Vulnerability CVE-2023-52566
Published: 2024-03-02

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

nilfs2: fix potential use after free in nilfs_gccache_submit_read_data()

In nilfs_gccache_submit_read_data(), brelse(bh) is called to drop the
reference count of bh when the call to nilfs_dat_translate() fails. If
the reference count hits 0 and its owner page gets unlocked, bh may be
freed. However, bh->b_page is dereferenced to put the page after that,
which may result in a use-after-free bug. This patch moves the release
operation after unlocking and putting the page.

NOTE: The function in question is only called in GC, and in combination
with current userland tools, address translation using DAT does not occur
in that function, so the code path that causes this issue will not be
executed. However, it is possible to run that code path by intentionally
modifying the userland GC library or by calling the GC ioctl directly.

[konishi.ryusuke@gmail.com: NOTE added to the commit log]

 References:
https://git.kernel.org/stable/c/fb1084e63ee56958b0a56e17a50a4fd86445b9c1
https://git.kernel.org/stable/c/bb61224f6abc8e71bfdf06d7c984e23460875f5b
https://git.kernel.org/stable/c/193b5a1c6c67c36b430989dc063fe7ea4e200a33
https://git.kernel.org/stable/c/7130a87ca32396eb9bf48b71a2d42259ae44c6c7
https://git.kernel.org/stable/c/3936e8714907cd55e37c7cc50e50229e4a9042e8
https://git.kernel.org/stable/c/980663f1d189eedafd18d80053d9cf3e2ceb5c8c
https://git.kernel.org/stable/c/28df4646ad8b433340772edc90ca709cdefc53e2
https://git.kernel.org/stable/c/7ee29facd8a9c5a26079148e36bcf07141b3a6bc
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