diff options
| author | Daniel Vetter <daniel.vetter@ffwll.ch> | 2022-05-06 00:04:13 +0200 |
|---|---|---|
| committer | Javier Martinez Canillas <javierm@redhat.com> | 2022-05-06 09:21:20 +0200 |
| commit | 89bfd4017e58faaf70411555e7f508495114e90b (patch) | |
| tree | f9f73d58ba65664f9d8774892f0aade0f9870610 /drivers/video/fbdev/core | |
| parent | 135332f34ba2662bc1e32b5c612e06a8cc41a053 (diff) | |
fbdev: Prevent possible use-after-free in fb_release()
Most fbdev drivers have issues with the fb_info lifetime, because call to
framebuffer_release() from their driver's .remove callback, rather than
doing from fbops.fb_destroy callback.
Doing that will destroy the fb_info too early, while references to it may
still exist, leading to a use-after-free error.
To prevent this, check the fb_info reference counter when attempting to
kfree the data structure in framebuffer_release(). That will leak it but
at least will prevent the mentioned error.
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Signed-off-by: Javier Martinez Canillas <javierm@redhat.com>
Reviewed-by: Thomas Zimmermann <tzimmermann@suse.de>
Link: https://patchwork.freedesktop.org/patch/msgid/20220505220413.365977-1-javierm@redhat.com
Diffstat (limited to 'drivers/video/fbdev/core')
| -rw-r--r-- | drivers/video/fbdev/core/fbsysfs.c | 4 |
1 files changed, 4 insertions, 0 deletions
diff --git a/drivers/video/fbdev/core/fbsysfs.c b/drivers/video/fbdev/core/fbsysfs.c index 26892940c213..82e31a2d845e 100644 --- a/drivers/video/fbdev/core/fbsysfs.c +++ b/drivers/video/fbdev/core/fbsysfs.c @@ -80,6 +80,10 @@ void framebuffer_release(struct fb_info *info) { if (!info) return; + + if (WARN_ON(refcount_read(&info->count))) + return; + kfree(info->apertures); kfree(info); } |