1 FreeBSD maintainer's guide to OpenSSH-portable
2 ==============================================
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.
9 01) Make sure your mail spool has plenty of free space. It'll fill up
10 pretty fast once you're done with this checklist.
12 02) Download the latest OpenSSH-portable tarball and signature from
13 OpenBSD (https://ftp.openbsd.org/pub/OpenBSD/OpenSSH/portable/).
15 03) Verify the signature:
17 $ gpg --verify openssh-X.YpZ.tar.gz.asc
19 04) Unpack the tarball in a suitable directory:
21 $ tar xf openssh-X.YpZ.tar.gz
23 05) Copy to a vendor branch:
26 $ git worktree add ../vendor/openssh freebsd/vendor/openssh
27 $ cd ../vendor/openssh
28 $ rsync --archive --delete --exclude=.git /path/to/openssh-X.YpZ/ ./
30 06) Take care of added / deleted files:
36 $ git commit -m "Vendor import of OpenSSH X.YpZ"
40 $ git tag -a -m "Tag OpenSSH X.YpZ" vendor/openssh/X.YpZ
42 At this point the vendor branch can be pushed to the FreeBSD repo via:
44 $ git push freebsd vendor/openssh
45 $ git push freebsd vendor/openssh/X.YpZ
47 Note the second "git push" command is used to push the tag, which is
48 not pushed by default.
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:
53 $ git push --dry-run --follow-tags freebsd vendor/openssh
54 $ git push --follow-tags freebsd vendor/openssh
56 The update and tag could instead be pushed later, along with the merge
57 to main, but pushing now allows others to collaborate.
59 09) Merge from the vendor branch:
61 $ git subtree merge -P crypto/openssh vendor/openssh
63 A number of files have been deleted from FreeBSD's copy of ssh,
64 including rendered man pages (which have a .0 extension). When
65 git prompts for these deleted files during the merge, choose 'd'
66 (leaving them deleted).
68 10) Resolve conflicts. Remember to bump the version addendum in
69 version.h, and update the default value in sshd_config and
72 11) Diff against the vendor branch:
74 $ git diff --diff-filter=M vendor/openssh/X.YpZ HEAD:crypto/openssh
76 Review the diff for any unexpected changes.
78 12) Run the configure script:
81 $ sh freebsd-configure.sh
83 13) Review changes to config.h very carefully.
85 Note that libwrap should not be defined in config.h; as of
86 r311585 (233932cc2a60) it is conditional on MK_TCP_WRAPPERS.
88 14) If source files have been added or removed, update the appropriate
89 makefiles to reflect changes in the vendor's Makefile.in.
91 15) Update ssh_namespace.h:
94 $ sh freebsd-namespace.sh
96 16) Build and install world, reboot, test. Pay particular attention
97 to pam_ssh(8), which gropes inside libssh and will break if
98 something significant changes or if ssh_namespace.h is out of
101 17) Check for references to obsolete configuration options
102 (e.g., ChallengeResponseAuthentication in sshd_config) which
103 may exist in release/ scripts.
105 18) Commit, and hunker down for the inevitable storm of complaints.
109 An overview of FreeBSD changes to OpenSSH-portable
110 ==================================================
112 1) Modified server-side defaults
114 We've modified some configuration defaults in sshd:
116 - UsePAM defaults to "yes".
117 - PermitRootLogin defaults to "no".
118 - PasswordAuthentication defaults to "no".
119 - VersionAddendum defaults to "FreeBSD-YYYYMMDD".
120 - UseDNS defaults to "yes".
122 2) Modified client-side defaults
124 We defaulted CheckHostIP to "no" in 2000 (a95c1225217b). Upstream has
125 now made the same change, and we no longer have any modified client-side
128 3) Canonic host names
130 We've added code to ssh.c to canonicize the target host name after
131 reading options but before trying to connect. This eliminates the
132 usual problem with duplicate known_hosts entries.
134 We added this support in 2002 (r99054 / bf2e2524a2ce). In 2014
135 upstream introduced CanonicalDomains and related options to serve a
136 similar purpose but they require environment-specific configuration.
138 4) setusercontext() environment
140 Our setusercontext(3) can set environment variables, which we must
141 take care to transfer to the child's environment.
145 Support for TCP wrappers was removed in upstream 6.7p1. We've
146 added it back by porting the 6.6p1 code forward.
148 TCP wrappers support in sshd will be disabled in HEAD and will
149 be removed from FreeBSD in the future.
151 6) Agent client reference counting
153 We've added code to ssh-agent.c to implement client reference
154 counting; the agent will automatically exit when the last client
157 7) Class-based login restrictions (27ceebbc2402)
159 We've added code to auth.c to enforce the host.allow, host.deny,
160 times.allow and times.deny login class capabilities, based on an
161 upstream submission from
162 https://github.com/openssh/openssh-portable/pull/262.
164 8) Blocklist integration
166 We include blocklist (https://github.com/zoulasc/blocklist) in FreeBSD,
167 and ssh is patched to report login failures to it.
171 A number of paths are changed to match FreeBSD's configuration (e.g.,
172 using /usr/local/ instead of /uxr/X11R6/).
176 Coverity reported a memory leak for which we proposed a fix in
177 https://reviews.freebsd.org/D37253 and sent to the upstream mailing list at
178 https://lists.mindrot.org/pipermail/openssh-unix-dev/2022-November/040497.html
180 Upstream subsequently fixed only one of the related leaks, so we reverted
181 the partial fix and applied our change.
185 We no longer have HPN patches (adaptive buffer size for increased
186 throughput on high-BxD links) or client-side VersionAddendum, but we
187 recognize and ignore the configuration options to avoid breaking
188 existing configurations.
192 This port was brought to you by (in no particular order) DARPA, NAI
193 Labs, ThinkSec, Nescafé, the Aberlour Glenlivet Distillery Co.,
194 Suzanne Vega, and a Sanford's #69 Deluxe Marker.