Overview
About vulnerability
In the Linux kernel, the following vulnerability has been resolved:
vhost_vdpa: assign irq bypass producer token correctly
We used to call irq_bypass_unregister_producer() in vhost_vdpa_setup_vq_irq() which is problematic as we don’t know if the token pointer is still valid or not.
Actually, we use the eventfd_ctx as the token so the life cycle of the token should be bound to the VHOST_SET_VRING_CALL instead of vhost_vdpa_setup_vq_irq() which could be called by set_status().
Fixing this by setting up irq bypass producer’s token when handling VHOST_SET_VRING_CALL and un-registering the producer before calling vhost_vring_ioctl() to prevent a possible use after free as eventfd could have been released in vhost_vring_ioctl(). And such registering and unregistering will only be done if DRIVER_OK is set.
Details
- Affected product:
- AlmaLinux 9.2 ESU
- Affected packages:
- kernel @ 5.14.0
In the Linux kernel, the following vulnerability has been resolved:
vhost_vdpa: assign irq bypass producer token correctly
We used to call irq_bypass_unregister_producer() in vhost_vdpa_setup_vq_irq() which is problematic as we don’t know if the token pointer is still valid or not.
Actually, we use the eventfd_ctx as the token so the life cycle of the token should be bound to the VHOST_SET_VRING_CALL instead of vhost_vdpa_setup_vq_irq() which could be called by set_status().
Fixing this by setting up irq bypass producer’s token when handling VHOST_SET_VRING_CALL and un-registering the producer before calling vhost_vring_ioctl() to prevent a possible use after free as eventfd could have been released in vhost_vring_ioctl(). And such registering and unregistering will only be done if DRIVER_OK is set.