1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * AppArmor security module 4 * 5 * This file contains AppArmor ipc mediation 6 * 7 * Copyright (C) 1998-2008 Novell/SUSE 8 * Copyright 2009-2017 Canonical Ltd. 9 */ 10 11 #include <linux/gfp.h> 12 #include <linux/ptrace.h> 13 14 #include "include/audit.h" 15 #include "include/capability.h" 16 #include "include/cred.h" 17 #include "include/policy.h" 18 #include "include/ipc.h" 19 #include "include/sig_names.h" 20 21 /** 22 * audit_ptrace_mask - convert mask to permission string 23 * @mask: permission mask to convert 24 * 25 * Returns: pointer to static string 26 */ 27 static const char *audit_ptrace_mask(u32 mask) 28 { 29 switch (mask) { 30 case MAY_READ: 31 return "read"; 32 case MAY_WRITE: 33 return "trace"; 34 case AA_MAY_BE_READ: 35 return "readby"; 36 case AA_MAY_BE_TRACED: 37 return "tracedby"; 38 } 39 return ""; 40 } 41 42 /* call back to audit ptrace fields */ 43 static void audit_ptrace_cb(struct audit_buffer *ab, void *va) 44 { 45 struct common_audit_data *sa = va; 46 47 if (aad(sa)->request & AA_PTRACE_PERM_MASK) { 48 audit_log_format(ab, " requested_mask=\"%s\"", 49 audit_ptrace_mask(aad(sa)->request)); 50 51 if (aad(sa)->denied & AA_PTRACE_PERM_MASK) { 52 audit_log_format(ab, " denied_mask=\"%s\"", 53 audit_ptrace_mask(aad(sa)->denied)); 54 } 55 } 56 audit_log_format(ab, " peer="); 57 aa_label_xaudit(ab, labels_ns(aad(sa)->label), aad(sa)->peer, 58 FLAGS_NONE, GFP_ATOMIC); 59 } 60 61 /* assumes check for PROFILE_MEDIATES is already done */ 62 /* TODO: conditionals */ 63 static int profile_ptrace_perm(struct aa_profile *profile, 64 struct aa_label *peer, u32 request, 65 struct common_audit_data *sa) 66 { 67 struct aa_perms perms = { }; 68 69 aad(sa)->peer = peer; 70 aa_profile_match_label(profile, peer, AA_CLASS_PTRACE, request, 71 &perms); 72 aa_apply_modes_to_perms(profile, &perms); 73 return aa_check_perms(profile, &perms, request, sa, audit_ptrace_cb); 74 } 75 76 static int profile_tracee_perm(struct aa_profile *tracee, 77 struct aa_label *tracer, u32 request, 78 struct common_audit_data *sa) 79 { 80 if (profile_unconfined(tracee) || unconfined(tracer) || 81 !PROFILE_MEDIATES(tracee, AA_CLASS_PTRACE)) 82 return 0; 83 84 return profile_ptrace_perm(tracee, tracer, request, sa); 85 } 86 87 static int profile_tracer_perm(struct aa_profile *tracer, 88 struct aa_label *tracee, u32 request, 89 struct common_audit_data *sa) 90 { 91 if (profile_unconfined(tracer)) 92 return 0; 93 94 if (PROFILE_MEDIATES(tracer, AA_CLASS_PTRACE)) 95 return profile_ptrace_perm(tracer, tracee, request, sa); 96 97 /* profile uses the old style capability check for ptrace */ 98 if (&tracer->label == tracee) 99 return 0; 100 101 aad(sa)->label = &tracer->label; 102 aad(sa)->peer = tracee; 103 aad(sa)->request = 0; 104 aad(sa)->error = aa_capable(&tracer->label, CAP_SYS_PTRACE, 105 CAP_OPT_NONE); 106 107 return aa_audit(AUDIT_APPARMOR_AUTO, tracer, sa, audit_ptrace_cb); 108 } 109 110 /** 111 * aa_may_ptrace - test if tracer task can trace the tracee 112 * @tracer: label of the task doing the tracing (NOT NULL) 113 * @tracee: task label to be traced 114 * @request: permission request 115 * 116 * Returns: %0 else error code if permission denied or error 117 */ 118 int aa_may_ptrace(struct aa_label *tracer, struct aa_label *tracee, 119 u32 request) 120 { 121 struct aa_profile *profile; 122 u32 xrequest = request << PTRACE_PERM_SHIFT; 123 DEFINE_AUDIT_DATA(sa, LSM_AUDIT_DATA_NONE, OP_PTRACE); 124 125 return xcheck_labels(tracer, tracee, profile, 126 profile_tracer_perm(profile, tracee, request, &sa), 127 profile_tracee_perm(profile, tracer, xrequest, &sa)); 128 } 129 130 131 static inline int map_signal_num(int sig) 132 { 133 if (sig > SIGRTMAX) 134 return SIGUNKNOWN; 135 else if (sig >= SIGRTMIN) 136 return sig - SIGRTMIN + SIGRT_BASE; 137 else if (sig < MAXMAPPED_SIG) 138 return sig_map[sig]; 139 return SIGUNKNOWN; 140 } 141 142 /** 143 * audit_signal_mask - convert mask to permission string 144 * @mask: permission mask to convert 145 * 146 * Returns: pointer to static string 147 */ 148 static const char *audit_signal_mask(u32 mask) 149 { 150 if (mask & MAY_READ) 151 return "receive"; 152 if (mask & MAY_WRITE) 153 return "send"; 154 return ""; 155 } 156 157 /** 158 * audit_cb - call back for signal specific audit fields 159 * @ab: audit_buffer (NOT NULL) 160 * @va: audit struct to audit values of (NOT NULL) 161 */ 162 static void audit_signal_cb(struct audit_buffer *ab, void *va) 163 { 164 struct common_audit_data *sa = va; 165 166 if (aad(sa)->request & AA_SIGNAL_PERM_MASK) { 167 audit_log_format(ab, " requested_mask=\"%s\"", 168 audit_signal_mask(aad(sa)->request)); 169 if (aad(sa)->denied & AA_SIGNAL_PERM_MASK) { 170 audit_log_format(ab, " denied_mask=\"%s\"", 171 audit_signal_mask(aad(sa)->denied)); 172 } 173 } 174 if (aad(sa)->signal == SIGUNKNOWN) 175 audit_log_format(ab, "signal=unknown(%d)", 176 aad(sa)->unmappedsig); 177 else if (aad(sa)->signal < MAXMAPPED_SIGNAME) 178 audit_log_format(ab, " signal=%s", sig_names[aad(sa)->signal]); 179 else 180 audit_log_format(ab, " signal=rtmin+%d", 181 aad(sa)->signal - SIGRT_BASE); 182 audit_log_format(ab, " peer="); 183 aa_label_xaudit(ab, labels_ns(aad(sa)->label), aad(sa)->peer, 184 FLAGS_NONE, GFP_ATOMIC); 185 } 186 187 static int profile_signal_perm(struct aa_profile *profile, 188 struct aa_label *peer, u32 request, 189 struct common_audit_data *sa) 190 { 191 struct aa_perms perms; 192 unsigned int state; 193 194 if (profile_unconfined(profile) || 195 !PROFILE_MEDIATES(profile, AA_CLASS_SIGNAL)) 196 return 0; 197 198 aad(sa)->peer = peer; 199 /* TODO: secondary cache check <profile, profile, perm> */ 200 state = aa_dfa_next(profile->policy.dfa, 201 profile->policy.start[AA_CLASS_SIGNAL], 202 aad(sa)->signal); 203 aa_label_match(profile, peer, state, false, request, &perms); 204 aa_apply_modes_to_perms(profile, &perms); 205 return aa_check_perms(profile, &perms, request, sa, audit_signal_cb); 206 } 207 208 int aa_may_signal(struct aa_label *sender, struct aa_label *target, int sig) 209 { 210 struct aa_profile *profile; 211 DEFINE_AUDIT_DATA(sa, LSM_AUDIT_DATA_NONE, OP_SIGNAL); 212 213 aad(&sa)->signal = map_signal_num(sig); 214 aad(&sa)->unmappedsig = sig; 215 return xcheck_labels(sender, target, profile, 216 profile_signal_perm(profile, target, MAY_WRITE, &sa), 217 profile_signal_perm(profile, sender, MAY_READ, &sa)); 218 } 219