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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);
- }
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