diff options
Diffstat (limited to 'security')
-rw-r--r-- | security/selinux/ss/services.c | 157 | ||||
-rw-r--r-- | security/selinux/ss/sidtab.c | 21 | ||||
-rw-r--r-- | security/selinux/ss/sidtab.h | 4 |
3 files changed, 145 insertions, 37 deletions
diff --git a/security/selinux/ss/services.c b/security/selinux/ss/services.c index 4a907e008a98..6f095c0dc658 100644 --- a/security/selinux/ss/services.c +++ b/security/selinux/ss/services.c @@ -1551,6 +1551,7 @@ static int security_context_to_sid_core(struct selinux_state *state, if (!str) goto out; } +retry: rcu_read_lock(); policy = rcu_dereference(state->policy); policydb = &policy->policydb; @@ -1564,6 +1565,15 @@ static int security_context_to_sid_core(struct selinux_state *state, } else if (rc) goto out_unlock; rc = sidtab_context_to_sid(sidtab, &context, sid); + if (rc == -ESTALE) { + rcu_read_unlock(); + if (context.str) { + str = context.str; + context.str = NULL; + } + context_destroy(&context); + goto retry; + } context_destroy(&context); out_unlock: rcu_read_unlock(); @@ -1713,7 +1723,7 @@ static int security_compute_sid(struct selinux_state *state, struct selinux_policy *policy; struct policydb *policydb; struct sidtab *sidtab; - struct class_datum *cladatum = NULL; + struct class_datum *cladatum; struct context *scontext, *tcontext, newcontext; struct sidtab_entry *sentry, *tentry; struct avtab_key avkey; @@ -1735,6 +1745,8 @@ static int security_compute_sid(struct selinux_state *state, goto out; } +retry: + cladatum = NULL; context_init(&newcontext); rcu_read_lock(); @@ -1879,6 +1891,11 @@ static int security_compute_sid(struct selinux_state *state, } /* Obtain the sid for the context. */ rc = sidtab_context_to_sid(sidtab, &newcontext, out_sid); + if (rc == -ESTALE) { + rcu_read_unlock(); + context_destroy(&newcontext); + goto retry; + } out_unlock: rcu_read_unlock(); context_destroy(&newcontext); @@ -2190,6 +2207,7 @@ void selinux_policy_commit(struct selinux_state *state, struct selinux_load_state *load_state) { struct selinux_policy *oldpolicy, *newpolicy = load_state->policy; + unsigned long flags; u32 seqno; oldpolicy = rcu_dereference_protected(state->policy, @@ -2211,7 +2229,13 @@ void selinux_policy_commit(struct selinux_state *state, seqno = newpolicy->latest_granting; /* Install the new policy. */ - rcu_assign_pointer(state->policy, newpolicy); + if (oldpolicy) { + sidtab_freeze_begin(oldpolicy->sidtab, &flags); + rcu_assign_pointer(state->policy, newpolicy); + sidtab_freeze_end(oldpolicy->sidtab, &flags); + } else { + rcu_assign_pointer(state->policy, newpolicy); + } /* Load the policycaps from the new policy */ security_load_policycaps(state, newpolicy); @@ -2355,13 +2379,15 @@ int security_port_sid(struct selinux_state *state, struct policydb *policydb; struct sidtab *sidtab; struct ocontext *c; - int rc = 0; + int rc; if (!selinux_initialized(state)) { *out_sid = SECINITSID_PORT; return 0; } +retry: + rc = 0; rcu_read_lock(); policy = rcu_dereference(state->policy); policydb = &policy->policydb; @@ -2380,6 +2406,10 @@ int security_port_sid(struct selinux_state *state, if (!c->sid[0]) { rc = sidtab_context_to_sid(sidtab, &c->context[0], &c->sid[0]); + if (rc == -ESTALE) { + rcu_read_unlock(); + goto retry; + } if (rc) goto out; } @@ -2406,13 +2436,15 @@ int security_ib_pkey_sid(struct selinux_state *state, struct policydb *policydb; struct sidtab *sidtab; struct ocontext *c; - int rc = 0; + int rc; if (!selinux_initialized(state)) { *out_sid = SECINITSID_UNLABELED; return 0; } +retry: + rc = 0; rcu_read_lock(); policy = rcu_dereference(state->policy); policydb = &policy->policydb; @@ -2433,6 +2465,10 @@ int security_ib_pkey_sid(struct selinux_state *state, rc = sidtab_context_to_sid(sidtab, &c->context[0], &c->sid[0]); + if (rc == -ESTALE) { + rcu_read_unlock(); + goto retry; + } if (rc) goto out; } @@ -2458,13 +2494,15 @@ int security_ib_endport_sid(struct selinux_state *state, struct policydb *policydb; struct sidtab *sidtab; struct ocontext *c; - int rc = 0; + int rc; if (!selinux_initialized(state)) { *out_sid = SECINITSID_UNLABELED; return 0; } +retry: + rc = 0; rcu_read_lock(); policy = rcu_dereference(state->policy); policydb = &policy->policydb; @@ -2485,6 +2523,10 @@ int security_ib_endport_sid(struct selinux_state *state, if (!c->sid[0]) { rc = sidtab_context_to_sid(sidtab, &c->context[0], &c->sid[0]); + if (rc == -ESTALE) { + rcu_read_unlock(); + goto retry; + } if (rc) goto out; } @@ -2508,7 +2550,7 @@ int security_netif_sid(struct selinux_state *state, struct selinux_policy *policy; struct policydb *policydb; struct sidtab *sidtab; - int rc = 0; + int rc; struct ocontext *c; if (!selinux_initialized(state)) { @@ -2516,6 +2558,8 @@ int security_netif_sid(struct selinux_state *state, return 0; } +retry: + rc = 0; rcu_read_lock(); policy = rcu_dereference(state->policy); policydb = &policy->policydb; @@ -2532,10 +2576,18 @@ int security_netif_sid(struct selinux_state *state, if (!c->sid[0] || !c->sid[1]) { rc = sidtab_context_to_sid(sidtab, &c->context[0], &c->sid[0]); + if (rc == -ESTALE) { + rcu_read_unlock(); + goto retry; + } if (rc) goto out; rc = sidtab_context_to_sid(sidtab, &c->context[1], &c->sid[1]); + if (rc == -ESTALE) { + rcu_read_unlock(); + goto retry; + } if (rc) goto out; } @@ -2585,6 +2637,7 @@ int security_node_sid(struct selinux_state *state, return 0; } +retry: rcu_read_lock(); policy = rcu_dereference(state->policy); policydb = &policy->policydb; @@ -2633,6 +2686,10 @@ int security_node_sid(struct selinux_state *state, rc = sidtab_context_to_sid(sidtab, &c->context[0], &c->sid[0]); + if (rc == -ESTALE) { + rcu_read_unlock(); + goto retry; + } if (rc) goto out; } @@ -2674,18 +2731,24 @@ int security_get_user_sids(struct selinux_state *state, struct sidtab *sidtab; struct context *fromcon, usercon; u32 *mysids = NULL, *mysids2, sid; - u32 mynel = 0, maxnel = SIDS_NEL; + u32 i, j, mynel, maxnel = SIDS_NEL; struct user_datum *user; struct role_datum *role; struct ebitmap_node *rnode, *tnode; - int rc = 0, i, j; + int rc; *sids = NULL; *nel = 0; if (!selinux_initialized(state)) - goto out; + return 0; + + mysids = kcalloc(maxnel, sizeof(*mysids), GFP_KERNEL); + if (!mysids) + return -ENOMEM; +retry: + mynel = 0; rcu_read_lock(); policy = rcu_dereference(state->policy); policydb = &policy->policydb; @@ -2705,11 +2768,6 @@ int security_get_user_sids(struct selinux_state *state, usercon.user = user->value; - rc = -ENOMEM; - mysids = kcalloc(maxnel, sizeof(*mysids), GFP_ATOMIC); - if (!mysids) - goto out_unlock; - ebitmap_for_each_positive_bit(&user->roles, rnode, i) { role = policydb->role_val_to_struct[i]; usercon.role = i + 1; @@ -2721,6 +2779,10 @@ int security_get_user_sids(struct selinux_state *state, continue; rc = sidtab_context_to_sid(sidtab, &usercon, &sid); + if (rc == -ESTALE) { + rcu_read_unlock(); + goto retry; + } if (rc) goto out_unlock; if (mynel < maxnel) { @@ -2743,14 +2805,14 @@ out_unlock: rcu_read_unlock(); if (rc || !mynel) { kfree(mysids); - goto out; + return rc; } rc = -ENOMEM; mysids2 = kcalloc(mynel, sizeof(*mysids2), GFP_KERNEL); if (!mysids2) { kfree(mysids); - goto out; + return rc; } for (i = 0, j = 0; i < mynel; i++) { struct av_decision dummy_avd; @@ -2763,12 +2825,10 @@ out_unlock: mysids2[j++] = mysids[i]; cond_resched(); } - rc = 0; kfree(mysids); *sids = mysids2; *nel = j; -out: - return rc; + return 0; } /** @@ -2781,6 +2841,9 @@ out: * Obtain a SID to use for a file in a filesystem that * cannot support xattr or use a fixed labeling behavior like * transition SIDs or task SIDs. + * + * WARNING: This function may return -ESTALE, indicating that the caller + * must retry the operation after re-acquiring the policy pointer! */ static inline int __security_genfs_sid(struct selinux_policy *policy, const char *fstype, @@ -2859,11 +2922,13 @@ int security_genfs_sid(struct selinux_state *state, return 0; } - rcu_read_lock(); - policy = rcu_dereference(state->policy); - retval = __security_genfs_sid(policy, - fstype, path, orig_sclass, sid); - rcu_read_unlock(); + do { + rcu_read_lock(); + policy = rcu_dereference(state->policy); + retval = __security_genfs_sid(policy, fstype, path, + orig_sclass, sid); + rcu_read_unlock(); + } while (retval == -ESTALE); return retval; } @@ -2886,7 +2951,7 @@ int security_fs_use(struct selinux_state *state, struct super_block *sb) struct selinux_policy *policy; struct policydb *policydb; struct sidtab *sidtab; - int rc = 0; + int rc; struct ocontext *c; struct superblock_security_struct *sbsec = sb->s_security; const char *fstype = sb->s_type->name; @@ -2897,6 +2962,8 @@ int security_fs_use(struct selinux_state *state, struct super_block *sb) return 0; } +retry: + rc = 0; rcu_read_lock(); policy = rcu_dereference(state->policy); policydb = &policy->policydb; @@ -2914,6 +2981,10 @@ int security_fs_use(struct selinux_state *state, struct super_block *sb) if (!c->sid[0]) { rc = sidtab_context_to_sid(sidtab, &c->context[0], &c->sid[0]); + if (rc == -ESTALE) { + rcu_read_unlock(); + goto retry; + } if (rc) goto out; } @@ -2921,6 +2992,10 @@ int security_fs_use(struct selinux_state *state, struct super_block *sb) } else { rc = __security_genfs_sid(policy, fstype, "/", SECCLASS_DIR, &sbsec->sid); + if (rc == -ESTALE) { + rcu_read_unlock(); + goto retry; + } if (rc) { sbsec->behavior = SECURITY_FS_USE_NONE; rc = 0; @@ -3130,12 +3205,13 @@ int security_sid_mls_copy(struct selinux_state *state, u32 len; int rc; - rc = 0; if (!selinux_initialized(state)) { *new_sid = sid; - goto out; + return 0; } +retry: + rc = 0; context_init(&newcon); rcu_read_lock(); @@ -3194,10 +3270,14 @@ int security_sid_mls_copy(struct selinux_state *state, } } rc = sidtab_context_to_sid(sidtab, &newcon, new_sid); + if (rc == -ESTALE) { + rcu_read_unlock(); + context_destroy(&newcon); + goto retry; + } out_unlock: rcu_read_unlock(); context_destroy(&newcon); -out: return rc; } @@ -3790,6 +3870,8 @@ int security_netlbl_secattr_to_sid(struct selinux_state *state, return 0; } +retry: + rc = 0; rcu_read_lock(); policy = rcu_dereference(state->policy); policydb = &policy->policydb; @@ -3816,23 +3898,24 @@ int security_netlbl_secattr_to_sid(struct selinux_state *state, goto out; } rc = -EIDRM; - if (!mls_context_isvalid(policydb, &ctx_new)) - goto out_free; + if (!mls_context_isvalid(policydb, &ctx_new)) { + ebitmap_destroy(&ctx_new.range.level[0].cat); + goto out; + } rc = sidtab_context_to_sid(sidtab, &ctx_new, sid); + ebitmap_destroy(&ctx_new.range.level[0].cat); + if (rc == -ESTALE) { + rcu_read_unlock(); + goto retry; + } if (rc) - goto out_free; + goto out; security_netlbl_cache_add(secattr, *sid); - - ebitmap_destroy(&ctx_new.range.level[0].cat); } else *sid = SECSID_NULL; - rcu_read_unlock(); - return 0; -out_free: - ebitmap_destroy(&ctx_new.range.level[0].cat); out: rcu_read_unlock(); return rc; diff --git a/security/selinux/ss/sidtab.c b/security/selinux/ss/sidtab.c index 5ee190bd30f5..656d50b09f76 100644 --- a/security/selinux/ss/sidtab.c +++ b/security/selinux/ss/sidtab.c @@ -39,6 +39,7 @@ int sidtab_init(struct sidtab *s) for (i = 0; i < SECINITSID_NUM; i++) s->isids[i].set = 0; + s->frozen = false; s->count = 0; s->convert = NULL; hash_init(s->context_to_sid); @@ -281,6 +282,15 @@ int sidtab_context_to_sid(struct sidtab *s, struct context *context, if (*sid) goto out_unlock; + if (unlikely(s->frozen)) { + /* + * This sidtab is now frozen - tell the caller to abort and + * get the new one. + */ + rc = -ESTALE; + goto out_unlock; + } + count = s->count; convert = s->convert; @@ -474,6 +484,17 @@ void sidtab_cancel_convert(struct sidtab *s) spin_unlock_irqrestore(&s->lock, flags); } +void sidtab_freeze_begin(struct sidtab *s, unsigned long *flags) __acquires(&s->lock) +{ + spin_lock_irqsave(&s->lock, *flags); + s->frozen = true; + s->convert = NULL; +} +void sidtab_freeze_end(struct sidtab *s, unsigned long *flags) __releases(&s->lock) +{ + spin_unlock_irqrestore(&s->lock, *flags); +} + static void sidtab_destroy_entry(struct sidtab_entry *entry) { context_destroy(&entry->context); diff --git a/security/selinux/ss/sidtab.h b/security/selinux/ss/sidtab.h index 80c744d07ad6..4eff0e49dcb2 100644 --- a/security/selinux/ss/sidtab.h +++ b/security/selinux/ss/sidtab.h @@ -86,6 +86,7 @@ struct sidtab { u32 count; /* access only under spinlock */ struct sidtab_convert_params *convert; + bool frozen; spinlock_t lock; #if CONFIG_SECURITY_SELINUX_SID2STR_CACHE_SIZE > 0 @@ -125,6 +126,9 @@ int sidtab_convert(struct sidtab *s, struct sidtab_convert_params *params); void sidtab_cancel_convert(struct sidtab *s); +void sidtab_freeze_begin(struct sidtab *s, unsigned long *flags) __acquires(&s->lock); +void sidtab_freeze_end(struct sidtab *s, unsigned long *flags) __releases(&s->lock); + int sidtab_context_to_sid(struct sidtab *s, struct context *context, u32 *sid); void sidtab_destroy(struct sidtab *s); |