CVE-2021-47554 vdpa_sim: avoid putting an uninitialized iova_domain
A null pointer dereference in the Linux kernel's vdpa_sim module can cause a system crash when an error occurs during device creation.
- 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-2021-47554?
CVE-2021-47554 is a medium-severity vulnerability in Linux kernel, published on 24 May 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:
vdpa_sim: avoid putting an uninitialized iova_domain
The system will crash if we put an uninitialized iova_domain, this could happen when an error occurs before initializing the iova_domain in vdpasim_create().
BUG: kernel NULL pointer dereference, address: 0000000000000000 ... RIP: 0010:__cpuhp_state_remove_instance+0x96/0x1c0 ... Call Trace: <TASK> put_iova_domain+0x29/0x220 vdpasim_free+0xd1/0x120 [vdpa_sim] vdpa_release_dev+0x21/0x40 [vdpa] device_release+0x33/0x90 kobject_release+0x63/0x160 vdpasim_create+0x127/0x2a0 [vdpa_sim] vdpasim_net_dev_add+0x7d/0xfe [vdpa_sim_net] vdpa_nl_cmd_dev_add_set_doit+0xe1/0x1a0 [vdpa] genl_family_rcv_msg_doit+0x112/0x140 genl_rcv_msg+0xdf/0x1d0 ...
So we must make sure the iova_domain is already initialized before put it.
In addition, we may get the following warning in this case: WARNING: ... drivers/iommu/iova.c:344 iova_cache_put+0x58/0x70
So we must make sure the iova_cache_put() is invoked only if the iova_cache_get() is already invoked. Let's fix it together.
Weakness: CWE-908
Which versions are affected by CVE-2021-47554?
It affects 1 product.
Products include Linux kernel.
How do I fix CVE-2021-47554?
Apply the vendor's patch.
Is CVE-2021-47554 being exploited?
There is no known exploitation of CVE-2021-47554 in the wild and no public exploit code.
Other vulnerabilities in Linux kernel
Sources
Also known as DEBIAN-CVE-2021-47554, UBUNTU-CVE-2021-47554.