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gentooGentoo FoundationGLSA-202210-33
HistoryOct 31, 2022 - 12:00 a.m.

Libtirpc: Denial of Service

2022-10-3100:00:00
Gentoo Foundation
security.gentoo.org
8

7.5 High

CVSS3

Attack Vector

NETWORK

Attack Complexity

LOW

Privileges Required

NONE

User Interaction

NONE

Scope

UNCHANGED

Confidentiality Impact

NONE

Integrity Impact

NONE

Availability Impact

HIGH

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

5 Medium

CVSS2

Access Vector

NETWORK

Access Complexity

LOW

Authentication

NONE

Confidentiality Impact

NONE

Integrity Impact

NONE

Availability Impact

PARTIAL

AV:N/AC:L/Au:N/C:N/I:N/A:P

0.005 Low

EPSS

Percentile

76.2%

Background

Libtirpc is a port of Sun’s Transport-Independent RPC library to Linux.

Description

Currently svc_run does not handle poll timeout and rendezvous_request does not handle EMFILE error returned from accept(2 as it used to. These two missing functionality were removed by commit b2c9430f46c4. The effect of not handling poll timeout allows idle TCP conections to remain ESTABLISHED indefinitely. When the number of connections reaches the limit of the open file descriptors (ulimit -n) then accept(2) fails with EMFILE. Since there is no handling of EMFILE error this causes svc_run() to get in a tight loop calling accept(2). This resulting in the RPC service of svc_run is being down, it’s no longer able to service any requests. Due to a lack of handling of certain error cases, connections to Libtirpc could remain ESTABLISHED indefinitely.

Impact

Denial of service can be achieved via establishing enough connections to Libtirpc to reach the limit of open file descriptors for the process.

Workaround

There is no known workaround at this time.

Resolution

All Libtirpc users should upgrade to the latest version:

 # emerge --sync
 # emerge --ask --oneshot --verbose ">=net-libs/libtirpc-1.3.2"
OSVersionArchitecturePackageVersionFilename
Gentooanyallnet-libs/libtirpc< 1.3.2UNKNOWN

7.5 High

CVSS3

Attack Vector

NETWORK

Attack Complexity

LOW

Privileges Required

NONE

User Interaction

NONE

Scope

UNCHANGED

Confidentiality Impact

NONE

Integrity Impact

NONE

Availability Impact

HIGH

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

5 Medium

CVSS2

Access Vector

NETWORK

Access Complexity

LOW

Authentication

NONE

Confidentiality Impact

NONE

Integrity Impact

NONE

Availability Impact

PARTIAL

AV:N/AC:L/Au:N/C:N/I:N/A:P

0.005 Low

EPSS

Percentile

76.2%

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