CVE-2011-2491

The Network Lock Manager (NLM) protocol implementation in the NFS client functionality in the Linux kernel before 3.0 allows local users to cause a denial of service (system hang) via a LOCK_UN flock system call.

Weakness

The product does not properly control the allocation and maintenance of a limited resource.

Affected Software

Potential Mitigations

• Mitigation of resource exhaustion attacks requires that the target system either:

• The first of these solutions is an issue in itself though, since it may allow attackers to prevent the use of the system by a particular valid user. If the attacker impersonates the valid user, they may be able to prevent the user from accessing the server in question.

• The second solution is simply difficult to effectively institute – and even when properly done, it does not provide a full solution. It simply makes the attack require more resources on the part of the attacker.

Related Attack Patterns

• https://cwe.mitre.org/data/definitions/147.html
• https://cwe.mitre.org/data/definitions/227.html
• https://cwe.mitre.org/data/definitions/492.html

References

• http://ftp.osuosl.org/pub/linux/kernel/v3.0/ChangeLog-3.0
• http://git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git%3Ba=commit%3Bh=0b760113a3a155269a3fba93a409c640031dd68f
• http://rhn.redhat.com/errata/RHSA-2011-1212.html
• http://www.openwall.com/lists/oss-security/2011/06/23/6
• https://bugzilla.redhat.com/show_bug.cgi?id=709393
• https://github.com/torvalds/linux/commit/0b760113a3a155269a3fba93a409c640031dd68f
• http://ftp.osuosl.org/pub/linux/kernel/v3.0/ChangeLog-3.0
• http://git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git%3Ba=commit%3Bh=0b760113a3a155269a3fba93a409c640031dd68f
• http://rhn.redhat.com/errata/RHSA-2011-1212.html
• http://www.openwall.com/lists/oss-security/2011/06/23/6
• https://bugzilla.redhat.com/show_bug.cgi?id=709393
• https://github.com/torvalds/linux/commit/0b760113a3a155269a3fba93a409c640031dd68f