diff options
| author | jym <jym@NetBSD.org> | 2011-12-04 19:24:58 +0000 |
|---|---|---|
| committer | jym <jym@NetBSD.org> | 2011-12-04 19:24:58 +0000 |
| commit | 6519e39ddd31a3a04e7f4a91345bcbbe8ca8efdc (patch) | |
| tree | 7535e85ea2a89ab05e6a1a1c69a1c90a982cae2e /sys/secmodel/securelevel | |
| parent | 982b01a29bee0addbe89b37157465fdbd0c6c024 (diff) | |
Implement the register/deregister/evaluation API for secmodel(9). It
allows registration of callbacks that can be used later for
cross-secmodel "safe" communication.
When a secmodel wishes to know a property maintained by another
secmodel, it has to submit a request to it so the other secmodel can
proceed to evaluating the request. This is done through the
secmodel_eval(9) call; example:
bool isroot;
error = secmodel_eval("org.netbsd.secmodel.suser", "is-root",
cred, &isroot);
if (error == 0 && !isroot)
result = KAUTH_RESULT_DENY;
This one asks the suser module if the credentials are assumed to be root
when evaluated by suser module. If the module is present, it will
respond. If absent, the call will return an error.
Args and command are arbitrarily defined; it's up to the secmodel(9) to
document what it expects.
Typical example is securelevel testing: when someone wants to know
whether securelevel is raised above a certain level or not, the caller
has to request this property to the secmodel_securelevel(9) module.
Given that securelevel module may be absent from system's context (thus
making access to the global "securelevel" variable impossible or
unsafe), this API can cope with this absence and return an error.
We are using secmodel_eval(9) to implement a secmodel_extensions(9)
module, which plugs with the bsd44, suser and securelevel secmodels
to provide the logic behind curtain, usermount and user_set_cpu_affinity
modes, without adding hooks to traditional secmodels. This solves a
real issue with the current secmodel(9) code, as usermount or
user_set_cpu_affinity are not really tied to secmodel_suser(9).
The secmodel_eval(9) is also used to restrict security.models settings
when securelevel is above 0, through the "is-securelevel-above"
evaluation:
- curtain can be enabled any time, but cannot be disabled if
securelevel is above 0.
- usermount/user_set_cpu_affinity can be disabled any time, but cannot
be enabled if securelevel is above 0.
Regarding sysctl(7) entries:
curtain and usermount are now found under security.models.extensions
tree. The security.curtain and vfs.generic.usermount are still
accessible for backwards compat.
Documentation is incoming, I am proof-reading my writings.
Written by elad@, reviewed and tested (anita test + interact for rights
tests) by me. ok elad@.
See also
http://mail-index.netbsd.org/tech-security/2011/11/29/msg000422.html
XXX might consider va0 mapping too.
XXX Having a secmodel(9) specific printf (like aprint_*) for reporting
secmodel(9) errors might be a good idea, but I am not sure on how
to design such a function right now.
Diffstat (limited to 'sys/secmodel/securelevel')
| -rw-r--r-- | sys/secmodel/securelevel/secmodel_securelevel.c | 38 | ||||
| -rw-r--r-- | sys/secmodel/securelevel/securelevel.h | 5 |
2 files changed, 39 insertions, 4 deletions
diff --git a/sys/secmodel/securelevel/secmodel_securelevel.c b/sys/secmodel/securelevel/secmodel_securelevel.c index adc19cd952f..d6d41a240ca 100644 --- a/sys/secmodel/securelevel/secmodel_securelevel.c +++ b/sys/secmodel/securelevel/secmodel_securelevel.c @@ -1,4 +1,4 @@ -/* $NetBSD: secmodel_securelevel.c,v 1.22 2011/11/28 20:57:51 jym Exp $ */ +/* $NetBSD: secmodel_securelevel.c,v 1.23 2011/12/04 19:25:00 jym Exp $ */ /*- * Copyright (c) 2006 Elad Efrat <elad@NetBSD.org> * All rights reserved. @@ -35,7 +35,7 @@ */ #include <sys/cdefs.h> -__KERNEL_RCSID(0, "$NetBSD: secmodel_securelevel.c,v 1.22 2011/11/28 20:57:51 jym Exp $"); +__KERNEL_RCSID(0, "$NetBSD: secmodel_securelevel.c,v 1.23 2011/12/04 19:25:00 jym Exp $"); #ifdef _KERNEL_OPT #include "opt_insecure.h" @@ -54,6 +54,7 @@ __KERNEL_RCSID(0, "$NetBSD: secmodel_securelevel.c,v 1.22 2011/11/28 20:57:51 jy #include <miscfs/specfs/specdev.h> +#include <secmodel/secmodel.h> #include <secmodel/securelevel/securelevel.h> MODULE(MODULE_CLASS_SECMODEL, securelevel, NULL); @@ -63,6 +64,7 @@ static int securelevel; static kauth_listener_t l_system, l_process, l_network, l_machdep, l_device, l_vnode; +static secmodel_t securelevel_sm; static struct sysctllog *securelevel_sysctl_log; /* @@ -116,7 +118,7 @@ sysctl_security_securelevel_setup(struct sysctllog **clog) sysctl_createv(clog, 0, &rnode, NULL, CTLFLAG_PERMANENT, CTLTYPE_STRING, "name", NULL, - NULL, 0, __UNCONST("Traditional NetBSD: Securelevel"), 0, + NULL, 0, __UNCONST(SECMODEL_SECURELEVEL_NAME), 0, CTL_CREATE, CTL_EOL); sysctl_createv(clog, 0, &rnode, NULL, @@ -180,12 +182,36 @@ secmodel_securelevel_stop(void) } static int +securelevel_eval(const char *what, void *arg, void *ret) +{ + int error = 0; + + if (strcasecmp(what, "is-securelevel-above") == 0) { + int level = (int)(uintptr_t)arg; + bool *bp = ret; + + *bp = (securelevel > level); + } else { + error = ENOENT; + } + + return error; +} + +static int securelevel_modcmd(modcmd_t cmd, void *arg) { int error = 0; switch (cmd) { case MODULE_CMD_INIT: + error = secmodel_register(&securelevel_sm, + SECMODEL_SECURELEVEL_ID, SECMODEL_SECURELEVEL_NAME, + NULL, securelevel_eval, NULL); + if (error != 0) + printf("securelevel_modcmd::init: secmodel_register " + "returned %d\n", error); + secmodel_securelevel_init(); secmodel_securelevel_start(); sysctl_security_securelevel_setup(&securelevel_sysctl_log); @@ -194,6 +220,12 @@ securelevel_modcmd(modcmd_t cmd, void *arg) case MODULE_CMD_FINI: sysctl_teardown(&securelevel_sysctl_log); secmodel_securelevel_stop(); + + error = secmodel_deregister(securelevel_sm); + if (error != 0) + printf("securelevel_modcmd::fini: secmodel_deregister " + "returned %d\n", error); + break; case MODULE_CMD_AUTOUNLOAD: diff --git a/sys/secmodel/securelevel/securelevel.h b/sys/secmodel/securelevel/securelevel.h index 9ce22fdfa0a..86ad594acd4 100644 --- a/sys/secmodel/securelevel/securelevel.h +++ b/sys/secmodel/securelevel/securelevel.h @@ -1,4 +1,4 @@ -/* $NetBSD: securelevel.h,v 1.3 2009/10/02 18:50:14 elad Exp $ */ +/* $NetBSD: securelevel.h,v 1.4 2011/12/04 19:25:00 jym Exp $ */ /*- * Copyright (c) 2006 Elad Efrat <elad@NetBSD.org> * All rights reserved. @@ -29,6 +29,9 @@ #ifndef _SECMODEL_SECURELEVEL_SECURELEVEL_H_ #define _SECMODEL_SECURELEVEL_SECURELEVEL_H_ +#define SECMODEL_SECURELEVEL_ID "org.netbsd.secmodel.securelevel" +#define SECMODEL_SECURELEVEL_NAME "Traditional NetBSD: Securelevel" + int secmodel_securelevel_sysctl(SYSCTLFN_PROTO); void secmodel_securelevel_init(void); |
