CVE-2011-1082

fs/eventpoll.c in the Linux kernel before 2.6.38 places epoll file descriptors within other epoll data structures without properly checking for (1) closed loops or (2) deep chains, which allows local users to cause a denial of service (deadlock or stack memory consumption) via a crafted application that makes epoll_create and epoll_ctl system calls.

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://git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git%3Ba=commit%3Bh=22bacca48a1755f79b7e0f192ddb9fbb7fc6e64e
• http://openwall.com/lists/oss-security/2011/03/02/1
• http://openwall.com/lists/oss-security/2011/03/02/2
• http://www.kernel.org/pub/linux/kernel/v2.6/ChangeLog-2.6.38
• https://bugzilla.redhat.com/show_bug.cgi?id=681575
• https://lkml.org/lkml/2011/2/5/220
• http://git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git%3Ba=commit%3Bh=22bacca48a1755f79b7e0f192ddb9fbb7fc6e64e
• http://openwall.com/lists/oss-security/2011/03/02/1
• http://openwall.com/lists/oss-security/2011/03/02/2
• http://www.kernel.org/pub/linux/kernel/v2.6/ChangeLog-2.6.38
• https://bugzilla.redhat.com/show_bug.cgi?id=681575
• https://lkml.org/lkml/2011/2/5/220