Vulnerability CVE-2023-52757

Vulnerability CVE-2023-52757

Published: 2024-05-21

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

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

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