CVE-2022-49419

Summary

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.

Affected Software

VendorProductVersion RangeStatus
LinuxLinuxf94aa46efaa087ec075c83e4508f943fb5e43977 < 0fac5f8fb1bc2fc4f8714bf5e743c9cc3f547c63affected
LinuxLinuxa1aac13288de2935dc1a9330a93b1ac92f1e2b72 < f605f5558ecc175ec70016a3c15f007cb6386531affected
LinuxLinuxb3c9a924aab61adbc29df110006aa03afe1a78ba < d260cad015945d1f4bb9b028a096f648506106a2affected
LinuxLinuxb3c9a924aab61adbc29df110006aa03afe1a78ba < acde4003efc16480375543638484d8f13f2e99a3affected
LinuxLinux5.15.41 < 5.15.46affected
LinuxLinux5.17.9 < 5.17.14affected
LinuxLinux5.18affected
LinuxLinux0 < 5.18unaffected
LinuxLinux5.15.46 <= 5.15.*unaffected
LinuxLinux5.17.14 <= 5.17.*unaffected
LinuxLinux5.18.3 <= 5.18.*unaffected
LinuxLinux5.19 <= *unaffected

Weaknesses

ADP Enrichment

CISA ADP Vulnrichment

  • SSVC:
  • Exploitation: none
    • Automatable: no
    • Technical Impact: total

References