Vulnerability CVE-2022-48872

Vulnerability CVE-2022-48872

Published: 2024-08-21

Description:

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

misc: fastrpc: Fix use-after-free race condition for maps

It is possible that in between calling fastrpc_map_get() until
map->fl->lock is taken in fastrpc_free_map(), another thread can call
fastrpc_map_lookup() and get a reference to a map that is about to be
deleted.

Rewrite fastrpc_map_get() to only increase the reference count of a map
if it's non-zero. Propagate this to callers so they can know if a map is
about to be deleted.

Fixes this warning:
refcount_t: addition on 0; use-after-free.
WARNING: CPU: 5 PID: 10100 at lib/refcount.c:25 refcount_warn_saturate
...
Call trace:
refcount_warn_saturate
[fastrpc_map_get inlined]
[fastrpc_map_lookup inlined]
fastrpc_map_create
fastrpc_internal_invoke
fastrpc_device_ioctl
__arm64_sys_ioctl
invoke_syscall

References:

https://git.kernel.org/stable/c/556dfdb226ce1e5231d8836159b23f8bb0395bf4

https://git.kernel.org/stable/c/b171d0d2cf1b8387c72c8d325c5d5746fa271e39

https://git.kernel.org/stable/c/61a0890cb95afec5c8a2f4a879de2b6220984ef1

https://git.kernel.org/stable/c/079c78c68714f7d8d58e66c477b0243b31806907

https://git.kernel.org/stable/c/96b328d119eca7563c1edcc4e1039a62e6370ecb

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