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WinDivert security improvements.

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(1) WinDivert will now reference the PROCESS that
opened the handle, and will not deref until the
handle is closed & all corresponding REFLECT
events have been completed.  This means the OPEN
REFLECT event will always return a valid PID.

(2) The packet queue size now also accounts for
internal overheads.
This commit is contained in:
basil00
2019-02-27 08:57:10 +08:00
parent 7fa04945c0
commit c084c8239b
4 changed files with 121 additions and 176 deletions
Download Patch File Download Diff File Expand all files Collapse all files
examples/windivertctl/windivertctl.c
+16 -110
View File
@@ -1,6 +1,6 @@
/*
* windivertctl.c
* (C) 2018, all rights reserved,
* (C) 2019, all rights reserved,
*
* This file is part of WinDivert.
*
@@ -50,19 +50,6 @@
#define MAX_PACKET 0xFFFF
#define MAX_FILTER_LEN 30000
/*
* Process info.
*/
typedef struct INFO
{
UINT32 process_id;
UINT32 ref_count;
HANDLE process;
struct INFO *next;
} INFO, *PINFO;
static INFO *open = NULL; // All open handles
/*
* Modes.
*/
@@ -73,95 +60,6 @@ typedef enum
KILLALL
} MODE;
/*
* Add a new process.
*/
static HANDLE add_process(UINT32 process_id)
{
PINFO info = open;
HANDLE process;
while (info != NULL)
{
if (info->process_id == process_id)
{
info->ref_count++;
return info->process;
}
info = info->next;
}
process = OpenProcess(PROCESS_QUERY_LIMITED_INFORMATION | PROCESS_TERMINATE,
FALSE, process_id);
info = (INFO *)malloc(sizeof(INFO));
if (info == NULL)
{
fprintf(stderr, "error: failed to allocate memory (%d)\n",
GetLastError());
exit(EXIT_FAILURE);
}
info->process_id = process_id;
info->process = process;
info->ref_count = 1;
info->next = open;
open = info;
return process;
}
/*
* Lookup a process.
*/
static HANDLE lookup_process(UINT32 process_id)
{
PINFO info = open;
while (info != NULL)
{
if (info->process_id == process_id)
{
return info->process;
}
info = info->next;
}
}
/*
* Remove an old process.
*/
static void remove_process(UINT32 process_id)
{
PINFO info = open, prev = NULL;
while (info != NULL)
{
if (info->process_id == process_id)
{
info->ref_count--;
if (info->ref_count > 0)
{
return;
}
break;
}
prev = info;
info = info->next;
}
if (info->process != NULL)
{
CloseHandle(info->process);
}
if (prev != NULL)
{
prev->next = info->next;
}
else
{
open = info->next;
}
free(info);
}
/*
* Entry.
*/
@@ -243,6 +141,17 @@ usage:
GetLastError());
return EXIT_FAILURE;
}
if (!WinDivertSetParam(handle, WINDIVERT_PARAM_QUEUE_LEN,
WINDIVERT_PARAM_QUEUE_LEN_MAX) ||
!WinDivertSetParam(handle, WINDIVERT_PARAM_QUEUE_SIZE,
WINDIVERT_PARAM_QUEUE_SIZE_MAX) ||
!WinDivertSetParam(handle, WINDIVERT_PARAM_QUEUE_TIME,
WINDIVERT_PARAM_QUEUE_TIME_MAX))
{
fprintf(stderr, "error: failed to set WinDivert handle params (%d)\n",
GetLastError());
return EXIT_FAILURE;
}
// Main loop:
console = GetStdHandle(STD_OUTPUT_HANDLE);
@@ -262,7 +171,6 @@ usage:
{
case WINDIVERT_EVENT_REFLECT_OPEN:
// Open handle:
process = add_process(addr.Reflect.ProcessId);
if (mode == KILLALL)
{
SetConsoleTextAttribute(console, FOREGROUND_RED);
@@ -282,7 +190,6 @@ usage:
{
continue;
}
process = lookup_process(addr.Reflect.ProcessId);
SetConsoleTextAttribute(console, FOREGROUND_RED);
fputs("CLOSE", stdout);
break;
@@ -291,6 +198,9 @@ usage:
fputs("???", stdout);
break;
}
process = OpenProcess(
PROCESS_QUERY_LIMITED_INFORMATION | PROCESS_TERMINATE,
FALSE, addr.Reflect.ProcessId);
SetConsoleTextAttribute(console,
FOREGROUND_RED | FOREGROUND_GREEN | FOREGROUND_BLUE);
fputs(" time=", stdout);
@@ -309,6 +219,7 @@ usage:
if (process != NULL)
{
path_len = GetProcessImageFileName(process, path, sizeof(path));
CloseHandle(process);
}
SetConsoleTextAttribute(console, FOREGROUND_RED | FOREGROUND_GREEN);
printf("%s", (path_len != 0? path: "???"));
@@ -391,11 +302,6 @@ usage:
SetConsoleTextAttribute(console,
FOREGROUND_RED | FOREGROUND_GREEN | FOREGROUND_BLUE);
putchar('\n');
if (addr.Event == WINDIVERT_EVENT_REFLECT_CLOSE)
{
remove_process(addr.Reflect.ProcessId);
}
}
if (!WinDivertClose(handle))