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 */ 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 * @sa: 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 sa->error on success, error code on failure 63 */ 64 static int audit_caps(struct common_audit_data *sa, struct aa_profile *profile, 65 int cap, int error) 66 { 67 struct audit_cache *ent; 68 int type = AUDIT_APPARMOR_AUTO; 69 70 aad(sa)->error = error; 71 72 if (likely(!error)) { 73 /* test if auditing is being forced */ 74 if (likely((AUDIT_MODE(profile) != AUDIT_ALL) && 75 !cap_raised(profile->caps.audit, cap))) 76 return 0; 77 type = AUDIT_APPARMOR_AUDIT; 78 } else if (KILL_MODE(profile) || 79 cap_raised(profile->caps.kill, cap)) { 80 type = AUDIT_APPARMOR_KILL; 81 } else if (cap_raised(profile->caps.quiet, cap) && 82 AUDIT_MODE(profile) != AUDIT_NOQUIET && 83 AUDIT_MODE(profile) != AUDIT_ALL) { 84 /* quiet auditing */ 85 return error; 86 } 87 88 /* Do simple duplicate message elimination */ 89 ent = &get_cpu_var(audit_cache); 90 if (profile == ent->profile && cap_raised(ent->caps, cap)) { 91 put_cpu_var(audit_cache); 92 if (COMPLAIN_MODE(profile)) 93 return complain_error(error); 94 return error; 95 } else { 96 aa_put_profile(ent->profile); 97 ent->profile = aa_get_profile(profile); 98 cap_raise(ent->caps, cap); 99 } 100 put_cpu_var(audit_cache); 101 102 return aa_audit(type, profile, sa, audit_cb); 103 } 104 105 /** 106 * profile_capable - test if profile allows use of capability @cap 107 * @profile: profile being enforced (NOT NULL, NOT unconfined) 108 * @cap: capability to test if allowed 109 * @opts: CAP_OPT_NOAUDIT bit determines whether audit record is generated 110 * @sa: audit data (MAY BE NULL indicating no auditing) 111 * 112 * Returns: 0 if allowed else -EPERM 113 */ 114 static int profile_capable(struct aa_profile *profile, int cap, 115 unsigned int opts, struct common_audit_data *sa) 116 { 117 int error; 118 119 if (cap_raised(profile->caps.allow, cap) && 120 !cap_raised(profile->caps.denied, cap)) 121 error = 0; 122 else 123 error = -EPERM; 124 125 if (opts & CAP_OPT_NOAUDIT) { 126 if (!COMPLAIN_MODE(profile)) 127 return error; 128 /* audit the cap request in complain mode but note that it 129 * should be optional. 130 */ 131 aad(sa)->info = "optional: no audit"; 132 } 133 134 return audit_caps(sa, profile, cap, error); 135 } 136 137 /** 138 * aa_capable - test permission to use capability 139 * @label: label being tested for capability (NOT NULL) 140 * @cap: capability to be tested 141 * @opts: CAP_OPT_NOAUDIT bit determines whether audit record is generated 142 * 143 * Look up capability in profile capability set. 144 * 145 * Returns: 0 on success, or else an error code. 146 */ 147 int aa_capable(struct aa_label *label, int cap, unsigned int opts) 148 { 149 struct aa_profile *profile; 150 int error = 0; 151 DEFINE_AUDIT_DATA(sa, LSM_AUDIT_DATA_CAP, OP_CAPABLE); 152 153 sa.u.cap = cap; 154 error = fn_for_each_confined(label, profile, 155 profile_capable(profile, cap, opts, &sa)); 156 157 return error; 158 } 159