1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * AppArmor security module 4 * 5 * This file contains AppArmor capability mediation functions 6 * 7 * Copyright (C) 1998-2008 Novell/SUSE 8 * Copyright 2009-2010 Canonical Ltd. 9 */ 10 11 #include <linux/capability.h> 12 #include <linux/errno.h> 13 #include <linux/gfp.h> 14 #include <linux/security.h> 15 16 #include "include/apparmor.h" 17 #include "include/capability.h" 18 #include "include/cred.h" 19 #include "include/policy.h" 20 #include "include/audit.h" 21 22 /* 23 * Table of capability names: we generate it from capabilities.h. 24 */ 25 #include "capability_names.h" 26 27 struct aa_sfs_entry aa_sfs_entry_caps[] = { 28 AA_SFS_FILE_STRING("mask", AA_SFS_CAPS_MASK), 29 { } 30 }; 31 32 struct audit_cache { 33 struct aa_profile *profile; 34 kernel_cap_t caps; 35 }; 36 37 static DEFINE_PER_CPU(struct audit_cache, audit_cache); 38 39 /** 40 * audit_cb - call back for capability components of audit struct 41 * @ab: audit buffer (NOT NULL) 42 * @va: audit struct to audit data from (NOT NULL) 43 */ audit_cb(struct audit_buffer * ab,void * va)44 static void audit_cb(struct audit_buffer *ab, void *va) 45 { 46 struct common_audit_data *sa = va; 47 48 audit_log_format(ab, " capname="); 49 audit_log_untrustedstring(ab, capability_names[sa->u.cap]); 50 } 51 52 /** 53 * audit_caps - audit a capability 54 * @ad: audit data 55 * @profile: profile being tested for confinement (NOT NULL) 56 * @cap: capability tested 57 * @error: error code returned by test 58 * 59 * Do auditing of capability and handle, audit/complain/kill modes switching 60 * and duplicate message elimination. 61 * 62 * Returns: 0 or ad->error on success, error code on failure 63 */ audit_caps(struct apparmor_audit_data * ad,struct aa_profile * profile,int cap,int error)64 static int audit_caps(struct apparmor_audit_data *ad, struct aa_profile *profile, 65 int cap, int error) 66 { 67 struct aa_ruleset *rules = list_first_entry(&profile->rules, 68 typeof(*rules), list); 69 struct audit_cache *ent; 70 int type = AUDIT_APPARMOR_AUTO; 71 72 ad->error = error; 73 74 if (likely(!error)) { 75 /* test if auditing is being forced */ 76 if (likely((AUDIT_MODE(profile) != AUDIT_ALL) && 77 !cap_raised(rules->caps.audit, cap))) 78 return 0; 79 type = AUDIT_APPARMOR_AUDIT; 80 } else if (KILL_MODE(profile) || 81 cap_raised(rules->caps.kill, cap)) { 82 type = AUDIT_APPARMOR_KILL; 83 } else if (cap_raised(rules->caps.quiet, cap) && 84 AUDIT_MODE(profile) != AUDIT_NOQUIET && 85 AUDIT_MODE(profile) != AUDIT_ALL) { 86 /* quiet auditing */ 87 return error; 88 } 89 90 /* Do simple duplicate message elimination */ 91 ent = &get_cpu_var(audit_cache); 92 if (profile == ent->profile && cap_raised(ent->caps, cap)) { 93 put_cpu_var(audit_cache); 94 if (COMPLAIN_MODE(profile)) 95 return complain_error(error); 96 return error; 97 } else { 98 aa_put_profile(ent->profile); 99 ent->profile = aa_get_profile(profile); 100 cap_raise(ent->caps, cap); 101 } 102 put_cpu_var(audit_cache); 103 104 return aa_audit(type, profile, ad, audit_cb); 105 } 106 107 /** 108 * profile_capable - test if profile allows use of capability @cap 109 * @profile: profile being enforced (NOT NULL, NOT unconfined) 110 * @cap: capability to test if allowed 111 * @opts: CAP_OPT_NOAUDIT bit determines whether audit record is generated 112 * @ad: audit data (MAY BE NULL indicating no auditing) 113 * 114 * Returns: 0 if allowed else -EPERM 115 */ profile_capable(struct aa_profile * profile,int cap,unsigned int opts,struct apparmor_audit_data * ad)116 static int profile_capable(struct aa_profile *profile, int cap, 117 unsigned int opts, struct apparmor_audit_data *ad) 118 { 119 struct aa_ruleset *rules = list_first_entry(&profile->rules, 120 typeof(*rules), list); 121 int error; 122 123 if (cap_raised(rules->caps.allow, cap) && 124 !cap_raised(rules->caps.denied, cap)) 125 error = 0; 126 else 127 error = -EPERM; 128 129 if (opts & CAP_OPT_NOAUDIT) { 130 if (!COMPLAIN_MODE(profile)) 131 return error; 132 /* audit the cap request in complain mode but note that it 133 * should be optional. 134 */ 135 ad->info = "optional: no audit"; 136 } 137 138 return audit_caps(ad, profile, cap, error); 139 } 140 141 /** 142 * aa_capable - test permission to use capability 143 * @subj_cred: cred we are testing capability against 144 * @label: label being tested for capability (NOT NULL) 145 * @cap: capability to be tested 146 * @opts: CAP_OPT_NOAUDIT bit determines whether audit record is generated 147 * 148 * Look up capability in profile capability set. 149 * 150 * Returns: 0 on success, or else an error code. 151 */ aa_capable(const struct cred * subj_cred,struct aa_label * label,int cap,unsigned int opts)152 int aa_capable(const struct cred *subj_cred, struct aa_label *label, 153 int cap, unsigned int opts) 154 { 155 struct aa_profile *profile; 156 int error = 0; 157 DEFINE_AUDIT_DATA(ad, LSM_AUDIT_DATA_CAP, AA_CLASS_CAP, OP_CAPABLE); 158 159 ad.subj_cred = subj_cred; 160 ad.common.u.cap = cap; 161 error = fn_for_each_confined(label, profile, 162 profile_capable(profile, cap, opts, &ad)); 163 164 return error; 165 } 166