Bug 1455493 (CVE-2017-9217) - CVE-2017-9217 systemd: Null pointer dereference in dns_packet_is_reply_for function
Summary: CVE-2017-9217 systemd: Null pointer dereference in dns_packet_is_reply_for fu...
Keywords:
Status: CLOSED NOTABUG
Alias: CVE-2017-9217
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: 1455495
Blocks: 1457410
TreeView+ depends on / blocked
 
Reported: 2017-05-25 10:38 UTC by Adam Mariš
Modified: 2021-02-17 02:06 UTC (History)
8 users (show)

Fixed In Version:
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Last Closed: 2019-06-08 03:13:27 UTC
Embargoed:

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Description Adam Mariš 2017-05-25 10:38:15 UTC 
systemd-resolved through 233 allows remote attackers to cause a denial of service (daemon crash) via a crafted DNS response with an empty question section.

Upstream bug:

https://github.com/systemd/systemd/pull/5998

Upstream patch:

https://github.com/systemd/systemd/pull/6020/commits/9e74e781f176f3b930d9c202e20532f011a5d7bc
Comment 1 Adam Mariš 2017-05-25 10:38:49 UTC 
Created systemd tracking bugs for this issue:

Affects: fedora-all [bug 1455495]
Comment 4 Adam Mariš 2017-06-02 09:01:53 UTC 
Analysis:

The issue was introduced in systemd v225 by following commit:

https://github.com/systemd/systemd/commit/f52e61da047d7fc74e83f12dbbf87e0cbcc51c73

The vulnerable code (dereferencing p->question->n_keys without first asserting on p->question) was first introduced in dns_transaction_process_reply function and later transferred to dns_packet_is_reply_for while doing refactoring in the following commit:

https://github.com/systemd/systemd/commit/8af5b883227ac8dfa796742b9edcc1647a5d4d6c

RHEL-7 ships systemd v219 that does not have this vulnerability.
Comment 5 Adam Mariš 2017-06-02 09:03:45 UTC 
Statement:

This issue did not affect the versions of systemd as shipped with Red Hat Enterprise Linux 7.
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