diff options
| -rw-r--r-- | config/lacme.conf | 41 | ||||
| -rwxr-xr-x | lacme | 77 | ||||
| -rwxr-xr-x | lacme-accountd | 37 | ||||
| -rw-r--r-- | lacme.md | 42 |
4 files changed, 159 insertions, 38 deletions
diff --git a/config/lacme.conf b/config/lacme.conf index d64276c..23313c7 100644 --- a/config/lacme.conf +++ b/config/lacme.conf @@ -4,12 +4,15 @@ #config-certs = /etc/lacme/lacme-certs.conf [client] -# The value of "socket" specifies the lacme-accountd(1) UNIX-domain -# socket to connect to for signature requests from the ACME client. -# lacme(1) aborts if the socket is readable or writable by other users, -# or if its parent directory is writable by other users. +# The value of "socket" specifies the path to the lacme-accountd(1) +# UNIX-domain socket to connect to for signature requests from the ACME +# client. lacme(1) aborts if the socket is readable or writable by +# other users, or if its parent directory is writable by other users. # Default: "$XDG_RUNTIME_DIR/S.lacme" if the XDG_RUNTIME_DIR environment # variable is set. +# This option is ignored when lacme-accountd(1) is spawned by lacme(1), +# since the two processes communicate through a socket pair. See the +# "accountd" section below for details. # #socket = /run/user/1000/S.lacme @@ -83,4 +86,34 @@ # #iptables = Yes + +# lacme-accound(1) section. Comment out the following section to make +# lacme(1) connect to an existing UNIX-domain socket bound by a running +# acme-accountd(1). +[accountd] + +# username to drop privileges to (setting both effective and real uid). +# Preserve root privileges if the value is empty. +# +#user = root + +# groupname to drop privileges to (setting both effective and real gid, +# and also setting the list of supplementary gids to that single group). +# Preserve root privileges if the value is empty. +# +#group = root + +# Path to the lacme-accountd(1) executable. +#command = /usr/bin/lacme-accountd + +# Path to the lacme-accountd(1) configuration file. +#config = /etc/lacme/lacme-accountd.conf + +# The (private) account key to use for signing requests. See +# lacme-accountd(1) for details. +#privkey = file:/path/to/account.key + +# Be quiet. +#quiet = Yes + ; vim:ft=dosini @@ -30,7 +30,7 @@ use File::Temp (); use Getopt::Long qw/:config posix_default no_ignore_case gnu_getopt auto_version/; use List::Util 'first'; use POSIX (); -use Socket qw/PF_INET PF_INET6 PF_UNIX INADDR_ANY IN6ADDR_ANY +use Socket qw/AF_UNIX PF_INET PF_INET6 PF_UNIX PF_UNSPEC INADDR_ANY IN6ADDR_ANY SOCK_STREAM SOL_SOCKET SO_REUSEADDR SHUT_RDWR/; use Config::Tiny (); @@ -82,6 +82,7 @@ do { my $h = Config::Tiny::->read_string($conf) or die Config::Tiny::->errstr()."\n"; my $defaults = delete $h->{_} // {}; + my $accountd = exists $h->{accountd} ? 1 : 0; my %valid = ( client => { socket => (defined $ENV{XDG_RUNTIME_DIR} ? "$ENV{XDG_RUNTIME_DIR}/S.lacme" : undef), @@ -99,6 +100,14 @@ do { command => '/usr/lib/lacme/webserver', iptables => 'Yes' + }, + accountd => { + user => '', + group => '', + command => '/usr/bin/lacme-accountd', + config => '/etc/lacme/lacme-accountd.conf', + privkey => undef, + quiet => 'Yes', } ); foreach my $s (keys %valid) { @@ -110,6 +119,7 @@ do { } die "Invalid section(s): ".join(', ', keys %$h)."\n" if %$h; $CONFIG->{_} = $defaults; + delete $CONFIG->{accountd} unless $accountd; }; # Regular expressions for domain validation @@ -388,31 +398,58 @@ sub acme_client($@) { my $args = shift; my @args = @_; - my @stat; + my $client; my $conf = $CONFIG->{client}; - my $sockname = $OPTS{socket} // $conf->{socket} // die "Missing socket option\n"; - $sockname = $sockname =~ /\A(\p{Print}+)\z/ ? $1 : die "Invalid socket name\n"; # untaint $sockname - - # ensure we're the only user with write access to the parent dir - my $dirname = $sockname =~ s/[^\/]+$//r; - @stat = stat($dirname) or die "Can't stat $dirname: $!"; - die "Error: insecure permissions on $dirname\n" if ($stat[2] & 0022) != 0; - - # ensure we're the only user with read/write access to the socket - @stat = stat($sockname) or die "Can't stat $sockname: $! (Is lacme-accountd running?)\n"; - die "Error: insecure permissions on $sockname\n" if ($stat[2] & 0066) != 0; - - # connect(2) to the socket - socket(my $client, PF_UNIX, SOCK_STREAM, 0) or die "socket: $!"; - my $sockaddr = Socket::sockaddr_un($sockname) // die "Invalid address $sockname\n"; - until (connect($client, $sockaddr)) { - next if $! == EINTR; # try again if connect(2) was interrupted by a signal - die "connect: $!"; + if (defined (my $accountd = $CONFIG->{accountd})) { + socketpair($client, my $s, AF_UNIX, SOCK_STREAM, PF_UNSPEC) or die "socketpair: $!"; + my $pid = fork() // "fork: $!"; + unless ($pid) { + drop_privileges($accountd->{user}, $accountd->{group}, '/'); + set_FD_CLOEXEC($s, 0); + $client->close() or die "Can't close: $!"; + my @cmd = ($accountd->{command}, '--fdopen='.fileno($s)); + push @cmd, '--config='.$accountd->{config} if defined $accountd->{config}; + push @cmd, '--privkey='.$accountd->{privkey} if defined $accountd->{privkey}; + push @cmd, '--quiet' unless lc $accountd->{quiet} eq 'no'; + push @cmd, '--debug' if $OPTS{debug}; + exec { $cmd[0] } @cmd or die; + } + print STDERR "[$$] Forking lacme-accountd, child PID $pid\n" if $OPTS{debug}; + $s->close() or die "Can't close: $!"; + push @CLEANUP, sub() { + print STDERR "[$$] Shutting down lacme-accountd\n" if $OPTS{debug}; + shutdown($client, SHUT_RDWR) or warn "shutdown: $!"; + kill 15 => $pid; + waitpid $pid => 0; + }; + } + else { + my @stat; + my $sockname = $OPTS{socket} // $conf->{socket} // die "Missing socket option\n"; + $sockname = $sockname =~ /\A(\p{Print}+)\z/ ? $1 : die "Invalid socket name\n"; # untaint $sockname + + # ensure we're the only user with write access to the parent dir + my $dirname = $sockname =~ s/[^\/]+$//r; + @stat = stat($dirname) or die "Can't stat $dirname: $!"; + die "Error: insecure permissions on $dirname\n" if ($stat[2] & 0022) != 0; + + # ensure we're the only user with read/write access to the socket + @stat = stat($sockname) or die "Can't stat $sockname: $! (Is lacme-accountd running?)\n"; + die "Error: insecure permissions on $sockname\n" if ($stat[2] & 0066) != 0; + + # connect(2) to the socket + socket($client, PF_UNIX, SOCK_STREAM, 0) or die "socket: $!"; + my $sockaddr = Socket::sockaddr_un($sockname) // die "Invalid address $sockname\n"; + until (connect($client, $sockaddr)) { + next if $! == EINTR; # try again if connect(2) was interrupted by a signal + die "connect: $!"; + } } # use execve(2) rather than a Perl pseudo-process to ensure that the # child doesn't have access to the parent's memory my @fileno = map { fileno($_) =~ /^(\d+)$/ ? $1 : die } ($CONFFILE, $client); # untaint fileno + set_FD_CLOEXEC($client, 1); spawn({%$args{qw/in out/}, child => sub() { drop_privileges($conf->{user}, $conf->{group}, $args->{chdir} // '/'); set_FD_CLOEXEC($_, 0) foreach ($CONFFILE, $client); diff --git a/lacme-accountd b/lacme-accountd index fbf1bcb..411538d 100755 --- a/lacme-accountd +++ b/lacme-accountd @@ -59,7 +59,7 @@ sub usage(;$$) { } exit $rv; } -usage(1) unless GetOptions(\%OPTS, qw/config=s privkey=s socket=s quiet|q debug help|h/); +usage(1) unless GetOptions(\%OPTS, qw/config=s privkey=s socket=s fdopen=i quiet|q debug help|h/); usage(0) if $OPTS{help}; do { @@ -137,7 +137,10 @@ $JWK = JSON::->new->encode($JWK); # to support the abstract namespace.) The downside is that we have to # delete the file manually. # -do { +if (defined $OPTS{fdopen}) { + die "Invalid file descriptor" unless $OPTS{fdopen} =~ /\A(\d+)\z/; + open $S, '+<&=', $1 or die "fdopen $1: $!"; +} else { my $sockname = $OPTS{socket} // (defined $ENV{XDG_RUNTIME_DIR} ? "$ENV{XDG_RUNTIME_DIR}/S.lacme" : undef); die "Missing socket option\n" unless defined $sockname; $sockname = $sockname =~ /\A(\p{Print}+)\z/ ? $1 : die "Invalid socket name\n"; # untaint $sockname @@ -165,26 +168,34 @@ do { # For each new connection, send the protocol version and the account key's # public parameters, then sign whatever comes in # -$SIG{PIPE} = 'IGNORE'; # ignore broken pipes -for (my $count = 0;; $count++) { - accept(my $conn, $S) or do { - next if $! == EINTR; # try again if accept(2) was interrupted by a signal - die "accept: $!"; - }; - print STDERR "[$count]>> Accepted new connection\n" unless $OPTS{quiet}; - +sub conn($;$) { + my $conn = shift; + my $count = shift; $conn->printflush( "$PROTOCOL_VERSION OK", "\r\n", $JWK, "\r\n" ); # sign whatever comes in while (defined (my $data = $conn->getline())) { $data =~ s/\r\n\z// or die; - print STDERR "[$count]>> Issuing SHA-256 signature for: $data\n" unless $OPTS{quiet}; + print STDERR "[$count] >>> Issuing SHA-256 signature for: $data\n" unless $OPTS{quiet}; my $sig = $SIGN->($data); $conn->printflush( encode_base64url($sig), "\r\n" ); } +} - print STDERR "[$count]>> Connection terminated\n" unless $OPTS{quiet}; - close $conn or warn "Can't close: $!"; +if (defined $OPTS{fdopen}) { + conn($S, $$); +} else { + $SIG{PIPE} = 'IGNORE'; # ignore broken pipes + for (my $count = 0;; $count++) { + accept(my $conn, $S) or do { + next if $! == EINTR; # try again if accept(2) was interrupted by a signal + die "accept: $!"; + }; + print STDERR "[$count] >>> Accepted new connection\n" unless $OPTS{quiet}; + conn($conn, $count); + print STDERR "[$count] >>> Connection terminated\n" unless $OPTS{quiet}; + close $conn or warn "Can't close: $!"; + } } @@ -26,7 +26,9 @@ with its own executable: the [ACME] client.) One can use the UNIX-domain socket forwarding facility of OpenSSH 6.7 and later to run [`lacme-accountd`(1)] and `lacme` on different - hosts. + hosts. Alternatively, the [`lacme-accountd`(1)] process can be + spawned by the “master” `lacme` process below; the communication + between the two then goes through a socket pair. 2. A “master” `lacme` process, which runs as root and is the only component with access to the private key material of the server @@ -249,6 +251,44 @@ This section is used for configuring the [ACME] webserver. automatically removed once `lacme` exits. Default: `Yes`. +`[accountd]` section +--------------------- + +This section is used for configuring the [`lacme-accountd`(1)] process. +If the section (including its header) is absent or commented out, +`lacme` connects to an existing UNIX-domain socket bound by a running +[`lacme-accountd`(1)]. + +*user* + +: The username to drop privileges to (setting both effective and real + uid). Preserve root privileges if the value is empty. + +*group* + +: The groupname to drop privileges to (setting both effective and real + gid, and also setting the list of supplementary gids to that single + group). + +*command* + +: Path to the [`lacme-accountd`(1)] executable. + Default: `/usr/bin/lacme-accountd`. + +*config* + +: Path to the [`lacme-accountd`(1)] configuration file. + Default: `/etc/lacme/lacme-accountd.conf`. + +*privkey* + +: The (private) account key to use for signing requests. See + [`lacme-accountd`(1)] for details. + +*quiet* + +: Be quiet. Possible values: `Yes`/`No`. + Certificate configuration file ============================== |