** Description changed: + [ Impact ] + + * An explanation of the effects of the bug on users and + + * justification for backporting the fix to the stable release. + + * In addition, it is helpful, but not required, to include an + explanation of how the upload fixes this bug. + + [ Test Plan ] + + * detailed instructions how to reproduce the bug + + * these should allow someone who is not familiar with the affected + package to reproduce the bug and verify that the updated package fixes + the problem. + + * if other testing is appropriate to perform before landing this update, + this should also be described here. + + [ Where problems could occur ] + + * Think about what the upload changes in the software. Imagine the change is + wrong or breaks something else: how would this show up? + + * It is assumed that any SRU candidate patch is well-tested before + upload and has a low overall risk of regression, but it's important + to make the effort to think about what ''could'' happen in the + event of a regression. + + * This must '''never''' be "None" or "Low", or entirely an argument as to why + your upload is low risk. + + * This both shows the SRU team that the risks have been considered, + and provides guidance to testers in regression-testing the SRU. + + [ Other Info ] + + * Anything else you think is useful to include + * Anticipate questions from users, SRU, +1 maintenance, security teams and the Technical Board + * and address these questions in advance + + [ Original description ] + upstream discussion: https://lists.thekelleys.org.uk/pipermail/dnsmasq- discuss/2022q3/016563.html in my journal, my dns service crash and restart just after: Dec 04 17:18:38 dnsmasq[199333]: no servers found in /run/NetworkManager/no-stub-resolv.conf, will retry oops report: https://errors.ubuntu.com/oops/29cf5e2e-92b1-11ee-9bdf- fa163ec44ecd ubuntu jammy, dnsmasq-base 2.86-1.1ubuntu0.3
** Changed in: dnsmasq (Ubuntu Jammy) Status: Triaged => In Progress ** Description changed: [ Impact ] - * An explanation of the effects of the bug on users and + dnsmasq "keeps an eye" on /etc/resolv.conf, and reloads it whenever the + file is updated. When that happens and for some reason there were no + "nameserver" declarations in the updated file, dnsmasq can crash. - * justification for backporting the fix to the stable release. + Here is a log of a reproducer: + $ dig +short @127.0.0.1 ubuntu.com + ;; communications error to 127.0.0.1#53: timed out + ;; communications error to 127.0.0.1#53: connection refused + ;; communications error to 127.0.0.1#53: connection refused + ;; no servers could be reached - * In addition, it is helpful, but not required, to include an - explanation of how the upload fixes this bug. + We can see the startup, then when resolv.conf is read again and no nameservers were found, and the crash: + Jan 03 13:57:13 j-dnsmasq-2045570 dnsmasq[1507]: started, version 2.86 cachesize 150 + Jan 03 13:57:13 j-dnsmasq-2045570 dnsmasq[1507]: DNS service limited to local subnets + Jan 03 13:57:13 j-dnsmasq-2045570 dnsmasq[1507]: compile time options: IPv6 GNU-getopt DBus no-UBus i18n IDN2 DHCP DHCPv6 no-Lua TFTP conntrack ipset auth cryptohash DNSSEC loop-detect inotify dumpfile + Jan 03 13:57:13 j-dnsmasq-2045570 dnsmasq[1507]: reading /etc/resolv.conf + Jan 03 13:57:13 j-dnsmasq-2045570 dnsmasq[1507]: using nameserver 10.0.100.1#53 + Jan 03 13:57:13 j-dnsmasq-2045570 dnsmasq[1507]: read /etc/hosts - 7 addresses + Jan 03 13:57:13 j-dnsmasq-2045570 systemd[1]: Started dnsmasq - A lightweight DHCP and caching DNS server. + Jan 03 13:58:01 j-dnsmasq-2045570 dnsmasq[1507]: no servers found in /etc/resolv.conf, will retry + Jan 03 13:58:22 j-dnsmasq-2045570 systemd[1]: dnsmasq.service: Main process exited, code=dumped, status=11/SEGV + Jan 03 13:58:22 j-dnsmasq-2045570 systemd[1]: dnsmasq.service: Failed with result 'core-dump'. + + dnsmasq has provisions for this situation, we can see that in the + 13:58:01 message where it says it will retry, but due to this bug, it + crashes instead. + [ Test Plan ] - * detailed instructions how to reproduce the bug + * detailed instructions how to reproduce the bug - * these should allow someone who is not familiar with the affected - package to reproduce the bug and verify that the updated package fixes - the problem. + * these should allow someone who is not familiar with the affected + package to reproduce the bug and verify that the updated package fixes + the problem. - * if other testing is appropriate to perform before landing this update, - this should also be described here. + * if other testing is appropriate to perform before landing this update, + this should also be described here. [ Where problems could occur ] - * Think about what the upload changes in the software. Imagine the change is - wrong or breaks something else: how would this show up? + * Think about what the upload changes in the software. Imagine the change is + wrong or breaks something else: how would this show up? - * It is assumed that any SRU candidate patch is well-tested before - upload and has a low overall risk of regression, but it's important - to make the effort to think about what ''could'' happen in the - event of a regression. + * It is assumed that any SRU candidate patch is well-tested before + upload and has a low overall risk of regression, but it's important + to make the effort to think about what ''could'' happen in the + event of a regression. - * This must '''never''' be "None" or "Low", or entirely an argument as to why - your upload is low risk. + * This must '''never''' be "None" or "Low", or entirely an argument as to why + your upload is low risk. - * This both shows the SRU team that the risks have been considered, - and provides guidance to testers in regression-testing the SRU. + * This both shows the SRU team that the risks have been considered, + and provides guidance to testers in regression-testing the SRU. [ Other Info ] - - * Anything else you think is useful to include - * Anticipate questions from users, SRU, +1 maintenance, security teams and the Technical Board - * and address these questions in advance + + * Anything else you think is useful to include + * Anticipate questions from users, SRU, +1 maintenance, security teams and the Technical Board + * and address these questions in advance [ Original description ] upstream discussion: https://lists.thekelleys.org.uk/pipermail/dnsmasq- discuss/2022q3/016563.html in my journal, my dns service crash and restart just after: Dec 04 17:18:38 dnsmasq[199333]: no servers found in /run/NetworkManager/no-stub-resolv.conf, will retry oops report: https://errors.ubuntu.com/oops/29cf5e2e-92b1-11ee-9bdf- fa163ec44ecd ubuntu jammy, dnsmasq-base 2.86-1.1ubuntu0.3 -- You received this bug notification because you are a member of Ubuntu Touch seeded packages, which is subscribed to dnsmasq in Ubuntu. https://bugs.launchpad.net/bugs/2045570 Title: dnsmasq crash when no servers in resolv.conf Status in dnsmasq package in Ubuntu: Fix Released Status in dnsmasq source package in Jammy: In Progress Bug description: [ Impact ] dnsmasq "keeps an eye" on /etc/resolv.conf, and reloads it whenever the file is updated. When that happens and for some reason there were no "nameserver" declarations in the updated file, dnsmasq can crash. Here is a log of a reproducer: $ dig +short @127.0.0.1 ubuntu.com ;; communications error to 127.0.0.1#53: timed out ;; communications error to 127.0.0.1#53: connection refused ;; communications error to 127.0.0.1#53: connection refused ;; no servers could be reached We can see the startup, then when resolv.conf is read again and no nameservers were found, and the crash: Jan 03 13:57:13 j-dnsmasq-2045570 dnsmasq[1507]: started, version 2.86 cachesize 150 Jan 03 13:57:13 j-dnsmasq-2045570 dnsmasq[1507]: DNS service limited to local subnets Jan 03 13:57:13 j-dnsmasq-2045570 dnsmasq[1507]: compile time options: IPv6 GNU-getopt DBus no-UBus i18n IDN2 DHCP DHCPv6 no-Lua TFTP conntrack ipset auth cryptohash DNSSEC loop-detect inotify dumpfile Jan 03 13:57:13 j-dnsmasq-2045570 dnsmasq[1507]: reading /etc/resolv.conf Jan 03 13:57:13 j-dnsmasq-2045570 dnsmasq[1507]: using nameserver 10.0.100.1#53 Jan 03 13:57:13 j-dnsmasq-2045570 dnsmasq[1507]: read /etc/hosts - 7 addresses Jan 03 13:57:13 j-dnsmasq-2045570 systemd[1]: Started dnsmasq - A lightweight DHCP and caching DNS server. Jan 03 13:58:01 j-dnsmasq-2045570 dnsmasq[1507]: no servers found in /etc/resolv.conf, will retry Jan 03 13:58:22 j-dnsmasq-2045570 systemd[1]: dnsmasq.service: Main process exited, code=dumped, status=11/SEGV Jan 03 13:58:22 j-dnsmasq-2045570 systemd[1]: dnsmasq.service: Failed with result 'core-dump'. dnsmasq has provisions for this situation, we can see that in the 13:58:01 message where it says it will retry, but due to this bug, it crashes instead. [ Test Plan ] * detailed instructions how to reproduce the bug * these should allow someone who is not familiar with the affected package to reproduce the bug and verify that the updated package fixes the problem. * if other testing is appropriate to perform before landing this update, this should also be described here. [ Where problems could occur ] * Think about what the upload changes in the software. Imagine the change is wrong or breaks something else: how would this show up? * It is assumed that any SRU candidate patch is well-tested before upload and has a low overall risk of regression, but it's important to make the effort to think about what ''could'' happen in the event of a regression. * This must '''never''' be "None" or "Low", or entirely an argument as to why your upload is low risk. * This both shows the SRU team that the risks have been considered, and provides guidance to testers in regression-testing the SRU. [ Other Info ] * Anything else you think is useful to include * Anticipate questions from users, SRU, +1 maintenance, security teams and the Technical Board * and address these questions in advance [ Original description ] upstream discussion: https://lists.thekelleys.org.uk/pipermail/dnsmasq- discuss/2022q3/016563.html in my journal, my dns service crash and restart just after: Dec 04 17:18:38 dnsmasq[199333]: no servers found in /run/NetworkManager/no-stub-resolv.conf, will retry oops report: https://errors.ubuntu.com/oops/29cf5e2e-92b1-11ee-9bdf- fa163ec44ecd ubuntu jammy, dnsmasq-base 2.86-1.1ubuntu0.3 To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/dnsmasq/+bug/2045570/+subscriptions -- Mailing list: https://launchpad.net/~touch-packages Post to : touch-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~touch-packages More help : https://help.launchpad.net/ListHelp