On Wed, 2016-11-30 at 12:00 -0500, Vladis Dronov wrote: > Hello, Eric, Marco, all, > > This is JFYI and a follow-up message. > > A further investigation was made to find out the Linux kernel commit which has > introduced the flaw. It appeared that previous Linux kernel versions are vulnerable, > down to v3.6-rc1. This fact was hidden by 'net.ipv4.tcp_fastopen' set to 0 by default, > and now it is easier to notice since kernel v3.12 due to commit 0d41cca490 where the > default was changed to 1. With 'net.ipv4.tcp_fastopen' set to 1, previous Linux > kernels (including RHEL-7 ones) are also vulnerable. > > The bug is here since tcp-fastopen feature was introduced in kernel v3.6-rc1, the first > commit when the reproducer starts to panic the kernel with net.ipv4.tcp_fastopen=1 set > is cf60af03ca, which is a part of commit sequence 2100c8d2d9..67da22d23f introducing > net-tcp-fastopen feature: > > $ git bisect bad cf60af03ca4e71134206809ea892e49b92a88896 > cf60af03ca4e71134206809ea892e49b92a88896 is the first bad commit > commit cf60af03ca4e71134206809ea892e49b92a88896 > Author: Yuchung Cheng <ycheng@xxxxxxxxxx> > Date: Thu Jul 19 06:43:09 2012 +0000 > > So, ideally, the upstream commit ac6e780070 which fixes the bug should have > "Fixes: cf60af03ca" statement, unfortunately, this investigation was not completed at > the time the patch was accepted upstream. And unfortunately I do not see other way > to add this information except making notes in a comment in the related code, which > seems weird. Well, the crash can happen way before Yuchung patch. It is a 0-day bug. -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html