7.8

CVE-2022-50219

bpf: Fix KASAN use-after-free Read in compute_effective_progs

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

bpf: Fix KASAN use-after-free Read in compute_effective_progs

Syzbot found a Use After Free bug in compute_effective_progs().
The reproducer creates a number of BPF links, and causes a fault
injected alloc to fail, while calling bpf_link_detach on them.
Link detach triggers the link to be freed by bpf_link_free(),
which calls __cgroup_bpf_detach() and update_effective_progs().
If the memory allocation in this function fails, the function restores
the pointer to the bpf_cgroup_link on the cgroup list, but the memory
gets freed just after it returns. After this, every subsequent call to
update_effective_progs() causes this already deallocated pointer to be
dereferenced in prog_list_length(), and triggers KASAN UAF error.

To fix this issue don't preserve the pointer to the prog or link in the
list, but remove it and replace it with a dummy prog without shrinking
the table. The subsequent call to __cgroup_bpf_detach() or
__cgroup_bpf_detach() will correct it.
Daten sind bereitgestellt durch National Vulnerability Database (NVD)
Linux ≫ Linux Kernel Version >= 5.7 < 5.10.138
Linux ≫ Linux Kernel Version >= 5.11 < 5.15.61
Linux ≫ Linux Kernel Version >= 5.16 < 5.18.18
Linux ≫ Linux Kernel Version >= 5.19 < 5.19.2
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Zu dieser CVE wurde keine Warnung gefunden.
EPSS Metriken
Typ Quelle Score Percentile
EPSS FIRST.org 0.19% 0.091
CVSS Metriken
Quelle Base Score Exploit Score Impact Score Vector String
nvd@nist.gov 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 Any operations using the original pointer are no longer valid because the memory "belongs" to the code that operates on the new pointer.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/3527e3cbb84d8868c4d4e91ba55915f96d39ec3d
Patch
https://git.kernel.org/stable/c/1f8ca9c40e6222ce431e9ba5dae3cccce8ef9443
Patch
https://git.kernel.org/stable/c/6336388715afa419cc97d0255bda3bba1b96b7ca
Patch
https://git.kernel.org/stable/c/be001f9da71eaa3b61e186fb88bde3279728bdca
Patch
https://git.kernel.org/stable/c/4c46091ee985ae84c60c5e95055d779fcd291d87
Patch