Bug 1335889 (CVE-2016-4794) - CVE-2016-4794 kernel: Use after free in array_map_alloc
Summary: CVE-2016-4794 kernel: Use after free in array_map_alloc
Keywords:
Status: CLOSED ERRATA
Alias: CVE-2016-4794
Product: Security Response
Classification: Other
Component: vulnerability
Version: unspecified
Hardware: All
OS: Linux
medium
medium
Target Milestone: ---
Assignee: Red Hat Product Security
QA Contact:
URL:
Whiteboard:
Depends On: 1335890 Engineering1344568 Engineering1344569 Engineering1344570 Engineering1344571 Engineering1344572 Engineering1344573 Engineering1344574 Engineering1344575
Blocks: Embargoed1336283
TreeView+ depends on / blocked
 
Reported: 2016-05-13 13:27 UTC by Adam Mariš
Modified: 2021-02-17 03:53 UTC (History)
31 users (show)

Fixed In Version:
Doc Type: Bug Fix
Doc Text:
Use after free vulnerability was found in percpu using previously allocated memory in bpf. First __alloc_percpu_gfp() is called, then the memory is freed with free_percpu() which triggers async pcpu_balance_work and then pcpu_extend_area_map could use a chunk after it has been freed.
Clone Of:
Environment:
Last Closed: 2019-06-08 02:51:50 UTC

Attachments (Terms of Use)


Links
System ID Private Priority Status Summary Last Updated
Red Hat Product Errata RHSA-2016:2574 0 normal SHIPPED_LIVE Important: kernel security, bug fix, and enhancement update 2016-11-03 12:06:10 UTC
Red Hat Product Errata RHSA-2016:2584 0 normal SHIPPED_LIVE Important: kernel-rt security, bug fix, and enhancement update 2016-11-03 12:08:49 UTC

Description Adam Mariš 2016-05-13 13:27:43 UTC 
Use after free vulnerability was found in percpu using previously allocated memory in bpf. First __alloc_percpu_gfp() is called, then the memory is freed with free_percpu() which triggers async pcpu_balance_work and then pcpu_extend_area_map is hitting use-after-free.

CVE request (contains reproducer):
http://seclists.org/oss-sec/2016/q2/332

1: percpu: fix synchronization between chunk->map_extend_work and chunk destruction
( https://www.mail-archive.com/netdev@vger.kernel.org/msg111820.html )

2: percpu: fix synchronization between synchronous map extension and chunk destruction
( https://www.mail-archive.com/netdev@vger.kernel.org/msg111747.html )
Comment 1 Adam Mariš 2016-05-13 13:28:34 UTC 
Created kernel tracking bugs for this issue:

Affects: fedora-all [bug 1335890]
Comment 8 Wade Mealing 2016-06-10 05:33:02 UTC 
Statement:

This issue does not affect the Linux kernels as shipped with Red Hat Enterprise Linux 4, 5 and 6.

This issue affects the Linux kernels as shipped with Red Hat Enterprise Linux 7 and MRG-2 and may be addressed in a future update.
Comment 11 Adam Mariš 2016-06-14 11:15:43 UTC 
Upstream patches:

https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=4f996e234dad488e5d9ba0858bc1bae12eff82c3

https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=6710e594f71ccaad8101bc64321152af7cd9ea28
Comment 12 errata-xmlrpc 2016-11-03 16:33:25 UTC 
This issue has been addressed in the following products:

  Red Hat Enterprise Linux 7

Via RHSA-2016:2574 https://rhn.redhat.com/errata/RHSA-2016-2574.html
Comment 13 errata-xmlrpc 2016-11-03 19:51:31 UTC 
This issue has been addressed in the following products:

  Red Hat Enterprise Linux 7

Via RHSA-2016:2584 https://rhn.redhat.com/errata/RHSA-2016-2584.html
Comment 14 errata-xmlrpc 2016-11-03 21:35:10 UTC 
This issue has been addressed in the following products:

  Red Hat Enterprise Linux 7

Via RHSA-2016:2574 https://rhn.redhat.com/errata/RHSA-2016-2574.html
Comment 15 errata-xmlrpc 2016-11-03 21:50:31 UTC 
This issue has been addressed in the following products:

  Red Hat Enterprise Linux 7

Via RHSA-2016:2584 https://rhn.redhat.com/errata/RHSA-2016-2584.html
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