Bug 2048925 (CVE-2021-45956)

Summary: CVE-2021-45956 dnsmasq: a heap-based buffer overflow in print_mac
Product: [Other] Security Response Reporter: Marian Rehak <mrehak>
Component: vulnerabilityAssignee: Red Hat Product Security <security-response-team>
Status: CLOSED NOTABUG QA Contact:
Severity: high Docs Contact:
Priority: high    
Version: unspecifiedCC: bdettelb, code, dbecker, dns-sig, dougsland, jburrell, jjoyce, jschluet, lhh, lpeer, mburns, pemensik, sclewis, slinaber, veillard, vkumar
Target Milestone: ---Keywords: Security
Target Release: ---   
Hardware: All   
OS: Linux   
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Last Closed: 2022-05-24 23:36:43 UTC Type: ---
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oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: --- Target Upstream Version:
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Bug Depends On: 2048926    
Bug Blocks: 2048923    

Description Marian Rehak 2022-02-01 08:17:18 UTC 
Dnsmasq 2.86 has a heap-based buffer overflow in print_mac (called from log_packet and dhcp_reply).

Reference:

https://github.com/google/oss-fuzz-vulns/blob/main/vulns/dnsmasq/OSV-2021-933.yaml
https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=35887
Comment 1 Marian Rehak 2022-02-01 08:18:21 UTC 
Created dnsmasq tracking bugs for this issue:

Affects: fedora-all [bug 2048926]
Comment 3 Petr Menšík 2022-02-16 23:35:52 UTC 
Because print_mac also uses daemon->namebuff as printout buffer, I expect this is too related to extract_name fixes. After applying PR [1] I were unable to reproduce this issue anymore. It seems to be related, probably this is also bogus issue.

1. https://github.com/google/oss-fuzz/pull/7293