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-rw-r--r--security/selinux/ss/services.c180
1 files changed, 175 insertions, 5 deletions
diff --git a/security/selinux/ss/services.c b/security/selinux/ss/services.c
index 8551952ef329..ab0cc0c7b944 100644
--- a/security/selinux/ss/services.c
+++ b/security/selinux/ss/services.c
@@ -88,6 +88,11 @@ static u32 latest_granting;
static int context_struct_to_string(struct context *context, char **scontext,
u32 *scontext_len);
+static int context_struct_compute_av(struct context *scontext,
+ struct context *tcontext,
+ u16 tclass,
+ u32 requested,
+ struct av_decision *avd);
/*
* Return the boolean value of a constraint expression
* when it is applied to the specified source and target
@@ -274,6 +279,100 @@ mls_ops:
}
/*
+ * security_boundary_permission - drops violated permissions
+ * on boundary constraint.
+ */
+static void type_attribute_bounds_av(struct context *scontext,
+ struct context *tcontext,
+ u16 tclass,
+ u32 requested,
+ struct av_decision *avd)
+{
+ struct context lo_scontext;
+ struct context lo_tcontext;
+ struct av_decision lo_avd;
+ struct type_datum *source
+ = policydb.type_val_to_struct[scontext->type - 1];
+ struct type_datum *target
+ = policydb.type_val_to_struct[tcontext->type - 1];
+ u32 masked = 0;
+
+ if (source->bounds) {
+ memset(&lo_avd, 0, sizeof(lo_avd));
+
+ memcpy(&lo_scontext, scontext, sizeof(lo_scontext));
+ lo_scontext.type = source->bounds;
+
+ context_struct_compute_av(&lo_scontext,
+ tcontext,
+ tclass,
+ requested,
+ &lo_avd);
+ if ((lo_avd.allowed & avd->allowed) == avd->allowed)
+ return; /* no masked permission */
+ masked = ~lo_avd.allowed & avd->allowed;
+ }
+
+ if (target->bounds) {
+ memset(&lo_avd, 0, sizeof(lo_avd));
+
+ memcpy(&lo_tcontext, tcontext, sizeof(lo_tcontext));
+ lo_tcontext.type = target->bounds;
+
+ context_struct_compute_av(scontext,
+ &lo_tcontext,
+ tclass,
+ requested,
+ &lo_avd);
+ if ((lo_avd.allowed & avd->allowed) == avd->allowed)
+ return; /* no masked permission */
+ masked = ~lo_avd.allowed & avd->allowed;
+ }
+
+ if (source->bounds && target->bounds) {
+ memset(&lo_avd, 0, sizeof(lo_avd));
+ /*
+ * lo_scontext and lo_tcontext are already
+ * set up.
+ */
+
+ context_struct_compute_av(&lo_scontext,
+ &lo_tcontext,
+ tclass,
+ requested,
+ &lo_avd);
+ if ((lo_avd.allowed & avd->allowed) == avd->allowed)
+ return; /* no masked permission */
+ masked = ~lo_avd.allowed & avd->allowed;
+ }
+
+ if (masked) {
+ struct audit_buffer *ab;
+ char *stype_name
+ = policydb.p_type_val_to_name[source->value - 1];
+ char *ttype_name
+ = policydb.p_type_val_to_name[target->value - 1];
+ char *tclass_name
+ = policydb.p_class_val_to_name[tclass - 1];
+
+ /* mask violated permissions */
+ avd->allowed &= ~masked;
+
+ /* notice to userspace via audit message */
+ ab = audit_log_start(current->audit_context,
+ GFP_ATOMIC, AUDIT_SELINUX_ERR);
+ if (!ab)
+ return;
+
+ audit_log_format(ab, "av boundary violation: "
+ "source=%s target=%s tclass=%s",
+ stype_name, ttype_name, tclass_name);
+ avc_dump_av(ab, tclass, masked);
+ audit_log_end(ab);
+ }
+}
+
+/*
* Compute access vectors based on a context structure pair for
* the permissions in a particular class.
*/
@@ -356,7 +455,7 @@ static int context_struct_compute_av(struct context *scontext,
avkey.source_type = i + 1;
avkey.target_type = j + 1;
for (node = avtab_search_node(&policydb.te_avtab, &avkey);
- node != NULL;
+ node;
node = avtab_search_node_next(node, avkey.specified)) {
if (node->key.specified == AVTAB_ALLOWED)
avd->allowed |= node->datum.data;
@@ -404,6 +503,14 @@ static int context_struct_compute_av(struct context *scontext,
PROCESS__DYNTRANSITION);
}
+ /*
+ * If the given source and target types have boundary
+ * constraint, lazy checks have to mask any violated
+ * permission and notice it to userspace via audit.
+ */
+ type_attribute_bounds_av(scontext, tcontext,
+ tclass, requested, avd);
+
return 0;
inval_class:
@@ -549,6 +656,69 @@ out:
return rc;
}
+/*
+ * security_bounded_transition - check whether the given
+ * transition is directed to bounded, or not.
+ * It returns 0, if @newsid is bounded by @oldsid.
+ * Otherwise, it returns error code.
+ *
+ * @oldsid : current security identifier
+ * @newsid : destinated security identifier
+ */
+int security_bounded_transition(u32 old_sid, u32 new_sid)
+{
+ struct context *old_context, *new_context;
+ struct type_datum *type;
+ int index;
+ int rc = -EINVAL;
+
+ read_lock(&policy_rwlock);
+
+ old_context = sidtab_search(&sidtab, old_sid);
+ if (!old_context) {
+ printk(KERN_ERR "SELinux: %s: unrecognized SID %u\n",
+ __func__, old_sid);
+ goto out;
+ }
+
+ new_context = sidtab_search(&sidtab, new_sid);
+ if (!new_context) {
+ printk(KERN_ERR "SELinux: %s: unrecognized SID %u\n",
+ __func__, new_sid);
+ goto out;
+ }
+
+ /* type/domain unchaned */
+ if (old_context->type == new_context->type) {
+ rc = 0;
+ goto out;
+ }
+
+ index = new_context->type;
+ while (true) {
+ type = policydb.type_val_to_struct[index - 1];
+ BUG_ON(!type);
+
+ /* not bounded anymore */
+ if (!type->bounds) {
+ rc = -EPERM;
+ break;
+ }
+
+ /* @newsid is bounded by @oldsid */
+ if (type->bounds == old_context->type) {
+ rc = 0;
+ break;
+ }
+ index = type->bounds;
+ }
+out:
+ read_unlock(&policy_rwlock);
+
+ return rc;
+}
+
+
/**
* security_compute_av - Compute access vector decisions.
* @ssid: source security identifier
@@ -794,7 +964,7 @@ static int string_to_context_struct(struct policydb *pol,
*p++ = 0;
typdatum = hashtab_search(pol->p_types.table, scontextp);
- if (!typdatum)
+ if (!typdatum || typdatum->attribute)
goto out;
ctx->type = typdatum->value;
@@ -1037,7 +1207,7 @@ static int security_compute_sid(u32 ssid,
/* If no permanent rule, also check for enabled conditional rules */
if (!avdatum) {
node = avtab_search_node(&policydb.te_cond_avtab, &avkey);
- for (; node != NULL; node = avtab_search_node_next(node, specified)) {
+ for (; node; node = avtab_search_node_next(node, specified)) {
if (node->key.specified & AVTAB_ENABLED) {
avdatum = &node->datum;
break;
@@ -2050,7 +2220,7 @@ int security_set_bools(int len, int *values)
policydb.bool_val_to_struct[i]->state = 0;
}
- for (cur = policydb.cond_list; cur != NULL; cur = cur->next) {
+ for (cur = policydb.cond_list; cur; cur = cur->next) {
rc = evaluate_cond_node(&policydb, cur);
if (rc)
goto out;
@@ -2102,7 +2272,7 @@ static int security_preserve_bools(struct policydb *p)
if (booldatum)
booldatum->state = bvalues[i];
}
- for (cur = p->cond_list; cur != NULL; cur = cur->next) {
+ for (cur = p->cond_list; cur; cur = cur->next) {
rc = evaluate_cond_node(p, cur);
if (rc)
goto out;
generated by cgit v1.2.3 (git 2.25.1) at 2024-12-27 13:35:16 +0000