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| author | Javier Martinez Canillas <javierm@redhat.com> | 2022-05-26 22:47:52 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2022-06-09 11:30:39 +0300 |
| commit | d260cad015945d1f4bb9b028a096f648506106a2 (patch) | |
| tree | e8264248414cb46e949bf164d05fb25b45970210 /drivers/video/fbdev | |
| parent | 0198032e52f94f09fb414408bb3d5e10a5b79d59 (diff) | |
| download | linux-d260cad015945d1f4bb9b028a096f648506106a2.tar.xz | |
video: fbdev: vesafb: Fix a use-after-free due early fb_info cleanup
[ Upstream commit acde4003efc16480375543638484d8f13f2e99a3 ]
Commit b3c9a924aab6 ("fbdev: vesafb: Cleanup fb_info in .fb_destroy rather
than .remove") fixed a use-after-free error due the vesafb driver freeing
the fb_info in the .remove handler instead of doing it in .fb_destroy.
This can happen if the .fb_destroy callback is executed after the .remove
callback, since the former tries to access a pointer freed by the latter.
But that change didn't take into account that another possible scenario is
that .fb_destroy is called before the .remove callback. For example, if no
process has the fbdev chardev opened by the time the driver is removed.
If that's the case, fb_info will be freed when unregister_framebuffer() is
called, making the fb_info pointer accessed in vesafb_remove() after that
to no longer be valid.
To prevent that, move the expression containing the info->par to happen
before the unregister_framebuffer() function call.
Fixes: b3c9a924aab6 ("fbdev: vesafb: Cleanup fb_info in .fb_destroy rather than .remove")
Reported-by: Pascal Ernster <dri-devel@hardfalcon.net>
Signed-off-by: Javier Martinez Canillas <javierm@redhat.com>
Tested-by: Pascal Ernster <dri-devel@hardfalcon.net>
Signed-off-by: Helge Deller <deller@gmx.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Diffstat (limited to 'drivers/video/fbdev')
| -rw-r--r-- | drivers/video/fbdev/vesafb.c | 5 |
1 files changed, 3 insertions, 2 deletions
diff --git a/drivers/video/fbdev/vesafb.c b/drivers/video/fbdev/vesafb.c index e25e8de5ff67..929d4775cb4b 100644 --- a/drivers/video/fbdev/vesafb.c +++ b/drivers/video/fbdev/vesafb.c @@ -490,11 +490,12 @@ static int vesafb_remove(struct platform_device *pdev) { struct fb_info *info = platform_get_drvdata(pdev); - /* vesafb_destroy takes care of info cleanup */ - unregister_framebuffer(info); if (((struct vesafb_par *)(info->par))->region) release_region(0x3c0, 32); + /* vesafb_destroy takes care of info cleanup */ + unregister_framebuffer(info); + return 0; } |