From: Micah Anderson Date: Tue, 18 Nov 2008 06:36:18 +0000 (-0500) Subject: Merge commit 'dkg/master' X-Git-Tag: monkeysphere_0.22-1~13^2 X-Git-Url: https://codewiz.org/gitweb?a=commitdiff_plain;h=647a0fc70e28d641d914f183489d815d4feb7e2b;hp=909d963139377f573b4350745b60606d65214c17;p=monkeysphere.git Merge commit 'dkg/master' --- diff --git a/changelog b/changelog index b9a9e21..4264fa4 120000 --- a/changelog +++ b/changelog @@ -1 +1 @@ -website/changelog \ No newline at end of file +packaging/debian/changelog \ No newline at end of file diff --git a/packaging/debian/changelog b/packaging/debian/changelog index 62f021e..39e4b33 100644 --- a/packaging/debian/changelog +++ b/packaging/debian/changelog @@ -1,3 +1,21 @@ +monkeysphere (0.22~pre-1) UNRELEASED; urgency=low + + * New upstream release: + [ Jameson Rollins ] + + - added info log output when a new key is added to known_hosts file. + - added some useful output to the ssh-proxycommand for "marginal" + cases where keys are found for host but do not have full validity. + - force ssh-keygen to read from stdin to get ssh key fingerprint. + + [ Daniel Kahn Gillmor ] + + - automatically output two copies of the host's public key: one + standard ssh public key file, and the other a minimal OpenPGP key with + just the latest valid self-sig. + + -- Jameson Graef Rollins Mon, 17 Nov 2008 18:15:43 -0500 + monkeysphere (0.21-2) unstable; urgency=low * actually rmdir /var/lib/monkeysphere-* during prerm if possible. diff --git a/src/common b/src/common index 297e7f3..51b0470 100644 --- a/src/common +++ b/src/common @@ -639,7 +639,7 @@ process_user_id() { ;; 'uid') # user ids if [ "$lastKey" != pub ] ; then - log verbose " - got a user ID after a sub key?! user IDs should only follow primary keys!" + log verbose " ! got a user ID after a sub key?! user IDs should only follow primary keys!" continue fi # if an acceptable user ID was already found, skip @@ -652,6 +652,8 @@ process_user_id() { if [ "$validity" = 'u' -o "$validity" = 'f' ] ; then # mark user ID acceptable uidOK=true + else + log debug " - unacceptable user ID validity ($validity)." fi else continue @@ -693,10 +695,12 @@ process_user_id() { # if sub key validity is not ok, skip if [ "$validity" != 'u' -a "$validity" != 'f' ] ; then + log debug " - unacceptable sub key validity ($validity)." continue fi # if sub key capability is not ok, skip if ! check_capability "$usage" $requiredCapability ; then + log debug " - unacceptable sub key capability ($usage)." continue fi @@ -742,6 +746,7 @@ process_user_id() { process_host_known_hosts() { local host local userID + local noKey= local nKeys local nKeysOK local ok @@ -768,8 +773,9 @@ process_host_known_hosts() { continue fi - # remove the old host key line, and note if removed - remove_line "$KNOWN_HOSTS" "$sshKey" + # remove any old host key line, and note if removed nothing is + # removed + remove_line "$KNOWN_HOSTS" "$sshKey" || noKey=true # if key OK, add new host line if [ "$ok" -eq '0' ] ; then @@ -788,6 +794,11 @@ process_host_known_hosts() { else ssh2known_hosts "$host" "$sshKey" >> "$KNOWN_HOSTS" fi + + # log if this is a new key to the known_hosts file + if [ "$noKey" ] ; then + log info "* new key for $host added to known_hosts file." + fi fi done diff --git a/src/monkeysphere-server b/src/monkeysphere-server index 5edaa4f..a1844ee 100755 --- a/src/monkeysphere-server +++ b/src/monkeysphere-server @@ -132,13 +132,13 @@ show_server_key() { fingerprint=$(fingerprint_server_key) gpg_authentication "--fingerprint --list-key --list-options show-unusable-uids $fingerprint" - # dumping to a file named ' ' so that the ssh-keygen output - # doesn't claim any potentially bogus hostname(s): - tmpkey=$(mktemp ${TMPDIR:-/tmp}/tmp.XXXXXXXXXX) || failure "Could not create temporary directory!" - gpg_authentication "--export $fingerprint" | openpgp2ssh "$fingerprint" 2>/dev/null > "$tmpkey" + # do some crazy "Here Strings" redirection to get the key to + # ssh-keygen, since it doesn't read from stdin cleanly echo -n "ssh fingerprint: " - ssh-keygen -l -f $tmpkey | awk '{ print $1, $2, $4 }' - rm -rf "$tmpkey" + ssh-keygen -l -f /dev/stdin \ + <<<$(gpg_authentication "--export $fingerprint" | \ + openpgp2ssh "$fingerprint" 2>/dev/null) | \ + awk '{ print $1, $2, $4 }' echo -n "OpenPGP fingerprint: " echo "$fingerprint" } @@ -399,7 +399,11 @@ EOF (umask 077 && \ gpg_host --export-secret-key "$fingerprint" | \ openpgp2ssh "$fingerprint" > "${SYSDATADIR}/ssh_host_rsa_key") - log info "private SSH host key output to file: ${SYSDATADIR}/ssh_host_rsa_key" + log info "SSH host private key output to file: ${SYSDATADIR}/ssh_host_rsa_key" + ssh-keygen -y -f "${SYSDATADIR}/ssh_host_rsa_key" > "${SYSDATADIR}/ssh_host_rsa_key.pub" + log info "SSH host public key output to file: ${SYSDATADIR}/ssh_host_rsa_key.pub" + gpg_authentication "--export-options export-minimal --armor --export 0x${fingerprint}\!" > "${SYSDATADIR}/ssh_host_rsa_key.pub.gpg" + log info "SSH host public key in OpenPGP form: ${SYSDATADIR}/ssh_host_rsa_key.pub.gpg" } # extend the lifetime of a host key: diff --git a/src/monkeysphere-ssh-proxycommand b/src/monkeysphere-ssh-proxycommand index 6276092..a609199 100755 --- a/src/monkeysphere-ssh-proxycommand +++ b/src/monkeysphere-ssh-proxycommand @@ -13,14 +13,130 @@ # established. Can be added to ~/.ssh/config as follows: # ProxyCommand monkeysphere-ssh-proxycommand %h %p +######################################################################## +PGRM=$(basename $0) + +SYSSHAREDIR=${MONKEYSPHERE_SYSSHAREDIR:-"/usr/share/monkeysphere"} +export SYSSHAREDIR +. "${SYSSHAREDIR}/common" || exit 1 + +######################################################################## +# FUNCTIONS ######################################################################## usage() { -cat <&2 + cat <&2 usage: ssh -o ProxyCommand="$(basename $0) %h %p" ... EOF } +log() { + echo "$@" >&2 +} + +output_no_valid_key() { + local sshKeyOffered + local userID + local type + local validity + local keyid + local uidfpr + local usage + local sshKeyGPG + local tmpkey + local sshFingerprint + local gpgSigOut + + userID="ssh://${HOSTP}" + + log "-------------------- Monkeysphere warning -------------------" + log "Monkeysphere found OpenPGP keys for this hostname, but none had full validity." + + # retrieve the actual ssh key + sshKeyOffered=$(ssh-keyscan -t rsa -p "$PORT" "$HOST" 2>/dev/null | awk '{ print $2, $3 }') + # FIXME: should we do any checks for failed keyscans, eg. host not + # found? + + # get the gpg info for userid + gpgOut=$(gpg --list-key --fixed-list-mode --with-colon \ + --with-fingerprint --with-fingerprint \ + ="$userID" 2>/dev/null) + + # find all 'pub' and 'sub' lines in the gpg output, which each + # represent a retrieved key for the user ID + echo "$gpgOut" | cut -d: -f1,2,5,10,12 | \ + while IFS=: read -r type validity keyid uidfpr usage ; do + case $type in + 'pub'|'sub') + # get the ssh key of the gpg key + sshKeyGPG=$(gpg2ssh "$keyid") + + # if one of keys found matches the one offered by the + # host, then output info + if [ "$sshKeyGPG" = "$sshKeyOffered" ] ; then + log "An OpenPGP key matching the ssh key offered by the host was found:" + log + + # do some crazy "Here Strings" redirection to get the key to + # ssh-keygen, since it doesn't read from stdin cleanly + sshFingerprint=$(ssh-keygen -l -f /dev/stdin \ + <<<$(echo "$sshKeyGPG") | \ + awk '{ print $2 }') + + # get the sigs for the matching key + gpgSigOut=$(gpg --check-sigs \ + --list-options show-uid-validity \ + "$keyid") + + # output the sigs, but only those on the user ID + # we are looking for + echo "$gpgSigOut" | awk ' +{ +if (match($0,"^pub")) { print; } +if (match($0,"^uid")) { ok=0; } +if (match($0,"^uid.*'$userID'$")) { ok=1; print; } +if (ok) { if (match($0,"^sig")) { print; } } +} +' >&2 + log + + # output the other user IDs for reference + if (echo "$gpgSigOut" | grep "^uid" | grep -v -q "$userID") ; then + log "Other user IDs on this key:" + echo "$gpgSigOut" | grep "^uid" | grep -v "$userID" >&2 + log + fi + + # output ssh fingerprint + log "RSA key fingerprint is ${sshFingerprint}." + + # this whole process is in a "while read" + # subshell. the only way to get information out + # of the subshell is to change the return code. + # therefore we return 1 here to indicate that a + # matching gpg key was found for the ssh key + # offered by the host + return 1 + fi + ;; + esac + done + + # if no key match was made (and the "while read" subshell returned + # 1) output how many keys were found + if (($? != 1)) ; then + log "None of the found keys matched the key offered by the host." + log "Run the following command for more info about the found keys:" + log "gpg --check-sigs --list-options show-uid-validity =${userID}" + # FIXME: should we do anything extra here if the retrieved + # host key is actually in the known_hosts file and the ssh + # connection will succeed? Should the user be warned? + # prompted? + fi + + log "-------------------- ssh continues below --------------------" +} + ######################################################################## # export the monkeysphere log level @@ -35,7 +151,7 @@ HOST="$1" PORT="$2" if [ -z "$HOST" ] ; then - echo "Host not specified." >&2 + log "Host not specified." usage exit 255 fi @@ -88,6 +204,39 @@ export MONKEYSPHERE_CHECK_KEYSERVER # update the known_hosts file for the host monkeysphere update-known_hosts "$HOSTP" +# output on depending on the return of the update-known_hosts +# subcommand, which is (ultimately) the return code of the +# update_known_hosts function in common +case $? in + 0) + # acceptable host key found so continue to ssh + true + ;; + 1) + # no hosts at all found so also continue (drop through to + # regular ssh host verification) + true + ;; + 2) + # at least one *bad* host key (and no good host keys) was + # found, so output some usefull information + output_no_valid_key + ;; + *) + # anything else drop through + true + ;; +esac + +# FIXME: what about the case where monkeysphere successfully finds a +# valid key for the host and adds it to the known_hosts file, but a +# different non-monkeysphere key for the host already exists in the +# known_hosts, and it is this non-ms key that is offered by the host? +# monkeysphere will succeed, and the ssh connection will succeed, and +# the user will be left with the impression that they are dealing with +# a OpenPGP/PKI host key when in fact they are not. should we use +# ssh-keyscan to compare the keys first? + # exec a netcat passthrough to host for the ssh connection if [ -z "$NO_CONNECT" ] ; then if (which nc 2>/dev/null >/dev/null); then diff --git a/utils/build-releasenote b/utils/build-releasenote index 522917c..b25a87c 100755 --- a/utils/build-releasenote +++ b/utils/build-releasenote @@ -4,7 +4,7 @@ VERSION=`head -n1 packaging/debian/changelog | sed 's/.*(\([^)]*\)).*/\1/'` { sed "s/__VERSION__/$VERSION/g" < utils/releasenote.header - head -n$(( $(grep -n '^ --' debian/changelog | head -n1 | cut -f1 -d:) - 2 )) debian/changelog | tail -n+3 + head -n$(( $(grep -n '^ --' packaging/debian/changelog | head -n1 | cut -f1 -d:) - 2 )) packaging/debian/changelog | tail -n+3 sed "s/__VERSION__/$VERSION/g" < utils/releasenote.footer } > "website/news/release-$VERSION.mdwn" diff --git a/website/bugs/useful-information.mdwn b/website/bugs/useful-information.mdwn deleted file mode 100644 index 0750354..0000000 --- a/website/bugs/useful-information.mdwn +++ /dev/null @@ -1,10 +0,0 @@ -I would like to know, at INFO (default) log level, when the -monkeyspehere makes a "real" modification to my known_hosts file; that -is, when it adds or deletes a key. - -Apparently this is hard because monkeysphere is currently configured to -delete all keys and then add good keys, so a key added for the first -time seems to the monkeysphere very similar to a key re-added ten -seconds after last login. - -Still, from a UI perspective, I want to know what monkeysphere is doing. diff --git a/website/bugs/useful_information.mdwn b/website/bugs/useful_information.mdwn new file mode 100644 index 0000000..025d678 --- /dev/null +++ b/website/bugs/useful_information.mdwn @@ -0,0 +1,50 @@ +I would like to know, at INFO (default) log level, when the +monkeyspehere makes a "real" modification to my known\_hosts file; that +is, when it adds or deletes a key. + +Apparently this is hard because monkeysphere is currently configured to +delete all keys and then add good keys, so a key added for the first +time seems to the monkeysphere very similar to a key re-added ten +seconds after last login. + +Still, from a UI perspective, I want to know what monkeysphere is doing. + +------ + +It looks like jrollins committed a change for reporting at INFO level +when a host key gets added by the monkeysphere: +2459fa3ea277d7b9289945748619eab1e3441e5c + +When i connect to a host whose key is not already present in my +known_hosts file, i get the following to stderr: + + ms: * new key for squeak.fifthhorseman.net added to known_hosts file. + +This doesn't fully close this bug, because we aren't notifying on key +deletion, afaict. + +------ + +So current log level DEBUG will output a message if the known host +file has been modified. If the issue is that you want to know at the +default log level everytime the known\_hots file is modified, then we +should just move this message to INFO instead of debug, and then maybe +remove the message that I added above. I was under the impression +that the issue was more about notification that a *new* key was added +to the known\_hosts file, and therefore the new INFO message above +fixed that problem. Should we do this instead? + +In general, more verbose log levels *do* tell the user what the +monkeysphere is doing. Moving to DEBUG log level will tell you pretty +much everything that happens. I do *not* think that this should be +the default log level, though. + +------ + +I wouldn't want to see an extremely verbose default log level. But i +do think that saying something like "key blah blah blah was stripped +from your known\_hosts file because it was expired" (for example) +would be useful. I think this case would occur infrequently enough +that it is worth reporting in the UI at the regular log level. + + --dkg diff --git a/website/doc.mdwn b/website/doc.mdwn index b60cf28..02b4184 100644 --- a/website/doc.mdwn +++ b/website/doc.mdwn @@ -8,6 +8,10 @@ * Getting started as a [user](/getting-started-user) * Getting started as a [server admin](/getting-started-admin) +## Going further ## + + * [Signing server keys](/signing-server-keys) + ## Under the hood ## * [Developing the monkeysphere](/community) @@ -15,7 +19,7 @@ ## References ## - * [Initial specifications at CMRG](http://cmrg.fifthhorseman.net/wiki/OpenPGPandSSH) + * [Initial Monkeysphere specifications at CMRG](http://cmrg.fifthhorseman.net/wiki/OpenPGPandSSH) * [OpenPGP (RFC 4880)](http://tools.ietf.org/html/rfc4880) * [Secure Shell Authentication Protocol (RFC 4252)](http://tools.ietf.org/html/rfc4252) * [URI scheme for SSH, RFC draft](http://tools.ietf.org/wg/secsh/draft-ietf-secsh-scp-sftp-ssh-uri/) diff --git a/website/getting-started-admin.mdwn b/website/getting-started-admin.mdwn index 6c8ad53..1c373ac 100644 --- a/website/getting-started-admin.mdwn +++ b/website/getting-started-admin.mdwn @@ -7,6 +7,7 @@ so that your users can have it automatically verified, and you can set up your machine to automatically identify connecting users by their presence in the OpenPGP web of trust. + Server host key publication --------------------------- To generate and publish a server host key: @@ -48,6 +49,7 @@ effect. As with any change to `sshd_config`, be sure to retain an existing session to the machine while you test your changes so you don't get locked out. + Monkeysphere authorized_keys maintenance ---------------------------------------- diff --git a/website/getting-started-user.mdwn b/website/getting-started-user.mdwn index 5dcb0d6..9b04edc 100644 --- a/website/getting-started-user.mdwn +++ b/website/getting-started-user.mdwn @@ -20,6 +20,7 @@ done with a simple cronjob. An example of crontab line to do this is: This would refresh your keychain every day at noon. + Install the monkeysphere software on your system ------------------------------------------------ @@ -31,8 +32,9 @@ installed on your system. If you can't (or don't want to) upgrade to GnuTLS 2.6 or later, there are patches for GnuTLS 2.4 available in [the Monkeysphere git repo](/community). + Keeping your `known_hosts` file in sync with your keyring ------------------------------------------------------------ +--------------------------------------------------------- With your keyring updated, you want to make sure that OpenSSH can still see the most recent trusted information about who the various @@ -47,6 +49,7 @@ key for that host to the `known_hosts` file if one is found. This command could be added to a crontab as well, if desired. + Using `monkeysphere-ssh-proxycommand`(1) ---------------------------------------- @@ -91,6 +94,7 @@ If you have more than one secret key, you'll need to specify the key you want to add the subkey to on the command line. + Using your OpenPGP authentication key for SSH --------------------------------------------- @@ -105,6 +109,7 @@ you can feed your authentication subkey to your ssh agent by running: FIXME: using the key with a single ssh connection? + Establish trust --------------- diff --git a/website/signing-host-keys.mdwn b/website/signing-host-keys.mdwn new file mode 100644 index 0000000..e0d26a7 --- /dev/null +++ b/website/signing-host-keys.mdwn @@ -0,0 +1,128 @@ +# Signing a server OpenPGP key # + +This page is meant to address the issue of signing server OpenPGP +keys. Servers are not people, so the circumstances under which one +should sign a server key are different from those under which one +should sign another person's key. + +# Why are signatures on the server key important? # + +In order for users to connect to a server in a monkeysphere-enabled +network, the server key must have *full* calculated validity from the +perspective of the connecting user. If the user has not themselves +signed the server's key, then the server's key can only be valid if +other people that the user trusts have signed the key. + +If only one person has signed the server's key, then the user must +fully trust the single person who has signed the server key. Full +trust should be granted sparingly and with consideration, though, so +unless the user knows the server admin very well, they will in general +not have full trust of this person. + +However, full trust of the server key can also be achieved if the +server key has been signed by three or more people that the user has + *marginal* trust of. In other words, three or more *marginally* +trusted signatures equals one *fully* trusted signature. It is much +more common for users to have marginal trust of other users in the Web +of Trust. For this reason, it is advisable to have as many people +sign the server key as possible. + +## What information should you have before signing a server key? ## + +Before signing the key of a person, you want to do two things: + +1. verify the identity of the person. +2. verify that the person is actually in control of the key that you +are signing. + +For a server, you want to do basically the same thing: + +1. verify the identity of the server. +2. verify that the server is actually in control of the key that you +are signing. + +However, with a server, verifying these things is a little trickier. + +Verifying that the server is in control of the key is, in principle, +straightforward. If you are logged on to the machine in question, +then you can check directly that the key exists on the system. + +What is not so straightforward is what exactly it means to "verify the +identity" of a remote server on the internet? The identity in this +case is the fully qualified domain name (FQDN) of the host. Verifying +this identity amounts to being sure that the host in question really +is located at that FQDN. + + +## Signing the server key ## + +If you are the person (or persons) that actually setup the server and +configured Monkeysphere and ssh on the server, then clearly you should +definitely sign the server key right away. When the server is first +setup, the persons who set it up are the only ones who can actually +vouch for the server key, so their signatures are necessary to get +things going. Their signatures are also necessary so that they can +verify the host key themselves and log into the server via +monkeysphere-enabled ssh in the future. + +If you did not set up the server initially, you do not have an +accumulated full trust of the person(s) who did, and you do not +necessarily have console access to the server directly, it's hard to +confidently verify the server identity and key ownership. You would +like to be able to walk up to the server, log in at the console, and +get the fingerprint of the ssh host key directly. But this is usually +untenable. + +However, it is still possible to verify the server identity *and* +server ownership of the key, even in this case. + + +## Remotely verifying server identify and key possession ## + +It is in fact possible to verify the identity and key ownership of a +server in one fell swoop with monkeysphere-enabled ssh. Here is the +procedure: + +> **Attempt to make a monkeysphere-enabled ssh connection to the host in +question. Monkeysphere will check that the ssh host key offered by the +host matches the OpenPGP key with the correct host FQDN user ID. If +the ssh host key and the OpenPGP key with the correct user ID match, +then you will have effectively:** + +>**1. verified the host identity, because you actually connected to the +host in question, which you know because you:** + +>**2. verified the host is in control of the key, because the ssh host +key offered by the host matches the OpenPGP key with correct host FQDN +user ID.** + +Here is an example: + + servo:~ 0$ ssh zimmermann.mayfirst.org + -------------------- Monkeysphere warning ------------------- + Monkeysphere found OpenPGP keys for this hostname, but none had full validity. + An OpenPGP key matching the ssh key offered by the host was found: + + pub 2048R/860E8F9C 2008-10-29 [expires: 2009-02-26] + uid [marginal] ssh://zimmermann.mayfirst.org + sig! 76CC057D 2008-11-15 Jamie McClelland + sig!3 860E8F9C 2008-10-29 ssh://zimmermann.mayfirst.org + sig! D21739E9 2008-10-29 Daniel Kahn Gillmor + sig! 1CF2D62A 2008-11-16 Micah Anderson + + RSA key fingerprint is 81:96:13:3e:24:c9:3c:5b:3c:6d:55:ba:58:85:e9:9e. + -------------------- ssh continues below -------------------- + The authenticity of host 'zimmermann.mayfirst.org ()' can't be established. + RSA key fingerprint is 81:96:13:3e:24:c9:3c:5b:3c:6d:55:ba:58:85:e9:9e. + No matching host key fingerprint found in DNS. + Are you sure you want to continue connecting (yes/no)? no + Host key verification failed. + servo:~ 255$ + +I have attempted to connect to the host zimmermann.mayfirst.org. +zimmermann's host key has only *marginal* validity for the FQDN user +ID in question, so I am not able to connect. However, the +monkeysphere has checked that the ssh host key actually does match the +OpenPGP key with the correct user ID `ssh://zimmermann.mayfirst.org`. +I have therefore verified the identity of zimmermann, and verified +that zimmermann is in possession of the key in question.