Ubuntu Security Notice 1529-1 - A flaw was discovered in the Linux kernel's macvtap device driver, which is used in KVM (Kernel-based Virtual Machine) to create a network bridge between host and guest. A privileged user in a guest could exploit this flaw to crash the host, if the vhost_net module is loaded with the experimental_zcopytx option enabled. An error was discovered in the Linux kernel's network TUN/TAP device implementation. A local user with access to the TUN/TAP interface (which is not available to unprivileged users until granted by a root user) could exploit this flaw to crash the system or potential gain administrative privileges. Various other issues were also addressed.
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Ubuntu Security Notice 1514-1 - A flaw was discovered in the Linux kernel's macvtap device driver, which is used in KVM (Kernel-based Virtual Machine) to create a network bridge between host and guest. A privileged user in a guest could exploit this flaw to crash the host, if the vhost_net module is loaded with the experimental_zcopytx option enabled. An error was discovered in the Linux kernel's network TUN/TAP device implementation. A local user with access to the TUN/TAP interface (which is not available to unprivileged users until granted by a root user) could exploit this flaw to crash the system or potential gain administrative privileges. Various other issues were also addressed.
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Red Hat Security Advisory 2012-0743-01 - The kernel packages contain the Linux kernel, the core of any Linux operating system. A local, unprivileged user could use an integer overflow flaw in drm_mode_dirtyfb_ioctl() to cause a denial of service or escalate their privileges. A buffer overflow flaw was found in the macvtap device driver, used for creating a bridged network between the guest and the host in KVM environments. A privileged guest user in a KVM guest could use this flaw to crash the host. Note: This issue only affected hosts that have the vhost_net module loaded with the experimental_zcopytx module option enabled, and that also have macvtap configured for at least one guest.
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