Merge system-wide Vixie cron updates.

I don't believe that anyone should be running system-wide cron processes these
days (the attack surface is rather large), but should use separate per-user or
per-service mcron daemon processes.  But mcron is advertised as a drop-in
Vixie replacement, so we should do what we can to make it safe in this use
case.

I've performed a basic vetting of the changes against vandalism, but haven't
verified the correctness of the code or done any checking; the changes are
being accepted on the basis that almost anything is an improvement on what
currently exists.

1 files changed, 39 insertions, 14 deletions

diff --git a/Makefile.am b/Makefile.am
index 09a0d6d..2a87d72 100755
--- a/Makefile.am
+++ b/Makefile.am
@@ -27,10 +27,17 @@ noinst_SCRIPTS =
 if MULTI_USER
 bin_SCRIPTS += bin/crontab
 sbin_SCRIPTS = bin/cron
+libexec_SCRIPTS = bin/crontab-access-real
+sbin_PROGRAMS = bin/crontab-access
 else
-noinst_SCRIPTS += bin/cron bin/crontab
+noinst_SCRIPTS += bin/cron bin/crontab bin/crontab-access-real
+noinst_PROGRAMS = bin/crontab-access
 endif
 
+# The dynamic linker should detect that it's being run for a setuid program,
+# but we take no chances.
+bin_crontab_access_LDFLAGS = -static
+
 # wrapper to be used in the build environment and for running tests.
 noinst_SCRIPTS += pre-inst-env
 
@@ -68,6 +75,7 @@ pkgscriptdir = $(pkgmoduledir)/scripts
 dist_pkgscript_DATA = \
   src/mcron/scripts/cron.scm \
   src/mcron/scripts/crontab.scm \
+  src/mcron/scripts/crontab-access.scm \
   src/mcron/scripts/mcron.scm
 
 pkgscriptgodir = $(pkgmodulegodir)/scripts
@@ -77,7 +85,13 @@ compiled_modules = \
   $(pkgmodulego_DATA) \
   $(pkgscriptgo_DATA)
 
-CLEANFILES = $(compiled_modules) bin/crontab bin/cron bin/mcron
+CLEANFILES = $(compiled_modules) \
+	bin/crontab \
+	bin/crontab-access \
+	src/crontab-access.c \
+	bin/crontab-access-real \
+        bin/cron \
+	bin/mcron
 DISTCLEANFILES = src/mcron/config.scm
 
 # Unset 'GUILE_LOAD_COMPILED_PATH' altogether while compiling.  Otherwise, if
@@ -100,10 +114,9 @@ DISTCLEANFILES = src/mcron/config.scm
 	  --warn=format --warn=unbound-variable --warn=arity-mismatch \
 	  --target="$(host)" --output="$@" "$<" $(devnull_verbose)
 
-
-bin/% : src/%.in Makefile
-	$(AM_V_GEN)$(MKDIR_P) bin ; \
-	  sed	-e 's,%PREFIX%,${prefix},g'				\
+do_subst = sed	-e 's,%PREFIX%,${prefix},g'				\
+		-e 's,%sbindir%,${sbindir},g'				\
+		-e 's,%libexecdir%,${libexecdir},g'			\
 		-e 's,%modsrcdir%,${guilesitedir},g'			\
 		-e 's,%modbuilddir%,${guilesitegodir},g'		\
 		-e 's,%localstatedir%,${localstatedir},g'		\
@@ -114,8 +127,17 @@ bin/% : src/%.in Makefile
 		-e 's,%PACKAGE_BUGREPORT%,@PACKAGE_BUGREPORT@,g'	\
 		-e 's,%PACKAGE_NAME%,@PACKAGE_NAME@,g'			\
 		-e 's,%PACKAGE_URL%,@PACKAGE_URL@,g'			\
-		-e 's,%GUILE%,$(GUILE),g'				\
-	   $< > $@ ; \
+		-e 's,%GUILE%,$(GUILE),g'
+
+src/mcron/config.scm: src/mcron/config.scm.in Makefile
+	$(AM_V_GEN)$(do_subst) $< > $@
+
+src/crontab-access.c: src/crontab-access.c.in Makefile
+	$(AM_V_GEN)$(do_subst) $< > $@
+
+bin/% : src/%.in Makefile
+	$(AM_V_GEN)$(MKDIR_P) bin ; \
+	  $(do_subst) $< > $@ ; \
 	  chmod a+x $@
 
 
@@ -153,6 +175,8 @@ EXTRA_DIST = \
   HACKING \
   src/cron.in \
   src/crontab.in \
+  src/crontab-access-real.in \
+  src/crontab-access.c.in \
   src/mcron.in \
   tests/init.sh \
   $(TESTS)
@@ -166,10 +190,10 @@ transform_exe = s/$(EXEEXT)$$//;$(transform);s/$$/$(EXEEXT)/
 
 install-exec-hook:
 if MULTI_USER
-	tcrontab=`echo crontab | sed '$(transform_exe)'`; \
-	chmod u+s $(DESTDIR)$(bindir)/$${tcrontab}
-	tcron=`echo cron | sed '$(transform_exe)'`; \
-	chmod u+s $(DESTDIR)$(sbindir)/$${tcron}
+	tcrontab=`echo crontab | sed '$(transform_exe)'`;
+	tcrontab_access=`echo crontab-access | sed '$(transform_exe)'`; \
+	chmod u+s $(DESTDIR)$(sbindir)/$${tcrontab_access}
+	tcron=`echo cron | sed '$(transform_exe)'`;
 endif
 	tmcron=`echo mcron | sed '$(transform_exe)'`;
 
@@ -178,8 +202,9 @@ installcheck-local:
 	tmcron=`echo mcron | sed '$(transform_exe)'`; \
 	test -e $(DESTDIR)$(bindir)/$${tmcron}
 if MULTI_USER
-	tcrontab=`echo crontab | sed '$(transform_exe)'`; \
-	test -u $(DESTDIR)$(bindir)/$${tcrontab}
+	tcrontab=`echo crontab | sed '$(transform_exe)'`;
+	tcrontab_access=`echo crontab | sed '$(transform_exe)'`; \
+	test -u $(DESTDIR)$(bindir)/$${tcrontab_access}
 	tcron=`echo cron | sed '$(transform_exe)'`; \
 	test -e $(DESTDIR)$(sbindir)/$${tcron}
 else !MULTI_USER