251 lines
8.1 KiB
Diff
251 lines
8.1 KiB
Diff
diff -up dhcp-4.2.2b1/client/dhclient.8.capability dhcp-4.2.2b1/client/dhclient.8
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--- dhcp-4.2.2b1/client/dhclient.8.capability 2011-07-01 15:09:06.603784531 +0200
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+++ dhcp-4.2.2b1/client/dhclient.8 2011-07-01 15:09:06.663783913 +0200
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@@ -118,6 +118,9 @@ dhclient - Dynamic Host Configuration Pr
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.B -w
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]
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[
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+.B -nc
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+]
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+[
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.B -B
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]
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[
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@@ -296,6 +299,32 @@ has been added or removed, so that the c
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address on that interface.
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.TP
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+.BI \-nc
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+Do not drop capabilities.
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+
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+Normally, if
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+.B dhclient
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+was compiled with libcap-ng support,
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+.B dhclient
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+drops most capabilities immediately upon startup. While more secure,
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+this greatly restricts the additional actions that hooks in
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+.B dhclient-script (8)
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+can take. (For example, any daemons that
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+.B dhclient-script (8)
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+starts or restarts will inherit the restricted capabilities as well,
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+which may interfere with their correct operation.) Thus, the
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+.BI \-nc
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+option can be used to prevent
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+.B dhclient
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+from dropping capabilities.
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+
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+The
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+.BI \-nc
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+option is ignored if
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+.B dhclient
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+was not compiled with libcap-ng support.
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+
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+.TP
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.BI \-B
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Set the BOOTP broadcast flag in request packets so servers will always
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broadcast replies.
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diff -up dhcp-4.2.2b1/client/dhclient.c.capability dhcp-4.2.2b1/client/dhclient.c
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--- dhcp-4.2.2b1/client/dhclient.c.capability 2011-07-01 15:09:06.644784107 +0200
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+++ dhcp-4.2.2b1/client/dhclient.c 2011-07-01 15:09:06.664783903 +0200
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@@ -39,6 +39,10 @@
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#include <limits.h>
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#include <dns/result.h>
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+#ifdef HAVE_LIBCAP_NG
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+#include <cap-ng.h>
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+#endif
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+
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/*
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* Defined in stdio.h when _GNU_SOURCE is set, but we don't want to define
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* that when building ISC code.
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@@ -141,6 +145,9 @@ main(int argc, char **argv) {
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int timeout_arg = 0;
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char *arg_conf = NULL;
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int arg_conf_len = 0;
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+#ifdef HAVE_LIBCAP_NG
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+ int keep_capabilities = 0;
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+#endif
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/* Initialize client globals. */
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memset(&default_duid, 0, sizeof(default_duid));
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@@ -410,6 +417,10 @@ main(int argc, char **argv) {
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}
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dhclient_request_options = argv[i];
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+ } else if (!strcmp(argv[i], "-nc")) {
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+#ifdef HAVE_LIBCAP_NG
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+ keep_capabilities = 1;
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+#endif
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} else if (argv[i][0] == '-') {
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usage();
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} else if (interfaces_requested < 0) {
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@@ -458,6 +469,19 @@ main(int argc, char **argv) {
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path_dhclient_script = s;
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}
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+#ifdef HAVE_LIBCAP_NG
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+ /* Drop capabilities */
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+ if (!keep_capabilities) {
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+ capng_clear(CAPNG_SELECT_CAPS);
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+ capng_update(CAPNG_ADD, CAPNG_EFFECTIVE|CAPNG_PERMITTED,
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+ CAP_DAC_OVERRIDE); // Drop this someday
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+ capng_updatev(CAPNG_ADD, CAPNG_EFFECTIVE|CAPNG_PERMITTED,
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+ CAP_NET_ADMIN, CAP_NET_RAW,
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+ CAP_NET_BIND_SERVICE, CAP_SYS_ADMIN, -1);
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+ capng_apply(CAPNG_SELECT_CAPS);
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+ }
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+#endif
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+
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/* Set up the initial dhcp option universe. */
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initialize_common_option_spaces();
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diff -up dhcp-4.2.2b1/client/dhclient-script.8.capability dhcp-4.2.2b1/client/dhclient-script.8
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--- dhcp-4.2.2b1/client/dhclient-script.8.capability 2011-07-01 15:09:06.604784521 +0200
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+++ dhcp-4.2.2b1/client/dhclient-script.8 2011-07-01 15:09:06.666783883 +0200
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@@ -239,6 +239,16 @@ repeatedly initialized to the values pro
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the other. Assuming the information provided by both servers is
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valid, this shouldn't cause any real problems, but it could be
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confusing.
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+.PP
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+Normally, if dhclient was compiled with libcap-ng support,
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+dhclient drops most capabilities immediately upon startup.
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+While more secure, this greatly restricts the additional actions that
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+hooks in dhclient-script can take. For example, any daemons that
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+dhclient-script starts or restarts will inherit the restricted
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+capabilities as well, which may interfere with their correct operation.
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+Thus, the
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+.BI \-nc
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+option can be used to prevent dhclient from dropping capabilities.
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.SH SEE ALSO
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dhclient(8), dhcpd(8), dhcrelay(8), dhclient.conf(5) and
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dhclient.leases(5).
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diff -up dhcp-4.2.2b1/client/Makefile.am.capability dhcp-4.2.2b1/client/Makefile.am
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--- dhcp-4.2.2b1/client/Makefile.am.capability 2011-07-01 15:09:06.526785327 +0200
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+++ dhcp-4.2.2b1/client/Makefile.am 2011-07-01 15:09:06.667783873 +0200
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@@ -5,7 +5,7 @@ dhclient_SOURCES = clparse.c dhclient.c
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scripts/netbsd scripts/nextstep scripts/openbsd \
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scripts/solaris scripts/openwrt
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dhclient_LDADD = ../common/libdhcp.a ../omapip/libomapi.a \
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- $(BIND9_LIBDIR) -ldns-export -lisc-export
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+ $(BIND9_LIBDIR) -ldns-export -lisc-export $(CAPNG_LDADD)
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man_MANS = dhclient.8 dhclient-script.8 dhclient.conf.5 dhclient.leases.5
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EXTRA_DIST = $(man_MANS)
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diff -up dhcp-4.2.2b1/configure.ac.capability dhcp-4.2.2b1/configure.ac
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--- dhcp-4.2.2b1/configure.ac.capability 2011-07-01 15:09:06.527785317 +0200
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+++ dhcp-4.2.2b1/configure.ac 2011-07-01 15:09:06.667783873 +0200
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@@ -449,6 +449,41 @@ AC_TRY_LINK(
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# Look for optional headers.
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AC_CHECK_HEADERS(sys/socket.h net/if_dl.h net/if6.h regex.h)
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+# look for capabilities library
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+AC_ARG_WITH(libcap-ng,
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+ [ --with-libcap-ng=[auto/yes/no] Add Libcap-ng support [default=auto]],,
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+ with_libcap_ng=auto)
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+
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+# Check for Libcap-ng API
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+#
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+# libcap-ng detection
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+if test x$with_libcap_ng = xno ; then
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+ have_libcap_ng=no;
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+else
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+ # Start by checking for header file
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+ AC_CHECK_HEADER(cap-ng.h, capng_headers=yes, capng_headers=no)
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+
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+ # See if we have libcap-ng library
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+ AC_CHECK_LIB(cap-ng, capng_clear,
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+ CAPNG_LDADD=-lcap-ng,)
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+
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+ # Check results are usable
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+ if test x$with_libcap_ng = xyes -a x$CAPNG_LDADD = x ; then
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+ AC_MSG_ERROR(libcap-ng support was requested and the library was not found)
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+ fi
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+ if test x$CAPNG_LDADD != x -a $capng_headers = no ; then
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+ AC_MSG_ERROR(libcap-ng libraries found but headers are missing)
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+ fi
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+fi
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+AC_SUBST(CAPNG_LDADD)
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+AC_MSG_CHECKING(whether to use libcap-ng)
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+if test x$CAPNG_LDADD != x ; then
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+ AC_DEFINE(HAVE_LIBCAP_NG,1,[libcap-ng support])
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+ AC_MSG_RESULT(yes)
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+else
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+ AC_MSG_RESULT(no)
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+fi
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+
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# Solaris needs some libraries for functions
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AC_SEARCH_LIBS(socket, [socket])
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AC_SEARCH_LIBS(inet_ntoa, [nsl])
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diff -up dhcp-4.2.2b1/relay/dhcrelay.c.capability dhcp-4.2.2b1/relay/dhcrelay.c
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--- dhcp-4.2.2b1/relay/dhcrelay.c.capability 2011-07-01 15:09:06.626784295 +0200
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+++ dhcp-4.2.2b1/relay/dhcrelay.c 2011-07-01 15:12:05.362223794 +0200
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@@ -36,6 +36,11 @@
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#include <syslog.h>
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#include <sys/time.h>
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+#ifdef HAVE_LIBCAP_NG
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+# include <cap-ng.h>
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+ int keep_capabilities = 0;
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+#endif
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+
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TIME default_lease_time = 43200; /* 12 hours... */
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TIME max_lease_time = 86400; /* 24 hours... */
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struct tree_cache *global_options[256];
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@@ -356,6 +361,10 @@ main(int argc, char **argv) {
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sl->next = upstreams;
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upstreams = sl;
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#endif
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+ } else if (!strcmp(argv[i], "-nc")) {
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+#ifdef HAVE_LIBCAP_NG
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+ keep_capabilities = 1;
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+#endif
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} else if (!strcmp(argv[i], "-pf")) {
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if (++i == argc)
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usage();
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@@ -426,6 +435,17 @@ main(int argc, char **argv) {
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#endif
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}
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+#ifdef HAVE_LIBCAP_NG
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+ /* Drop capabilities */
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+ if (!keep_capabilities) {
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+ capng_clear(CAPNG_SELECT_BOTH);
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+ capng_updatev(CAPNG_ADD, CAPNG_EFFECTIVE|CAPNG_PERMITTED,
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+ CAP_NET_RAW, CAP_NET_BIND_SERVICE, -1);
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+ capng_apply(CAPNG_SELECT_BOTH);
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+ log_info ("Dropped all unnecessary capabilities.");
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+ }
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+#endif
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+
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if (!quiet) {
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log_info("%s %s", message, PACKAGE_VERSION);
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log_info(copyright);
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@@ -573,6 +593,15 @@ main(int argc, char **argv) {
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dhcpv6_packet_handler = do_packet6;
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#endif
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+#ifdef HAVE_LIBCAP_NG
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+ /* Drop all capabilities */
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+ if (!keep_capabilities) {
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+ capng_clear(CAPNG_SELECT_BOTH);
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+ capng_apply(CAPNG_SELECT_BOTH);
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+ log_info ("Dropped all capabilities.");
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+ }
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+#endif
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+
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/* Start dispatching packets and timeouts... */
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dispatch();
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diff -up dhcp-4.2.2b1/relay/Makefile.am.capability dhcp-4.2.2b1/relay/Makefile.am
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--- dhcp-4.2.2b1/relay/Makefile.am.capability 2011-07-01 15:09:06.546785121 +0200
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+++ dhcp-4.2.2b1/relay/Makefile.am 2011-07-01 15:09:06.670783841 +0200
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@@ -3,7 +3,7 @@ AM_CPPFLAGS = -DLOCALSTATEDIR='"@localst
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sbin_PROGRAMS = dhcrelay
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dhcrelay_SOURCES = dhcrelay.c
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dhcrelay_LDADD = ../common/libdhcp.a ../omapip/libomapi.a \
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- $(BIND9_LIBDIR) -ldns-export -lisc-export
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+ $(BIND9_LIBDIR) -ldns-export -lisc-export $(CAPNG_LDADD)
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man_MANS = dhcrelay.8
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EXTRA_DIST = $(man_MANS)
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