[Libguestfs] [PATCH nbdkit 2/2] ip: Add filtering by process ID, user ID and group ID.

--- filters/ip/nbdkit-ip-filter.pod | 54 ++++++++++++++++++++++---- tests/Makefile.am | 14 ++++++- filters/ip/ip.c | 67 ++++++++++++++++++++++++++++++--- tests/test-ip-filter-gid.sh | 51 +++++++++++++++++++++++++ tests/test-ip-filter-pid.sh | 52 +++++++++++++++++++++++++ tests/test-ip-filter-uid.sh | 51 +++++++++++++++++++++++++ 6 files changed, 274 insertions(+), 15 deletions(-) diff --git a/filters/ip/nbdkit-ip-filter.pod b/filters/ip/nbdkit-ip-filter.pod index 17108617..1f5a7e63 100644 --- a/filters/ip/nbdkit-ip-filter.pod +++ b/filters/ip/nbdkit-ip-filter.pod @@ -1,6 +1,7 @@ =head1 NAME -nbdkit-ip-filter - filter clients by IP address +nbdkit-ip-filter - filter clients by IP address, process ID, user ID +or group ID =head1 SYNOPSIS @@ -14,6 +15,9 @@ address. Usually it is better to control this outside nbdkit, for example using TCP wrappers or a firewall, but this filter can be used if these are not available. +nbdkit E<ge> 1.24 added the ability to filter Unix domain sockets by +process ID, user ID and group ID. This currently only works on Linux. + =head1 EXAMPLES nbdkit --filter=ip [...] allow=127.0.0.1,::1 deny=all @@ -31,10 +35,22 @@ network. Allow IPv6 clients to connect from anywhere, deny all IPv4 connections. + nbdkit -U /tmp/sock --filter=ip [...] allow=pid:1234 deny=all + +Only process ID 1234 can connect to the server over the local Unix +domain socket. + + nbdkit -U $tmpdir/sock --filter=ip [...] allow=uid:`id -u` deny=all + +Only allow the same user who runs nbdkit to connect over the socket. +If you use this, it is better to use it as an additional line of +defence: Also create a temporary directory, make sure it is only +accessible by the user, and place the socket there. + =head1 RULES -When a client connects, this filter checks its IP address against the -allow and deny lists as follows: +When a client connects, this filter checks its source address against +the allow and deny lists as follows: =over 4 @@ -66,8 +82,7 @@ list of any of the following: =item B<any> -These keywords (which both have the same meaning) match any IP -address. +These keywords (which both have the same meaning) match any source. =item B<allipv4> @@ -100,6 +115,26 @@ address representations can be used (see S<RFC 5952>). This matches a range of IPv6 addresses C<A:B:.../NN>. +=item B<pid:>PID + +(nbdkit E<ge> 1.24, Linux only) + +This matches the process ID C<PID>. + +=item B<uid:>UID + +(nbdkit E<ge> 1.24, Linux only) + +This matches the user ID C<UID> (which must be numeric, you cannot use +a user name). + +=item B<gid:>GID + +(nbdkit E<ge> 1.24, Linux only) + +This matches the group ID C<GID> (which must be numeric, you cannot +use a group name). + =back =head2 Not filtered @@ -107,8 +142,11 @@ This matches a range of IPv6 addresses C<A:B:.../NN>. If neither the C<allow> nor the C<deny> parameter is given the filter does nothing. -The filter permits non-IP connections, such as Unix domain sockets or -AF_VSOCK. +C<AF_VSOCK> connections are always unfiltered. + +Unix domain sockets were always unfiltered in S<nbdkit E<le> 1.22>. +In S<nbdkit E<ge> 1.24> it is possible to apply filtering to them on +Linux. =head1 PARAMETERS @@ -155,4 +193,4 @@ Richard W.M. Jones =head1 COPYRIGHT -Copyright (C) 2019 Red Hat Inc. +Copyright (C) 2019-2020 Red Hat Inc. diff --git a/tests/Makefile.am b/tests/Makefile.am index b5b06810..cacbbce9 100644 --- a/tests/Makefile.am +++ b/tests/Makefile.am @@ -1437,8 +1437,18 @@ test_gzip_CFLAGS = $(WARNINGS_CFLAGS) $(LIBGUESTFS_CFLAGS) test_gzip_LDADD = libtest.la $(LIBGUESTFS_LIBS) # ip filter test. -TESTS += test-ip-filter.sh -EXTRA_DIST += test-ip-filter.sh +TESTS += \ + test-ip-filter.sh \ + test-ip-filter-pid.sh \ + test-ip-filter-uid.sh \ + test-ip-filter-gid.sh \ + $(NULL) +EXTRA_DIST += \ + test-ip-filter.sh \ + test-ip-filter-pid.sh \ + test-ip-filter-uid.sh \ + test-ip-filter-gid.sh \ + $(NULL) # limit filter test. TESTS += test-limit.sh diff --git a/filters/ip/ip.c b/filters/ip/ip.c index 6e64042d..25a6c3a7 100644 --- a/filters/ip/ip.c +++ b/filters/ip/ip.c @@ -62,12 +62,13 @@ int ip_debug_rules; struct rule { struct rule *next; - enum { BAD = 0, ANY, ANYV4, ANYV6, IPV4, IPV6 } type; + enum { BAD = 0, ANY, ANYV4, ANYV6, IPV4, IPV6, PID, UID, GID } type; union { - struct in_addr ipv4; + struct in_addr ipv4; /* for IPV4, IPV6 */ struct in6_addr ipv6; + int id; /* for PID, UID and GID */ } u; - unsigned prefixlen; + unsigned prefixlen; /* for IPV4, IPV6 */ }; static struct rule *allow_rules, *allow_rules_last; @@ -100,6 +101,16 @@ print_rule (const char *name, const struct rule *rule) nbdkit_debug ("%s=ipv6:[%s]/%u", name, u.addr6, rule->prefixlen); break; + case PID: + nbdkit_debug ("%s=pid:%d", name, rule->u.id); + break; + case UID: + nbdkit_debug ("%s=uid:%d", name, rule->u.id); + break; + case GID: + nbdkit_debug ("%s=gid:%d", name, rule->u.id); + break; + case BAD: nbdkit_debug ("%s=BAD(!)", name); break; @@ -227,6 +238,37 @@ parse_rule (const char *paramname, return 0; } + if (n >= 4 && ascii_strncasecmp (value, "pid:", 4) == 0) { + new_rule->type = PID; + if (nbdkit_parse_int ("pid:", &value[4], &new_rule->u.id) == -1) + return -1; + if (new_rule->u.id <= 0) { + nbdkit_error ("pid: parameter out of range"); + return -1; + } + return 0; + } + if (n >= 4 && ascii_strncasecmp (value, "uid:", 4) == 0) { + new_rule->type = UID; + if (nbdkit_parse_int ("uid:", &value[4], &new_rule->u.id) == -1) + return -1; + if (new_rule->u.id < 0) { + nbdkit_error ("uid: parameter out of range"); + return -1; + } + return 0; + } + if (n >= 4 && ascii_strncasecmp (value, "gid:", 4) == 0) { + new_rule->type = GID; + if (nbdkit_parse_int ("gid:", &value[4], &new_rule->u.id) == -1) + return -1; + if (new_rule->u.id < 0) { + nbdkit_error ("gid: parameter out of range"); + return -1; + } + return 0; + } + /* Address with prefixlen. */ if ((p = strchr (value, '/')) != NULL) { size_t pllen = &value[n] - &p[1]; @@ -401,6 +443,19 @@ matches_rule (const struct rule *rule, sin6 = (struct sockaddr_in6 *) addr; return ipv6_equal (sin6->sin6_addr, rule->u.ipv6, rule->prefixlen); + /* Note these work even if the underlying nbdkit_peer_* call fails. */ + case PID: + if (family != AF_UNIX) return false; + return nbdkit_peer_pid () == rule->u.id; + + case UID: + if (family != AF_UNIX) return false; + return nbdkit_peer_uid () == rule->u.id; + + case GID: + if (family != AF_UNIX) return false; + return nbdkit_peer_gid () == rule->u.id; + case BAD: default: abort (); @@ -432,8 +487,10 @@ check_if_allowed (const struct sockaddr *addr) { int family = ((struct sockaddr_in *)addr)->sin_family; - /* There's an implicit allow all for non-IP sockets, see the manual. */ - if (family != AF_INET && family != AF_INET6) + /* There's an implicit allow all for non-IP, non-Unix sockets, + * see the manual. + */ + if (family != AF_INET && family != AF_INET6 && family != AF_UNIX) return true; if (matches_rules_list (allow_rules, family, addr)) diff --git a/tests/test-ip-filter-gid.sh b/tests/test-ip-filter-gid.sh new file mode 100755 index 00000000..d02407f3 --- /dev/null +++ b/tests/test-ip-filter-gid.sh @@ -0,0 +1,51 @@ +#!/usr/bin/env bash +# nbdkit +# Copyright (C) 2020 Red Hat Inc. +# +# Redistribution and use in source and binary forms, with or without +# modification, are permitted provided that the following conditions are +# met: +# +# * Redistributions of source code must retain the above copyright +# notice, this list of conditions and the following disclaimer. +# +# * Redistributions in binary form must reproduce the above copyright +# notice, this list of conditions and the following disclaimer in the +# documentation and/or other materials provided with the distribution. +# +# * Neither the name of Red Hat nor the names of its contributors may be +# used to endorse or promote products derived from this software without +# specific prior written permission. +# +# THIS SOFTWARE IS PROVIDED BY RED HAT AND CONTRIBUTORS ''AS IS'' AND +# ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, +# THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A +# PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL RED HAT OR +# CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, +# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT +# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF +# USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND +# ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, +# OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT +# OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF +# SUCH DAMAGE. + +# Test the ip filter with gid: parameter. + +source ./functions.sh +set -e +set -x + +requires qemu-img --version +# This requires Linux. +requires_linux_kernel_version 2.6 + +nbdkit -U - -v -D ip.rules=1 --filter=ip null allow=gid:`id -g` deny=all \ + --run 'qemu-img info $nbd' + +# This is expected to fail. +if nbdkit -U - -v -D ip.rules=1 --filter=ip null deny=gid:`id -g` \ + --run 'qemu-img info $nbd'; then + echo "$0: expected test to fail" + exit 1 +fi diff --git a/tests/test-ip-filter-pid.sh b/tests/test-ip-filter-pid.sh new file mode 100755 index 00000000..d14f3a42 --- /dev/null +++ b/tests/test-ip-filter-pid.sh @@ -0,0 +1,52 @@ +#!/usr/bin/env bash +# nbdkit +# Copyright (C) 2020 Red Hat Inc. +# +# Redistribution and use in source and binary forms, with or without +# modification, are permitted provided that the following conditions are +# met: +# +# * Redistributions of source code must retain the above copyright +# notice, this list of conditions and the following disclaimer. +# +# * Redistributions in binary form must reproduce the above copyright +# notice, this list of conditions and the following disclaimer in the +# documentation and/or other materials provided with the distribution. +# +# * Neither the name of Red Hat nor the names of its contributors may be +# used to endorse or promote products derived from this software without +# specific prior written permission. +# +# THIS SOFTWARE IS PROVIDED BY RED HAT AND CONTRIBUTORS ''AS IS'' AND +# ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, +# THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A +# PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL RED HAT OR +# CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, +# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT +# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF +# USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND +# ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, +# OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT +# OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF +# SUCH DAMAGE. + +# Test the ip filter with pid: parameter. + +source ./functions.sh +set -e +set -x + +requires qemu-img --version +# This requires Linux. +requires_linux_kernel_version 2.6 + +# This is expected to fail. +if nbdkit -U - -v -D ip.rules=1 --filter=ip null allow=pid:$$ deny=all \ + --run 'qemu-img info $nbd'; then + echo "$0: expected test to fail" + exit 1 +fi + +# This is expected to work. +nbdkit -U - -v -D ip.rules=1 --filter=ip null deny=pid:$$ \ + --run 'qemu-img info $nbd' diff --git a/tests/test-ip-filter-uid.sh b/tests/test-ip-filter-uid.sh new file mode 100755 index 00000000..dc6ab679 --- /dev/null +++ b/tests/test-ip-filter-uid.sh @@ -0,0 +1,51 @@ +#!/usr/bin/env bash +# nbdkit +# Copyright (C) 2020 Red Hat Inc. +# +# Redistribution and use in source and binary forms, with or without +# modification, are permitted provided that the following conditions are +# met: +# +# * Redistributions of source code must retain the above copyright +# notice, this list of conditions and the following disclaimer. +# +# * Redistributions in binary form must reproduce the above copyright +# notice, this list of conditions and the following disclaimer in the +# documentation and/or other materials provided with the distribution. +# +# * Neither the name of Red Hat nor the names of its contributors may be +# used to endorse or promote products derived from this software without +# specific prior written permission. +# +# THIS SOFTWARE IS PROVIDED BY RED HAT AND CONTRIBUTORS ''AS IS'' AND +# ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, +# THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A +# PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL RED HAT OR +# CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, +# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT +# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF +# USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND +# ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, +# OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT +# OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF +# SUCH DAMAGE. + +# Test the ip filter with uid: parameter. + +source ./functions.sh +set -e +set -x + +requires qemu-img --version +# This requires Linux. +requires_linux_kernel_version 2.6 + +nbdkit -U - -v -D ip.rules=1 --filter=ip null allow=uid:`id -u` deny=all \ + --run 'qemu-img info $nbd' + +# This is expected to fail. +if nbdkit -U - -v -D ip.rules=1 --filter=ip null deny=uid:`id -u` \ + --run 'qemu-img info $nbd'; then + echo "$0: expected test to fail" + exit 1 +fi -- 2.27.0