From 64dbf07474d011540ca479a2e87fe998f570d6e3 Mon Sep 17 00:00:00 2001 From: Eric Paris Date: Mon, 31 Mar 2008 12:17:33 +1100 Subject: [PATCH] selinux: introduce permissive types Introduce the concept of a permissive type. A new ebitmap is introduced to the policy database which indicates if a given type has the permissive bit set or not. This bit is tested for the scontext of any denial. The bit is meaningless on types which only appear as the target of a decision and never the source. A domain running with a permissive type will be allowed to perform any action similarly to when the system is globally set permissive. Signed-off-by: Eric Paris Acked-by: Stephen Smalley Signed-off-by: James Morris --- security/selinux/Kconfig | 2 +- security/selinux/avc.c | 9 +++++---- security/selinux/include/security.h | 5 ++++- security/selinux/ss/policydb.c | 11 +++++++++++ security/selinux/ss/policydb.h | 2 ++ security/selinux/ss/services.c | 25 +++++++++++++++++++++++++ 6 files changed, 48 insertions(+), 6 deletions(-) diff --git a/security/selinux/Kconfig b/security/selinux/Kconfig index 2b517d618672..a436d1cfa88b 100644 --- a/security/selinux/Kconfig +++ b/security/selinux/Kconfig @@ -145,7 +145,7 @@ config SECURITY_SELINUX_POLICYDB_VERSION_MAX config SECURITY_SELINUX_POLICYDB_VERSION_MAX_VALUE int "NSA SELinux maximum supported policy format version value" depends on SECURITY_SELINUX_POLICYDB_VERSION_MAX - range 15 22 + range 15 23 default 19 help This option sets the value for the maximum policy format version diff --git a/security/selinux/avc.c b/security/selinux/avc.c index cb3f0ce0b00a..a4fc6e6d038a 100644 --- a/security/selinux/avc.c +++ b/security/selinux/avc.c @@ -893,12 +893,13 @@ int avc_has_perm_noaudit(u32 ssid, u32 tsid, denied = requested & ~(p_ae->avd.allowed); if (denied) { - if (selinux_enforcing || (flags & AVC_STRICT)) + if (flags & AVC_STRICT) rc = -EACCES; + else if (!selinux_enforcing || security_permissive_sid(ssid)) + avc_update_node(AVC_CALLBACK_GRANT, requested, ssid, + tsid, tclass); else - if (node) - avc_update_node(AVC_CALLBACK_GRANT,requested, - ssid,tsid,tclass); + rc = -EACCES; } rcu_read_unlock(); diff --git a/security/selinux/include/security.h b/security/selinux/include/security.h index 315b4ec1e12a..dd70aa084637 100644 --- a/security/selinux/include/security.h +++ b/security/selinux/include/security.h @@ -26,13 +26,14 @@ #define POLICYDB_VERSION_AVTAB 20 #define POLICYDB_VERSION_RANGETRANS 21 #define POLICYDB_VERSION_POLCAP 22 +#define POLICYDB_VERSION_PERMISSIVE 23 /* Range of policy versions we understand*/ #define POLICYDB_VERSION_MIN POLICYDB_VERSION_BASE #ifdef CONFIG_SECURITY_SELINUX_POLICYDB_VERSION_MAX #define POLICYDB_VERSION_MAX CONFIG_SECURITY_SELINUX_POLICYDB_VERSION_MAX_VALUE #else -#define POLICYDB_VERSION_MAX POLICYDB_VERSION_POLCAP +#define POLICYDB_VERSION_MAX POLICYDB_VERSION_PERMISSIVE #endif #define CONTEXT_MNT 0x01 @@ -69,6 +70,8 @@ struct av_decision { u32 seqno; }; +int security_permissive_sid(u32 sid); + int security_compute_av(u32 ssid, u32 tsid, u16 tclass, u32 requested, struct av_decision *avd); diff --git a/security/selinux/ss/policydb.c b/security/selinux/ss/policydb.c index 325551cd7fc7..6bdb0ff6a927 100644 --- a/security/selinux/ss/policydb.c +++ b/security/selinux/ss/policydb.c @@ -111,6 +111,11 @@ static struct policydb_compat_info policydb_compat[] = { .version = POLICYDB_VERSION_POLCAP, .sym_num = SYM_NUM, .ocon_num = OCON_NUM, + }, + { + .version = POLICYDB_VERSION_PERMISSIVE, + .sym_num = SYM_NUM, + .ocon_num = OCON_NUM, } }; @@ -194,6 +199,7 @@ static int policydb_init(struct policydb *p) goto out_free_symtab; ebitmap_init(&p->policycaps); + ebitmap_init(&p->permissive_map); out: return rc; @@ -687,6 +693,7 @@ void policydb_destroy(struct policydb *p) kfree(p->type_attr_map); kfree(p->undefined_perms); ebitmap_destroy(&p->policycaps); + ebitmap_destroy(&p->permissive_map); return; } @@ -1570,6 +1577,10 @@ int policydb_read(struct policydb *p, void *fp) ebitmap_read(&p->policycaps, fp) != 0) goto bad; + if (p->policyvers >= POLICYDB_VERSION_PERMISSIVE && + ebitmap_read(&p->permissive_map, fp) != 0) + goto bad; + info = policydb_lookup_compat(p->policyvers); if (!info) { printk(KERN_ERR "SELinux: unable to find policy compat info " diff --git a/security/selinux/ss/policydb.h b/security/selinux/ss/policydb.h index c4ce996e202c..ba593a3da877 100644 --- a/security/selinux/ss/policydb.h +++ b/security/selinux/ss/policydb.h @@ -243,6 +243,8 @@ struct policydb { struct ebitmap policycaps; + struct ebitmap permissive_map; + unsigned int policyvers; unsigned int reject_unknown : 1; diff --git a/security/selinux/ss/services.c b/security/selinux/ss/services.c index face5795c760..eefa89ce77a7 100644 --- a/security/selinux/ss/services.c +++ b/security/selinux/ss/services.c @@ -417,6 +417,31 @@ inval_class: return -EINVAL; } +/* + * Given a sid find if the type has the permissive flag set + */ +int security_permissive_sid(u32 sid) +{ + struct context *context; + u32 type; + int rc; + + POLICY_RDLOCK; + + context = sidtab_search(&sidtab, sid); + BUG_ON(!context); + + type = context->type; + /* + * we are intentionally using type here, not type-1, the 0th bit may + * someday indicate that we are globally setting permissive in policy. + */ + rc = ebitmap_get_bit(&policydb.permissive_map, type); + + POLICY_RDUNLOCK; + return rc; +} + static int security_validtrans_handle_fail(struct context *ocontext, struct context *ncontext, struct context *tcontext,