Bug 572007 (CVE-2010-0729) - CVE-2010-0729 kernel: ia64: ptrace: peek_or_poke requests miss ptrace_check_attach()
Summary: CVE-2010-0729 kernel: ia64: ptrace: peek_or_poke requests miss ptrace_check_a...
Alias: CVE-2010-0729
Product: Security Response
Classification: Other
Component: vulnerability
Version: unspecified
Hardware: ia64
OS: Linux
Target Milestone: ---
Assignee: Red Hat Product Security
QA Contact:
Depends On: 567321 572008 572009
TreeView+ depends on / blocked
Reported: 2010-03-10 00:20 UTC by Eugene Teo (Security Response)
Modified: 2021-11-12 20:04 UTC (History)
10 users (show)

Fixed In Version:
Doc Type: Bug Fix
Doc Text:
Clone Of:
Last Closed: 2015-08-24 16:05:00 UTC

Attachments (Terms of Use)

System ID Private Priority Status Summary Last Updated
Red Hat Product Errata RHSA-2010:0394 0 normal SHIPPED_LIVE Important: kernel security, bug fix, and enhancement update 2010-05-05 13:05:05 UTC

Description Eugene Teo (Security Response) 2010-03-10 00:20:05 UTC
(Internal git) Commit c31d1f3f363a5c3b6dbd4d6daa36fa0f4273e948 "a64: fix deadlock in ia64 sys_ptrace" moved ptrace_check_attach() from find_thread_for_addr() to tasklist-is-not-held area. However it introduced other problems.

In the likely case, when rbs_child == child, ptrace_check_attach() is never called. Otherwise we do ptrace_check_attach(rbs_child) twice. This means that any peek/poke request can silently fail and fool the tracer.

With this patch the logic is

	if (rbs_child != child) {
		// we should use rbs_child ...
		if (!ptrace_check_attach(rbs_child))
			child = rbs_child;

		// but if check_attach() fails we continue to
		// use child, we are doing as well as we can.

To simplify the error-handling and the logic, this patch changes the code to detect the likely rbs_child == child case earlier, right after find_thread_for_addr().

This only affects Red Hat Enterprise Linux 4.

Comment 5 Eugene Teo (Security Response) 2010-03-10 00:31:56 UTC
From Oleg, the problem is, ptrace_check_attach() also verifies the caller is the tracer and thus it have the rights to do "anything it wants" with the tracee.

But since ptrace_check_attach() can be missed, any user can do ptrace() on any target even without PTRACE_ATTACH.

Comment 6 errata-xmlrpc 2010-05-05 13:05:12 UTC
This issue has been addressed in following products:

  Red Hat Enterprise Linux 4

Via RHSA-2010:0394 https://rhn.redhat.com/errata/RHSA-2010-0394.html

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