1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * AppArmor security module 4 * 5 * This file contains AppArmor security identifier (secid) manipulation fns 6 * 7 * Copyright 2009-2017 Canonical Ltd. 8 * 9 * AppArmor allocates a unique secid for every label used. If a label 10 * is replaced it receives the secid of the label it is replacing. 11 */ 12 13 #include <linux/errno.h> 14 #include <linux/err.h> 15 #include <linux/gfp.h> 16 #include <linux/slab.h> 17 #include <linux/spinlock.h> 18 #include <linux/xarray.h> 19 20 #include "include/cred.h" 21 #include "include/lib.h" 22 #include "include/secid.h" 23 #include "include/label.h" 24 #include "include/policy_ns.h" 25 26 /* 27 * secids - do not pin labels with a refcount. They rely on the label 28 * properly updating/freeing them 29 */ 30 #define AA_FIRST_SECID 2 31 32 static DEFINE_XARRAY_FLAGS(aa_secids, XA_FLAGS_LOCK_IRQ | XA_FLAGS_TRACK_FREE); 33 34 int apparmor_display_secid_mode; 35 36 /* 37 * TODO: allow policy to reserve a secid range? 38 * TODO: add secid pinning 39 * TODO: use secid_update in label replace 40 */ 41 42 /* 43 * see label for inverse aa_label_to_secid 44 */ 45 struct aa_label *aa_secid_to_label(u32 secid) 46 { 47 return xa_load(&aa_secids, secid); 48 } 49 50 static int apparmor_label_to_secctx(struct aa_label *label, 51 struct lsm_context *cp) 52 { 53 /* TODO: cache secctx and ref count so we don't have to recreate */ 54 int flags = FLAG_VIEW_SUBNS | FLAG_HIDDEN_UNCONFINED | FLAG_ABS_ROOT; 55 int len; 56 57 if (!label) 58 return -EINVAL; 59 60 if (apparmor_display_secid_mode) 61 flags |= FLAG_SHOW_MODE; 62 63 if (cp) 64 len = aa_label_asxprint(&cp->context, root_ns, label, 65 flags, GFP_ATOMIC); 66 else 67 len = aa_label_snxprint(NULL, 0, root_ns, label, flags); 68 69 if (len < 0) 70 return -ENOMEM; 71 72 if (cp) { 73 cp->len = len; 74 cp->id = LSM_ID_APPARMOR; 75 } 76 77 return len; 78 } 79 80 int apparmor_secid_to_secctx(u32 secid, struct lsm_context *cp) 81 { 82 struct aa_label *label = aa_secid_to_label(secid); 83 84 return apparmor_label_to_secctx(label, cp); 85 } 86 87 int apparmor_lsmprop_to_secctx(struct lsm_prop *prop, struct lsm_context *cp) 88 { 89 struct aa_label *label; 90 91 label = prop->apparmor.label; 92 93 return apparmor_label_to_secctx(label, cp); 94 } 95 96 int apparmor_secctx_to_secid(const char *secdata, u32 seclen, u32 *secid) 97 { 98 struct aa_label *label; 99 100 label = aa_label_strn_parse(&root_ns->unconfined->label, secdata, 101 seclen, GFP_KERNEL, false, false); 102 if (IS_ERR(label)) 103 return PTR_ERR(label); 104 *secid = label->secid; 105 106 return 0; 107 } 108 109 void apparmor_release_secctx(struct lsm_context *cp) 110 { 111 if (cp->id == LSM_ID_APPARMOR) { 112 kfree(cp->context); 113 cp->context = NULL; 114 cp->id = LSM_ID_UNDEF; 115 } 116 } 117 118 /** 119 * aa_alloc_secid - allocate a new secid for a profile 120 * @label: the label to allocate a secid for 121 * @gfp: memory allocation flags 122 * 123 * Returns: 0 with @label->secid initialized 124 * <0 returns error with @label->secid set to AA_SECID_INVALID 125 */ 126 int aa_alloc_secid(struct aa_label *label, gfp_t gfp) 127 { 128 unsigned long flags; 129 int ret; 130 131 xa_lock_irqsave(&aa_secids, flags); 132 ret = __xa_alloc(&aa_secids, &label->secid, label, 133 XA_LIMIT(AA_FIRST_SECID, INT_MAX), gfp); 134 xa_unlock_irqrestore(&aa_secids, flags); 135 136 if (ret < 0) { 137 label->secid = AA_SECID_INVALID; 138 return ret; 139 } 140 141 return 0; 142 } 143 144 /** 145 * aa_free_secid - free a secid 146 * @secid: secid to free 147 */ 148 void aa_free_secid(u32 secid) 149 { 150 unsigned long flags; 151 152 xa_lock_irqsave(&aa_secids, flags); 153 __xa_erase(&aa_secids, secid); 154 xa_unlock_irqrestore(&aa_secids, flags); 155 } 156