security/apparmor/audit.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * AppArmor security module
   4  *
   5  * This file contains AppArmor auditing functions
   6  *
   7  * Copyright (C) 1998-2008 Novell/SUSE
   8  * Copyright 2009-2010 Canonical Ltd.
   9  */
  10
  11 #include <linux/audit.h>
  12 #include <linux/socket.h>
  13
  14 #include "include/apparmor.h"
  15 #include "include/audit.h"
  16 #include "include/policy.h"
  17 #include "include/policy_ns.h"
  18 #include "include/secid.h"
  19
  20 const char *const audit_mode_names[] = {
  21         "normal",
  22         "quiet_denied",
  23         "quiet",
  24         "noquiet",
  25         "all"
  26 };
  27
  28 static const char *const aa_audit_type[] = {
  29         "AUDIT",
  30         "ALLOWED",
  31         "DENIED",
  32         "HINT",
  33         "STATUS",
  34         "ERROR",
  35         "KILLED",
  36         "AUTO"
  37 };
  38
  39 /*
  40  * Currently AppArmor auditing is fed straight into the audit framework.
  41  *
  42  * TODO:
  43  * netlink interface for complain mode
  44  * user auditing, - send user auditing to netlink interface
  45  * system control of whether user audit messages go to system log
  46  */
  47
  48 /**
  49  * audit_base - core AppArmor function.
  50  * @ab: audit buffer to fill (NOT NULL)
  51  * @ca: audit structure containing data to audit (NOT NULL)
  52  *
  53  * Record common AppArmor audit data from @sa
  54  */
  55 static void audit_pre(struct audit_buffer *ab, void *ca)
  56 {
  57         struct common_audit_data *sa = ca;
  58
  59         if (aa_g_audit_header) {
  60                 audit_log_format(ab, "apparmor=");
  61                 audit_log_string(ab, aa_audit_type[aad(sa)->type]);
  62         }
  63
  64         if (aad(sa)->op) {
  65                 audit_log_format(ab, " operation=");
  66                 audit_log_string(ab, aad(sa)->op);
  67         }
  68
  69         if (aad(sa)->info) {
  70                 audit_log_format(ab, " info=");
  71                 audit_log_string(ab, aad(sa)->info);
  72                 if (aad(sa)->error)
  73                         audit_log_format(ab, " error=%d", aad(sa)->error);
  74         }
  75
  76         if (aad(sa)->label) {
  77                 struct aa_label *label = aad(sa)->label;
  78
  79                 if (label_isprofile(label)) {
  80                         struct aa_profile *profile = labels_profile(label);
  81
  82                         if (profile->ns != root_ns) {
  83                                 audit_log_format(ab, " namespace=");
  84                                 audit_log_untrustedstring(ab,
  85                                                        profile->ns->base.hname);
  86                         }
  87                         audit_log_format(ab, " profile=");
  88                         audit_log_untrustedstring(ab, profile->base.hname);
  89                 } else {
  90                         audit_log_format(ab, " label=");
  91                         aa_label_xaudit(ab, root_ns, label, FLAG_VIEW_SUBNS,
  92                                         GFP_ATOMIC);
  93                 }
  94         }
  95
  96         if (aad(sa)->name) {
  97                 audit_log_format(ab, " name=");
  98                 audit_log_untrustedstring(ab, aad(sa)->name);
  99         }
 100 }
 101
 102 /**
 103  * aa_audit_msg - Log a message to the audit subsystem
 104  * @sa: audit event structure (NOT NULL)
 105  * @cb: optional callback fn for type specific fields (MAYBE NULL)
 106  */
 107 void aa_audit_msg(int type, struct common_audit_data *sa,
 108                   void (*cb) (struct audit_buffer *, void *))
 109 {
 110         aad(sa)->type = type;
 111         common_lsm_audit(sa, audit_pre, cb);
 112 }
 113
 114 /**
 115  * aa_audit - Log a profile based audit event to the audit subsystem
 116  * @type: audit type for the message
 117  * @profile: profile to check against (NOT NULL)
 118  * @sa: audit event (NOT NULL)
 119  * @cb: optional callback fn for type specific fields (MAYBE NULL)
 120  *
 121  * Handle default message switching based off of audit mode flags
 122  *
 123  * Returns: error on failure
 124  */
 125 int aa_audit(int type, struct aa_profile *profile, struct common_audit_data *sa,
 126              void (*cb) (struct audit_buffer *, void *))
 127 {
 128         AA_BUG(!profile);
 129
 130         if (type == AUDIT_APPARMOR_AUTO) {
 131                 if (likely(!aad(sa)->error)) {
 132                         if (AUDIT_MODE(profile) != AUDIT_ALL)
 133                                 return 0;
 134                         type = AUDIT_APPARMOR_AUDIT;
 135                 } else if (COMPLAIN_MODE(profile))
 136                         type = AUDIT_APPARMOR_ALLOWED;
 137                 else
 138                         type = AUDIT_APPARMOR_DENIED;
 139         }
 140         if (AUDIT_MODE(profile) == AUDIT_QUIET ||
 141             (type == AUDIT_APPARMOR_DENIED &&
 142              AUDIT_MODE(profile) == AUDIT_QUIET))
 143                 return aad(sa)->error;
 144
 145         if (KILL_MODE(profile) && type == AUDIT_APPARMOR_DENIED)
 146                 type = AUDIT_APPARMOR_KILL;
 147
 148         aad(sa)->label = &profile->label;
 149
 150         aa_audit_msg(type, sa, cb);
 151
 152         if (aad(sa)->type == AUDIT_APPARMOR_KILL)
 153                 (void)send_sig_info(SIGKILL, NULL,
 154                         sa->type == LSM_AUDIT_DATA_TASK && sa->u.tsk ?
 155                                     sa->u.tsk : current);
 156
 157         if (aad(sa)->type == AUDIT_APPARMOR_ALLOWED)
 158                 return complain_error(aad(sa)->error);
 159
 160         return aad(sa)->error;
 161 }
 162
 163 struct aa_audit_rule {
 164         struct aa_label *label;
 165 };
 166
 167 void aa_audit_rule_free(void *vrule)
 168 {
 169         struct aa_audit_rule *rule = vrule;
 170
 171         if (rule) {
 172                 if (!IS_ERR(rule->label))
 173                         aa_put_label(rule->label);
 174                 kfree(rule);
 175         }
 176 }
 177
 178 int aa_audit_rule_init(u32 field, u32 op, char *rulestr, void **vrule)
 179 {
 180         struct aa_audit_rule *rule;
 181
 182         switch (field) {
 183         case AUDIT_SUBJ_ROLE:
 184                 if (op != Audit_equal && op != Audit_not_equal)
 185                         return -EINVAL;
 186                 break;
 187         default:
 188                 return -EINVAL;
 189         }
 190
 191         rule = kzalloc(sizeof(struct aa_audit_rule), GFP_KERNEL);
 192
 193         if (!rule)
 194                 return -ENOMEM;
 195
 196         /* Currently rules are treated as coming from the root ns */
 197         rule->label = aa_label_parse(&root_ns->unconfined->label, rulestr,
 198                                      GFP_KERNEL, true, false);
 199         if (IS_ERR(rule->label)) {
 200                 int err = PTR_ERR(rule->label);
 201                 aa_audit_rule_free(rule);
 202                 return err;
 203         }
 204
 205         *vrule = rule;
 206         return 0;
 207 }
 208
 209 int aa_audit_rule_known(struct audit_krule *rule)
 210 {
 211         int i;
 212
 213         for (i = 0; i < rule->field_count; i++) {
 214                 struct audit_field *f = &rule->fields[i];
 215
 216                 switch (f->type) {
 217                 case AUDIT_SUBJ_ROLE:
 218                         return 1;
 219                 }
 220         }
 221
 222         return 0;
 223 }
 224
 225 int aa_audit_rule_match(u32 sid, u32 field, u32 op, void *vrule)
 226 {
 227         struct aa_audit_rule *rule = vrule;
 228         struct aa_label *label;
 229         int found = 0;
 230
 231         label = aa_secid_to_label(sid);
 232
 233         if (!label)
 234                 return -ENOENT;
 235
 236         if (aa_label_is_subset(label, rule->label))
 237                 found = 1;
 238
 239         switch (field) {
 240         case AUDIT_SUBJ_ROLE:
 241                 switch (op) {
 242                 case Audit_equal:
 243                         return found;
 244                 case Audit_not_equal:
 245                         return !found;
 246                 }
 247         }
 248         return 0;
 249 }