hEvent = CreateEvent(NULL, FALSE, FALSE, NULL);
+    if (overlapped.hEvent == NULL) 
+        return GetLastError();
 
     /* Attempt to start the async read operation */
     if (!ReadFile(handle, buffer, count, NULL, &overlapped)) {
@@ -50,6 +52,7 @@ int guac_read_from_handle(
          * return it as the error code immediately.
          */ 
         if (error != ERROR_IO_PENDING) {
+            CloseHandle(overlapped.hEvent);
             return error;
         }
         
@@ -59,10 +62,14 @@ int guac_read_from_handle(
      * Wait on the result of the read. If any error occurs when waiting,
      * return the error.
      */
-    if (!GetOverlappedResult(handle, &overlapped, num_bytes_read, TRUE)) 
-        return GetLastError();
+    if (!GetOverlappedResult(handle, &overlapped, num_bytes_read, TRUE)) {
+        DWORD error = GetLastError();
+        CloseHandle(overlapped.hEvent);
+        return error;
+    }
     
     /* No errors occured, so the read was successful */
+    CloseHandle(overlapped.hEvent);
     return 0;
 
 }
@@ -75,6 +82,8 @@ int guac_write_to_handle(
      */
     OVERLAPPED overlapped = { 0 };
     overlapped.hEvent = CreateEvent(NULL, FALSE, FALSE, NULL);
+    if (overlapped.hEvent == NULL) 
+        return GetLastError();
 
     /* Attempt to start the async write operation */
     if (!WriteFile(handle, buffer, count, NULL, &overlapped)) {
@@ -85,8 +94,10 @@ int guac_write_to_handle(
          * If an error other than the expected ERROR_IO_PENDING happens,
          * return it as the error code immediately.
          */ 
-        if (error != ERROR_IO_PENDING) 
+        if (error != ERROR_IO_PENDING) {
+            CloseHandle(overlapped.hEvent);
             return error;
+        }
         
     }
 
@@ -94,10 +105,14 @@ int guac_write_to_handle(
      * Wait on the result of the write. If any error occurs when waiting,
      * return the error.
      */
-    if (!GetOverlappedResult(handle, &overlapped, num_bytes_written, TRUE)) 
-        return GetLastError();
+    if (!GetOverlappedResult(handle, &overlapped, num_bytes_written, TRUE)) {
+        DWORD error = GetLastError();
+        CloseHandle(overlapped.hEvent);
+        return error;
+    }
 
     /* No errors occured, so the write was successful */
+    CloseHandle(overlapped.hEvent);
     return 0;
     
 }
\ No newline at end of file
diff --git a/src/libguac/wait-handle.c b/src/libguac/wait-handle.c
index 0e3133868..bfba875b2 100644
--- a/src/libguac/wait-handle.c
+++ b/src/libguac/wait-handle.c
@@ -28,10 +28,12 @@
 
 int guac_wait_for_handle(HANDLE handle, int usec_timeout) {
 
+    /* Create an event to be used to signal comm events */
     HANDLE event = CreateEvent(NULL, FALSE, FALSE, NULL);
+    if (event == NULL) 
+        return GetLastError();
+
     OVERLAPPED overlapped = { 0 };
-    
-    /* Set the event to be used to signal comm events */
     overlapped.hEvent = event;
 
     /* Request to wait for new data to be available */
@@ -41,8 +43,10 @@ int guac_wait_for_handle(HANDLE handle, int usec_timeout) {
         DWORD error = GetLastError();
 
         /* ERROR_IO_PENDING is expected in overlapped mode */
-        if (error != ERROR_IO_PENDING) 
+        if (error != ERROR_IO_PENDING) {
+            CloseHandle(event);
             return error;
+        }
 
     }
 
@@ -51,17 +55,22 @@ int guac_wait_for_handle(HANDLE handle, int usec_timeout) {
     DWORD result = WaitForSingleObject(event, millis);
     
     /* The wait attempt failed */ 
-    if (result == WAIT_FAILED)
+    if (result == WAIT_FAILED) {
+        CloseHandle(event);
         return GetLastError();
+    }
 
     /* The event was signalled, which should indicate data is ready */
-    else if (result == WAIT_OBJECT_0)
+    else if (result == WAIT_OBJECT_0) {
+        CloseHandle(event);
         return 0;
+    }
 
     /* 
      * If the event didn't trigger and the wait didn't fail, data just isn't 
      * ready yet.
      */
+    CloseHandle(event);
     return -1;
     
 }