Bug 1116303 – VUL-1: CVE-2018-18955: kernel-source: broken uid/gid mapping for nested user namespaces with >5 ranges (; since 4.15; fixed in 4.18.19 and 4.19.2)

Bug 1116303 - (CVE-2018-18955) VUL-1: CVE-2018-18955: kernel-source: broken uid/gid mapping for nested user namespaces with >5 ranges (; since 4.15; fixed in 4.18.19 and 4.19.2)

(CVE-2018-18955)
Summary:	VUL-1: CVE-2018-18955: kernel-source: broken uid/gid mapping for nested user ...

Status:	RESOLVED UPSTREAM

Classification:	Novell Products
Product:	SUSE Security Incidents
Classification:	Novell Products
Component:	Incidents
Version:	unspecified
Hardware:	Other Other

Priority:	P4 - Low Severity: Minor
Target Milestone:	---
Assigned To:	Security Team bot
QA Contact:	Security Team bot

URL:	https://smash.suse.de/issue/219347/
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Reported:	2018-11-16 08:51 UTC by Marcus Meissner
Modified:	2019-01-08 07:28 UTC (History)
CC List:	2 users (show)

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Found By:	Security Response Team
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Description Marcus Meissner 2018-11-16 08:51:07 UTC

CVE-2018-18955

In Linux kernel versions since 4.15, map_write() in
kernel/user_namespace.c handles nested user namespaces with more than
5 UID or GID ranges incorrectly. This can allow a user who has
CAP_SYS_ADMIN in a user namespace which maps at least 6 UIDs or GIDs
to bypass access controls on resources outside the namespace.

This is CVE-2018-18955.

https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=d2f007dbe7e4c9583eea6eb04d60001e85c6f1bd
https://cdn.kernel.org/pub/linux/kernel/v4.x/ChangeLog-4.18.19
https://cdn.kernel.org/pub/linux/kernel/v4.x/ChangeLog-4.19.2
https://bugs.chromium.org/p/project-zero/issues/detail?id=1712

Comment 1 Marcus Meissner 2018-11-16 09:01:28 UTC

we do not seem to have backported the problematic fix from 6397fac4915a to our kernels ... but please cross check.

Comment 3 Marcus Meissner 2019-01-08 07:28:59 UTC

is resolved upstream