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

FreeBSD -- Kernel stack disclosure in Linux compatibility layer

Affected packages
10.3 <= FreeBSD-kernel < 10.3_4
10.2 <= FreeBSD-kernel < 10.2_18
10.1 <= FreeBSD-kernel < 10.1_35
9.3 <= FreeBSD-kernel < 9.3_43

Details

VuXML ID 7c5d64dd-600a-11e6-a6c3-14dae9d210b8
Discovery 2016-05-31
Entry 2016-08-11

Problem Description:

The implementation of the TIOCGSERIAL ioctl(2) does not clear the output struct before copying it out to userland.

The implementation of the Linux sysinfo() system call does not clear the output struct before copying it out to userland.

Impact:

An unprivileged user can read a portion of uninitialised kernel stack data, which may contain sensitive information, such as the stack guard, portions of the file cache or terminal buffers, which an attacker might leverage to obtain elevated privileges.

References

FreeBSD Advisory SA-16:20.linux