CVE-2023-52699 sysv: don't call sb_bread() with pointers_lock held
A race condition in the Linux kernel SysV filesystem causes a deadlock when sb_bread() is called with a lock held, leading to denial of service.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2023-52699?
CVE-2023-52699 is a medium-severity vulnerability in Debian Debian Linux, published on 19 May 2024. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official 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).
Weakness: CWE-667
Which versions are affected by CVE-2023-52699?
It affects 2 products.
Products include Debian Debian Linux, Linux kernel.
How do I fix CVE-2023-52699?
Apply the vendor's patch.
Is CVE-2023-52699 being exploited?
There is no known exploitation of CVE-2023-52699 in the wild and no public exploit code.
Other vulnerabilities in Debian Debian Linux
Sources
Also known as BELL-CVE-2023-52699, DEBIAN-CVE-2023-52699, GHSA-29pq-gr25-8674, UBUNTU-CVE-2023-52699.