From 0719aaf5ead7555b7b7a4a080ebf2826a871384e Mon Sep 17 00:00:00 2001 From: Guido Trentalancia Date: Wed, 3 Feb 2010 16:40:20 +0100 Subject: [PATCH] selinux: allow MLS->non-MLS and vice versa upon policy reload Allow runtime switching between different policy types (e.g. from a MLS/MCS policy to a non-MLS/non-MCS policy or viceversa). Signed-off-by: Guido Trentalancia Acked-by: Stephen Smalley Signed-off-by: James Morris --- security/selinux/include/security.h | 3 +- security/selinux/selinuxfs.c | 3 +- security/selinux/ss/context.h | 12 ------ security/selinux/ss/mls.c | 26 ++++++------ security/selinux/ss/mls.h | 2 + security/selinux/ss/mls_types.h | 7 +--- security/selinux/ss/policydb.c | 24 ++--------- security/selinux/ss/policydb.h | 4 ++ security/selinux/ss/services.c | 62 ++++++++++++++++++++++++++--- 9 files changed, 84 insertions(+), 59 deletions(-) diff --git a/security/selinux/include/security.h b/security/selinux/include/security.h index 022cf067aa3f..1f7c2491d3dc 100644 --- a/security/selinux/include/security.h +++ b/security/selinux/include/security.h @@ -57,7 +57,6 @@ struct netlbl_lsm_secattr; extern int selinux_enabled; -extern int selinux_mls_enabled; /* Policy capabilities */ enum { @@ -80,6 +79,8 @@ extern int selinux_policycap_openperm; /* limitation of boundary depth */ #define POLICYDB_BOUNDS_MAXDEPTH 4 +int security_mls_enabled(void); + int security_load_policy(void *data, size_t len); int security_policycap_supported(unsigned int req_cap); diff --git a/security/selinux/selinuxfs.c b/security/selinux/selinuxfs.c index b7bb0f5ec07c..a1cfc464bbb9 100644 --- a/security/selinux/selinuxfs.c +++ b/security/selinux/selinuxfs.c @@ -282,7 +282,8 @@ static ssize_t sel_read_mls(struct file *filp, char __user *buf, char tmpbuf[TMPBUFLEN]; ssize_t length; - length = scnprintf(tmpbuf, TMPBUFLEN, "%d", selinux_mls_enabled); + length = scnprintf(tmpbuf, TMPBUFLEN, "%d", + security_mls_enabled()); return simple_read_from_buffer(buf, count, ppos, tmpbuf, length); } diff --git a/security/selinux/ss/context.h b/security/selinux/ss/context.h index d9dd7a2f6a8a..45e8fb0515f8 100644 --- a/security/selinux/ss/context.h +++ b/security/selinux/ss/context.h @@ -41,9 +41,6 @@ static inline int mls_context_cpy(struct context *dst, struct context *src) { int rc; - if (!selinux_mls_enabled) - return 0; - dst->range.level[0].sens = src->range.level[0].sens; rc = ebitmap_cpy(&dst->range.level[0].cat, &src->range.level[0].cat); if (rc) @@ -64,9 +61,6 @@ static inline int mls_context_cpy_low(struct context *dst, struct context *src) { int rc; - if (!selinux_mls_enabled) - return 0; - dst->range.level[0].sens = src->range.level[0].sens; rc = ebitmap_cpy(&dst->range.level[0].cat, &src->range.level[0].cat); if (rc) @@ -82,9 +76,6 @@ static inline int mls_context_cpy_low(struct context *dst, struct context *src) static inline int mls_context_cmp(struct context *c1, struct context *c2) { - if (!selinux_mls_enabled) - return 1; - return ((c1->range.level[0].sens == c2->range.level[0].sens) && ebitmap_cmp(&c1->range.level[0].cat, &c2->range.level[0].cat) && (c1->range.level[1].sens == c2->range.level[1].sens) && @@ -93,9 +84,6 @@ static inline int mls_context_cmp(struct context *c1, struct context *c2) static inline void mls_context_destroy(struct context *c) { - if (!selinux_mls_enabled) - return; - ebitmap_destroy(&c->range.level[0].cat); ebitmap_destroy(&c->range.level[1].cat); mls_context_init(c); diff --git a/security/selinux/ss/mls.c b/security/selinux/ss/mls.c index 443ae7370144..372b773f8210 100644 --- a/security/selinux/ss/mls.c +++ b/security/selinux/ss/mls.c @@ -39,7 +39,7 @@ int mls_compute_context_len(struct context *context) struct ebitmap *e; struct ebitmap_node *node; - if (!selinux_mls_enabled) + if (!policydb.mls_enabled) return 0; len = 1; /* for the beginning ":" */ @@ -93,7 +93,7 @@ void mls_sid_to_context(struct context *context, struct ebitmap *e; struct ebitmap_node *node; - if (!selinux_mls_enabled) + if (!policydb.mls_enabled) return; scontextp = *scontext; @@ -200,7 +200,7 @@ int mls_context_isvalid(struct policydb *p, struct context *c) { struct user_datum *usrdatum; - if (!selinux_mls_enabled) + if (!p->mls_enabled) return 1; if (!mls_range_isvalid(p, &c->range)) @@ -253,7 +253,7 @@ int mls_context_to_sid(struct policydb *pol, struct cat_datum *catdatum, *rngdatum; int l, rc = -EINVAL; - if (!selinux_mls_enabled) { + if (!pol->mls_enabled) { if (def_sid != SECSID_NULL && oldc) *scontext += strlen(*scontext)+1; return 0; @@ -387,7 +387,7 @@ int mls_from_string(char *str, struct context *context, gfp_t gfp_mask) char *tmpstr, *freestr; int rc; - if (!selinux_mls_enabled) + if (!policydb.mls_enabled) return -EINVAL; /* we need freestr because mls_context_to_sid will change @@ -407,7 +407,7 @@ int mls_from_string(char *str, struct context *context, gfp_t gfp_mask) /* * Copies the MLS range `range' into `context'. */ -static inline int mls_range_set(struct context *context, +int mls_range_set(struct context *context, struct mls_range *range) { int l, rc = 0; @@ -427,7 +427,7 @@ static inline int mls_range_set(struct context *context, int mls_setup_user_range(struct context *fromcon, struct user_datum *user, struct context *usercon) { - if (selinux_mls_enabled) { + if (policydb.mls_enabled) { struct mls_level *fromcon_sen = &(fromcon->range.level[0]); struct mls_level *fromcon_clr = &(fromcon->range.level[1]); struct mls_level *user_low = &(user->range.level[0]); @@ -477,7 +477,7 @@ int mls_convert_context(struct policydb *oldp, struct ebitmap_node *node; int l, i; - if (!selinux_mls_enabled) + if (!policydb.mls_enabled) return 0; for (l = 0; l < 2; l++) { @@ -516,7 +516,7 @@ int mls_compute_sid(struct context *scontext, struct range_trans rtr; struct mls_range *r; - if (!selinux_mls_enabled) + if (!policydb.mls_enabled) return 0; switch (specified) { @@ -559,7 +559,7 @@ int mls_compute_sid(struct context *scontext, void mls_export_netlbl_lvl(struct context *context, struct netlbl_lsm_secattr *secattr) { - if (!selinux_mls_enabled) + if (!policydb.mls_enabled) return; secattr->attr.mls.lvl = context->range.level[0].sens - 1; @@ -579,7 +579,7 @@ void mls_export_netlbl_lvl(struct context *context, void mls_import_netlbl_lvl(struct context *context, struct netlbl_lsm_secattr *secattr) { - if (!selinux_mls_enabled) + if (!policydb.mls_enabled) return; context->range.level[0].sens = secattr->attr.mls.lvl + 1; @@ -601,7 +601,7 @@ int mls_export_netlbl_cat(struct context *context, { int rc; - if (!selinux_mls_enabled) + if (!policydb.mls_enabled) return 0; rc = ebitmap_netlbl_export(&context->range.level[0].cat, @@ -629,7 +629,7 @@ int mls_import_netlbl_cat(struct context *context, { int rc; - if (!selinux_mls_enabled) + if (!policydb.mls_enabled) return 0; rc = ebitmap_netlbl_import(&context->range.level[0].cat, diff --git a/security/selinux/ss/mls.h b/security/selinux/ss/mls.h index 1276715aaa8b..cd9152632e54 100644 --- a/security/selinux/ss/mls.h +++ b/security/selinux/ss/mls.h @@ -39,6 +39,8 @@ int mls_context_to_sid(struct policydb *p, int mls_from_string(char *str, struct context *context, gfp_t gfp_mask); +int mls_range_set(struct context *context, struct mls_range *range); + int mls_convert_context(struct policydb *oldp, struct policydb *newp, struct context *context); diff --git a/security/selinux/ss/mls_types.h b/security/selinux/ss/mls_types.h index b6e943a21061..03bed52a8052 100644 --- a/security/selinux/ss/mls_types.h +++ b/security/selinux/ss/mls_types.h @@ -15,6 +15,7 @@ #define _SS_MLS_TYPES_H_ #include "security.h" +#include "ebitmap.h" struct mls_level { u32 sens; /* sensitivity */ @@ -27,18 +28,12 @@ struct mls_range { static inline int mls_level_eq(struct mls_level *l1, struct mls_level *l2) { - if (!selinux_mls_enabled) - return 1; - return ((l1->sens == l2->sens) && ebitmap_cmp(&l1->cat, &l2->cat)); } static inline int mls_level_dom(struct mls_level *l1, struct mls_level *l2) { - if (!selinux_mls_enabled) - return 1; - return ((l1->sens >= l2->sens) && ebitmap_contains(&l1->cat, &l2->cat)); } diff --git a/security/selinux/ss/policydb.c b/security/selinux/ss/policydb.c index 5b92c0219207..23c6e53c102c 100644 --- a/security/selinux/ss/policydb.c +++ b/security/selinux/ss/policydb.c @@ -52,8 +52,6 @@ static char *symtab_name[SYM_NUM] = { }; #endif -int selinux_mls_enabled; - static unsigned int symtab_sizes[SYM_NUM] = { 2, 32, @@ -455,7 +453,7 @@ static int policydb_index_others(struct policydb *p) printk(KERN_DEBUG "SELinux: %d users, %d roles, %d types, %d bools", p->p_users.nprim, p->p_roles.nprim, p->p_types.nprim, p->p_bools.nprim); - if (selinux_mls_enabled) + if (p->mls_enabled) printk(", %d sens, %d cats", p->p_levels.nprim, p->p_cats.nprim); printk("\n"); @@ -1717,14 +1715,12 @@ int policydb_read(struct policydb *p, void *fp) int i, j, rc; __le32 buf[4]; u32 nodebuf[8]; - u32 len, len2, config, nprim, nel, nel2; + u32 len, len2, nprim, nel, nel2; char *policydb_str; struct policydb_compat_info *info; struct range_trans *rt; struct mls_range *r; - config = 0; - rc = policydb_init(p); if (rc) goto out; @@ -1772,7 +1768,7 @@ int policydb_read(struct policydb *p, void *fp) kfree(policydb_str); policydb_str = NULL; - /* Read the version, config, and table sizes. */ + /* Read the version and table sizes. */ rc = next_entry(buf, fp, sizeof(u32)*4); if (rc < 0) goto bad; @@ -1787,13 +1783,7 @@ int policydb_read(struct policydb *p, void *fp) } if ((le32_to_cpu(buf[1]) & POLICYDB_CONFIG_MLS)) { - if (ss_initialized && !selinux_mls_enabled) { - printk(KERN_ERR "SELinux: Cannot switch between non-MLS" - " and MLS policies\n"); - goto bad; - } - selinux_mls_enabled = 1; - config |= POLICYDB_CONFIG_MLS; + p->mls_enabled = 1; if (p->policyvers < POLICYDB_VERSION_MLS) { printk(KERN_ERR "SELinux: security policydb version %d " @@ -1801,12 +1791,6 @@ int policydb_read(struct policydb *p, void *fp) p->policyvers); goto bad; } - } else { - if (ss_initialized && selinux_mls_enabled) { - printk(KERN_ERR "SELinux: Cannot switch between MLS and" - " non-MLS policies\n"); - goto bad; - } } p->reject_unknown = !!(le32_to_cpu(buf[1]) & REJECT_UNKNOWN); p->allow_unknown = !!(le32_to_cpu(buf[1]) & ALLOW_UNKNOWN); diff --git a/security/selinux/ss/policydb.h b/security/selinux/ss/policydb.h index 193736b64de8..26d9adf8542b 100644 --- a/security/selinux/ss/policydb.h +++ b/security/selinux/ss/policydb.h @@ -27,6 +27,8 @@ #include "symtab.h" #include "avtab.h" #include "sidtab.h" +#include "ebitmap.h" +#include "mls_types.h" #include "context.h" #include "constraint.h" @@ -185,6 +187,8 @@ struct genfs { /* The policy database */ struct policydb { + int mls_enabled; + /* symbol tables */ struct symtab symtab[SYM_NUM]; #define p_commons symtab[SYM_COMMONS] diff --git a/security/selinux/ss/services.c b/security/selinux/ss/services.c index 2abbc49914e6..4e976f58b980 100644 --- a/security/selinux/ss/services.c +++ b/security/selinux/ss/services.c @@ -26,6 +26,10 @@ * * Added support for bounds domain and audit messaged on masked permissions * + * Updated: Guido Trentalancia + * + * Added support for runtime switching of the policy type + * * Copyright (C) 2008, 2009 NEC Corporation * Copyright (C) 2006, 2007 Hewlett-Packard Development Company, L.P. * Copyright (C) 2004-2006 Trusted Computer Solutions, Inc. @@ -232,6 +236,10 @@ static void map_decision(u16 tclass, struct av_decision *avd, } } +int security_mls_enabled(void) +{ + return policydb.mls_enabled; +} /* * Return the boolean value of a constraint expression @@ -1550,6 +1558,8 @@ static int convert_context(u32 key, { struct convert_context_args *args; struct context oldc; + struct ocontext *oc; + struct mls_range *range; struct role_datum *role; struct type_datum *typdatum; struct user_datum *usrdatum; @@ -1620,9 +1630,39 @@ static int convert_context(u32 key, goto bad; c->type = typdatum->value; - rc = mls_convert_context(args->oldp, args->newp, c); - if (rc) - goto bad; + /* Convert the MLS fields if dealing with MLS policies */ + if (args->oldp->mls_enabled && args->newp->mls_enabled) { + rc = mls_convert_context(args->oldp, args->newp, c); + if (rc) + goto bad; + } else if (args->oldp->mls_enabled && !args->newp->mls_enabled) { + /* + * Switching between MLS and non-MLS policy: + * free any storage used by the MLS fields in the + * context for all existing entries in the sidtab. + */ + mls_context_destroy(c); + } else if (!args->oldp->mls_enabled && args->newp->mls_enabled) { + /* + * Switching between non-MLS and MLS policy: + * ensure that the MLS fields of the context for all + * existing entries in the sidtab are filled in with a + * suitable default value, likely taken from one of the + * initial SIDs. + */ + oc = args->newp->ocontexts[OCON_ISID]; + while (oc && oc->sid[0] != SECINITSID_UNLABELED) + oc = oc->next; + if (!oc) { + printk(KERN_ERR "SELinux: unable to look up" + " the initial SIDs list\n"); + goto bad; + } + range = &oc->context[0].range; + rc = mls_range_set(c, range); + if (rc) + goto bad; + } /* Check the validity of the new context. */ if (!policydb_context_isvalid(args->newp, c)) { @@ -1718,6 +1758,12 @@ int security_load_policy(void *data, size_t len) if (policydb_read(&newpolicydb, fp)) return -EINVAL; + /* If switching between different policy types, log MLS status */ + if (policydb.mls_enabled && !newpolicydb.mls_enabled) + printk(KERN_INFO "SELinux: Disabling MLS support...\n"); + else if (!policydb.mls_enabled && newpolicydb.mls_enabled) + printk(KERN_INFO "SELinux: Enabling MLS support...\n"); + rc = policydb_load_isids(&newpolicydb, &newsidtab); if (rc) { printk(KERN_ERR "SELinux: unable to load the initial SIDs\n"); @@ -1749,8 +1795,12 @@ int security_load_policy(void *data, size_t len) args.oldp = &policydb; args.newp = &newpolicydb; rc = sidtab_map(&newsidtab, convert_context, &args); - if (rc) + if (rc) { + printk(KERN_ERR "SELinux: unable to convert the internal" + " representation of contexts in the new SID" + " table\n"); goto err; + } /* Save the old policydb and SID table to free later. */ memcpy(&oldpolicydb, &policydb, sizeof policydb); @@ -2346,7 +2396,7 @@ int security_sid_mls_copy(u32 sid, u32 mls_sid, u32 *new_sid) u32 len; int rc = 0; - if (!ss_initialized || !selinux_mls_enabled) { + if (!ss_initialized || !policydb.mls_enabled) { *new_sid = sid; goto out; } @@ -2447,7 +2497,7 @@ int security_net_peersid_resolve(u32 nlbl_sid, u32 nlbl_type, /* we don't need to check ss_initialized here since the only way both * nlbl_sid and xfrm_sid are not equal to SECSID_NULL would be if the * security server was initialized and ss_initialized was true */ - if (!selinux_mls_enabled) { + if (!policydb.mls_enabled) { *peer_sid = SECSID_NULL; return 0; } -- GitLab