1 FreeBSD maintainer's guide to OpenSSH-portable 2 ============================================== 3 4 These instructions assume you have a clone of the FreeBSD git repo 5 main branch in src/freebsd/main, and will store vendor trees under 6 src/freebsd/vendor/. In addition, this assumes there is a "freebsd" 7 origin pointing to git(repo).freebsd.org/src.git. 8 900) Make sure your mail spool has plenty of free space. It'll fill up 10 pretty fast once you're done with this checklist. 11 1201) Download the latest OpenSSH-portable tarball and signature from 13 OpenBSD (https://ftp.openbsd.org/pub/OpenBSD/OpenSSH/portable/). 14 1502) Verify the signature: 16 17 $ gpg --verify openssh-X.YpZ.tar.gz.asc 18 1903) Unpack the tarball in a suitable directory: 20 21 $ tar xf openssh-X.YpZ.tar.gz 22 2304) Copy to a vendor branch: 24 25 $ cd src/freebsd/main 26 $ git worktree add ../vendor/openssh freebsd/vendor/openssh 27 $ cd ../vendor/openssh 28 $ rsync --archive --delete --exclude=.git /path/to/openssh-X.YpZ/ ./ 29 3005) Take care of added / deleted files: 31 32 $ git add -A 33 3406) Commit: 35 36 $ git commit -m "Vendor import of OpenSSH X.YpZ" 37 3807) Tag: 39 40 $ git tag -a -m "Tag OpenSSH X.YpZ" vendor/openssh/X.YpZ 41 42 At this point the vendor branch can be pushed to the FreeBSD repo via: 43 44 $ git push freebsd vendor/openssh 45 $ git push freebsd vendor/openssh/X.YpZ 46 47 Note the second "git push" command is used to push the tag, which is 48 not pushed by default. 49 50 It is also possible to push the branch and tag together, but use 51 --dry-run first to ensure that no undesired tags will be pushed: 52 53 $ git push --dry-run --follow-tags freebsd vendor/openssh 54 $ git push --follow-tags freebsd vendor/openssh 55 56 The update and tag could instead be pushed later, along with the merge 57 to main, but pushing now allows others to collaborate. 58 5908) Check out head and run the pre-merge script, which strips our RCS 60 tags from files that have them: 61 62 $ cd src/freebsd/main/crypto/openssh 63 $ sh freebsd-pre-merge.sh 64 6509) Merge from the vendor branch: 66 67 $ git subtree merge -P crypto/openssh vendor/openssh 68 69 A number of files have been deleted from FreeBSD's copy of ssh, 70 including rendered man pages (which have a .0 extension). When 71 git prompts for these deleted files during the merge, choose 'd' 72 (leaving them deleted). 73 740A) Resolve conflicts. Remember to bump the version addendum in 75 version.h, and update the default value in ssh{,d}_config and 76 ssh{,d}_config.5. 77 780B) Diff against the vendor branch: 79 80 $ git diff --diff-filter=M vendor/openssh/X.YpZ HEAD:crypto/openssh 81 82 Files that have modifications relative to the vendor code, and 83 only those files, must have the svn:keywords property set to 84 FreeBSD=%H and be listed in the 'keywords' file created by the 85 pre-merge script. 86 870C) Run the post-merge script, which re-adds RCS tags to files that 88 need them: 89 90 $ sh freebsd-post-merge.sh 91 92 These tags are not used with git, but we will leave them in place as 93 long as svn-based FreeBSD 12.x is supported. 94 950D) Run the configure script: 96 97 $ sh freebsd-configure.sh 98 990E) Review changes to config.h very carefully. 100 101 Note that libwrap should not be defined in config.h; as of 102 r311585 (233932cc2a60) it is conditional on MK_TCP_WRAPPERS. 103 1040F) If source files have been added or removed, update the appropriate 105 makefiles to reflect changes in the vendor's Makefile.in. 106 10710) Update ssh_namespace.h: 108 109 $ sh freebsd-namespace.sh 110 11111) Build and install world, reboot, test. Pay particular attention 112 to pam_ssh(8), which gropes inside libssh and will break if 113 something significant changes or if ssh_namespace.h is out of 114 whack. 115 11612) Update nanobsd's copies of the ssh config files: 117 118 tools/tools/nanobsd/rescue/Files/etc/ssh/ssh_config 119 tools/tools/nanobsd/rescue/Files/etc/ssh/sshd_config 120 12113) Check for references to obsolete configuration options 122 (e.g., ChallengeResponseAuthentication in sshd_config) which 123 may exist in release/ scripts. 124 12514) Commit, and hunker down for the inevitable storm of complaints. 126 127 128 129 An overview of FreeBSD changes to OpenSSH-portable 130 ================================================== 131 1320) VersionAddendum 133 134 The SSH protocol allows for a human-readable version string of up 135 to 40 characters to be appended to the protocol version string. 136 FreeBSD takes advantage of this to include a date indicating the 137 "patch level", so people can easily determine whether their system 138 is vulnerable when an OpenSSH advisory goes out. Some people, 139 however, dislike advertising their patch level in the protocol 140 handshake, so we've added a VersionAddendum configuration variable 141 to allow them to change or disable it. Upstream added support for 142 VersionAddendum on the server side, but we also support it on the 143 client side. 144 1451) Modified server-side defaults 146 147 We've modified some configuration defaults in sshd: 148 149 - UsePAM defaults to "yes". 150 - PermitRootLogin defaults to "no". 151 - X11Forwarding defaults to "yes". 152 - PasswordAuthentication defaults to "no". 153 - VersionAddendum defaults to "FreeBSD-YYYYMMDD". 154 - PrivilegeSeparation defaults to "sandbox". 155 - UseDNS defaults to "yes". 156 1572) Modified client-side defaults 158 159 We've modified some configuration defaults in ssh: 160 161 - CheckHostIP defaults to "no". 162 - VerifyHostKeyDNS defaults to "yes" if built with LDNS. 163 - VersionAddendum defaults to "FreeBSD-YYYYMMDD". 164 1653) Canonic host names 166 167 We've added code to ssh.c to canonicize the target host name after 168 reading options but before trying to connect. This eliminates the 169 usual problem with duplicate known_hosts entries. 170 1714) setusercontext() environment 172 173 Our setusercontext(3) can set environment variables, which we must 174 take care to transfer to the child's environment. 175 1765) TCP wrappers 177 178 Support for TCP wrappers was removed in upstream 6.7p1. We've 179 added it back by porting the 6.6p1 code forward. 180 181 TCP wrappers support in sshd will be disabled in HEAD and will 182 be removed from FreeBSD in the future. 183 1846) Agent client reference counting 185 186 We've added code to ssh-agent.c to implement client reference 187 counting; the agent will automatically exit when the last client 188 disconnects. 189 1907) Class-based login restrictions (27ceebbc2402) 191 192 We've added code to auth.c to enforce the host.allow, host.deny, 193 times.allow and times.deny login class capabilities, based on an 194 upstream submission from 195 https://github.com/openssh/openssh-portable/pull/262. 196 1978) HPN 198 199 We no longer have the HPN patches (adaptive buffer size for 200 increased throughput on high-BxD links), but we recognize and 201 ignore HPN-related configuration options to avoid breaking existing 202 configurations. 203 204 205 206This port was brought to you by (in no particular order) DARPA, NAI 207Labs, ThinkSec, Nescafé, the Aberlour Glenlivet Distillery Co., 208Suzanne Vega, and a Sanford's #69 Deluxe Marker. 209 210 -- des@FreeBSD.org 211