CVE-2023-53593

Technical Description

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

cifs: Release folio lock on fscache read hit.

Under the current code, when cifs_readpage_worker is called, the call

contract is that the callee should unlock the page. This is documented

in the read_folio section of Documentation/filesystems/vfs.rst as:

> The filesystem should unlock the folio once the read has completed,

> whether it was successful or not.

Without this change, when fscache is in use and cache hit occurs during

a read, the page lock is leaked, producing the following stack on

subsequent reads (via mmap) to the page:

$ cat /proc/3890/task/12864/stack

[<0>] folio_wait_bit_common+0x124/0x350

[<0>] filemap_read_folio+0xad/0xf0

[<0>] filemap_fault+0x8b1/0xab0

[<0>] __do_fault+0x39/0x150

[<0>] do_fault+0x25c/0x3e0

[<0>] __handle_mm_fault+0x6ca/0xc70

[<0>] handle_mm_fault+0xe9/0x350

[<0>] do_user_addr_fault+0x225/0x6c0

[<0>] exc_page_fault+0x84/0x1b0

[<0>] asm_exc_page_fault+0x27/0x30

This requires a re

Remediation

Check the references section for vendor advisories and patches from linux. Update linux_kernel to the latest patched version. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

Affected Products

References