Linux Kernel up to 5.15.5 vdpa_sim vdpasim_create null pointer dereference

Summaryinfo

A vulnerability, which was classified as critical, was found in Linux Kernel up to 5.15.5. This vulnerability affects the function vdpasim_create of the component vdpa_sim. Executing a manipulation can lead to null pointer dereference. This vulnerability is registered as CVE-2021-47554. No exploit is available. You should upgrade the affected component.

Detailsinfo

A vulnerability has been found in Linux Kernel up to 5.15.5 and classified as critical. This vulnerability affects the function vdpasim_create of the component vdpa_sim. The manipulation with an unknown input leads to a null pointer dereference vulnerability. The CWE definition for the vulnerability is CWE-476. A NULL pointer dereference occurs when the application dereferences a pointer that it expects to be valid, but is NULL, typically causing a crash or exit. As an impact it is known to affect availability. CVE summarizes:

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: 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.

The advisory is available at git.kernel.org. This vulnerability was named CVE-2021-47554. The exploitation appears to be difficult. Technical details are known, but there is no available exploit.

Upgrading to version 5.15.6 eliminates this vulnerability. Applying the patch e4d58ac67e63/bb93ce4b150d is able to eliminate this problem. The bugfix is ready for download at git.kernel.org. The best possible mitigation is suggested to be upgrading to the latest version.

If you want to get best quality of vulnerability data, you may have to visit VulDB.

Productinfo

Type

• Operating System

Vendor

• Linux

Name

• Kernel

Version

• 5.15.0
• 5.15.1
• 5.15.2
• 5.15.3
• 5.15.4
• 5.15.5

License

• open-source

Website

• Vendor: https://www.kernel.org/

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If you want to get best quality of vulnerability data, you may have to visit VulDB.

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