Bug 1729931 (CVE-2019-10638) - CVE-2019-10638 Kernel: net: weak IP ID generation leads to remote device tracking
Summary: CVE-2019-10638 Kernel: net: weak IP ID generation leads to remote device trac...
Keywords:
Status: NEW
Alias: CVE-2019-10638
Product: Security Response
Classification: Other
Component: vulnerability
Version: unspecified
Hardware: All
OS: Linux
low
low
Target Milestone: ---
Assignee: Red Hat Product Security
QA Contact:
URL:
Whiteboard:
Depends On: 1718503 1733067 1733068 1733069 1733071 1729932 1733070
Blocks: 1729937
TreeView+ depends on / blocked
 
Reported: 2019-07-15 11:10 UTC by Marian Rehak
Modified: 2019-09-29 15:16 UTC (History)
45 users (show)

Fixed In Version:
Doc Type: Bug Fix
Doc Text:
A flaw was found in the way the Linux kernel derived the IP ID field from a partial kernel space address returned by a net_hash_mix() function. A remote user could observe a weak IP ID generation in this field to track Linux devices.
Clone Of:
Environment:
Last Closed:


Attachments (Terms of Use)

Description Marian Rehak 2019-07-15 11:10:00 UTC
When IP packet fragmentation is ON, IP Identification(ID) field of the IP header 
is used, during packet reassembly on the destination host, to identify fragments 
which belong to the same packet. IP ID field is required to be unique and same 
across all fragments of an IP packet. IP packet fragments are identified by a 
tuple with following fields

    (source address|destination address|protocol|IP-ID)

The Linux kernel derived this IP ID field from partial kernel space address 
returned by net_hash_mix() function, which is then used with a hash function to 
compute the IP ID field.

A remote user could observe this IP ID field to deduce the hash key used to
derive its value. This could enable a remote user to track particular Linux
devices.

Upstream fix:
-------------
  -> https://git.kernel.org/linus/df453700e8d81b1bdafdf684365ee2b9431fb702

Issue introduced by:
--------------------
  -> https://git.kernel.org/linus/b6a7719aedd7e5c0f2df7641aa47386111682df4
  -> https://git.kernel.org/linus/5a352dd0a3aac03b443c94828dfd7144261c8636

Comment 1 Marian Rehak 2019-07-15 11:10:16 UTC
Created kernel tracking bugs for this issue:

Affects: fedora-all [bug 1729932]

Comment 3 Prasad J Pandit 2019-07-28 08:10:48 UTC
External References:

https://arxiv.org/pdf/1906.10478.pdf

Comment 4 Prasad J Pandit 2019-08-06 06:58:24 UTC
Statement:

This issue does not affect the versions of Linux kernel as shipped with Red Hat Enterprise Linux 5 and Red Hat Enterprise Linux 6.

This issue affects the version of Linux kernel as shipped with Red Hat Enterprise Linux 7,  8 and Red Hat Enterprise MRG 2. Future kernel updates for Red Hat Enterprise Linux 7, 8 and Red Hat Enterprise MRG 2 may address this issue.


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