Description

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

smb: client: fix potential deadlock when releasing mids

All release_mid() callers seem to hold a reference of @mid so there is
no need to call kref_put(&mid->refcount, __release_mid) under
@server->mid_lock spinlock. If they don't, then an use-after-free bug
would have occurred anyways.

By getting rid of such spinlock also fixes a potential deadlock as
shown below

CPU 0 CPU 1
------------------------------------------------------------------
cifs_demultiplex_thread() cifs_debug_data_proc_show()
release_mid()
spin_lock(&server->mid_lock);
spin_lock(&cifs_tcp_ses_lock)
spin_lock(&server->mid_lock)
__release_mid()
smb2_find_smb_tcon()
spin_lock(&cifs_tcp_ses_lock) *deadlock*

Classification

CVE ID: CVE-2023-52757

Affected Products

Vendor: Linux

Product: Linux

Exploit Prediction Scoring System (EPSS)

EPSS Score: 0.04% (probability of being exploited)

EPSS Percentile: 5.06% (scored less or equal to compared to others)

EPSS Date: 2025-02-03 (when was this score calculated)

References

https://git.kernel.org/stable/c/9eb44db68c5b7f5aa22b8fc7de74a3e2e08d1f29
https://git.kernel.org/stable/c/b9bb9607b1fc12fca51f5632da25b36975f599bf
https://git.kernel.org/stable/c/c1a5962f1462b64fe7b69f20a4b6af8067bc2d26
https://git.kernel.org/stable/c/e6322fd177c6885a21dd4609dc5e5c973d1a2eb7

Timeline