Bug 1368369 (CVE-2016-6866)

Summary: CVE-2016-6866 slock: Null pointer dereference results in segmentation fault
Product: [Other] Security Response Reporter: Andrej Nemec <anemec>
Component: vulnerabilityAssignee: Red Hat Product Security <security-response-team>
Status: CLOSED ERRATA QA Contact:
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Priority: low    
Version: unspecifiedCC: ppisar, psabata
Target Milestone: ---Keywords: Security
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Hardware: All   
OS: Linux   
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Last Closed: 2016-11-25 08:19:11 UTC Type: ---
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oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
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Bug Depends On: 1368370    
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Upstream fix none

Description Andrej Nemec 2016-08-19 08:28:01 UTC 
The screen locking application slock (http://tools.suckless.org/slock/)
calls crypt(3) and uses the return value for strcmp(3) without checking
to see if the return value of crypt(3) was a NULL pointer. If the hash
returned by (getspnam()->sp_pwdp) is invalid, crypt(3) will return NULL
and set errno to EINVAL. This will cause slock to segfault which then
leaves the machine unprotected.

References:

http://seclists.org/oss-sec/2016/q3/328
http://s1m0n.dft-labs.eu/files/slock/
Comment 1 Andrej Nemec 2016-08-19 08:28:24 UTC 
Created slock tracking bugs for this issue:

Affects: fedora-all [bug 1368370]
Comment 2 Petr Pisar 2016-08-31 06:07:00 UTC 
Created attachment 1196223 [details]
Upstream fix
Comment 3 Fedora Update System 2016-09-05 17:53:21 UTC 
slock-1.3-2.fc25 has been pushed to the Fedora 25 stable repository. If problems still persist, please make note of it in this bug report.
Comment 4 Fedora Update System 2016-09-09 16:53:12 UTC 
slock-1.3-2.fc23 has been pushed to the Fedora 23 stable repository. If problems still persist, please make note of it in this bug report.
Comment 5 Fedora Update System 2016-09-09 16:54:34 UTC 
slock-1.3-2.fc24 has been pushed to the Fedora 24 stable repository. If problems still persist, please make note of it in this bug report.