Red Hat Bugzilla – Bug 499541
kernel: proc: avoid information leaks to non-privileged processes [rhel-5.4]
Last modified: 2013-09-29 22:08:11 EDT
Description of problem:
By using the same test as is used for /proc/pid/maps and /proc/pid/smaps, only allow processes that can ptrace() a given process to see information that might be used to bypass address space layout randomization (ASLR). These include eip, esp, wchan, and start_stack in /proc/pid/stat as well as the non-symbolic output from /proc/pid/wchan.
ASLR can be bypassed by sampling eip as shown by the proof-of-concept code at http://code.google.com/p/fuzzyaslr/ As part of a presentation (http://www.cr0.org/paper/to-jt-linux-alsr-leak.pdf) esp and wchan were also noted as possibly usable information leaks as well. The start_stack address also leaks potentially useful information.
Upstream commit: http://git.kernel.org/linus/f83ce3e6b02d5e48b3a43b001390e2b58820389d
Created attachment 342773 [details]
This request was evaluated by Red Hat Product Management for inclusion in a Red
Hat Enterprise Linux maintenance release. Product Management has requested
further review of this request by Red Hat Engineering, for potential
inclusion in a Red Hat Enterprise Linux Update release for currently deployed
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