svn commit: r219129 - in head/sys: compat/freebsd32 conf kern sys
Robert Watson
rwatson at FreeBSD.org
Tue Mar 1 13:23:37 UTC 2011
Author: rwatson
Date: Tue Mar 1 13:23:37 2011
New Revision: 219129
URL: http://svn.freebsd.org/changeset/base/219129
Log:
Add initial support for Capsicum's Capability Mode to the FreeBSD kernel,
compiled conditionally on options CAPABILITIES:
Add a new credential flag, CRED_FLAG_CAPMODE, which indicates that a
subject (typically a process) is in capability mode.
Add two new system calls, cap_enter(2) and cap_getmode(2), which allow
setting and querying (but never clearing) the flag.
Export the capability mode flag via process information sysctls.
Sponsored by: Google, Inc.
Reviewed by: anderson
Discussed with: benl, kris, pjd
Obtained from: Capsicum Project
MFC after: 3 months
Added:
head/sys/kern/sys_capability.c (contents, props changed)
Modified:
head/sys/compat/freebsd32/syscalls.master
head/sys/conf/NOTES
head/sys/conf/options
head/sys/kern/kern_proc.c
head/sys/kern/syscalls.master
head/sys/sys/ucred.h
head/sys/sys/user.h
Modified: head/sys/compat/freebsd32/syscalls.master
==============================================================================
--- head/sys/compat/freebsd32/syscalls.master Tue Mar 1 13:14:28 2011 (r219128)
+++ head/sys/compat/freebsd32/syscalls.master Tue Mar 1 13:23:37 2011 (r219129)
@@ -952,8 +952,8 @@
513 AUE_LPATHCONF NOPROTO { int lpathconf(char *path, int name); }
514 AUE_CAP_NEW UNIMPL cap_new
515 AUE_CAP_GETRIGHTS UNIMPL cap_getrights
-516 AUE_CAP_ENTER UNIMPL cap_enter
-517 AUE_CAP_GETMODE UNIMPL cap_getmode
+516 AUE_CAP_ENTER NOPROTO { int cap_enter(void); }
+517 AUE_CAP_GETMODE NOPROTO { int cap_getmode(u_int *modep); }
518 AUE_PDFORK UNIMPL pdfork
519 AUE_PDKILL UNIMPL pdkill
520 AUE_PDGETPID UNIMPL pdgetpid
Modified: head/sys/conf/NOTES
==============================================================================
--- head/sys/conf/NOTES Tue Mar 1 13:14:28 2011 (r219128)
+++ head/sys/conf/NOTES Tue Mar 1 13:23:37 2011 (r219129)
@@ -1157,6 +1157,9 @@ options MAC_SEEOTHERUIDS
options MAC_STUB
options MAC_TEST
+# Support for Capsicum
+options CAPABILIITES
+
#####################################################################
# CLOCK OPTIONS
Modified: head/sys/conf/options
==============================================================================
--- head/sys/conf/options Tue Mar 1 13:14:28 2011 (r219128)
+++ head/sys/conf/options Tue Mar 1 13:23:37 2011 (r219129)
@@ -63,6 +63,7 @@ SYSCTL_DEBUG opt_sysctl.h
ADAPTIVE_LOCKMGRS
ALQ
AUDIT opt_global.h
+CAPABILITIES opt_capabilities.h
CODA_COMPAT_5 opt_coda.h
COMPAT_43 opt_compat.h
COMPAT_43TTY opt_compat.h
Modified: head/sys/kern/kern_proc.c
==============================================================================
--- head/sys/kern/kern_proc.c Tue Mar 1 13:14:28 2011 (r219128)
+++ head/sys/kern/kern_proc.c Tue Mar 1 13:23:37 2011 (r219129)
@@ -725,7 +725,9 @@ fill_kinfo_proc_only(struct proc *p, str
kp->ki_uid = cred->cr_uid;
kp->ki_ruid = cred->cr_ruid;
kp->ki_svuid = cred->cr_svuid;
- kp->ki_cr_flags = cred->cr_flags;
+ kp->ki_cr_flags = 0;
+ if (cred->cr_flags & CRED_FLAG_CAPMODE)
+ kp->ki_cr_flags |= KI_CRF_CAPABILITY_MODE;
/* XXX bde doesn't like KI_NGROUPS */
if (cred->cr_ngroups > KI_NGROUPS) {
kp->ki_ngroups = KI_NGROUPS;
Added: head/sys/kern/sys_capability.c
==============================================================================
--- /dev/null 00:00:00 1970 (empty, because file is newly added)
+++ head/sys/kern/sys_capability.c Tue Mar 1 13:23:37 2011 (r219129)
@@ -0,0 +1,123 @@
+/*-
+ * Copyright (c) 2008-2011 Robert N. M. Watson
+ * Copyright (c) 2010-2011 Jonathan Anderson
+ * All rights reserved.
+ *
+ * This software was developed at the University of Cambridge Computer
+ * Laboratory with support from a grant from Google, Inc.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ * 2. 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.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR 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 THE AUTHOR 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.
+ */
+
+/*
+ * FreeBSD kernel capability facility.
+ *
+ * Currently, this file implements only capability mode; capabilities
+ * (rights-refined file descriptors) will follow.
+ *
+ */
+
+#include "opt_capabilities.h"
+
+#include <sys/cdefs.h>
+__FBSDID("$FreeBSD$");
+
+#include <sys/param.h>
+#include <sys/capability.h>
+#include <sys/file.h>
+#include <sys/filedesc.h>
+#include <sys/kernel.h>
+#include <sys/lock.h>
+#include <sys/mutex.h>
+#include <sys/proc.h>
+#include <sys/sysproto.h>
+#include <sys/sysctl.h>
+#include <sys/systm.h>
+#include <sys/ucred.h>
+
+#include <security/audit/audit.h>
+
+#include <vm/uma.h>
+#include <vm/vm.h>
+
+#ifdef CAPABILITIES
+
+/*
+ * We don't currently have any MIB entries for sysctls, but we do expose
+ * security.capabilities so that it's easy to tell if options CAPABILITIES is
+ * compiled into the kernel.
+ */
+SYSCTL_NODE(_security, OID_AUTO, capabilities, CTLFLAG_RW, 0, "Capsicum");
+
+/*
+ * System call to enter capability mode for the process.
+ */
+int
+cap_enter(struct thread *td, struct cap_enter_args *uap)
+{
+ struct ucred *newcred, *oldcred;
+ struct proc *p;
+
+ if (IN_CAPABILITY_MODE(td))
+ return (0);
+
+ newcred = crget();
+ p = td->td_proc;
+ PROC_LOCK(p);
+ oldcred = p->p_ucred;
+ crcopy(newcred, oldcred);
+ newcred->cr_flags |= CRED_FLAG_CAPMODE;
+ p->p_ucred = newcred;
+ PROC_UNLOCK(p);
+ crfree(oldcred);
+ return (0);
+}
+
+/*
+ * System call to query whether the process is in capability mode.
+ */
+int
+cap_getmode(struct thread *td, struct cap_getmode_args *uap)
+{
+ u_int i;
+
+ i = (IN_CAPABILITY_MODE(td)) ? 1 : 0;
+ return (copyout(&i, uap->modep, sizeof(i)));
+}
+
+#else /* !CAPABILITIES */
+
+int
+cap_enter(struct thread *td, struct cap_enter_args *uap)
+{
+
+ return (ENOSYS);
+}
+
+int
+cap_getmode(struct thread *td, struct cap_getmode_args *uap)
+{
+
+ return (ENOSYS);
+}
+
+#endif /* CAPABILITIES */
Modified: head/sys/kern/syscalls.master
==============================================================================
--- head/sys/kern/syscalls.master Tue Mar 1 13:14:28 2011 (r219128)
+++ head/sys/kern/syscalls.master Tue Mar 1 13:23:37 2011 (r219129)
@@ -916,8 +916,8 @@
513 AUE_LPATHCONF STD { int lpathconf(char *path, int name); }
514 AUE_CAP_NEW UNIMPL cap_new
515 AUE_CAP_GETRIGHTS UNIMPL cap_getrights
-516 AUE_CAP_ENTER UNIMPL cap_enter
-517 AUE_CAP_GETMODE UNIMPL cap_getmode
+516 AUE_CAP_ENTER STD { int cap_enter(void); }
+517 AUE_CAP_GETMODE STD { int cap_getmode(u_int *modep); }
518 AUE_PDFORK UNIMPL pdfork
519 AUE_PDKILL UNIMPL pdkill
520 AUE_PDGETPID UNIMPL pdgetpid
Modified: head/sys/sys/ucred.h
==============================================================================
--- head/sys/sys/ucred.h Tue Mar 1 13:14:28 2011 (r219128)
+++ head/sys/sys/ucred.h Tue Mar 1 13:23:37 2011 (r219129)
@@ -70,6 +70,11 @@ struct ucred {
#define XU_NGROUPS 16
/*
+ * Flags for cr_flags.
+ */
+#define CRED_FLAG_CAPMODE 0x00000001 /* In capability mode. */
+
+/*
* This is the external representation of struct ucred.
*/
struct xucred {
Modified: head/sys/sys/user.h
==============================================================================
--- head/sys/sys/user.h Tue Mar 1 13:14:28 2011 (r219128)
+++ head/sys/sys/user.h Tue Mar 1 13:23:37 2011 (r219129)
@@ -101,9 +101,11 @@
#define KI_NGROUPS 16 /* number of groups in ki_groups */
#define LOGNAMELEN 17 /* size of returned ki_login */
+/* Flags for the process credential. */
+#define KI_CRF_CAPABILITY_MODE 0x00000001
/*
- * Steal a bit from ki_cr_flags (cr_flags is never used) to indicate
- * that the cred had more than KI_NGROUPS groups.
+ * Steal a bit from ki_cr_flags to indicate that the cred had more than
+ * KI_NGROUPS groups.
*/
#define KI_CRF_GRP_OVERFLOW 0x80000000
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