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SYNTHESIS OF THE VULNERABILITY

A local attacker can use a lock on a NFS file in order to stop the
kernel.

Severity: 2/4

Consequences: administrator access/rights, denial of service of
computer

Provenance: user shell

Means of attack: 1 attack

Ability of attacker: technician (2/4)

Confidence: confirmed by the editor (5/5)

Diffusion of the vulnerable configuration: high (3/3)

Creation date: 09/11/2009

IMPACTED PRODUCTS

– Linux kernel

DESCRIPTION OF THE VULNERABILITY

The state structure contains the NFS state of a file.

The nfs4_proc_lock() and nfs4_proc_setlk() functions from file
fs/nfs/nfs4proc.c obtain a lock on a file. The state structure can
be NULL. The nfs4_proc_setlk() function therefore dereference a
NULL pointer.

A local attacker can thus use a lock on a NFS file in order to
stop the kernel.

An attacker can also use this vulnerability with
VIGILANCE-VUL-8953 (https://vigilance.fr/tree/1/8953)/VIGILANCE-VUL-8861
(https://vigilance.fr/tree/1/8861) in order to elevate his
privileges.

CHARACTERISTICS

Identifiers: BID-36936, CVE-2009-3726, VIGILANCE-VUL-9180

http://vigilance.fr/vulnerability/Linux-kernel-NULL-dereference-via-nfs4-proc-lock-9180