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SUSE:SLE-12-SP2:GA
qemu-linux-user.7445
0436-ui-vnc-fix-potential-memory-corrupt.patch
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File 0436-ui-vnc-fix-potential-memory-corrupt.patch of Package qemu-linux-user.7445
From 8a5b81cf02db7eaa3c0508b7021c3d89d7ed1e5c Mon Sep 17 00:00:00 2001 From: Peter Lieven <pl@kamp.de> Date: Mon, 30 Jun 2014 10:57:51 +0200 Subject: [PATCH] ui/vnc: fix potential memory corruption issues this patch makes the VNC server work correctly if the server surface and the guest surface have different sizes. Basically the server surface is adjusted to not exceed VNC_MAX_WIDTH x VNC_MAX_HEIGHT and additionally the width is rounded up to multiple of VNC_DIRTY_PIXELS_PER_BIT. If we have a resolution whose width is not dividable by VNC_DIRTY_PIXELS_PER_BIT we now get a small black bar on the right of the screen. If the surface is too big to fit the limits only the upper left area is shown. On top of that this fixes 2 memory corruption issues: The first was actually discovered during playing around with a Windows 7 vServer. During resolution change in Windows 7 it happens sometimes that Windows changes to an intermediate resolution where server_stride % cmp_bytes != 0 (in vnc_refresh_server_surface). This happens only if width % VNC_DIRTY_PIXELS_PER_BIT != 0. The second is a theoretical issue, but is maybe exploitable by the guest. If for some reason the guest surface size is bigger than VNC_MAX_WIDTH x VNC_MAX_HEIGHT we end up in severe corruption since this limit is nowhere enforced. Signed-off-by: Peter Lieven <pl@kamp.de> Signed-off-by: Gerd Hoffmann <kraxel@redhat.com> (cherry picked from commit bea60dd7679364493a0d7f5b54316c767cf894ef) [BR: BSC#1026612 CVE-2017-2633] Signed-off-by: Bruce Rogers <brogers@suse.com> --- ui/vnc.c | 149 +++++++++++++++++++++++++++++---------------------------------- ui/vnc.h | 14 +++--- 2 files changed, 77 insertions(+), 86 deletions(-) diff --git a/ui/vnc.c b/ui/vnc.c index 0111be6ee0..cb5c7eca51 100644 --- a/ui/vnc.c +++ b/ui/vnc.c @@ -428,14 +428,10 @@ static void framebuffer_update_request(VncState *vs, int incremental, static void vnc_refresh(DisplayChangeListener *dcl); static int vnc_refresh_server_surface(VncDisplay *vd); -static void vnc_dpy_update(DisplayChangeListener *dcl, - int x, int y, int w, int h) -{ - VncDisplay *vd = container_of(dcl, VncDisplay, dcl); - struct VncSurface *s = &vd->guest; - int width = surface_width(vd->ds); - int height = surface_height(vd->ds); - +static void vnc_set_area_dirty(DECLARE_BITMAP(dirty[VNC_MAX_HEIGHT], + VNC_MAX_WIDTH / VNC_DIRTY_PIXELS_PER_BIT), + int width, int height, + int x, int y, int w, int h) { /* this is needed this to ensure we updated all affected * blocks if x % VNC_DIRTY_PIXELS_PER_BIT != 0 */ w += (x % VNC_DIRTY_PIXELS_PER_BIT); @@ -447,11 +443,22 @@ static void vnc_dpy_update(DisplayChangeListener *dcl, h = MIN(y + h, height); for (; y < h; y++) { - bitmap_set(s->dirty[y], x / VNC_DIRTY_PIXELS_PER_BIT, + bitmap_set(dirty[y], x / VNC_DIRTY_PIXELS_PER_BIT, DIV_ROUND_UP(w, VNC_DIRTY_PIXELS_PER_BIT)); } } +static void vnc_dpy_update(DisplayChangeListener *dcl, + int x, int y, int w, int h) +{ + VncDisplay *vd = container_of(dcl, VncDisplay, dcl); + struct VncSurface *s = &vd->guest; + int width = pixman_image_get_width(vd->server); + int height = pixman_image_get_height(vd->server); + + vnc_set_area_dirty(s->dirty, width, height, x, y, w, h); +} + void vnc_framebuffer_update(VncState *vs, int x, int y, int w, int h, int32_t encoding) { @@ -513,17 +520,15 @@ void buffer_advance(Buffer *buf, size_t len) static void vnc_desktop_resize(VncState *vs) { - DisplaySurface *ds = vs->vd->ds; - if (vs->csock == -1 || !vnc_has_feature(vs, VNC_FEATURE_RESIZE)) { return; } - if (vs->client_width == surface_width(ds) && - vs->client_height == surface_height(ds)) { + if (vs->client_width == pixman_image_get_width(vs->vd->server) && + vs->client_height == pixman_image_get_height(vs->vd->server)) { return; } - vs->client_width = surface_width(ds); - vs->client_height = surface_height(ds); + vs->client_width = pixman_image_get_width(vs->vd->server); + vs->client_height = pixman_image_get_height(vs->vd->server); vnc_lock_output(vs); vnc_write_u8(vs, VNC_MSG_SERVER_FRAMEBUFFER_UPDATE); vnc_write_u8(vs, 0); @@ -567,31 +572,24 @@ void *vnc_server_fb_ptr(VncDisplay *vd, int x, int y) ptr += x * VNC_SERVER_FB_BYTES; return ptr; } -/* this sets only the visible pixels of a dirty bitmap */ -#define VNC_SET_VISIBLE_PIXELS_DIRTY(bitmap, w, h) {\ - int y;\ - memset(bitmap, 0x00, sizeof(bitmap));\ - for (y = 0; y < h; y++) {\ - bitmap_set(bitmap[y], 0,\ - DIV_ROUND_UP(w, VNC_DIRTY_PIXELS_PER_BIT));\ - } \ - } static void vnc_dpy_switch(DisplayChangeListener *dcl, DisplaySurface *surface) { VncDisplay *vd = container_of(dcl, VncDisplay, dcl); VncState *vs; + int width, height; vnc_abort_display_jobs(vd); /* server surface */ qemu_pixman_image_unref(vd->server); vd->ds = surface; + width = MIN(VNC_MAX_WIDTH, ROUND_UP(surface_width(vd->ds), + VNC_DIRTY_PIXELS_PER_BIT)); + height = MIN(VNC_MAX_HEIGHT, surface_height(vd->ds)); vd->server = pixman_image_create_bits(VNC_SERVER_FB_FORMAT, - surface_width(vd->ds), - surface_height(vd->ds), - NULL, 0); + width, height, NULL, 0); /* guest surface */ #if 0 /* FIXME */ @@ -601,9 +599,9 @@ static void vnc_dpy_switch(DisplayChangeListener *dcl, qemu_pixman_image_unref(vd->guest.fb); vd->guest.fb = pixman_image_ref(surface->image); vd->guest.format = surface->format; - VNC_SET_VISIBLE_PIXELS_DIRTY(vd->guest.dirty, - surface_width(vd->ds), - surface_height(vd->ds)); + memset(vd->guest.dirty, 0x00, sizeof(vd->guest.dirty)); + vnc_set_area_dirty(vd->guest.dirty, width, height, 0, 0, + width, height); QTAILQ_FOREACH(vs, &vd->clients, next) { vnc_colordepth(vs); @@ -611,9 +609,9 @@ static void vnc_dpy_switch(DisplayChangeListener *dcl, if (vs->vd->cursor) { vnc_cursor_define(vs); } - VNC_SET_VISIBLE_PIXELS_DIRTY(vs->dirty, - surface_width(vd->ds), - surface_height(vd->ds)); + memset(vs->dirty, 0x00, sizeof(vs->dirty)); + vnc_set_area_dirty(vs->dirty, width, height, 0, 0, + width, height); } } @@ -817,8 +815,8 @@ static int vnc_update_client(VncState *vs, int has_dirty, bool sync) */ job = vnc_job_new(vs); - height = MIN(pixman_image_get_height(vd->server), vs->client_height); - width = MIN(pixman_image_get_width(vd->server), vs->client_width); + height = pixman_image_get_height(vd->server); + width = pixman_image_get_width(vd->server); y = 0; for (;;) { @@ -1412,8 +1410,8 @@ static void check_pointer_type_change(Notifier *notifier, void *data) vnc_write_u8(vs, 0); vnc_write_u16(vs, 1); vnc_framebuffer_update(vs, absolute, 0, - surface_width(vs->vd->ds), - surface_height(vs->vd->ds), + pixman_image_get_width(vs->vd->server), + pixman_image_get_height(vs->vd->server), VNC_ENCODING_POINTER_TYPE_CHANGE); vnc_unlock_output(vs); vnc_flush(vs); @@ -1431,8 +1429,8 @@ static void pointer_event(VncState *vs, int button_mask, int x, int y) [INPUT_BUTTON_WHEEL_DOWN] = 0x10, }; QemuConsole *con = vs->vd->dcl.con; - int width = surface_width(vs->vd->ds); - int height = surface_height(vs->vd->ds); + int width = pixman_image_get_width(vs->vd->server); + int height = pixman_image_get_height(vs->vd->server); if (vs->last_bmask != button_mask) { qemu_input_update_buttons(con, bmap, vs->last_bmask, button_mask); @@ -1762,29 +1760,18 @@ static void ext_key_event(VncState *vs, int down, } static void framebuffer_update_request(VncState *vs, int incremental, - int x_position, int y_position, - int w, int h) + int x, int y, int w, int h) { - int i; - const size_t width = surface_width(vs->vd->ds) / VNC_DIRTY_PIXELS_PER_BIT; - const size_t height = surface_height(vs->vd->ds); - - if (y_position > height) { - y_position = height; - } - if (y_position + h >= height) { - h = height - y_position; - } + int width = pixman_image_get_width(vs->vd->server); + int height = pixman_image_get_height(vs->vd->server); vs->need_update = 1; - if (!incremental) { - vs->force_update = 1; - for (i = 0; i < h; i++) { - bitmap_set(vs->dirty[y_position + i], 0, width); - bitmap_clear(vs->dirty[y_position + i], width, - VNC_DIRTY_BITS - width); - } + + if (incremental) { + return; } + + vnc_set_area_dirty(vs->dirty, width, height, x, y, w, h); } static void send_ext_key_event_ack(VncState *vs) @@ -1794,8 +1781,8 @@ static void send_ext_key_event_ack(VncState *vs) vnc_write_u8(vs, 0); vnc_write_u16(vs, 1); vnc_framebuffer_update(vs, 0, 0, - surface_width(vs->vd->ds), - surface_height(vs->vd->ds), + pixman_image_get_width(vs->vd->server), + pixman_image_get_height(vs->vd->server), VNC_ENCODING_EXT_KEY_EVENT); vnc_unlock_output(vs); vnc_flush(vs); @@ -1808,8 +1795,8 @@ static void send_ext_audio_ack(VncState *vs) vnc_write_u8(vs, 0); vnc_write_u16(vs, 1); vnc_framebuffer_update(vs, 0, 0, - surface_width(vs->vd->ds), - surface_height(vs->vd->ds), + pixman_image_get_width(vs->vd->server), + pixman_image_get_height(vs->vd->server), VNC_ENCODING_AUDIO); vnc_unlock_output(vs); vnc_flush(vs); @@ -2026,8 +2013,8 @@ static void vnc_colordepth(VncState *vs) vnc_write_u8(vs, 0); vnc_write_u16(vs, 1); /* number of rects */ vnc_framebuffer_update(vs, 0, 0, - surface_width(vs->vd->ds), - surface_height(vs->vd->ds), + pixman_image_get_width(vs->vd->server), + pixman_image_get_height(vs->vd->server), VNC_ENCODING_WMVi); pixel_format_message(vs); vnc_unlock_output(vs); @@ -2249,8 +2236,8 @@ static int protocol_client_init(VncState *vs, uint8_t *data, size_t len) } vnc_set_share_mode(vs, mode); - vs->client_width = surface_width(vs->vd->ds); - vs->client_height = surface_height(vs->vd->ds); + vs->client_width = pixman_image_get_width(vs->vd->server); + vs->client_height = pixman_image_get_height(vs->vd->server); vnc_write_u16(vs, vs->client_width); vnc_write_u16(vs, vs->client_height); @@ -2617,12 +2604,12 @@ static void vnc_rect_updated(VncDisplay *vd, int x, int y, struct timeval * tv) static int vnc_refresh_server_surface(VncDisplay *vd) { - int width = pixman_image_get_width(vd->guest.fb); - int height = pixman_image_get_height(vd->guest.fb); - int y; + int width = MIN(pixman_image_get_width(vd->guest.fb), + pixman_image_get_width(vd->server)); + int height = MIN(pixman_image_get_height(vd->guest.fb), + pixman_image_get_height(vd->server)); + int cmp_bytes, server_stride, min_stride, guest_stride, y = 0; uint8_t *guest_row0 = NULL, *server_row0; - int guest_stride = 0, server_stride; - int cmp_bytes; VncState *vs; int has_dirty = 0; pixman_image_t *tmpbuf = NULL; @@ -2639,10 +2626,10 @@ static int vnc_refresh_server_surface(VncDisplay *vd) * Check and copy modified bits from guest to server surface. * Update server dirty map. */ - cmp_bytes = VNC_DIRTY_PIXELS_PER_BIT * VNC_SERVER_FB_BYTES; - if (cmp_bytes > vnc_server_fb_stride(vd)) { - cmp_bytes = vnc_server_fb_stride(vd); - } + server_row0 = (uint8_t *)pixman_image_get_data(vd->server); + server_stride = guest_stride = pixman_image_get_stride(vd->server); + cmp_bytes = MIN(VNC_DIRTY_PIXELS_PER_BIT * VNC_SERVER_FB_BYTES, + server_stride); if (vd->guest.format != VNC_SERVER_FB_FORMAT) { int width = pixman_image_get_width(vd->server); tmpbuf = qemu_pixman_linebuf_create(VNC_SERVER_FB_FORMAT, width); @@ -2650,10 +2637,8 @@ static int vnc_refresh_server_surface(VncDisplay *vd) guest_row0 = (uint8_t *)pixman_image_get_data(vd->guest.fb); guest_stride = pixman_image_get_stride(vd->guest.fb); } - server_row0 = (uint8_t *)pixman_image_get_data(vd->server); - server_stride = pixman_image_get_stride(vd->server); + min_stride = MIN(server_stride, guest_stride); - y = 0; for (;;) { int x; uint8_t *guest_ptr, *server_ptr; @@ -2679,13 +2664,17 @@ static int vnc_refresh_server_surface(VncDisplay *vd) for (; x < DIV_ROUND_UP(width, VNC_DIRTY_PIXELS_PER_BIT); x++, guest_ptr += cmp_bytes, server_ptr += cmp_bytes) { + int _cmp_bytes = cmp_bytes; if (!test_and_clear_bit(x, vd->guest.dirty[y])) { continue; } - if (memcmp(server_ptr, guest_ptr, cmp_bytes) == 0) { + if ((x + 1) * cmp_bytes > min_stride) { + _cmp_bytes = min_stride - x * cmp_bytes; + } + if (memcmp(server_ptr, guest_ptr, _cmp_bytes) == 0) { continue; } - memcpy(server_ptr, guest_ptr, cmp_bytes); + memcpy(server_ptr, guest_ptr, _cmp_bytes); if (!vd->non_adaptive) { vnc_rect_updated(vd, x * VNC_DIRTY_PIXELS_PER_BIT, y, &tv); diff --git a/ui/vnc.h b/ui/vnc.h index 6606a427df..ed656fd314 100644 --- a/ui/vnc.h +++ b/ui/vnc.h @@ -77,14 +77,15 @@ typedef void VncSendHextileTile(VncState *vs, void *last_fg, int *has_bg, int *has_fg); -/* VNC_MAX_WIDTH must be a multiple of 16. */ -#define VNC_MAX_WIDTH 2560 -#define VNC_MAX_HEIGHT 2048 - /* VNC_DIRTY_PIXELS_PER_BIT is the number of dirty pixels represented - * by one bit in the dirty bitmap */ + * 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) @@ -126,7 +127,8 @@ typedef struct VncRectStat VncRectStat; struct VncSurface { struct timeval last_freq_check; - DECLARE_BITMAP(dirty[VNC_MAX_HEIGHT], VNC_MAX_WIDTH / 16); + 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;
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