CVE-2023-52699 Information

May 20, 2024 cve

Description

In the Linux kernel the following vulnerability has been resolved:

sysv: don’t call sb_bread() with pointers_lock held

syzbot is reporting sleep in atomic context in SysV filesystem [1] for sb_bread() is called with rw_spinlock held.

A \write_lock(&pointers_lock) => read_lock(&pointers_lock) deadlock\ bug and a \sb_bread() with write_lock(&pointers_lock)\ bug were introduced by \Replace BKL for chain locking with sysvfs-private rwlock\ in Linux 2.5.12.

Then [PATCH] err1-40: sysvfs locking fix\ in Linux 2.6.8 fixed the former bug by moving pointers_lock lock to the callers but instead introduced a \sb_bread() with read_lock(&pointers_lock)\ bug (which made this problem easier to hit).

Al Viro suggested that why not to do like get_branch()/get_block()/ find_shared() in Minix filesystem does. And doing like that is almost a revert of [PATCH] err1-40: sysvfs locking fix\ except that get_branch() from with find_shared() is called without write_lock(&pointers_lock).

Reference

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