FreeBSD maintainer's guide to OpenSSH-portable ============================================== These instructions assume you have a clone of the FreeBSD git repo main branch in src/freebsd/main, and will store vendor trees under src/freebsd/vendor/. In addition, this assumes there is a "freebsd" origin pointing to git(repo).freebsd.org/src.git. 00) Make sure your mail spool has plenty of free space. It'll fill up pretty fast once you're done with this checklist. 01) Download the latest OpenSSH-portable tarball and signature from OpenBSD (https://ftp.openbsd.org/pub/OpenBSD/OpenSSH/portable/). 02) Verify the signature: $ gpg --verify openssh-X.YpZ.tar.gz.asc 03) Unpack the tarball in a suitable directory: $ tar xf openssh-X.YpZ.tar.gz 04) Copy to a vendor branch: $ cd src/freebsd/main $ git worktree add ../vendor/openssh freebsd/vendor/openssh $ cd ../vendor/openssh $ rsync --archive --delete --exclude=.git /path/to/openssh-X.YpZ/ ./ 05) Take care of added / deleted files: $ git add -A 06) Commit: $ git commit -m "Vendor import of OpenSSH X.YpZ" 07) Tag: $ git tag -a -m "Tag OpenSSH X.YpZ" vendor/openssh/X.YpZ At this point the vendor branch can be pushed to the FreeBSD repo via: $ git push freebsd vendor/openssh (It could also be pushed later on, along with the merge to main, but pushing now allows others to collaborate.) 08) Check out head and run the pre-merge script, which strips our RCS tags from files that have them: $ cd src/freebsd/main/crypto/openssh $ sh freebsd-pre-merge.sh 09) Merge from the vendor branch: $ git subtree merge -P crypto/openssh vendor/openssh A number of files have been deleted from FreeBSD's copy of ssh, including rendered man pages (which have a .0 extension). When git prompts for these deleted files during the merge, choose 'd' (leaving them deleted). 0A) Resolve conflicts. Remember to bump the version addendum in version.h, and update the default value in ssh{,d}_config and ssh{,d}_config.5. 0B) Diff against the vendor branch: $ git diff --diff-filter=M vendor/openssh/X.YpZ HEAD:crypto/openssh Files that have modifications relative to the vendor code, and only those files, must have the svn:keywords property set to FreeBSD=%H and be listed in the 'keywords' file created by the pre-merge script. 0C) Run the post-merge script, which re-adds RCS tags to files that need them: $ sh freebsd-post-merge.sh These tags are not used with git, but we will leave them in place as long as svn-based FreeBSD 11.x and 12.x are supported. 0D) Run the configure script: $ sh freebsd-configure.sh 0E) Review changes to config.h very carefully. Note that libwrap should not be defined in config.h; as of r311585 (233932cc2a60) it is conditional on MK_TCP_WRAPPERS. 0F) If source files have been added or removed, update the appropriate makefiles to reflect changes in the vendor's Makefile.in. 10) Update ssh_namespace.h: $ sh freebsd-namespace.sh 11) Build and install world, reboot, test. Pay particular attention to pam_ssh(8), which gropes inside libssh and will break if something significant changes or if ssh_namespace.h is out of whack. 12) Commit, and hunker down for the inevitable storm of complaints. An overview of FreeBSD changes to OpenSSH-portable ================================================== * don't free string returned by login_getcapstr(3) Committed upstream as f060c2bc85d59d111fa18a12eb3872ee4b9f7e97 * Use login_getpwclass() instead of login_getclass() Committed upstream as 3d05e5881ceb2e48e1948ba14292216b56ed792e 0) VersionAddendum The SSH protocol allows for a human-readable version string of up to 40 characters to be appended to the protocol version string. FreeBSD takes advantage of this to include a date indicating the "patch level", so people can easily determine whether their system is vulnerable when an OpenSSH advisory goes out. Some people, however, dislike advertising their patch level in the protocol handshake, so we've added a VersionAddendum configuration variable to allow them to change or disable it. Upstream added support for VersionAddendum on the server side, but we also support it on the client side. 1) Modified server-side defaults We've modified some configuration defaults in sshd: - UsePAM defaults to "yes". - PermitRootLogin defaults to "no". - X11Forwarding defaults to "yes". - PasswordAuthentication defaults to "no". - VersionAddendum defaults to "FreeBSD-YYYYMMDD". - PrivilegeSeparation defaults to "sandbox". - UseDNS defaults to "yes". 2) Modified client-side defaults We've modified some configuration defaults in ssh: - CheckHostIP defaults to "no". - VerifyHostKeyDNS defaults to "yes" if built with LDNS. - VersionAddendum defaults to "FreeBSD-YYYYMMDD". 3) Canonic host names We've added code to ssh.c to canonicize the target host name after reading options but before trying to connect. This eliminates the usual problem with duplicate known_hosts entries. 4) setusercontext() environment Our setusercontext(3) can set environment variables, which we must take care to transfer to the child's environment. 5) TCP wrappers Support for TCP wrappers was removed in upstream 6.7p1. We've added it back by porting the 6.6p1 code forward. TCP wrappers support in sshd will be disabled in HEAD and will be removed from FreeBSD in the future. 6) Agent client reference counting We've added code to ssh-agent.c to implement client reference counting; the agent will automatically exit when the last client disconnects. 7) Class-based login restrictions We've added code to auth2.c to enforce the host.allow, host.deny, times.allow and times.deny login class capabilities. 8) HPN We no longer have the HPN patches (adaptive buffer size for increased throughput on high-BxD links), but we recognize and ignore HPN-related configuration options to avoid breaking existing configurations. This port was brought to you by (in no particular order) DARPA, NAI Labs, ThinkSec, Nescafé, the Aberlour Glenlivet Distillery Co., Suzanne Vega, and a Sanford's #69 Deluxe Marker. -- des@FreeBSD.org $FreeBSD$