1 files changed, 126 insertions, 26 deletions

diff --git a/security/apparmor/secid.c b/security/apparmor/secid.c
index 3a3edbad0b21..28caf66b9033 100644
--- a/security/apparmor/secid.c
+++ b/security/apparmor/secid.c
@@ -1,48 +1,144 @@
+// SPDX-License-Identifier: GPL-2.0-only
 /*
  * AppArmor security module
  *
  * This file contains AppArmor security identifier (secid) manipulation fns
  *
- * Copyright 2009-2010 Canonical Ltd.
+ * Copyright 2009-2017 Canonical Ltd.
  *
- * This program is free software; you can redistribute it and/or
- * modify it under the terms of the GNU General Public License as
- * published by the Free Software Foundation, version 2 of the
- * License.
- *
- *
- * AppArmor allocates a unique secid for every profile loaded.  If a profile
- * is replaced it receives the secid of the profile it is replacing.
- *
- * The secid value of 0 is invalid.
+ * AppArmor allocates a unique secid for every label used. If a label
+ * is replaced it receives the secid of the label it is replacing.
  */
 
-#include <linux/spinlock.h>
 #include <linux/errno.h>
 #include <linux/err.h>
+#include <linux/gfp.h>
+#include <linux/slab.h>
+#include <linux/spinlock.h>
+#include <linux/xarray.h>
 
+#include "include/cred.h"
+#include "include/lib.h"
 #include "include/secid.h"
+#include "include/label.h"
+#include "include/policy_ns.h"
+
+/*
+ * secids - do not pin labels with a refcount. They rely on the label
+ * properly updating/freeing them
+ */
+#define AA_FIRST_SECID 2
+
+static DEFINE_XARRAY_FLAGS(aa_secids, XA_FLAGS_LOCK_IRQ | XA_FLAGS_TRACK_FREE);
+
+int apparmor_display_secid_mode;
+
+/*
+ * TODO: allow policy to reserve a secid range?
+ * TODO: add secid pinning
+ * TODO: use secid_update in label replace
+ */
+
+/*
+ * see label for inverse aa_label_to_secid
+ */
+struct aa_label *aa_secid_to_label(u32 secid)
+{
+	return xa_load(&aa_secids, secid);
+}
+
+static int apparmor_label_to_secctx(struct aa_label *label,
+				    struct lsm_context *cp)
+{
+	/* TODO: cache secctx and ref count so we don't have to recreate */
+	int flags = FLAG_VIEW_SUBNS | FLAG_HIDDEN_UNCONFINED | FLAG_ABS_ROOT;
+	int len;
+
+	if (!label)
+		return -EINVAL;
+
+	if (apparmor_display_secid_mode)
+		flags |= FLAG_SHOW_MODE;
+
+	if (cp)
+		len = aa_label_asxprint(&cp->context, root_ns, label,
+					flags, GFP_ATOMIC);
+	else
+		len = aa_label_snxprint(NULL, 0, root_ns, label, flags);
 
-/* global counter from which secids are allocated */
-static u32 global_secid;
-static DEFINE_SPINLOCK(secid_lock);
+	if (len < 0)
+		return -ENOMEM;
 
-/* TODO FIXME: add secid to profile mapping, and secid recycling */
+	if (cp) {
+		cp->len = len;
+		cp->id = LSM_ID_APPARMOR;
+	}
+
+	return len;
+}
+
+int apparmor_secid_to_secctx(u32 secid, struct lsm_context *cp)
+{
+	struct aa_label *label = aa_secid_to_label(secid);
+
+	return apparmor_label_to_secctx(label, cp);
+}
+
+int apparmor_lsmprop_to_secctx(struct lsm_prop *prop, struct lsm_context *cp)
+{
+	struct aa_label *label;
+
+	label = prop->apparmor.label;
+
+	return apparmor_label_to_secctx(label, cp);
+}
+
+int apparmor_secctx_to_secid(const char *secdata, u32 seclen, u32 *secid)
+{
+	struct aa_label *label;
+
+	label = aa_label_strn_parse(&root_ns->unconfined->label, secdata,
+				    seclen, GFP_KERNEL, false, false);
+	if (IS_ERR(label))
+		return PTR_ERR(label);
+	*secid = label->secid;
+
+	return 0;
+}
+
+void apparmor_release_secctx(struct lsm_context *cp)
+{
+	if (cp->id == LSM_ID_APPARMOR) {
+		kfree(cp->context);
+		cp->context = NULL;
+		cp->id = LSM_ID_UNDEF;
+	}
+}
 
 /**
  * aa_alloc_secid - allocate a new secid for a profile
+ * @label: the label to allocate a secid for
+ * @gfp: memory allocation flags
+ *
+ * Returns: 0 with @label->secid initialized
+ *          <0 returns error with @label->secid set to AA_SECID_INVALID
  */
-u32 aa_alloc_secid(void)
+int aa_alloc_secid(struct aa_label *label, gfp_t gfp)
 {
-	u32 secid;
+	unsigned long flags;
+	int ret;
+
+	xa_lock_irqsave(&aa_secids, flags);
+	ret = __xa_alloc(&aa_secids, &label->secid, label,
+			XA_LIMIT(AA_FIRST_SECID, INT_MAX), gfp);
+	xa_unlock_irqrestore(&aa_secids, flags);
 
-	/*
-	 * TODO FIXME: secid recycling - part of profile mapping table
-	 */
-	spin_lock(&secid_lock);
-	secid = (++global_secid);
-	spin_unlock(&secid_lock);
-	return secid;
+	if (ret < 0) {
+		label->secid = AA_SECID_INVALID;
+		return ret;
+	}
+
+	return 0;
 }
 
 /**
@@ -51,5 +147,9 @@ u32 aa_alloc_secid(void)
  */
 void aa_free_secid(u32 secid)
 {
-	;			/* NOP ATM */
+	unsigned long flags;
+
+	xa_lock_irqsave(&aa_secids, flags);
+	__xa_erase(&aa_secids, secid);
+	xa_unlock_irqrestore(&aa_secids, flags);
 }