Bug 1838000 (CVE-2020-12723)
| Summary: | CVE-2020-12723 perl: corruption of intermediate language state of compiled regular expression due to recursive S_study_chunk() calls leads to DoS | ||
|---|---|---|---|
| Product: | [Other] Security Response | Reporter: | msiddiqu |
| Component: | vulnerability | Assignee: | Red Hat Product Security <security-response-team> |
| Status: | CLOSED ERRATA | QA Contact: | |
| Severity: | medium | Docs Contact: | |
| Priority: | medium | ||
| Version: | unspecified | CC: | caillon+fedoraproject, cwarfiel, ekirby, iarnell, jplesnik, kasal, kyoshida, mmaslano, perl-devel, perl-maint-list, rhughes, sandmann, security-response-team, snavale, spotrh, surpatil, tvainio |
| Target Milestone: | --- | Keywords: | Security |
| Target Release: | --- | ||
| Hardware: | All | ||
| OS: | Linux | ||
| Whiteboard: | |||
| Fixed In Version: | perl 5.30.3, perl 5.28.3 | Doc Type: | If docs needed, set a value |
| Doc Text: | Story Points: | --- | |
| Clone Of: | Environment: | ||
| Last Closed: | 2021-02-02 14:41:45 UTC | Type: | --- |
| Regression: | --- | Mount Type: | --- |
| Documentation: | --- | CRM: | |
| Verified Versions: | Category: | --- | |
| oVirt Team: | --- | RHEL 7.3 requirements from Atomic Host: | |
| Cloudforms Team: | --- | Target Upstream Version: | |
| Embargoed: | |||
| Bug Depends On: | 1839278, 1839279, 1839280, 1844664, 1909860, 1929870, 1933098, 1938330, 1945144 | ||
| Bug Blocks: | 1838017 | ||
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Description
msiddiqu
2020-05-20 11:01:33 UTC
Acknowledgments: Name: Sergey Aleynikov (In reply to Todd Cullum from comment #4) > Mitigation: > > To mitigate this flaw, developers should not pass untrusted or uncontrolled > data to the Perl regular expression engine; especially in cases where the > regular expression is used in input sanitization, validation, or filtering. This flaw is about compiling an untrusted regular expression. Not about matching an untrusted text. Mitigation: To mitigate this flaw, developers should not allow untrusted regular expressions to be compiled by the Perl regular expression compiler. This flaw is caused by code in the S_study_chunk() routine of regcomp.c which handles the GOSUB regopcode. S_study_chunk() performs recursive calls which could mutate data that an outer call was already working on, when handling a GOSUB opcode. Upstream's patch has added booleans called in_gosub, mutate_ok, and was_mutate_ok which are set and checked before mutations occur to ensure that the current recursion depth does not mutate data being worked on by an outer frame. Instead, the outer frame should handle the mutation to avoid corrupting the intermediate language representation of the regular expression and the possibility of an attacker inserting instructions into compiled Perl regular expressions. Upstream issues: https://github.com/Perl/perl5/issues/16947 https://github.com/Perl/perl5/issues/17743 References: https://github.com/Perl/perl5/blob/blead/pod/perl5303delta.pod https://github.com/Perl/perl5/compare/v5.30.2...v5.30.3 Created perl tracking bugs for this issue: Affects: fedora-all [bug 1844664] The fixes are now published in Perl versions 5.28.3 and 5.30.3. https://metacpan.org/pod/release/XSAWYERX/perl-5.28.3/pod/perldelta.pod https://metacpan.org/pod/release/XSAWYERX/perl-5.30.3/pod/perldelta.pod This issue has been addressed in the following products: Red Hat Enterprise Linux 7 Via RHSA-2021:0343 https://access.redhat.com/errata/RHSA-2021:0343 This bug is now closed. Further updates for individual products will be reflected on the CVE page(s): https://access.redhat.com/security/cve/cve-2020-12723 This issue has been addressed in the following products: Red Hat Enterprise Linux 8 Via RHSA-2021:0557 https://access.redhat.com/errata/RHSA-2021:0557 This issue has been addressed in the following products: Red Hat Enterprise Linux 7.6 Extended Update Support Via RHSA-2021:0883 https://access.redhat.com/errata/RHSA-2021:0883 This issue has been addressed in the following products: Red Hat Enterprise Linux 7.7 Extended Update Support Via RHSA-2021:1032 https://access.redhat.com/errata/RHSA-2021:1032 This issue has been addressed in the following products: Red Hat Enterprise Linux 7.4 Advanced Update Support Red Hat Enterprise Linux 7.4 Update Services for SAP Solutions Red Hat Enterprise Linux 7.4 Telco Extended Update Support Via RHSA-2021:1266 https://access.redhat.com/errata/RHSA-2021:1266 This issue has been addressed in the following products: Red Hat Enterprise Linux 8.2 Extended Update Support Via RHSA-2021:2184 https://access.redhat.com/errata/RHSA-2021:2184 |