Hi Mathew, I have the knowledge of the code, I will rebase the debdiffs for V/T/P
Note: I checked and Xenial has the patch already. -- You received this bug notification because you are a member of Ubuntu Touch seeded packages, which is subscribed to ntp in Ubuntu. https://bugs.launchpad.net/bugs/1481388 Title: NTP : Use-after-free in routing socket code after dropping root Status in NTP: Fix Released Status in ntp package in Ubuntu: Fix Released Status in ntp source package in Precise: In Progress Status in ntp source package in Trusty: In Progress Status in ntp source package in Vivid: In Progress Status in ntp source package in Wily: Fix Released Status in ntp package in Debian: Fix Released Bug description: [Impact] * User experienced repeated segfaults at the same instruction pointer i/o error on routing socket No buffer space available - disabling segfault at 31 ip 0000000000000031 sp 00007ffff9f11788 error 14 in libpthread-2.15.so[7f967a5d9000+18000] The remove_ and delete_ functions remove the current element from the asyncio_reader_list, and free it, respectively. We then return back to the loop at the top, wherein the asyncio_reader variable still points at the now-freed element, whose contents are (in theory) now scrambled by having link pointers, etc, from internal malloc state overlaying the data. [Test Case] You can easily reproduce the bug by : - Lowering the sysctl value net.core.rmem_max $ sysctl -w net.core.wmem_max=<LOWER_VALUE> This sets the max OS send buffer size for all types of connections. - Adding multiple network interfaces and static routes. [Regression Potential] None expected since the fix is already available upstream (https://github.com/ntp-project/ntp.git) and Debian package. If after installing the patch, user are receiving this kind of message in /var/log/syslog : "routing socket reports: No buffer space available". The next step, would be to increase the "net.core.rmem_max" and "net.core.wmem_max" values equally until the "routing socket reports: No buffer space available" message no longer showed up. [Other Info] NTP upstream (https://github.com/ntp-project/ntp.git) [Bug 2224] Use-after-free in routing socket code after dropping root. - Commit: d6df9d3 [Bug 2890] Ignore ENOBUFS on routing netlink socket. - Commit: db47bd4 The use-after-free bug has been fix in Debian release (closes: #795315) Will submit the ignore-ENOBUFS-on-routing-netlink-socket in Debian in the next days. [Original Description] We have 1 server (among hundreds) that its ntp service is crashing. A few minute/seconds after a start attempts we can see the following in syslog: ntpd[2729]: peers refreshed ntpd[2729]: Listening on routing socket on fd #49 for interface updates ntpd[2729]: i/o error on routing socket No buffer space available - disabling kernel: [157516.495224] ntpd[2729]: segfault at 31 ip 0000000000000031 sp 00007ffff9f11788 error 14 in libpthread-2.15.so[7f967a5d9000+18000] OS: Ubuntu 12.04.4 LTS Kernel: 3.11.0-19-generic I tried to compare it to other servers, and the only thing I could find that is different is that while it's up (before it crashes) I can see the following when running "lsof | grep ntp": ntpd 2729 ntp 49u sock 0,7 0t0 2473952565 can't identify protocol. To manage notifications about this bug go to: https://bugs.launchpad.net/ntp/+bug/1481388/+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
