1 files changed, 167 insertions, 0 deletions
diff --git a/security/apparmor/secid.c b/security/apparmor/secid.c
new file mode 100644
index 000000000..4ccec1bcf
--- /dev/null
+++ b/security/apparmor/secid.c
@@ -0,0 +1,167 @@
+/*
+ * AppArmor security module
+ *
+ * This file contains AppArmor security identifier (secid) manipulation fns
+ *
+ * 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 label used. If a label
+ * is replaced it receives the secid of the label it is replacing.
+ */
+
+#include <linux/errno.h>
+#include <linux/err.h>
+#include <linux/gfp.h>
+#include <linux/idr.h>
+#include <linux/slab.h>
+#include <linux/spinlock.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 1
+
+static DEFINE_IDR(aa_secids);
+static DEFINE_SPINLOCK(secid_lock);
+
+/*
+ * TODO: allow policy to reserve a secid range?
+ * TODO: add secid pinning
+ * TODO: use secid_update in label replace
+ */
+
+/**
+ * aa_secid_update - update a secid mapping to a new label
+ * @secid: secid to update
+ * @label: label the secid will now map to
+ */
+void aa_secid_update(u32 secid, struct aa_label *label)
+{
+	unsigned long flags;
+
+	spin_lock_irqsave(&secid_lock, flags);
+	idr_replace(&aa_secids, label, secid);
+	spin_unlock_irqrestore(&secid_lock, flags);
+}
+
+/**
+ *
+ * see label for inverse aa_label_to_secid
+ */
+struct aa_label *aa_secid_to_label(u32 secid)
+{
+	struct aa_label *label;
+
+	rcu_read_lock();
+	label = idr_find(&aa_secids, secid);
+	rcu_read_unlock();
+
+	return label;
+}
+
+int apparmor_secid_to_secctx(u32 secid, char **secdata, u32 *seclen)
+{
+	/* TODO: cache secctx and ref count so we don't have to recreate */
+	struct aa_label *label = aa_secid_to_label(secid);
+	int len;
+
+	AA_BUG(!seclen);
+
+	if (!label)
+		return -EINVAL;
+
+	if (secdata)
+		len = aa_label_asxprint(secdata, root_ns, label,
+					FLAG_SHOW_MODE | FLAG_VIEW_SUBNS |
+					FLAG_HIDDEN_UNCONFINED | FLAG_ABS_ROOT,
+					GFP_ATOMIC);
+	else
+		len = aa_label_snxprint(NULL, 0, root_ns, label,
+					FLAG_SHOW_MODE | FLAG_VIEW_SUBNS |
+					FLAG_HIDDEN_UNCONFINED | FLAG_ABS_ROOT);
+	if (len < 0)
+		return -ENOMEM;
+
+	*seclen = len;
+
+	return 0;
+}
+
+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(char *secdata, u32 seclen)
+{
+	kfree(secdata);
+}
+
+/**
+ * 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
+ */
+int aa_alloc_secid(struct aa_label *label, gfp_t gfp)
+{
+	unsigned long flags;
+	int ret;
+
+	idr_preload(gfp);
+	spin_lock_irqsave(&secid_lock, flags);
+	ret = idr_alloc(&aa_secids, label, AA_FIRST_SECID, 0, GFP_ATOMIC);
+	spin_unlock_irqrestore(&secid_lock, flags);
+	idr_preload_end();
+
+	if (ret < 0) {
+		label->secid = AA_SECID_INVALID;
+		return ret;
+	}
+
+	AA_BUG(ret == AA_SECID_INVALID);
+	label->secid = ret;
+	return 0;
+}
+
+/**
+ * aa_free_secid - free a secid
+ * @secid: secid to free
+ */
+void aa_free_secid(u32 secid)
+{
+	unsigned long flags;
+
+	spin_lock_irqsave(&secid_lock, flags);
+	idr_remove(&aa_secids, secid);
+	spin_unlock_irqrestore(&secid_lock, flags);
+}
+
+void aa_secids_init(void)
+{
+	idr_init_base(&aa_secids, AA_FIRST_SECID);
+}