Description

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

SUNRPC: Fix RPC client cleaned up the freed pipefs dentries

RPC client pipefs dentries cleanup is in separated rpc_remove_pipedir()
workqueue,which takes care about pipefs superblock locking.
In some special scenarios, when kernel frees the pipefs sb of the
current client and immediately alloctes a new pipefs sb,
rpc_remove_pipedir function would misjudge the existence of pipefs
sb which is not the one it used to hold. As a result,
the rpc_remove_pipedir would clean the released freed pipefs dentries.

To fix this issue, rpc_remove_pipedir should check whether the
current pipefs sb is consistent with the original pipefs sb.

This error can be catched by KASAN:
=========================================================
[ 250.497700] BUG: KASAN: slab-use-after-free in dget_parent+0x195/0x200
[ 250.498315] Read of size 4 at addr ffff88800a2ab804 by task kworker/0:18/106503
[ 250.500549] Workqueue: events rpc_free_client_work
[ 250.501001] Call Trace:
[ 250.502880] kasan_report+0xb6/0xf0
[ 250.503209] ? dget_parent+0x195/0x200
[ 250.503561] dget_parent+0x195/0x200
[ 250.503897] ? __pfx_rpc_clntdir_depopulate+0x10/0x10
[ 250.504384] rpc_rmdir_depopulate+0x1b/0x90
[ 250.504781] rpc_remove_client_dir+0xf5/0x150
[ 250.505195] rpc_free_client_work+0xe4/0x230
[ 250.505598] process_one_work+0x8ee/0x13b0
...
[ 22.039056] Allocated by task 244:
[ 22.039390] kasan_save_stack+0x22/0x50
[ 22.03...

Classification

CVE ID: CVE-2023-52803

Affected Products

Vendor: Linux

Product: Linux

Exploit Prediction Scoring System (EPSS)

EPSS Score: 0.04% (probability of being exploited)

EPSS Percentile: 15.26% (scored less or equal to compared to others)

EPSS Date: 2025-02-04 (when was this score calculated)

References

https://git.kernel.org/stable/c/17866066b8ac1cc38fb449670bc15dc9fee4b40a
https://git.kernel.org/stable/c/7d61d1da2ed1f682c41cae0c8d4719cdaccee5c5
https://git.kernel.org/stable/c/dedf2a0eb9448ae73b270743e6ea9b108189df46
https://git.kernel.org/stable/c/194454afa6aa9d6ed74f0c57127bc8beb27c20df
https://git.kernel.org/stable/c/7749fd2dbef72a52b5c9ffdbf877691950ed4680
https://git.kernel.org/stable/c/1cdb52ffd6600a37bd355d8dce58ecd03e55e618
https://git.kernel.org/stable/c/cc2e7ebbeb1d0601f7f3c8d93b78fcc03a95e44a
https://git.kernel.org/stable/c/bfca5fb4e97c46503ddfc582335917b0cc228264

Timeline