3 files changed, 271 insertions, 4 deletions

diff --git a/security/selinux/ss/mls.c b/security/selinux/ss/mls.c
index 640d0bfdbc68..7bc5b6440f70 100644
--- a/security/selinux/ss/mls.c
+++ b/security/selinux/ss/mls.c
@@ -8,7 +8,7 @@
  *
  *      Support for enhanced MLS infrastructure.
  *
- * Copyright (C) 2004-2005 Trusted Computer Solutions, Inc.
+ * Copyright (C) 2004-2006 Trusted Computer Solutions, Inc.
  */
 
 #include <linux/kernel.h>
@@ -264,7 +264,7 @@ int mls_context_to_sid(char oldc,
 
         if (!selinux_mls_enabled) {
                 if (def_sid != SECSID_NULL && oldc)
-                        *scontext += strlen(*scontext);
+                        *scontext += strlen(*scontext)+1;
                 return 0;
         }
 
@@ -385,6 +385,34 @@ out:
 }
 
 /*
+ * Set the MLS fields in the security context structure
+ * `context' based on the string representation in
+ * the string `str'.  This function will allocate temporary memory with the
+ * given constraints of gfp_mask.
+ */
+int mls_from_string(char *str, struct context *context, gfp_t gfp_mask)
+{
+        char *tmpstr, *freestr;
+        int rc;
+
+        if (!selinux_mls_enabled)
+                return -EINVAL;
+
+        /* we need freestr because mls_context_to_sid will change
+           the value of tmpstr */
+        tmpstr = freestr = kstrdup(str, gfp_mask);
+        if (!tmpstr) {
+                rc = -ENOMEM;
+        } else {
+                rc = mls_context_to_sid(':', &tmpstr, context,
+                                        NULL, SECSID_NULL);
+                kfree(freestr);
+        }
+
+        return rc;
+}
+
+/*
  * Copies the effective MLS range from `src' into `dst'.
  */
 static inline int mls_scopy_context(struct context *dst,
diff --git a/security/selinux/ss/mls.h b/security/selinux/ss/mls.h
index 03de697c8058..fbb42f07dd7c 100644
--- a/security/selinux/ss/mls.h
+++ b/security/selinux/ss/mls.h
@@ -8,7 +8,7 @@
  *
  *      Support for enhanced MLS infrastructure.
  *
- * Copyright (C) 2004-2005 Trusted Computer Solutions, Inc.
+ * Copyright (C) 2004-2006 Trusted Computer Solutions, Inc.
  */
 
 #ifndef _SS_MLS_H_
@@ -27,6 +27,8 @@ int mls_context_to_sid(char oldc,
                        struct sidtab *s,
                        u32 def_sid);
 
+int mls_from_string(char *str, struct context *context, gfp_t gfp_mask);
+
 int mls_convert_context(struct policydb *oldp,
                         struct policydb *newp,
                         struct context *context);
diff --git a/security/selinux/ss/services.c b/security/selinux/ss/services.c
index 61492485de84..c284dbb8b8c0 100644
--- a/security/selinux/ss/services.c
+++ b/security/selinux/ss/services.c
@@ -7,12 +7,13 @@
  * Updated: Trusted Computer Solutions, Inc. <dgoeddel@trustedcs.com>
  *
  *      Support for enhanced MLS infrastructure.
+ *      Support for context based audit filters.
  *
  * Updated: Frank Mayer <mayerf@tresys.com> and Karl MacMillan <kmacmillan@tresys.com>
  *
  *      Added conditional policy language extensions
  *
- * Copyright (C) 2004-2005 Trusted Computer Solutions, Inc.
+ * Copyright (C) 2004-2006 Trusted Computer Solutions, Inc.
  * Copyright (C) 2003 - 2004 Tresys Technology, LLC
  * Copyright (C) 2003 Red Hat, Inc., James Morris <jmorris@redhat.com>
  *      This program is free software; you can redistribute it and/or modify
@@ -593,6 +594,10 @@ int security_sid_to_context(u32 sid, char **scontext, u32 *scontext_len)
 
                         *scontext_len = strlen(initial_sid_to_string[sid]) + 1;
                         scontextp = kmalloc(*scontext_len,GFP_ATOMIC);
+                        if (!scontextp) {
+                                rc = -ENOMEM;
+                                goto out;
+                        }
                         strcpy(scontextp, initial_sid_to_string[sid]);
                         *scontext = scontextp;
                         goto out;
@@ -1811,3 +1816,235 @@ out:
         POLICY_RDUNLOCK;
         return rc;
 }
+
+struct selinux_audit_rule {
+        u32 au_seqno;
+        struct context au_ctxt;
+};
+
+void selinux_audit_rule_free(struct selinux_audit_rule *rule)
+{
+        if (rule) {
+                context_destroy(&rule->au_ctxt);
+                kfree(rule);
+        }
+}
+
+int selinux_audit_rule_init(u32 field, u32 op, char *rulestr,
+                            struct selinux_audit_rule **rule)
+{
+        struct selinux_audit_rule *tmprule;
+        struct role_datum *roledatum;
+        struct type_datum *typedatum;
+        struct user_datum *userdatum;
+        int rc = 0;
+
+        *rule = NULL;
+
+        if (!ss_initialized)
+                return -ENOTSUPP;
+
+        switch (field) {
+        case AUDIT_SE_USER:
+        case AUDIT_SE_ROLE:
+        case AUDIT_SE_TYPE:
+                /* only 'equals' and 'not equals' fit user, role, and type */
+                if (op != AUDIT_EQUAL && op != AUDIT_NOT_EQUAL)
+                        return -EINVAL;
+                break;
+        case AUDIT_SE_SEN:
+        case AUDIT_SE_CLR:
+                /* we do not allow a range, indicated by the presense of '-' */
+                if (strchr(rulestr, '-'))
+                        return -EINVAL;
+                break;
+        default:
+                /* only the above fields are valid */
+                return -EINVAL;
+        }
+
+        tmprule = kzalloc(sizeof(struct selinux_audit_rule), GFP_KERNEL);
+        if (!tmprule)
+                return -ENOMEM;
+
+        context_init(&tmprule->au_ctxt);
+
+        POLICY_RDLOCK;
+
+        tmprule->au_seqno = latest_granting;
+
+        switch (field) {
+        case AUDIT_SE_USER:
+                userdatum = hashtab_search(policydb.p_users.table, rulestr);
+                if (!userdatum)
+                        rc = -EINVAL;
+                else
+                        tmprule->au_ctxt.user = userdatum->value;
+                break;
+        case AUDIT_SE_ROLE:
+                roledatum = hashtab_search(policydb.p_roles.table, rulestr);
+                if (!roledatum)
+                        rc = -EINVAL;
+                else
+                        tmprule->au_ctxt.role = roledatum->value;
+                break;
+        case AUDIT_SE_TYPE:
+                typedatum = hashtab_search(policydb.p_types.table, rulestr);
+                if (!typedatum)
+                        rc = -EINVAL;
+                else
+                        tmprule->au_ctxt.type = typedatum->value;
+                break;
+        case AUDIT_SE_SEN:
+        case AUDIT_SE_CLR:
+                rc = mls_from_string(rulestr, &tmprule->au_ctxt, GFP_ATOMIC);
+                break;
+        }
+
+        POLICY_RDUNLOCK;
+
+        if (rc) {
+                selinux_audit_rule_free(tmprule);
+                tmprule = NULL;
+        }
+
+        *rule = tmprule;
+
+        return rc;
+}
+
+int selinux_audit_rule_match(u32 ctxid, u32 field, u32 op,
+                             struct selinux_audit_rule *rule,
+                             struct audit_context *actx)
+{
+        struct context *ctxt;
+        struct mls_level *level;
+        int match = 0;
+
+        if (!rule) {
+                audit_log(actx, GFP_ATOMIC, AUDIT_SELINUX_ERR,
+                          "selinux_audit_rule_match: missing rule\n");
+                return -ENOENT;
+        }
+
+        POLICY_RDLOCK;
+
+        if (rule->au_seqno < latest_granting) {
+                audit_log(actx, GFP_ATOMIC, AUDIT_SELINUX_ERR,
+                          "selinux_audit_rule_match: stale rule\n");
+                match = -ESTALE;
+                goto out;
+        }
+
+        ctxt = sidtab_search(&sidtab, ctxid);
+        if (!ctxt) {
+                audit_log(actx, GFP_ATOMIC, AUDIT_SELINUX_ERR,
+                          "selinux_audit_rule_match: unrecognized SID %d\n",
+                          ctxid);
+                match = -ENOENT;
+                goto out;
+        }
+
+        /* a field/op pair that is not caught here will simply fall through
+           without a match */
+        switch (field) {
+        case AUDIT_SE_USER:
+                switch (op) {
+                case AUDIT_EQUAL:
+                        match = (ctxt->user == rule->au_ctxt.user);
+                        break;
+                case AUDIT_NOT_EQUAL:
+                        match = (ctxt->user != rule->au_ctxt.user);
+                        break;
+                }
+                break;
+        case AUDIT_SE_ROLE:
+                switch (op) {
+                case AUDIT_EQUAL:
+                        match = (ctxt->role == rule->au_ctxt.role);
+                        break;
+                case AUDIT_NOT_EQUAL:
+                        match = (ctxt->role != rule->au_ctxt.role);
+                        break;
+                }
+                break;
+        case AUDIT_SE_TYPE:
+                switch (op) {
+                case AUDIT_EQUAL:
+                        match = (ctxt->type == rule->au_ctxt.type);
+                        break;
+                case AUDIT_NOT_EQUAL:
+                        match = (ctxt->type != rule->au_ctxt.type);
+                        break;
+                }
+                break;
+        case AUDIT_SE_SEN:
+        case AUDIT_SE_CLR:
+                level = (op == AUDIT_SE_SEN ?
+                         &ctxt->range.level[0] : &ctxt->range.level[1]);
+                switch (op) {
+                case AUDIT_EQUAL:
+                        match = mls_level_eq(&rule->au_ctxt.range.level[0],
+                                             level);
+                        break;
+                case AUDIT_NOT_EQUAL:
+                        match = !mls_level_eq(&rule->au_ctxt.range.level[0],
+                                              level);
+                        break;
+                case AUDIT_LESS_THAN:
+                        match = (mls_level_dom(&rule->au_ctxt.range.level[0],
+                                               level) &&
+                                 !mls_level_eq(&rule->au_ctxt.range.level[0],
+                                               level));
+                        break;
+                case AUDIT_LESS_THAN_OR_EQUAL:
+                        match = mls_level_dom(&rule->au_ctxt.range.level[0],
+                                              level);
+                        break;
+                case AUDIT_GREATER_THAN:
+                        match = (mls_level_dom(level,
+                                              &rule->au_ctxt.range.level[0]) &&
+                                 !mls_level_eq(level,
+                                               &rule->au_ctxt.range.level[0]));
+                        break;
+                case AUDIT_GREATER_THAN_OR_EQUAL:
+                        match = mls_level_dom(level,
+                                              &rule->au_ctxt.range.level[0]);
+                        break;
+                }
+        }
+
+out:
+        POLICY_RDUNLOCK;
+        return match;
+}
+
+static int (*aurule_callback)(void) = NULL;
+
+static int aurule_avc_callback(u32 event, u32 ssid, u32 tsid,
+                               u16 class, u32 perms, u32 *retained)
+{
+        int err = 0;
+
+        if (event == AVC_CALLBACK_RESET && aurule_callback)
+                err = aurule_callback();
+        return err;
+}
+
+static int __init aurule_init(void)
+{
+        int err;
+
+        err = avc_add_callback(aurule_avc_callback, AVC_CALLBACK_RESET,
+                               SECSID_NULL, SECSID_NULL, SECCLASS_NULL, 0);
+        if (err)
+                panic("avc_add_callback() failed, error %d\n", err);
+
+        return err;
+}
+__initcall(aurule_init);
+
+void selinux_audit_set_callback(int (*callback)(void))
+{
+        aurule_callback = callback;
+}