A flaw was found in the way the Linux kernel's floppy driver handled user space provided data in certain error code paths while processing FDRAWCMD IOCTL commands. A local user with write access to /dev/fdX could use this flaw to free (using the kfree() function) arbitrary kernel memory. (CVE-2014-1737, Important) It was found that the Linux kernel's floppy driver leaked internal kernel memory addresses to user space during the processing of the FDRAWCMD IOCTL command. A local user with write access to /dev/fdX could use this flaw to obtain information about the kernel heap arrangement. (CVE-2014-1738, Low) Note: A local user with write access to /dev/fdX could use these two flaws (CVE-2014-1737 in combination with CVE-2014-1738) to escalate their privileges on the system.

It was found that espfix funcionality (when returning to userspace with a 16 bit stack, the CPU will not restore the high word of esp for us on executing iret and thus potentially leaks kernel addresses; espfix fixes this) does not work for 32-bit KVM paravirt guests.

A local unprivileged user could potentially use this flaw to leak kernel stack addresses.

Proposed upstream patch: http://www.spinics.net/lists/kvm/msg111458.html

Acknowledgements:

Red Hat would like to thank Andy Lutomirski for reporting this issue.

A flaw was found in the way the Linux kernel's Crypto subsystem handled automatic loading of kernel modules. A local user could use this flaw to load any installed kernel module, and thus increase the attack surface of the running kernel.

Last updated 24 July 2024