Bug 19691 - Fix answer matching in dual A/AAAA lookups in libresolv
Summary: Fix answer matching in dual A/AAAA lookups in libresolv
Status: NEW
Alias: None
Product: glibc
Classification: Unclassified
Component: network (show other bugs)
Version: 2.24
: P2 normal
Target Milestone: ---
Assignee: Not yet assigned to anyone
URL:
Keywords:
Depends on: 19689
Blocks:
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Reported: 2016-02-20 13:26 UTC by Florian Weimer
Modified: 2020-09-11 13:02 UTC (History)
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Last reconfirmed:
fweimer: security-

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Description Florian Weimer 2016-02-20 13:26:24 UTC 
libresolv does not correctly match answers, particularly if the A and AAAA queries have the same 16-bit DNS transaction ID.

Bug 19689 will fix this for the UDP case.  The TCP case needs to be fixed as well because servers are permitted to reorder TCP responses to avoid head-of-line blocking.

This will improve the detection (in nss_dns) of broken recursive resolvers which do not react well to AAAA queries more reliable.