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 00) 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 01) Download the latest OpenSSH-portable tarball and signature from
13 OpenBSD (https://ftp.openbsd.org/pub/OpenBSD/OpenSSH/portable/).
15 02) Verify the signature:
17 $ gpg --verify openssh-X.YpZ.tar.gz.asc
19 03) Unpack the tarball in a suitable directory:
21 $ tar xf openssh-X.YpZ.tar.gz
23 04) 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 05) 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 08) Check out head and run the pre-merge script, which strips our RCS
43 tags from files that have them:
45 $ cd src/freebsd/main/crypto/openssh
46 $ sh freebsd-pre-merge.sh
48 09) Merge from the vendor branch:
50 $ git subtree merge -P crypto/openssh vendor/openssh
52 A number of files have been deleted from FreeBSD's copy of ssh,
53 including rendered man pages (which have a .0 extension). When
54 git prompts for these deleted files during the merge, choose 'd'
55 (leaving them deleted).
57 0A) Resolve conflicts. Remember to bump the version addendum in
58 version.h, and update the default value in ssh{,d}_config and
61 0B) Diff against the vendor branch:
63 $ git diff --diff-filter=M vendor/openssh/X.YpZ HEAD:crypto/openssh
65 Files that have modifications relative to the vendor code, and
66 only those files, must have the svn:keywords property set to
67 FreeBSD=%H and be listed in the 'keywords' file created by the
70 0C) Run the post-merge script, which re-adds RCS tags to files that
73 $ sh freebsd-post-merge.sh
75 These tags are not used with git, but we will leave them in place as
76 long as svn-based FreeBSD 11.x and 12.x are supported.
78 0D) Run the configure script:
80 $ sh freebsd-configure.sh
82 0E) Review changes to config.h very carefully.
84 Note that libwrap should not be defined in config.h; as of
85 r311585 (233932cc2a60) it is conditional on MK_TCP_WRAPPERS.
87 0F) If source files have been added or removed, update the appropriate
88 makefiles to reflect changes in the vendor's Makefile.in.
90 10) Update ssh_namespace.h:
92 $ sh freebsd-namespace.sh
94 11) Build and install world, reboot, test. Pay particular attention
95 to pam_ssh(8), which gropes inside libssh and will break if
96 something significant changes or if ssh_namespace.h is out of
99 12) Commit, and hunker down for the inevitable storm of complaints.
103 An overview of FreeBSD changes to OpenSSH-portable
104 ==================================================
106 * don't free string returned by login_getcapstr(3)
108 Committed upstream as f060c2bc85d59d111fa18a12eb3872ee4b9f7e97
110 * Use login_getpwclass() instead of login_getclass()
112 Committed upstream as 3d05e5881ceb2e48e1948ba14292216b56ed792e
116 The SSH protocol allows for a human-readable version string of up
117 to 40 characters to be appended to the protocol version string.
118 FreeBSD takes advantage of this to include a date indicating the
119 "patch level", so people can easily determine whether their system
120 is vulnerable when an OpenSSH advisory goes out. Some people,
121 however, dislike advertising their patch level in the protocol
122 handshake, so we've added a VersionAddendum configuration variable
123 to allow them to change or disable it. Upstream added support for
124 VersionAddendum on the server side, but we also support it on the
127 1) Modified server-side defaults
129 We've modified some configuration defaults in sshd:
131 - UsePAM defaults to "yes".
132 - PermitRootLogin defaults to "no".
133 - X11Forwarding defaults to "yes".
134 - PasswordAuthentication defaults to "no".
135 - VersionAddendum defaults to "FreeBSD-YYYYMMDD".
136 - PrivilegeSeparation defaults to "sandbox".
137 - UseDNS defaults to "yes".
139 2) Modified client-side defaults
141 We've modified some configuration defaults in ssh:
143 - CheckHostIP defaults to "no".
144 - VerifyHostKeyDNS defaults to "yes" if built with LDNS.
145 - VersionAddendum defaults to "FreeBSD-YYYYMMDD".
147 3) Canonic host names
149 We've added code to ssh.c to canonicize the target host name after
150 reading options but before trying to connect. This eliminates the
151 usual problem with duplicate known_hosts entries.
153 4) setusercontext() environment
155 Our setusercontext(3) can set environment variables, which we must
156 take care to transfer to the child's environment.
160 Support for TCP wrappers was removed in upstream 6.7p1. We've
161 added it back by porting the 6.6p1 code forward.
163 TCP wrappers support in sshd will be disabled in HEAD and will
164 be removed from FreeBSD in the future.
166 6) Agent client reference counting
168 We've added code to ssh-agent.c to implement client reference
169 counting; the agent will automatically exit when the last client
172 7) Class-based login restrictions
174 We've added code to auth2.c to enforce the host.allow, host.deny,
175 times.allow and times.deny login class capabilities.
179 We no longer have the HPN patches (adaptive buffer size for
180 increased throughput on high-BxD links), but we recognize and
181 ignore HPN-related configuration options to avoid breaking existing
186 This port was brought to you by (in no particular order) DARPA, NAI
187 Labs, ThinkSec, Nescafé, the Aberlour Glenlivet Distillery Co.,
188 Suzanne Vega, and a Sanford's #69 Deluxe Marker.