Re: [RFC PATCH-for-7.2 3/4] hw/display/qxl: Pass requested buffer size to qxl_phys2virt()

[Marc-André Lureau]

On Fri, Nov 25, 2022 at 9:35 PM Philippe Mathieu-Daudé
<philmd@linaro.org> wrote:
>
> Currently qxl_phys2virt() doesn't check for buffer overrun.
> In order to do so in the next commit, pass the buffer size
> as argument.
>
> Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>



> ---
> RFC: Please double-check qxl_render_update_area_unlocked()
> ---
>  hw/display/qxl-logger.c | 11 ++++++++---
>  hw/display/qxl-render.c | 11 +++++++----
>  hw/display/qxl.c        | 14 +++++++++-----
>  hw/display/qxl.h        |  4 +++-
>  4 files changed, 27 insertions(+), 13 deletions(-)
>
> diff --git a/hw/display/qxl-logger.c b/hw/display/qxl-logger.c
> index 1bcf803db6..35c38f6252 100644
> --- a/hw/display/qxl-logger.c
> +++ b/hw/display/qxl-logger.c
> @@ -106,7 +106,7 @@ static int qxl_log_image(PCIQXLDevice *qxl, QXLPHYSICAL 
> addr, int group_id)
>      QXLImage *image;
>      QXLImageDescriptor *desc;
>
> -    image = qxl_phys2virt(qxl, addr, group_id);
> +    image = qxl_phys2virt(qxl, addr, group_id, sizeof(QXLImage));
>      if (!image) {
>          return 1;
>      }
> @@ -214,7 +214,8 @@ int qxl_log_cmd_cursor(PCIQXLDevice *qxl, QXLCursorCmd 
> *cmd, int group_id)
>                  cmd->u.set.position.y,
>                  cmd->u.set.visible ? "yes" : "no",
>                  cmd->u.set.shape);
> -        cursor = qxl_phys2virt(qxl, cmd->u.set.shape, group_id);
> +        cursor = qxl_phys2virt(qxl, cmd->u.set.shape, group_id,
> +                               sizeof(QXLCursor));
>          if (!cursor) {
>              return 1;
>          }
> @@ -236,6 +237,7 @@ int qxl_log_command(PCIQXLDevice *qxl, const char *ring, 
> QXLCommandExt *ext)
>  {
>      bool compat = ext->flags & QXL_COMMAND_FLAG_COMPAT;
>      void *data;
> +    size_t datasz;
>      int ret;
>
>      if (!qxl->cmdlog) {
> @@ -249,15 +251,18 @@ int qxl_log_command(PCIQXLDevice *qxl, const char 
> *ring, QXLCommandExt *ext)
>
>      switch (ext->cmd.type) {
>      case QXL_CMD_DRAW:
> +        datasz = compat ? sizeof(QXLCompatDrawable) : sizeof(QXLDrawable);
>          break;
>      case QXL_CMD_SURFACE:
> +        datasz = sizeof(QXLSurfaceCmd);
>          break;
>      case QXL_CMD_CURSOR:
> +        datasz = sizeof(QXLCursorCmd);
>          break;
>      default:
>          goto out;
>      }
> -    data = qxl_phys2virt(qxl, ext->cmd.data, ext->group_id);
> +    data = qxl_phys2virt(qxl, ext->cmd.data, ext->group_id, datasz);
>      if (!data) {
>          return 1;
>      }
> diff --git a/hw/display/qxl-render.c b/hw/display/qxl-render.c
> index ca217004bf..1b0a50c1aa 100644
> --- a/hw/display/qxl-render.c
> +++ b/hw/display/qxl-render.c
> @@ -107,7 +107,8 @@ static void qxl_render_update_area_unlocked(PCIQXLDevice 
> *qxl)
>          qxl->guest_primary.resized = 0;
>          qxl->guest_primary.data = qxl_phys2virt(qxl,
>                                                  
> qxl->guest_primary.surface.mem,
> -                                                MEMSLOT_GROUP_GUEST);
> +                                                MEMSLOT_GROUP_GUEST,
> +                                                sizeof(uint32_t) * width * 
> height);

It looks wrong, I think it should be:

qxl->guest_primary.abs_stride * height * qxl->guest_primary.bytes_pp

>          if (!qxl->guest_primary.data) {
>              goto end;
>          }
> @@ -228,7 +229,7 @@ static void qxl_unpack_chunks(void *dest, size_t size, 
> PCIQXLDevice *qxl,
>          if (offset == size) {
>              return;
>          }
> -        chunk = qxl_phys2virt(qxl, chunk->next_chunk, group_id);
> +        chunk = qxl_phys2virt(qxl, chunk->next_chunk, group_id, bytes);
>          if (!chunk) {
>              return;
>          }
> @@ -295,7 +296,8 @@ fail:
>  /* called from spice server thread context only */
>  int qxl_render_cursor(PCIQXLDevice *qxl, QXLCommandExt *ext)
>  {
> -    QXLCursorCmd *cmd = qxl_phys2virt(qxl, ext->cmd.data, ext->group_id);
> +    QXLCursorCmd *cmd = qxl_phys2virt(qxl, ext->cmd.data, ext->group_id,
> +                                      sizeof(QXLCursorCmd));
>      QXLCursor *cursor;
>      QEMUCursor *c;
>
> @@ -314,7 +316,8 @@ int qxl_render_cursor(PCIQXLDevice *qxl, QXLCommandExt 
> *ext)
>      }
>      switch (cmd->type) {
>      case QXL_CURSOR_SET:
> -        cursor = qxl_phys2virt(qxl, cmd->u.set.shape, ext->group_id);
> +        cursor = qxl_phys2virt(qxl, cmd->u.set.shape, ext->group_id,
> +                               sizeof(QXLCursor));
>          if (!cursor) {
>              return 1;
>          }
> diff --git a/hw/display/qxl.c b/hw/display/qxl.c
> index 5b10f697f1..231d733250 100644
> --- a/hw/display/qxl.c
> +++ b/hw/display/qxl.c
> @@ -274,7 +274,8 @@ static void qxl_spice_monitors_config_async(PCIQXLDevice 
> *qxl, int replay)
>                                            QXL_IO_MONITORS_CONFIG_ASYNC));
>      }
>
> -    cfg = qxl_phys2virt(qxl, qxl->guest_monitors_config, 
> MEMSLOT_GROUP_GUEST);
> +    cfg = qxl_phys2virt(qxl, qxl->guest_monitors_config, MEMSLOT_GROUP_GUEST,
> +                        sizeof(QXLMonitorsConfig));
>      if (cfg != NULL && cfg->count == 1) {
>          qxl->guest_primary.resized = 1;
>          qxl->guest_head0_width  = cfg->heads[0].width;
> @@ -459,7 +460,8 @@ static int qxl_track_command(PCIQXLDevice *qxl, struct 
> QXLCommandExt *ext)
>      switch (le32_to_cpu(ext->cmd.type)) {
>      case QXL_CMD_SURFACE:
>      {
> -        QXLSurfaceCmd *cmd = qxl_phys2virt(qxl, ext->cmd.data, 
> ext->group_id);
> +        QXLSurfaceCmd *cmd = qxl_phys2virt(qxl, ext->cmd.data, ext->group_id,
> +                                           sizeof(QXLSurfaceCmd));
>
>          if (!cmd) {
>              return 1;
> @@ -494,7 +496,8 @@ static int qxl_track_command(PCIQXLDevice *qxl, struct 
> QXLCommandExt *ext)
>      }
>      case QXL_CMD_CURSOR:
>      {
> -        QXLCursorCmd *cmd = qxl_phys2virt(qxl, ext->cmd.data, ext->group_id);
> +        QXLCursorCmd *cmd = qxl_phys2virt(qxl, ext->cmd.data, ext->group_id,
> +                                          sizeof(QXLCursorCmd));
>
>          if (!cmd) {
>              return 1;
> @@ -1456,7 +1459,8 @@ static bool qxl_get_check_slot_offset(PCIQXLDevice 
> *qxl, QXLPHYSICAL pqxl,
>  }
>
>  /* can be also called from spice server thread context */
> -void *qxl_phys2virt(PCIQXLDevice *qxl, QXLPHYSICAL pqxl, int group_id)
> +void *qxl_phys2virt(PCIQXLDevice *qxl, QXLPHYSICAL pqxl, int group_id,
> +                    size_t size)
>  {
>      uint64_t offset;
>      uint32_t slot;
> @@ -1964,7 +1968,7 @@ static void qxl_dirty_surfaces(PCIQXLDevice *qxl)
>          }
>
>          cmd = qxl_phys2virt(qxl, qxl->guest_surfaces.cmds[i],
> -                            MEMSLOT_GROUP_GUEST);
> +                            MEMSLOT_GROUP_GUEST, sizeof(QXLSurfaceCmd));
>          assert(cmd);
>          assert(cmd->type == QXL_SURFACE_CMD_CREATE);
>          qxl_dirty_one_surface(qxl, cmd->u.surface_create.data,
> diff --git a/hw/display/qxl.h b/hw/display/qxl.h
> index 78b3a6c9ba..bf03138ab4 100644
> --- a/hw/display/qxl.h
> +++ b/hw/display/qxl.h
> @@ -153,6 +153,7 @@ OBJECT_DECLARE_SIMPLE_TYPE(PCIQXLDevice, PCI_QXL)
>   * @qxl: QXL device
>   * @phys: physical offset of buffer within the VRAM
>   * @group_id: memory slot group
> + * @size: size of the buffer
>   *
>   * Returns a host pointer to a buffer placed at offset @phys within the
>   * active slot @group_id of the PCI VGA RAM memory region associated with
> @@ -166,7 +167,8 @@ OBJECT_DECLARE_SIMPLE_TYPE(PCIQXLDevice, PCI_QXL)
>   * the incoming ram_addr_t.
>   *
>   */
> -void *qxl_phys2virt(PCIQXLDevice *qxl, QXLPHYSICAL phys, int group_id);
> +void *qxl_phys2virt(PCIQXLDevice *qxl, QXLPHYSICAL phys, int group_id,
> +                    size_t size);
>  void qxl_set_guest_bug(PCIQXLDevice *qxl, const char *msg, ...)
>      G_GNUC_PRINTF(2, 3);
>
> --
> 2.38.1
>
>


-- 
Marc-André Lureau