Description (CNA)
In the Linux kernel, the following vulnerability has been resolved: media: as102: fix to not free memory after the device is registered in as102_usb_probe() In as102_usb driver, the following race condition occurs: ``` CPU0 CPU1 as102_usb_probe() kzalloc(); // alloc as102_dev_t .... usb_register_dev(); fd = sys_open("/path/to/dev"); // open as102 fd .... usb_deregister_dev(); .... kfree(); // free as102_dev_t .... sys_close(fd); as102_release() // UAF!! as102_usb_release() kfree(); // DFB!! ``` When a USB character device registered with usb_register_dev() is later unregistered (via usb_deregister_dev() or disconnect), the device node is removed so new open() calls fail. However, file descriptors that are already open do not go away immediately: they remain valid until the last reference is dropped and the driver's .release() is invoked. In as102, as102_usb_probe() calls usb_register_dev() and then, on an error path, does usb_deregister_dev() and frees as102_dev_t right away. If userspace raced a successful open() before the deregistration, that open FD will later hit as102_release() --> as102_usb_release() and access or free as102_dev_t again, occur a race to use-after-free and double-free vuln. The fix is to never kfree(as102_dev_t) directly once usb_register_dev() has succeeded. After deregistration, defer freeing memory to .release(). In other words, let release() perform the last kfree when the final open FD is closed.
Affected (CNA)
| Vendor / product | Versions |
|---|---|
| Linux / Linux | affected cd19f7d3e39b3160595d56bb3e3a2bf4f7f4669c before 0d36653a3a821e5a974798adb347b3ea09332914; affected cd19f7d3e39b3160595d56bb3e3a2bf4f7f4669c before 25d500cf391e384356a612b85cf60b353ad3cd0c; affected cd19f7d3e39b3160595d56bb3e3a2bf4f7f4669c before 07ceb444c8f627cf863864d4274b5a77769725ed; affected cd19f7d3e39b3160595d56bb3e3a2bf4f7f4669c before cb8092038e95dc1113a68e63762de40fff61ba71; affected cd19f7d3e39b3160595d56bb3e3a2bf4f7f4669c before 582fbecb3756330006fe1950762412a68c2cacd2; affected cd19f7d3e39b3160595d56bb3e3a2bf4f7f4669c before 09e9206008b887aa553733bd915d73131071a086; affected cd19f7d3e39b3160595d56bb3e3a2bf4f7f4669c before 2eeae47a438694408189138048a786be99954032; affected cd19f7d3e39b3160595d56bb3e3a2bf4f7f4669c before 7e5aedf6059cba2a669d86caeaf5a51f33ec85a1; affected cd19f7d3e39b3160595d56bb3e3a2bf4f7f4669c before 8bd29dbe03fc5b0f039ab2395ff37b64236d2f0c |
| Linux / Linux | affected 3.14; unaffected 0 before 3.14; unaffected 5.10.258 through 5.10.*; unaffected 5.15.209 through 5.15.*; unaffected 6.1.175 through 6.1.*; unaffected 6.6.136 through 6.6.*; unaffected 6.12.83 through 6.12.*; unaffected 6.18.24 through 6.18.*; unaffected 6.19.14 through 6.19.*; unaffected 7.0.1 through 7.0.*; unaffected 7.1 through * |
CWE
No CWE identifiers supplied.
References
- https://git.kernel.org/stable/c/0d36653a3a821e5a974798adb347b3ea09332914
- https://git.kernel.org/stable/c/25d500cf391e384356a612b85cf60b353ad3cd0c
- https://git.kernel.org/stable/c/07ceb444c8f627cf863864d4274b5a77769725ed
- https://git.kernel.org/stable/c/cb8092038e95dc1113a68e63762de40fff61ba71
- https://git.kernel.org/stable/c/582fbecb3756330006fe1950762412a68c2cacd2
- https://git.kernel.org/stable/c/09e9206008b887aa553733bd915d73131071a086
- https://git.kernel.org/stable/c/2eeae47a438694408189138048a786be99954032
- https://git.kernel.org/stable/c/7e5aedf6059cba2a669d86caeaf5a51f33ec85a1
- https://git.kernel.org/stable/c/8bd29dbe03fc5b0f039ab2395ff37b64236d2f0c