Linux Kernel “vmsplice()” System Call Vulnerabilities

Subject: [SA28835] Linux Kernel “vmsplice()” System Call Vulnerabilities
Date: Tuesday 12 February 2008
From: Secunia Security Advisories
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TITLE:
Linux Kernel “vmsplice()” System Call Vulnerabilities

SECUNIA ADVISORY ID:
SA28835

VERIFY ADVISORY:
http://secunia.com/advisories/28835/

CRITICAL:
Less critical

IMPACT:
Exposure of sensitive information, Privilege escalation, DoS

WHERE:
Local system

OPERATING SYSTEM:
Linux Kernel 2.6.x
http://secunia.com/product/2719/

DESCRIPTION:
Some vulnerabilities have been reported in the Linux Kernel, which
can be exploited by malicious, local users to cause a DoS (Denial of
Service), disclose potentially sensitive information, and gain
escalated privileges.

The vulnerabilities are caused due to the missing verification of
parameters within the “vmsplice_to_user()”,
“copy_from_user_mmap_sem()”, and “get_iovec_page_array()” functions
in fs/splice.c before using them to perform certain memory
operations. This can be exploited to e.g. read or write to arbitrary
kernel memory via a specially crafted “vmsplice()” system call.

Successful exploitation allows attackers to e.g. gain “root”
privileges.

Note: The affected system call first appeared in version 2.6.17.

SOLUTION:
Update to version 2.6.23.16 or 2.6.24.2.

PROVIDED AND/OR DISCOVERED BY:
Wojciech Purczynskiof iSEC Security Research and qaaz

ORIGINAL ADVISORY:
iSEC Security Research:
http://www.isec.pl/vulnerabilities/isec-0026-vmsplice_to_kernel.txt

qaaz:
http://milw0rm.com/exploits/5092
http://milw0rm.com/exploits/5093

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About:
This Advisory was delivered by Secunia as a free service to help
everybody keeping their systems up to date against the latest
vulnerabilities.

Subscribe:
http://secunia.com/secunia_security_advisories/

Definitions: (Criticality, Where etc.)
http://secunia.com/about_secunia_advisories/

Please Note:
Secunia recommends that you verify all advisories you receive by
clicking the link.
Secunia NEVER sends attached files with advisories.
Secunia does not advise people to install third party patches, only
use those supplied by the vendor.

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One Response to “Linux Kernel “vmsplice()” System Call Vulnerabilities”

  1. SiiN Says:

    How can you discover if my system is vulnerable?
    SSH to the server and run the following command:

    /bin/grep -ri vmsplice /boot/System.map-$(uname -r)

    If the system returns no results/nothing, that means your system is NOT
    vulnerable.

    If the system returns something like:

    c048fdf7 T sys_vmsplice
    You may need to patch the kernel

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