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qemu-e2k/ui/vnc.h
Daniel P. Berrange a2bebfd6e0 CVE-2015-1779: incrementally decode websocket frames 
The logic for decoding websocket frames wants to fully
decode the frame header and payload, before allowing the
VNC server to see any of the payload data. There is no
size limit on websocket payloads, so this allows a
malicious network client to consume 2^64 bytes in memory
in QEMU. It can trigger this denial of service before
the VNC server even performs any authentication.

The fix is to decode the header, and then incrementally
decode the payload data as it is needed. With this fix
the websocket decoder will allow at most 4k of data to
be buffered before decoding and processing payload.

Signed-off-by: Daniel P. Berrange <berrange@redhat.com>

[ kraxel: fix frequent spurious disconnects, suggested by Peter Maydell ]

  @@ -361,7 +361,7 @@ int vncws_decode_frame_payload(Buffer *input,
  -        *payload_size = input->offset;
  +        *payload_size = *payload_remain;

[ kraxel: fix 32bit build ]

  @@ -306,7 +306,7 @@ struct VncState
  -    uint64_t ws_payload_remain;
  +    size_t ws_payload_remain;

Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
2015-04-01 17:11:34 +02:00

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/*
* QEMU VNC display driver
*
* Copyright (C) 2006 Anthony Liguori <anthony@codemonkey.ws>
* Copyright (C) 2006 Fabrice Bellard
* Copyright (C) 2009 Red Hat, Inc
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*/
#ifndef __QEMU_VNC_H
#define __QEMU_VNC_H
#include "qemu-common.h"
#include "qemu/queue.h"
#include "qemu/thread.h"
#include "ui/console.h"
#include "audio/audio.h"
#include "qemu/bitmap.h"
#include <zlib.h>
#include <stdbool.h>
#include "keymaps.h"
#include "vnc-palette.h"
#include "vnc-enc-zrle.h"
#include "qapi-types.h"
// #define _VNC_DEBUG 1
#ifdef _VNC_DEBUG
#define VNC_DEBUG(fmt, ...) do { fprintf(stderr, fmt, ## __VA_ARGS__); } while (0)
#else
#define VNC_DEBUG(fmt, ...) do { } while (0)
#endif
/*****************************************************************************
*
* Core data structures
*
*****************************************************************************/
typedef struct Buffer
{
size_t capacity;
size_t offset;
uint8_t *buffer;
} Buffer;
typedef struct VncState VncState;
typedef struct VncJob VncJob;
typedef struct VncRect VncRect;
typedef struct VncRectEntry VncRectEntry;
typedef int VncReadEvent(VncState *vs, uint8_t *data, size_t len);
typedef void VncWritePixels(VncState *vs, void *data, int size);
typedef void VncSendHextileTile(VncState *vs,
int x, int y, int w, int h,
void *last_bg,
void *last_fg,
int *has_bg, int *has_fg);
/* VNC_DIRTY_PIXELS_PER_BIT is the number of dirty pixels represented
* by one bit in the dirty bitmap, should be a power of 2 */
#define VNC_DIRTY_PIXELS_PER_BIT 16
/* VNC_MAX_WIDTH must be a multiple of VNC_DIRTY_PIXELS_PER_BIT. */
#define VNC_MAX_WIDTH ROUND_UP(2560, VNC_DIRTY_PIXELS_PER_BIT)
#define VNC_MAX_HEIGHT 2048
/* VNC_DIRTY_BITS is the number of bits in the dirty bitmap. */
#define VNC_DIRTY_BITS (VNC_MAX_WIDTH / VNC_DIRTY_PIXELS_PER_BIT)
/* VNC_DIRTY_BPL (BPL = bits per line) might be greater than
* VNC_DIRTY_BITS due to alignment */
#define VNC_DIRTY_BPL(x) (sizeof((x)->dirty) / VNC_MAX_HEIGHT * BITS_PER_BYTE)
#define VNC_STAT_RECT 64
#define VNC_STAT_COLS (VNC_MAX_WIDTH / VNC_STAT_RECT)
#define VNC_STAT_ROWS (VNC_MAX_HEIGHT / VNC_STAT_RECT)
#define VNC_AUTH_CHALLENGE_SIZE 16
typedef struct VncDisplay VncDisplay;
#ifdef CONFIG_VNC_TLS
#include "vnc-tls.h"
#include "vnc-auth-vencrypt.h"
#endif
#ifdef CONFIG_VNC_SASL
#include "vnc-auth-sasl.h"
#endif
#ifdef CONFIG_VNC_WS
#include "vnc-ws.h"
#endif
struct VncRectStat
{
/* time of last 10 updates, to find update frequency */
struct timeval times[10];
int idx;
double freq; /* Update frequency (in Hz) */
bool updated; /* Already updated during this refresh */
};
typedef struct VncRectStat VncRectStat;
struct VncSurface
{
struct timeval last_freq_check;
DECLARE_BITMAP(dirty[VNC_MAX_HEIGHT],
VNC_MAX_WIDTH / VNC_DIRTY_PIXELS_PER_BIT);
VncRectStat stats[VNC_STAT_ROWS][VNC_STAT_COLS];
pixman_image_t *fb;
pixman_format_code_t format;
};
typedef enum VncShareMode {
VNC_SHARE_MODE_CONNECTING = 1,
VNC_SHARE_MODE_SHARED,
VNC_SHARE_MODE_EXCLUSIVE,
VNC_SHARE_MODE_DISCONNECTED,
} VncShareMode;
typedef enum VncSharePolicy {
VNC_SHARE_POLICY_IGNORE = 1,
VNC_SHARE_POLICY_ALLOW_EXCLUSIVE,
VNC_SHARE_POLICY_FORCE_SHARED,
} VncSharePolicy;
struct VncDisplay
{
QTAILQ_HEAD(, VncState) clients;
int num_connecting;
int num_shared;
int num_exclusive;
int connections_limit;
VncSharePolicy share_policy;
int lsock;
#ifdef CONFIG_VNC_WS
int lwebsock;
bool ws_enabled;
#endif
DisplaySurface *ds;
DisplayChangeListener dcl;
kbd_layout_t *kbd_layout;
int lock_key_sync;
QemuMutex mutex;
QEMUCursor *cursor;
int cursor_msize;
uint8_t *cursor_mask;
struct VncSurface guest; /* guest visible surface (aka ds->surface) */
pixman_image_t *server; /* vnc server surface */
const char *id;
QTAILQ_ENTRY(VncDisplay) next;
bool enabled;
bool is_unix;
char *password;
time_t expires;
int auth;
int subauth; /* Used by VeNCrypt */
int ws_auth; /* Used by websockets */
bool ws_tls; /* Used by websockets */
bool lossy;
bool non_adaptive;
#ifdef CONFIG_VNC_TLS
VncDisplayTLS tls;
#endif
#ifdef CONFIG_VNC_SASL
VncDisplaySASL sasl;
#endif
};
typedef struct VncTight {
int type;
uint8_t quality;
uint8_t compression;
uint8_t pixel24;
Buffer tight;
Buffer tmp;
Buffer zlib;
Buffer gradient;
#ifdef CONFIG_VNC_JPEG
Buffer jpeg;
#endif
#ifdef CONFIG_VNC_PNG
Buffer png;
#endif
int levels[4];
z_stream stream[4];
} VncTight;
typedef struct VncHextile {
VncSendHextileTile *send_tile;
} VncHextile;
typedef struct VncZlib {
Buffer zlib;
Buffer tmp;
z_stream stream;
int level;
} VncZlib;
typedef struct VncZrle {
int type;
Buffer fb;
Buffer zrle;
Buffer tmp;
Buffer zlib;
z_stream stream;
VncPalette palette;
} VncZrle;
typedef struct VncZywrle {
int buf[VNC_ZRLE_TILE_WIDTH * VNC_ZRLE_TILE_HEIGHT];
} VncZywrle;
struct VncRect
{
int x;
int y;
int w;
int h;
};
struct VncRectEntry
{
struct VncRect rect;
QLIST_ENTRY(VncRectEntry) next;
};
struct VncJob
{
VncState *vs;
QLIST_HEAD(, VncRectEntry) rectangles;
QTAILQ_ENTRY(VncJob) next;
};
struct VncState
{
int csock;
DECLARE_BITMAP(dirty[VNC_MAX_HEIGHT], VNC_DIRTY_BITS);
uint8_t **lossy_rect; /* Not an Array to avoid costly memcpy in
* vnc-jobs-async.c */
VncDisplay *vd;
int need_update;
int force_update;
int has_dirty;
uint32_t features;
int absolute;
int last_x;
int last_y;
uint32_t last_bmask;
int client_width;
int client_height;
VncShareMode share_mode;
uint32_t vnc_encoding;
int major;
int minor;
int auth;
int subauth; /* Used by VeNCrypt */
char challenge[VNC_AUTH_CHALLENGE_SIZE];
#ifdef CONFIG_VNC_TLS
VncStateTLS tls;
#endif
#ifdef CONFIG_VNC_SASL
VncStateSASL sasl;
#endif
#ifdef CONFIG_VNC_WS
bool encode_ws;
bool websocket;
#endif /* CONFIG_VNC_WS */
VncClientInfo *info;
Buffer output;
Buffer input;
#ifdef CONFIG_VNC_WS
Buffer ws_input;
Buffer ws_output;
size_t ws_payload_remain;
WsMask ws_payload_mask;
#endif
/* current output mode information */
VncWritePixels *write_pixels;
PixelFormat client_pf;
pixman_format_code_t client_format;
bool client_be;
CaptureVoiceOut *audio_cap;
struct audsettings as;
VncReadEvent *read_handler;
size_t read_handler_expect;
/* input */
uint8_t modifiers_state[256];
QEMUPutLEDEntry *led;
bool abort;
bool initialized;
QemuMutex output_mutex;
QEMUBH *bh;
Buffer jobs_buffer;
/* Encoding specific, if you add something here, don't forget to
* update vnc_async_encoding_start()
*/
VncTight tight;
VncZlib zlib;
VncHextile hextile;
VncZrle zrle;
VncZywrle zywrle;
Notifier mouse_mode_notifier;
QTAILQ_ENTRY(VncState) next;
};
/*****************************************************************************
*
* Authentication modes
*
*****************************************************************************/
enum {
VNC_AUTH_INVALID = 0,
VNC_AUTH_NONE = 1,
VNC_AUTH_VNC = 2,
VNC_AUTH_RA2 = 5,
VNC_AUTH_RA2NE = 6,
VNC_AUTH_TIGHT = 16,
VNC_AUTH_ULTRA = 17,
VNC_AUTH_TLS = 18, /* Supported in GTK-VNC & VINO */
VNC_AUTH_VENCRYPT = 19, /* Supported in GTK-VNC & VeNCrypt */
VNC_AUTH_SASL = 20, /* Supported in GTK-VNC & VINO */
};
enum {
VNC_AUTH_VENCRYPT_PLAIN = 256,
VNC_AUTH_VENCRYPT_TLSNONE = 257,
VNC_AUTH_VENCRYPT_TLSVNC = 258,
VNC_AUTH_VENCRYPT_TLSPLAIN = 259,
VNC_AUTH_VENCRYPT_X509NONE = 260,
VNC_AUTH_VENCRYPT_X509VNC = 261,
VNC_AUTH_VENCRYPT_X509PLAIN = 262,
VNC_AUTH_VENCRYPT_X509SASL = 263,
VNC_AUTH_VENCRYPT_TLSSASL = 264,
};
/*****************************************************************************
*
* Encoding types
*
*****************************************************************************/
#define VNC_ENCODING_RAW 0x00000000
#define VNC_ENCODING_COPYRECT 0x00000001
#define VNC_ENCODING_RRE 0x00000002
#define VNC_ENCODING_CORRE 0x00000004
#define VNC_ENCODING_HEXTILE 0x00000005
#define VNC_ENCODING_ZLIB 0x00000006
#define VNC_ENCODING_TIGHT 0x00000007
#define VNC_ENCODING_ZLIBHEX 0x00000008
#define VNC_ENCODING_TRLE 0x0000000f
#define VNC_ENCODING_ZRLE 0x00000010
#define VNC_ENCODING_ZYWRLE 0x00000011
#define VNC_ENCODING_COMPRESSLEVEL0 0xFFFFFF00 /* -256 */
#define VNC_ENCODING_QUALITYLEVEL0 0xFFFFFFE0 /* -32 */
#define VNC_ENCODING_XCURSOR 0xFFFFFF10 /* -240 */
#define VNC_ENCODING_RICH_CURSOR 0xFFFFFF11 /* -239 */
#define VNC_ENCODING_POINTER_POS 0xFFFFFF18 /* -232 */
#define VNC_ENCODING_LASTRECT 0xFFFFFF20 /* -224 */
#define VNC_ENCODING_DESKTOPRESIZE 0xFFFFFF21 /* -223 */
#define VNC_ENCODING_POINTER_TYPE_CHANGE 0XFFFFFEFF /* -257 */
#define VNC_ENCODING_EXT_KEY_EVENT 0XFFFFFEFE /* -258 */
#define VNC_ENCODING_AUDIO 0XFFFFFEFD /* -259 */
#define VNC_ENCODING_TIGHT_PNG 0xFFFFFEFC /* -260 */
#define VNC_ENCODING_LED_STATE 0XFFFFFEFB /* -261 */
#define VNC_ENCODING_WMVi 0x574D5669
/*****************************************************************************
*
* Other tight constants
*
*****************************************************************************/
/*
* Vendors known by TightVNC: standard VNC/RealVNC, TridiaVNC, and TightVNC.
*/
#define VNC_TIGHT_CCB_RESET_MASK (0x0f)
#define VNC_TIGHT_CCB_TYPE_MASK (0x0f << 4)
#define VNC_TIGHT_CCB_TYPE_FILL (0x08 << 4)
#define VNC_TIGHT_CCB_TYPE_JPEG (0x09 << 4)
#define VNC_TIGHT_CCB_TYPE_PNG (0x0A << 4)
#define VNC_TIGHT_CCB_BASIC_MAX (0x07 << 4)
#define VNC_TIGHT_CCB_BASIC_ZLIB (0x03 << 4)
#define VNC_TIGHT_CCB_BASIC_FILTER (0x04 << 4)
/*****************************************************************************
*
* Features
*
*****************************************************************************/
#define VNC_FEATURE_RESIZE 0
#define VNC_FEATURE_HEXTILE 1
#define VNC_FEATURE_POINTER_TYPE_CHANGE 2
#define VNC_FEATURE_WMVI 3
#define VNC_FEATURE_TIGHT 4
#define VNC_FEATURE_ZLIB 5
#define VNC_FEATURE_COPYRECT 6
#define VNC_FEATURE_RICH_CURSOR 7
#define VNC_FEATURE_TIGHT_PNG 8
#define VNC_FEATURE_ZRLE 9
#define VNC_FEATURE_ZYWRLE 10
#define VNC_FEATURE_LED_STATE 11
#define VNC_FEATURE_RESIZE_MASK (1 << VNC_FEATURE_RESIZE)
#define VNC_FEATURE_HEXTILE_MASK (1 << VNC_FEATURE_HEXTILE)
#define VNC_FEATURE_POINTER_TYPE_CHANGE_MASK (1 << VNC_FEATURE_POINTER_TYPE_CHANGE)
#define VNC_FEATURE_WMVI_MASK (1 << VNC_FEATURE_WMVI)
#define VNC_FEATURE_TIGHT_MASK (1 << VNC_FEATURE_TIGHT)
#define VNC_FEATURE_ZLIB_MASK (1 << VNC_FEATURE_ZLIB)
#define VNC_FEATURE_COPYRECT_MASK (1 << VNC_FEATURE_COPYRECT)
#define VNC_FEATURE_RICH_CURSOR_MASK (1 << VNC_FEATURE_RICH_CURSOR)
#define VNC_FEATURE_TIGHT_PNG_MASK (1 << VNC_FEATURE_TIGHT_PNG)
#define VNC_FEATURE_ZRLE_MASK (1 << VNC_FEATURE_ZRLE)
#define VNC_FEATURE_ZYWRLE_MASK (1 << VNC_FEATURE_ZYWRLE)
#define VNC_FEATURE_LED_STATE_MASK (1 << VNC_FEATURE_LED_STATE)
/* Client -> Server message IDs */
#define VNC_MSG_CLIENT_SET_PIXEL_FORMAT 0
#define VNC_MSG_CLIENT_SET_ENCODINGS 2
#define VNC_MSG_CLIENT_FRAMEBUFFER_UPDATE_REQUEST 3
#define VNC_MSG_CLIENT_KEY_EVENT 4
#define VNC_MSG_CLIENT_POINTER_EVENT 5
#define VNC_MSG_CLIENT_CUT_TEXT 6
#define VNC_MSG_CLIENT_VMWARE_0 127
#define VNC_MSG_CLIENT_CALL_CONTROL 249
#define VNC_MSG_CLIENT_XVP 250
#define VNC_MSG_CLIENT_SET_DESKTOP_SIZE 251
#define VNC_MSG_CLIENT_TIGHT 252
#define VNC_MSG_CLIENT_GII 253
#define VNC_MSG_CLIENT_VMWARE_1 254
#define VNC_MSG_CLIENT_QEMU 255
/* Server -> Client message IDs */
#define VNC_MSG_SERVER_FRAMEBUFFER_UPDATE 0
#define VNC_MSG_SERVER_SET_COLOUR_MAP_ENTRIES 1
#define VNC_MSG_SERVER_BELL 2
#define VNC_MSG_SERVER_CUT_TEXT 3
#define VNC_MSG_SERVER_VMWARE_0 127
#define VNC_MSG_SERVER_CALL_CONTROL 249
#define VNC_MSG_SERVER_XVP 250
#define VNC_MSG_SERVER_TIGHT 252
#define VNC_MSG_SERVER_GII 253
#define VNC_MSG_SERVER_VMWARE_1 254
#define VNC_MSG_SERVER_QEMU 255
/* QEMU client -> server message IDs */
#define VNC_MSG_CLIENT_QEMU_EXT_KEY_EVENT 0
#define VNC_MSG_CLIENT_QEMU_AUDIO 1
/* QEMU server -> client message IDs */
#define VNC_MSG_SERVER_QEMU_AUDIO 1
/* QEMU client -> server audio message IDs */
#define VNC_MSG_CLIENT_QEMU_AUDIO_ENABLE 0
#define VNC_MSG_CLIENT_QEMU_AUDIO_DISABLE 1
#define VNC_MSG_CLIENT_QEMU_AUDIO_SET_FORMAT 2
/* QEMU server -> client audio message IDs */
#define VNC_MSG_SERVER_QEMU_AUDIO_END 0
#define VNC_MSG_SERVER_QEMU_AUDIO_BEGIN 1
#define VNC_MSG_SERVER_QEMU_AUDIO_DATA 2
/*****************************************************************************
*
* Internal APIs
*
*****************************************************************************/
/* Event loop functions */
void vnc_client_read(void *opaque);
void vnc_client_write(void *opaque);
long vnc_client_read_buf(VncState *vs, uint8_t *data, size_t datalen);
long vnc_client_write_buf(VncState *vs, const uint8_t *data, size_t datalen);
/* Protocol I/O functions */
void vnc_write(VncState *vs, const void *data, size_t len);
void vnc_write_u32(VncState *vs, uint32_t value);
void vnc_write_s32(VncState *vs, int32_t value);
void vnc_write_u16(VncState *vs, uint16_t value);
void vnc_write_u8(VncState *vs, uint8_t value);
void vnc_flush(VncState *vs);
void vnc_read_when(VncState *vs, VncReadEvent *func, size_t expecting);
void vnc_disconnect_finish(VncState *vs);
void vnc_init_state(VncState *vs);
/* Buffer I/O functions */
uint32_t read_u32(uint8_t *data, size_t offset);
/* Protocol stage functions */
void vnc_client_error(VncState *vs);
int vnc_client_io_error(VncState *vs, int ret, int last_errno);
void start_client_init(VncState *vs);
void start_auth_vnc(VncState *vs);
/* Buffer management */
void buffer_reserve(Buffer *buffer, size_t len);
void buffer_reset(Buffer *buffer);
void buffer_free(Buffer *buffer);
void buffer_append(Buffer *buffer, const void *data, size_t len);
void buffer_advance(Buffer *buf, size_t len);
uint8_t *buffer_end(Buffer *buffer);
/* Misc helpers */
char *vnc_socket_local_addr(const char *format, int fd);
char *vnc_socket_remote_addr(const char *format, int fd);
static inline uint32_t vnc_has_feature(VncState *vs, int feature) {
return (vs->features & (1 << feature));
}
/* Framebuffer */
void vnc_framebuffer_update(VncState *vs, int x, int y, int w, int h,
int32_t encoding);
/* server fb is in PIXMAN_x8r8g8b8 */
#define VNC_SERVER_FB_FORMAT PIXMAN_FORMAT(32, PIXMAN_TYPE_ARGB, 0, 8, 8, 8)
#define VNC_SERVER_FB_BITS (PIXMAN_FORMAT_BPP(VNC_SERVER_FB_FORMAT))
#define VNC_SERVER_FB_BYTES ((VNC_SERVER_FB_BITS+7)/8)
void *vnc_server_fb_ptr(VncDisplay *vd, int x, int y);
int vnc_server_fb_stride(VncDisplay *vd);
void vnc_convert_pixel(VncState *vs, uint8_t *buf, uint32_t v);
double vnc_update_freq(VncState *vs, int x, int y, int w, int h);
void vnc_sent_lossy_rect(VncState *vs, int x, int y, int w, int h);
/* Encodings */
int vnc_send_framebuffer_update(VncState *vs, int x, int y, int w, int h);
int vnc_raw_send_framebuffer_update(VncState *vs, int x, int y, int w, int h);
int vnc_hextile_send_framebuffer_update(VncState *vs, int x,
int y, int w, int h);
void vnc_hextile_set_pixel_conversion(VncState *vs, int generic);
void *vnc_zlib_zalloc(void *x, unsigned items, unsigned size);
void vnc_zlib_zfree(void *x, void *addr);
int vnc_zlib_send_framebuffer_update(VncState *vs, int x, int y, int w, int h);
void vnc_zlib_clear(VncState *vs);
int vnc_tight_send_framebuffer_update(VncState *vs, int x, int y, int w, int h);
int vnc_tight_png_send_framebuffer_update(VncState *vs, int x, int y,
int w, int h);
void vnc_tight_clear(VncState *vs);
int vnc_zrle_send_framebuffer_update(VncState *vs, int x, int y, int w, int h);
int vnc_zywrle_send_framebuffer_update(VncState *vs, int x, int y, int w, int h);
void vnc_zrle_clear(VncState *vs);
#endif /* __QEMU_VNC_H */
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