1 /* 2 * AppArmor security module 3 * 4 * This file contains AppArmor ipc mediation 5 * 6 * Copyright (C) 1998-2008 Novell/SUSE 7 * Copyright 2009-2017 Canonical Ltd. 8 * 9 * This program is free software; you can redistribute it and/or 10 * modify it under the terms of the GNU General Public License as 11 * published by the Free Software Foundation, version 2 of the 12 * License. 13 */ 14 15 #include <linux/gfp.h> 16 #include <linux/ptrace.h> 17 18 #include "include/audit.h" 19 #include "include/capability.h" 20 #include "include/cred.h" 21 #include "include/policy.h" 22 #include "include/ipc.h" 23 #include "include/sig_names.h" 24 25 /** 26 * audit_ptrace_mask - convert mask to permission string 27 * @buffer: buffer to write string to (NOT NULL) 28 * @mask: permission mask to convert 29 */ 30 static void audit_ptrace_mask(struct audit_buffer *ab, u32 mask) 31 { 32 switch (mask) { 33 case MAY_READ: 34 audit_log_string(ab, "read"); 35 break; 36 case MAY_WRITE: 37 audit_log_string(ab, "trace"); 38 break; 39 case AA_MAY_BE_READ: 40 audit_log_string(ab, "readby"); 41 break; 42 case AA_MAY_BE_TRACED: 43 audit_log_string(ab, "tracedby"); 44 break; 45 } 46 } 47 48 /* call back to audit ptrace fields */ 49 static void audit_ptrace_cb(struct audit_buffer *ab, void *va) 50 { 51 struct common_audit_data *sa = va; 52 53 if (aad(sa)->request & AA_PTRACE_PERM_MASK) { 54 audit_log_format(ab, " requested_mask="); 55 audit_ptrace_mask(ab, aad(sa)->request); 56 57 if (aad(sa)->denied & AA_PTRACE_PERM_MASK) { 58 audit_log_format(ab, " denied_mask="); 59 audit_ptrace_mask(ab, aad(sa)->denied); 60 } 61 } 62 audit_log_format(ab, " peer="); 63 aa_label_xaudit(ab, labels_ns(aad(sa)->label), aad(sa)->peer, 64 FLAGS_NONE, GFP_ATOMIC); 65 } 66 67 /* assumes check for PROFILE_MEDIATES is already done */ 68 /* TODO: conditionals */ 69 static int profile_ptrace_perm(struct aa_profile *profile, 70 struct aa_label *peer, u32 request, 71 struct common_audit_data *sa) 72 { 73 struct aa_perms perms = { }; 74 75 aad(sa)->peer = peer; 76 aa_profile_match_label(profile, peer, AA_CLASS_PTRACE, request, 77 &perms); 78 aa_apply_modes_to_perms(profile, &perms); 79 return aa_check_perms(profile, &perms, request, sa, audit_ptrace_cb); 80 } 81 82 static int profile_tracee_perm(struct aa_profile *tracee, 83 struct aa_label *tracer, u32 request, 84 struct common_audit_data *sa) 85 { 86 if (profile_unconfined(tracee) || unconfined(tracer) || 87 !PROFILE_MEDIATES(tracee, AA_CLASS_PTRACE)) 88 return 0; 89 90 return profile_ptrace_perm(tracee, tracer, request, sa); 91 } 92 93 static int profile_tracer_perm(struct aa_profile *tracer, 94 struct aa_label *tracee, u32 request, 95 struct common_audit_data *sa) 96 { 97 if (profile_unconfined(tracer)) 98 return 0; 99 100 if (PROFILE_MEDIATES(tracer, AA_CLASS_PTRACE)) 101 return profile_ptrace_perm(tracer, tracee, request, sa); 102 103 /* profile uses the old style capability check for ptrace */ 104 if (&tracer->label == tracee) 105 return 0; 106 107 aad(sa)->label = &tracer->label; 108 aad(sa)->peer = tracee; 109 aad(sa)->request = 0; 110 aad(sa)->error = aa_capable(&tracer->label, CAP_SYS_PTRACE, 1); 111 112 return aa_audit(AUDIT_APPARMOR_AUTO, tracer, sa, audit_ptrace_cb); 113 } 114 115 /** 116 * aa_may_ptrace - test if tracer task can trace the tracee 117 * @tracer: label of the task doing the tracing (NOT NULL) 118 * @tracee: task label to be traced 119 * @request: permission request 120 * 121 * Returns: %0 else error code if permission denied or error 122 */ 123 int aa_may_ptrace(struct aa_label *tracer, struct aa_label *tracee, 124 u32 request) 125 { 126 struct aa_profile *profile; 127 u32 xrequest = request << PTRACE_PERM_SHIFT; 128 DEFINE_AUDIT_DATA(sa, LSM_AUDIT_DATA_NONE, OP_PTRACE); 129 130 return xcheck_labels(tracer, tracee, profile, 131 profile_tracer_perm(profile, tracee, request, &sa), 132 profile_tracee_perm(profile, tracer, xrequest, &sa)); 133 } 134 135 136 static inline int map_signal_num(int sig) 137 { 138 if (sig > SIGRTMAX) 139 return SIGUNKNOWN; 140 else if (sig >= SIGRTMIN) 141 return sig - SIGRTMIN + SIGRT_BASE; 142 else if (sig < MAXMAPPED_SIG) 143 return sig_map[sig]; 144 return SIGUNKNOWN; 145 } 146 147 /** 148 * audit_file_mask - convert mask to permission string 149 * @buffer: buffer to write string to (NOT NULL) 150 * @mask: permission mask to convert 151 */ 152 static void audit_signal_mask(struct audit_buffer *ab, u32 mask) 153 { 154 if (mask & MAY_READ) 155 audit_log_string(ab, "receive"); 156 if (mask & MAY_WRITE) 157 audit_log_string(ab, "send"); 158 } 159 160 /** 161 * audit_cb - call back for signal specific audit fields 162 * @ab: audit_buffer (NOT NULL) 163 * @va: audit struct to audit values of (NOT NULL) 164 */ 165 static void audit_signal_cb(struct audit_buffer *ab, void *va) 166 { 167 struct common_audit_data *sa = va; 168 169 if (aad(sa)->request & AA_SIGNAL_PERM_MASK) { 170 audit_log_format(ab, " requested_mask="); 171 audit_signal_mask(ab, aad(sa)->request); 172 if (aad(sa)->denied & AA_SIGNAL_PERM_MASK) { 173 audit_log_format(ab, " denied_mask="); 174 audit_signal_mask(ab, aad(sa)->denied); 175 } 176 } 177 if (aad(sa)->signal == SIGUNKNOWN) 178 audit_log_format(ab, "signal=unknown(%d)", 179 aad(sa)->unmappedsig); 180 else if (aad(sa)->signal < MAXMAPPED_SIGNAME) 181 audit_log_format(ab, " signal=%s", sig_names[aad(sa)->signal]); 182 else 183 audit_log_format(ab, " signal=rtmin+%d", 184 aad(sa)->signal - SIGRT_BASE); 185 audit_log_format(ab, " peer="); 186 aa_label_xaudit(ab, labels_ns(aad(sa)->label), aad(sa)->peer, 187 FLAGS_NONE, GFP_ATOMIC); 188 } 189 190 static int profile_signal_perm(struct aa_profile *profile, 191 struct aa_label *peer, u32 request, 192 struct common_audit_data *sa) 193 { 194 struct aa_perms perms; 195 unsigned int state; 196 197 if (profile_unconfined(profile) || 198 !PROFILE_MEDIATES(profile, AA_CLASS_SIGNAL)) 199 return 0; 200 201 aad(sa)->peer = peer; 202 /* TODO: secondary cache check <profile, profile, perm> */ 203 state = aa_dfa_next(profile->policy.dfa, 204 profile->policy.start[AA_CLASS_SIGNAL], 205 aad(sa)->signal); 206 aa_label_match(profile, peer, state, false, request, &perms); 207 aa_apply_modes_to_perms(profile, &perms); 208 return aa_check_perms(profile, &perms, request, sa, audit_signal_cb); 209 } 210 211 int aa_may_signal(struct aa_label *sender, struct aa_label *target, int sig) 212 { 213 struct aa_profile *profile; 214 DEFINE_AUDIT_DATA(sa, LSM_AUDIT_DATA_NONE, OP_SIGNAL); 215 216 aad(&sa)->signal = map_signal_num(sig); 217 aad(&sa)->unmappedsig = sig; 218 return xcheck_labels(sender, target, profile, 219 profile_signal_perm(profile, target, MAY_WRITE, &sa), 220 profile_signal_perm(profile, sender, MAY_READ, &sa)); 221 } 222