CVE-2022-48819 tcp: take care of mixed splice()/sendmsg(MSG_ZEROCOPY) case
A Linux kernel TCP vulnerability allows attackers to trigger a warning and potential denial of service by mixing splice and zero-copy send operations.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2022-48819?
CVE-2022-48819 is a medium-severity denial of service vulnerability in Linux kernel, published on 16 Jul 2024. It can only be exploited from the same machine or local network, with no action from the victim.
Official description
In the Linux kernel, the following vulnerability has been resolved:
tcp: take care of mixed splice()/sendmsg(MSG_ZEROCOPY) case
syzbot found that mixing sendpage() and sendmsg(MSG_ZEROCOPY) calls over the same TCP socket would again trigger the infamous warning in inet_sock_destruct()
WARN_ON(sk_forward_alloc_get(sk));
While Talal took into account a mix of regular copied data and MSG_ZEROCOPY one in the same skb, the sendpage() path has been forgotten.
We want the charging to happen for sendpage(), because pages could be coming from a pipe. What is missing is the downgrading of pure zerocopy status to make sure sk_forward_alloc will stay synced.
Add tcp_downgrade_zcopy_pure() helper so that we can use it from the two callers.
Which versions are affected by CVE-2022-48819?
It affects 1 product.
Products include Linux kernel.
How do I fix CVE-2022-48819?
Apply the vendor's patch.
Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.
Is CVE-2022-48819 being exploited?
There is no known exploitation of CVE-2022-48819 in the wild and no public exploit code.
Other vulnerabilities in Linux kernel
Sources
Also known as DEBIAN-CVE-2022-48819, GHSA-9pvc-v9gg-mq34, UBUNTU-CVE-2022-48819.