FreeBSD VuXML: Documenting security issues in FreeBSD and the FreeBSD Ports Collection

qemu and xen-tools -- denial of service vulnerabilities in AMD PC-Net II NIC support

Affected packages
qemu < 2.5.0
qemu-devel < 2.5.0
qemu-sbruno < 2.5.50.g20151224
qemu-user-static < 2.5.50.g20151224
xen-tools < 4.5.2_1

Details

VuXML ID 405446f4-b1b3-11e5-9728-002590263bf5
Discovery 2015-11-30
Entry 2016-01-03
Modified 2016-01-06

Prasad J Pandit, Red Hat Product Security Team, reports:

Qemu emulator built with the AMD PC-Net II Ethernet Controller support is vulnerable to a heap buffer overflow flaw. While receiving packets in the loopback mode, it appends CRC code to the receive buffer. If the data size given is same as the receive buffer size, the appended CRC code overwrites 4 bytes beyond this 's->buffer' array.

A privileged(CAP_SYS_RAWIO) user inside guest could use this flaw to crash the Qemu instance resulting in DoS or potentially execute arbitrary code with privileges of the Qemu process on the host.

The AMD PC-Net II emulator(hw/net/pcnet.c), while receiving packets from a remote host(non-loopback mode), fails to validate the received data size, thus resulting in a buffer overflow issue. It could potentially lead to arbitrary code execution on the host, with privileges of the Qemu process. It requires the guest NIC to have larger MTU limit.

A remote user could use this flaw to crash the guest instance resulting in DoS or potentially execute arbitrary code on a remote host with privileges of the Qemu process.

References

CVE Name CVE-2015-7504
CVE Name CVE-2015-7512
URL http://git.qemu.org/?p=qemu.git;a=commit;h=837f21aacf5a714c23ddaadbbc5212f9b661e3f7
URL http://git.qemu.org/?p=qemu.git;a=commit;h=8b98a2f07175d46c3f7217639bd5e03f2ec56343
URL http://www.openwall.com/lists/oss-security/2015/11/30/2
URL http://www.openwall.com/lists/oss-security/2015/11/30/3
URL http://xenbits.xen.org/xsa/advisory-162.html
URL https://github.com/seanbruno/qemu-bsd-user/commit/837f21aacf5a714c23ddaadbbc5212f9b661e3f7
URL https://github.com/seanbruno/qemu-bsd-user/commit/8b98a2f07175d46c3f7217639bd5e03f2ec56343