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2010

Making Linux Protection Mechanisms Egalitarian with UserFS

9 years 7 months ago
Making Linux Protection Mechanisms Egalitarian with UserFS
UserFS provides egalitarian OS protection mechanisms in Linux. UserFS allows any user--not just the system administrator--to allocate Unix user IDs, to use chroot, and to set up firewall rules in order to confine untrusted code. One key idea in UserFS is representing user IDs as files in a /proc-like file system, thus allowing applications to manage user IDs like any other files, by setting permissions and passing file descriptors over Unix domain sockets. UserFS addresses several challenges in making user IDs egalitarian, including accountability, resource allocation, persistence, and UID reuse. We have ported several applications to take advantage of UserFS; by changing just tens to hundreds of lines of code, we prevented attackers from exploiting application-level vulnerabilities, such as code injection or missing ACL checks in a PHP-based wiki application. Implementing UserFS requires minimal changes to the Linux kernel--a single 3,000-line kernel module--and incurs no performance...
Taesoo Kim, Nickolai Zeldovich
Added 15 Feb 2011
Updated 15 Feb 2011
Type Journal
Year 2010
Where USS
Authors Taesoo Kim, Nickolai Zeldovich
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