REDHAT-BUG-697822
First published: Tue Apr 19 2011(Updated: )
A signedness issue has been found in next_pidmap() function when the "last" parameter is negative as next_pidmap() just quietly accepted whatever "last" pid that was passed in, which is not all that safe when one of the users is /proc. Setting f_pos to negative value when accessing /proc via readdir()/getdents() resulted in sign extension of this value when map pointer was being constructed. This later lead to #GP becasue the final pointer was not cannonical (x86_64). map = &pid_ns->pidmap[(last + 1)/BITS_PER_PAGE]; ffffffff810ac3b4: 48 63 f6 movslq %esi,%rsi <- sign extension (f_pos+-) ffffffff810ac3b7: 81 e2 ff 7f 00 00 and $0x7fff,%edx ffffffff810ac3bd: 48 c1 ee 0f shr $0xf,%rsi ffffffff810ac3c1: 48 c1 e6 04 shl $0x4,%rsi ffffffff810ac3c5: 48 8d 5c 37 08 lea 0x8(%rdi,%rsi,1),%rbx ... if (unlikely(!map->page)) ffffffff810ac3cc: 48 8b 7b 08 mov 0x8(%rbx),%rdi <- #GP Only x86_64 architecture seems to be vulnerable to this particular issue (tested ppc64, s390x, ia64). Reference: <a href="http://groups.google.com/group/fa.linux.kernel/browse_thread/thread/93c1088451fd3522/4a28ecb7f755a88d?#4a28ecb7f755a88d">http://groups.google.com/group/fa.linux.kernel/browse_thread/thread/93c1088451fd3522/4a28ecb7f755a88d?#4a28ecb7f755a88d</a> Upstream commit: <a href="http://git.kernel.org/linus/c78193e9">http://git.kernel.org/linus/c78193e9</a> <a href="http://git.kernel.org/linus/d8bdc59f">http://git.kernel.org/linus/d8bdc59f</a> Acknowledgements: Red Hat would like to thank Robert Swiecki for reporting this issue.
| Affected Software | Affected Version | How to fix |
|---|---|---|
| Red Hat Linux |
Never miss a vulnerability like this again
Sign up to SecAlerts for real-time vulnerability data matched to your software, aggregated from hundreds of sources.
Reference Links
- http://groups.google.com/group/fa.linux.kernel/browse_thread/thread/93c1088451fd3522/4a28ecb7f755a88d?#4a28ecb7f755a88d
- http://git.kernel.org/linus/c78193e9
- http://git.kernel.org/linus/d8bdc59f
- https://rhn.redhat.com/errata/RHSA-2011-0927.html
- https://rhn.redhat.com/errata/RHSA-2011-1189.html
- https://rhn.redhat.com/errata/RHSA-2011-1253.html
- https://access.redhat.com/support/policy/updates/errata/
- https://bugzilla.redhat.com/show_bug.cgi?id=697822
Frequently Asked Questions
What is the severity of REDHAT-BUG-697822?
The severity of REDHAT-BUG-697822 is considered high due to the potential for privilege escalation.
How do I fix REDHAT-BUG-697822?
To fix REDHAT-BUG-697822, upgrade to the latest version of the Red Hat Linux Kernel that includes the related patch.
What systems are affected by REDHAT-BUG-697822?
REDHAT-BUG-697822 affects users running specific versions of the Red Hat Linux Kernel.
What are the implications of REDHAT-BUG-697822?
The implications of REDHAT-BUG-697822 include possible security vulnerabilities when accessing the /proc filesystem.
Is there a workaround for REDHAT-BUG-697822 until a fix is applied?
A temporary workaround for REDHAT-BUG-697822 involves restricting user permissions on /proc until the kernel is updated.
- agent/references
- agent/type
- agent/last-modified-date
- agent/first-publish-date
- collector/redhat-bugzilla
- source/Red Hat
- alias/CVE-2011-1593
- agent/severity
- agent/description
- agent/event
- agent/source
- agent/tags
- agent/softwarecombine
- agent/guess-ai
- agent/software-canonical-lookup
- agent/software-canonical-lookup-request
- vendor/red hat
- canonical/red hat linux