added a uid_wrapper library

This library intercepts seteuid and related calls, and simulates them
in a manner similar to the nss_wrapper and socket_wrapper
libraries. This allows us to enable the vfs_unixuid NTVFS module in
the build farm, which means we are more likely to catch errors in the
token manipulation.

The simulation is not complete, but it is enough for Samba4 for
now. The major areas of incompleteness are:

 - no emulation of setreuid, setresuid or saved uids. These would be
   needed for use in Samba3

 - no emulation of ruid changing. That would also be needed for Samba3

 - no attempt to emulate file ownership changing, so code that (for
   example) tests whether st.st_uid matches geteuid() needs special
   handling

17 files changed, 265 insertions, 7 deletions

diff --git a/lib/uid_wrapper/config.m4 b/lib/uid_wrapper/config.m4
new file mode 100644
index 0000000000..db6537bf95
--- /dev/null
+++ b/lib/uid_wrapper/config.m4
@@ -0,0 +1,16 @@
+AC_ARG_ENABLE(uid-wrapper,
+AS_HELP_STRING([--enable-uid-wrapper], [Turn on uid wrapper library (default=no)]))
+
+HAVE_UID_WRAPPER=no
+
+if eval "test x$developer = xyes"; then
+	enable_uid_wrapper=yes
+fi
+
+if eval "test x$enable_uid_wrapper = xyes"; then
+        AC_DEFINE(UID_WRAPPER,1,[Use uid wrapper library])
+	HAVE_UID_WRAPPER=yes
+fi
+
+AC_SUBST(HAVE_UID_WRAPPER)
+AC_SUBST(UID_WRAPPER_OBJS)
diff --git a/lib/uid_wrapper/config.mk b/lib/uid_wrapper/config.mk
new file mode 100644
index 0000000000..1bebc68118
--- /dev/null
+++ b/lib/uid_wrapper/config.mk
@@ -0,0 +1,9 @@
+##############################
+# Start SUBSYSTEM UID_WRAPPER
+[SUBSYSTEM::UID_WRAPPER]
+PRIVATE_DEPENDENCIES = LIBTALLOC
+# End SUBSYSTEM UID_WRAPPER
+##############################
+
+UID_WRAPPER_OBJ_FILES = $(uidwrappersrcdir)/uid_wrapper.o
+
diff --git a/lib/uid_wrapper/uid_wrapper.c b/lib/uid_wrapper/uid_wrapper.c
new file mode 100644
index 0000000000..e009fa0b5c
--- /dev/null
+++ b/lib/uid_wrapper/uid_wrapper.c
@@ -0,0 +1,147 @@
+/*
+   Copyright (C) Andrew Tridgell 2009
+ 
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 3 of the License, or
+   (at your option) any later version.
+   
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+   
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#define UID_WRAPPER_NOT_REPLACE
+#include "includes.h"
+#include "system/passwd.h"
+#include "system/filesys.h"
+
+#ifndef _PUBLIC_
+#define _PUBLIC_
+#endif
+
+/*
+  we keep the virtualised euid/egid/groups information here
+ */
+static struct {
+	bool initialised;
+	bool enabled;
+	uid_t euid;
+	gid_t egid;
+	unsigned ngroups;
+	gid_t *groups;
+} uwrap;
+
+static void uwrap_init(void)
+{
+	if (uwrap.initialised) return;
+	uwrap.initialised = true;
+	if (getenv("UID_WRAPPER")) {
+		uwrap.enabled = true;
+	}
+}
+
+_PUBLIC_ int uwrap_seteuid(uid_t euid)
+{
+	uwrap_init();
+	if (!uwrap.enabled) {
+		return seteuid(euid);
+	}
+	/* assume for now that the ruid stays as root */
+	uwrap.euid = euid;
+	return 0;
+}
+
+_PUBLIC_ uid_t uwrap_geteuid(void)
+{
+	uwrap_init();
+	if (!uwrap.enabled) {
+		return geteuid();
+	}
+	return uwrap.euid;
+}
+
+_PUBLIC_ int uwrap_setegid(gid_t egid)
+{
+	uwrap_init();
+	if (!uwrap.enabled) {
+		return setegid(egid);
+	}
+	/* assume for now that the ruid stays as root */
+	uwrap.egid = egid;
+	return 0;
+}
+
+_PUBLIC_ uid_t uwrap_getegid(void)
+{
+	uwrap_init();
+	if (!uwrap.enabled) {
+		return getegid();
+	}
+	return uwrap.egid;
+}
+
+_PUBLIC_ int uwrap_setgroups(size_t size, const gid_t *list)
+{
+	uwrap_init();
+	if (!uwrap.enabled) {
+		return setgroups(size, list);
+	}
+
+	talloc_free(uwrap.groups);
+	uwrap.ngroups = 0;
+
+	uwrap.groups = talloc_array(talloc_autofree_context(), gid_t, size);
+	if (uwrap.groups == NULL) {
+		errno = ENOMEM;
+		return -1;
+	}
+	memcpy(uwrap.groups, list, size*sizeof(gid_t));
+	uwrap.ngroups = size;
+	return 0;
+}
+
+_PUBLIC_ int uwrap_getgroups(int size, gid_t *list)
+{
+	uwrap_init();
+	if (!uwrap.enabled) {
+		return getgroups(size, list);
+	}
+
+	if (size > uwrap.ngroups) {
+		size = uwrap.ngroups;
+	}
+	if (size == 0) {
+		return uwrap.ngroups;
+	}
+	if (size < uwrap.ngroups) {
+		errno = EINVAL;
+		return -1;
+	}
+	memcpy(list, uwrap.groups, size*sizeof(gid_t));
+	return 0;
+}
+
+_PUBLIC_ uid_t uwrap_getuid(void)
+{
+	uwrap_init();
+	if (!uwrap.enabled) {
+		return getuid();
+	}
+	/* we don't simulate ruid changing */
+	return 0;
+}
+
+_PUBLIC_ gid_t uwrap_getgid(void)
+{
+	uwrap_init();
+	if (!uwrap.enabled) {
+		return getgid();
+	}
+	/* we don't simulate rgid changing */
+	return 0;
+}
diff --git a/lib/uid_wrapper/uid_wrapper.h b/lib/uid_wrapper/uid_wrapper.h
new file mode 100644
index 0000000000..e2df613f50
--- /dev/null
+++ b/lib/uid_wrapper/uid_wrapper.h
@@ -0,0 +1,61 @@
+/*
+   Copyright (C) Andrew Tridgell 2009
+ 
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 3 of the License, or
+   (at your option) any later version.
+   
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+   
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#ifndef __UID_WRAPPER_H__
+#define __UID_WRAPPER_H__
+
+#ifdef seteuid
+#undef seteuid
+#endif
+#define seteuid	uwrap_seteuid
+
+#ifdef setegid
+#undef setegid
+#endif
+#define setegid	uwrap_setegid
+
+#ifdef geteuid
+#undef geteuid
+#endif
+#define geteuid	uwrap_geteuid
+
+#ifdef getegid
+#undef getegid
+#endif
+#define getegid	uwrap_getegid
+
+#ifdef setgroups
+#undef setgroups
+#endif
+#define setgroups uwrap_setgroups
+
+#ifdef getgroups
+#undef getgroups
+#endif
+#define getgroups uwrap_getgroups
+
+#ifdef getuid
+#undef getuid
+#endif
+#define getuid	uwrap_getuid
+
+#ifdef getgid
+#undef getgid
+#endif
+#define getgid	uwrap_getgid
+
+#endif /* __UID_WRAPPER_H__ */
diff --git a/lib/util/config.mk b/lib/util/config.mk
index ad39096c56..47e026865e 100644
--- a/lib/util/config.mk
+++ b/lib/util/config.mk
@@ -54,6 +54,7 @@ PUBLIC_HEADERS += $(addprefix $(libutilsrcdir)/, util.h \
 ASN1_UTIL_OBJ_FILES = $(libutilsrcdir)/asn1.o
 
 [SUBSYSTEM::UNIX_PRIVS]
+PRIVATE_DEPENDENCIES = UID_WRAPPER
 
 UNIX_PRIVS_OBJ_FILES = $(libutilsrcdir)/unix_privs.o
 
diff --git a/lib/util/util.c b/lib/util/util.c
index f49d25865c..dea140148f 100644
--- a/lib/util/util.c
+++ b/lib/util/util.c
@@ -135,10 +135,12 @@ _PUBLIC_ bool directory_create_or_exist(const char *dname, uid_t uid,
 		}
 		if ((st.st_uid != uid) || 
 		    ((st.st_mode & 0777) != dir_perms)) {
+#ifndef UID_WRAPPER_REPLACE
 			DEBUG(0, ("invalid permissions on directory "
 				  "%s\n", dname));
 			umask(old_umask);
 			return false;
+#endif
 		}
 	}
 	return true;
diff --git a/nsswitch/config.mk b/nsswitch/config.mk
index 264032e530..9a04f3bc37 100644
--- a/nsswitch/config.mk
+++ b/nsswitch/config.mk
@@ -30,7 +30,8 @@ PRIVATE_DEPENDENCIES = \
 		LIBWBCLIENT \
 		LIBTEVENT \
 		UTIL_TEVENT \
-		LIBASYNC_REQ
+		LIBASYNC_REQ \
+		UID_WRAPPER
 # End BINARY nsstest
 #################################
 
diff --git a/selftest/target/Samba4.pm b/selftest/target/Samba4.pm
index d2c11e4f32..db5900d0ae 100644
--- a/selftest/target/Samba4.pm
+++ b/selftest/target/Samba4.pm
@@ -113,6 +113,8 @@ sub check_or_start($$$)
 		$ENV{NSS_WRAPPER_PASSWD} = $env_vars->{NSS_WRAPPER_PASSWD};
 		$ENV{NSS_WRAPPER_GROUP} = $env_vars->{NSS_WRAPPER_GROUP};
 
+		$ENV{UID_WRAPPER} = "1";
+
 		# Start slapd before samba, but with the fifo on stdin
 		if (defined($self->{ldap})) {
 		    $self->slapd_start($env_vars) or 
@@ -773,7 +775,6 @@ sub provision($$$$$$$)
 [tmp]
 	path = $ctx->{tmpdir}
 	read only = no
-	ntvfs handler = posix
 	posix:sharedelay = 100000
 	posix:eadb = $ctx->{lockdir}/eadb.tdb
 	posix:oplocktimeout = 3
@@ -782,7 +783,6 @@ sub provision($$$$$$$)
 [test1]
 	path = $ctx->{tmpdir}/test1
 	read only = no
-	ntvfs handler = posix
 	posix:sharedelay = 100000
 	posix:eadb = $ctx->{lockdir}/eadb.tdb
 	posix:oplocktimeout = 3
@@ -791,7 +791,6 @@ sub provision($$$$$$$)
 [test2]
 	path = $ctx->{tmpdir}/test2
 	read only = no
-	ntvfs handler = posix
 	posix:sharedelay = 100000
 	posix:eadb = $ctx->{lockdir}/eadb.tdb
 	posix:oplocktimeout = 3
diff --git a/source4/Makefile b/source4/Makefile
index d6ae887066..24e58bc37a 100644
--- a/source4/Makefile
+++ b/source4/Makefile
@@ -75,6 +75,7 @@ libcmdlinesrcdir := lib/cmdline
 poptsrcdir := ../lib/popt
 socketwrappersrcdir := ../lib/socket_wrapper
 nsswrappersrcdir := ../lib/nss_wrapper
+uidwrappersrcdir := ../lib/uid_wrapper
 appwebsrcdir := lib/appweb
 libstreamsrcdir := lib/stream
 libutilsrcdir := ../lib/util
diff --git a/source4/auth/ntlm/config.mk b/source4/auth/ntlm/config.mk
index 561d14ad10..cb9c3b6cc9 100644
--- a/source4/auth/ntlm/config.mk
+++ b/source4/auth/ntlm/config.mk
@@ -57,7 +57,7 @@ auth_developer_OBJ_FILES = $(addprefix $(authsrcdir)/ntlm/, auth_developer.o)
 [MODULE::auth_unix]
 INIT_FUNCTION = auth_unix_init
 SUBSYSTEM = auth
-PRIVATE_DEPENDENCIES = CRYPT PAM PAM_ERRORS NSS_WRAPPER
+PRIVATE_DEPENDENCIES = CRYPT PAM PAM_ERRORS NSS_WRAPPER UID_WRAPPER
 
 auth_unix_OBJ_FILES = $(addprefix $(authsrcdir)/ntlm/, auth_unix.o)
 
diff --git a/source4/configure.ac b/source4/configure.ac
index 7c5f310aa9..3f10419a42 100644
--- a/source4/configure.ac
+++ b/source4/configure.ac
@@ -125,6 +125,7 @@ m4_include(ntvfs/posix/config.m4)
 m4_include(ntvfs/unixuid/config.m4)
 m4_include(../lib/socket_wrapper/config.m4)
 m4_include(../lib/nss_wrapper/config.m4)
+m4_include(../lib/uid_wrapper/config.m4)
 m4_include(auth/config.m4)
 m4_include(kdc/config.m4)
 m4_include(ntvfs/sysdep/config.m4)
diff --git a/source4/heimdal_build/config.h b/source4/heimdal_build/config.h
index 6a82637b2d..8830942e30 100644
--- a/source4/heimdal_build/config.h
+++ b/source4/heimdal_build/config.h
@@ -27,4 +27,9 @@
 
 #undef HAVE_KRB5_ENCRYPT_BLOCK
 
+#if defined(UID_WRAPPER) && !defined(UID_WRAPPER_REPLACE) && !defined(UID_WRAPPER_NOT_REPLACE)
+#define UID_WRAPPER_REPLACE
+#include "../uid_wrapper/uid_wrapper.h"
+#endif
+
 #endif
diff --git a/source4/heimdal_build/internal.mk b/source4/heimdal_build/internal.mk
index c0f3b6be99..52281807b5 100644
--- a/source4/heimdal_build/internal.mk
+++ b/source4/heimdal_build/internal.mk
@@ -598,7 +598,8 @@ PRIVATE_DEPENDENCIES = \
 			HEIMDAL_ROKEN_PROGNAME \
 			HEIMDAL_ROKEN_CLOSEFROM \
 			RESOLV \
-			LIBREPLACE_NETWORK
+			LIBREPLACE_NETWORK \
+			UID_WRAPPER
 # End SUBSYSTEM HEIMDAL_ROKEN
 #######################
 
diff --git a/source4/include/includes.h b/source4/include/includes.h
index 4862a62e22..37c6115f0f 100644
--- a/source4/include/includes.h
+++ b/source4/include/includes.h
@@ -73,4 +73,9 @@
 #define TALLOC_ABORT(reason) smb_panic(reason)
 #endif
 
+#if defined(UID_WRAPPER) && !defined(UID_WRAPPER_REPLACE) && !defined(UID_WRAPPER_NOT_REPLACE)
+#define UID_WRAPPER_REPLACE
+#include "../uid_wrapper/uid_wrapper.h"
+#endif
+
 #endif /* _INCLUDES_H */
diff --git a/source4/main.mk b/source4/main.mk
index b4a82017c8..4d7fd584f8 100644
--- a/source4/main.mk
+++ b/source4/main.mk
@@ -19,6 +19,7 @@ mkinclude lib/events/config.mk
 mkinclude lib/cmdline/config.mk
 mkinclude ../lib/socket_wrapper/config.mk
 mkinclude ../lib/nss_wrapper/config.mk
+mkinclude ../lib/uid_wrapper/config.mk
 mkinclude lib/stream/config.mk
 mkinclude ../lib/util/config.mk
 mkinclude ../lib/tdr/config.mk
diff --git a/source4/ntvfs/posix/pvfs_acl.c b/source4/ntvfs/posix/pvfs_acl.c
index 1adced44aa..f5a00c08a8 100644
--- a/source4/ntvfs/posix/pvfs_acl.c
+++ b/source4/ntvfs/posix/pvfs_acl.c
@@ -473,6 +473,14 @@ NTSTATUS pvfs_access_check_unix(struct pvfs_state *pvfs,
 		max_bits |= SEC_STD_ALL;
 	}
 
+#ifdef UID_WRAPPER_REPLACE
+	/* when running with the uid wrapper, files will be created
+	   owned by the ruid, but we may have a different simulated 
+	   euid. We need to force the permission bits as though the 
+	   files owner matches the euid */
+	max_bits |= SEC_STD_ALL;
+#endif
+
 	if (*access_mask == SEC_FLAG_MAXIMUM_ALLOWED) {
 		*access_mask = max_bits;
 		return NT_STATUS_OK;
diff --git a/source4/ntvfs/unixuid/config.mk b/source4/ntvfs/unixuid/config.mk
index 6377657cec..105ba2f535 100644
--- a/source4/ntvfs/unixuid/config.mk
+++ b/source4/ntvfs/unixuid/config.mk
@@ -3,7 +3,7 @@
 [MODULE::ntvfs_unixuid]
 INIT_FUNCTION = ntvfs_unixuid_init
 SUBSYSTEM = ntvfs
-PRIVATE_DEPENDENCIES = SAMDB NSS_WRAPPER
+PRIVATE_DEPENDENCIES = SAMDB NSS_WRAPPER UID_WRAPPER
 # End MODULE ntvfs_unixuid
 ################################################