diff mbox series

ui/console: fix three double frees in png_save()

Message ID 20220918162308.25191-1-vr_qemu@t-online.de (mailing list archive)
State New, archived
Headers show
Series ui/console: fix three double frees in png_save() | expand

Commit Message

Volker Rümelin Sept. 18, 2022, 4:23 p.m. UTC
The png_destroy_write_struct() function frees all memory used by
libpng. Don't use the glib auto cleanup mechanism to free the
memory allocated by libpng again. For the pixman image, use only the
auto cleanup mechanism and remove the qemu_pixman_image_unref()
function call to prevent another double free.

Resolves: https://gitlab.com/qemu-project/qemu/-/issues/1210
Signed-off-by: Volker Rümelin <vr_qemu@t-online.de>
---
 ui/console.c | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

Comments

Philippe Mathieu-Daudé Sept. 18, 2022, 6:31 p.m. UTC | #1
+Kshitij

On Sun, Sep 18, 2022 at 6:24 PM Volker Rümelin <vr_qemu@t-online.de> wrote:
>
> The png_destroy_write_struct() function frees all memory used by
> libpng. Don't use the glib auto cleanup mechanism to free the
> memory allocated by libpng again. For the pixman image, use only the
> auto cleanup mechanism and remove the qemu_pixman_image_unref()
> function call to prevent another double free.
>
> Resolves: https://gitlab.com/qemu-project/qemu/-/issues/1210
> Signed-off-by: Volker Rümelin <vr_qemu@t-online.de>
> ---
>  ui/console.c | 5 ++---
>  1 file changed, 2 insertions(+), 3 deletions(-)
>
> diff --git a/ui/console.c b/ui/console.c
> index 765892f84f..030e75bc71 100644
> --- a/ui/console.c
> +++ b/ui/console.c
> @@ -304,8 +304,8 @@ static bool png_save(int fd, pixman_image_t *image, Error **errp)
>  {
>      int width = pixman_image_get_width(image);
>      int height = pixman_image_get_height(image);
> -    g_autofree png_struct *png_ptr = NULL;
> -    g_autofree png_info *info_ptr = NULL;
> +    png_struct *png_ptr;
> +    png_info *info_ptr = NULL;

No need to NULL-initialize.

Fixes: 9a0a119a38 ("Added parameter to take screenshot with screendump as PNG")
Tested-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>

>      g_autoptr(pixman_image_t) linebuf =
>                              qemu_pixman_linebuf_create(PIXMAN_a8r8g8b8, width);
>      uint8_t *buf = (uint8_t *)pixman_image_get_data(linebuf);
> @@ -346,7 +346,6 @@ static bool png_save(int fd, pixman_image_t *image, Error **errp)
>          qemu_pixman_linebuf_fill(linebuf, image, width, 0, y);
>          png_write_row(png_ptr, buf);
>      }
> -    qemu_pixman_image_unref(linebuf);
>
>      png_write_end(png_ptr, NULL);
>
> --
> 2.35.3
>
>
diff mbox series

Patch

diff --git a/ui/console.c b/ui/console.c
index 765892f84f..030e75bc71 100644
--- a/ui/console.c
+++ b/ui/console.c
@@ -304,8 +304,8 @@  static bool png_save(int fd, pixman_image_t *image, Error **errp)
 {
     int width = pixman_image_get_width(image);
     int height = pixman_image_get_height(image);
-    g_autofree png_struct *png_ptr = NULL;
-    g_autofree png_info *info_ptr = NULL;
+    png_struct *png_ptr;
+    png_info *info_ptr = NULL;
     g_autoptr(pixman_image_t) linebuf =
                             qemu_pixman_linebuf_create(PIXMAN_a8r8g8b8, width);
     uint8_t *buf = (uint8_t *)pixman_image_get_data(linebuf);
@@ -346,7 +346,6 @@  static bool png_save(int fd, pixman_image_t *image, Error **errp)
         qemu_pixman_linebuf_fill(linebuf, image, width, 0, y);
         png_write_row(png_ptr, buf);
     }
-    qemu_pixman_image_unref(linebuf);
 
     png_write_end(png_ptr, NULL);