7.8

CVE-2022-49419

video: fbdev: vesafb: Fix a use-after-free due early fb_info cleanup

In the Linux kernel, the following vulnerability has been resolved:

video: fbdev: vesafb: Fix a use-after-free due early fb_info cleanup

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.
Daten sind bereitgestellt durch National Vulnerability Database (NVD)
Linux ≫ Linux Kernel Version >= 5.15.41 < 5.15.46
Linux ≫ Linux Kernel Version >= 5.17.9 < 5.17.14
Linux ≫ Linux Kernel Version >= 5.18 < 5.18.3
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EPSS Metriken
Typ Quelle Score Percentile
EPSS FIRST.org 0.25% 0.164
CVSS Metriken
Quelle Base Score Exploit Score Impact Score Vector String
134c704f-9b21-4f2e-91b3-4a467353bcc0 7.8 1.8 5.9
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
CWE-416 Use After Free

The product reuses or references memory after it has been freed. At some point afterward, the memory may be allocated again and saved in another pointer, while the original pointer references a location somewhere within the new allocation. Any operations using the original pointer are no longer valid because the memory "belongs" to the code that operates on the new pointer.

https://git.kernel.org/stable/c/0fac5f8fb1bc2fc4f8714bf5e743c9cc3f547c63
Patch
https://git.kernel.org/stable/c/acde4003efc16480375543638484d8f13f2e99a3
Patch
https://git.kernel.org/stable/c/d260cad015945d1f4bb9b028a096f648506106a2
Patch
https://git.kernel.org/stable/c/f605f5558ecc175ec70016a3c15f007cb6386531
Patch