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-rw-r--r--security/apparmor/secid.c148
1 files changed, 148 insertions, 0 deletions
diff --git a/security/apparmor/secid.c b/security/apparmor/secid.c
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index 0000000000..83d3d1e6d9
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+++ b/security/apparmor/secid.c
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+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * AppArmor security module
+ *
+ * This file contains AppArmor security identifier (secid) manipulation fns
+ *
+ * Copyright 2009-2017 Canonical Ltd.
+ *
+ * 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/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
+ */
+
+/**
+ * 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;
+
+ xa_lock_irqsave(&aa_secids, flags);
+ __xa_store(&aa_secids, secid, label, 0);
+ xa_unlock_irqrestore(&aa_secids, flags);
+}
+
+/*
+ * see label for inverse aa_label_to_secid
+ */
+struct aa_label *aa_secid_to_label(u32 secid)
+{
+ return xa_load(&aa_secids, secid);
+}
+
+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 flags = FLAG_VIEW_SUBNS | FLAG_HIDDEN_UNCONFINED | FLAG_ABS_ROOT;
+ int len;
+
+ AA_BUG(!seclen);
+
+ if (!label)
+ return -EINVAL;
+
+ if (apparmor_display_secid_mode)
+ flags |= FLAG_SHOW_MODE;
+
+ if (secdata)
+ len = aa_label_asxprint(secdata, root_ns, label,
+ flags, GFP_ATOMIC);
+ else
+ len = aa_label_snxprint(NULL, 0, root_ns, label, flags);
+
+ 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;
+
+ 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);
+
+ if (ret < 0) {
+ label->secid = AA_SECID_INVALID;
+ return ret;
+ }
+
+ return 0;
+}
+
+/**
+ * aa_free_secid - free a secid
+ * @secid: secid to free
+ */
+void aa_free_secid(u32 secid)
+{
+ unsigned long flags;
+
+ xa_lock_irqsave(&aa_secids, flags);
+ __xa_erase(&aa_secids, secid);
+ xa_unlock_irqrestore(&aa_secids, flags);
+}