1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239
|
/*
* pam_abl - a PAM module and program for automatic blacklisting of hosts and users
*
* Copyright (C) 2005-2012
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#include "rule.h"
#include <errno.h>
#include <ctype.h>
#include <string.h>
int parse_long(const char **sp, long *lp) {
long l = 0;
if (!isdigit(**sp)) {
return EINVAL;
}
while (isdigit(**sp)) {
l = l * 10 + *(*sp)++ - '0';
}
*lp = l;
return 0;
}
/* Parse a time specification in the form
* <digits>[s|m|h|d]
*/
static int parse_time(const char **sp, long *tp) {
long t;
int err;
if (err = parse_long(sp, &t), 0 != err) {
return err;
}
/* Handle the multiplier suffix */
switch (**sp) {
case 'd':
t *= 24;
case 'h':
t *= 60;
case 'm':
t *= 60;
case 's':
(*sp)++;
default:
;
}
*tp = t;
return 0;
}
int rule_parse_time(const char *p, long *t, long min) {
int err;
if (err = parse_time(&p, t), 0 != err) {
*t = min;
return err;
}
if (*p != '\0') {
*t = min;
return EINVAL;
}
if (*t < min) {
*t = min;
}
return 0;
}
static size_t wordlen(const char *rp) {
size_t l = 0;
while (*rp != '\0' &&
*rp != '/' &&
*rp != '|' &&
*rp != ':' &&
!isspace(*rp)) {
rp++;
l++;
}
return l;
}
static int match(log_context *log, const char *pattern, const char *target, size_t len) {
log_debug(log, "match('%s', '%s', %d)", pattern, target, len);
if (!pattern)
return 0;
return (len == strlen(pattern)) && (memcmp(pattern, target, len) == 0);
}
static int matchname(log_context *log, const char *user, const char *service,
const char **rp) {
size_t l = wordlen(*rp);
int ok;
log_debug(log, "Check %s/%s against %s(%d)", user, service, *rp, l);
ok = (l != 0) && ((l == 1 && **rp == '*') || match(log, user, *rp, l));
(*rp) += l;
if (ok) {
log_debug(log, "Name part matches, **rp = '%c'", **rp);
}
if (**rp == '/') {
(*rp)++;
l = wordlen(*rp);
ok &= (l != 0) && ((l == 1 && **rp == '*') || match(log, service, *rp, l));
(*rp) += l;
}
log_debug(log, "%satch!", ok ? "M" : "No m");
return ok;
}
static int matchnames(log_context *log, const char *user, const char *service,
const char **rp) {
int ok = matchname(log, user, service, rp);
while (**rp == '|') {
(*rp)++;
ok |= matchname(log, user, service, rp);
}
return ok;
}
static long howmany(log_context *log, AuthState *history, time_t now, long limit) {
if (firstAttempt(history))
return -1;
long i = 0;
AuthAttempt attempt;
while (!nextAttempt(history, &attempt)) {
if (difftime(now, attempt.m_time) <= (double) limit)
++i;
}
log_debug(log, "howmany(%ld) = %ld", limit, i);
return i;
}
static int matchperiod(log_context *log, AuthState *history, time_t now, const char **rp) {
int err;
long count, period;
log_debug(log, "matchperiod(%p, %u, '%s')", history, getNofAttempts(history), *rp);
if (err = parse_long(rp, &count), 0 != err) {
return 0;
}
log_debug(log, "count is %ld, **rp='%c'", count, **rp);
if (**rp != '/') {
return 0;
}
(*rp)++;
if (err = parse_time(rp, &period), 0 != err) {
return 0;
}
log_debug(log, "period is %ld, **rp='%c'", period, **rp);
log_debug(log, "Checking %ld/%ld", count, period);
return howmany(log, history, now, period) >= count;
}
int rule_matchperiods(log_context *log, AuthState *history, time_t now, const char **rp) {
if (matchperiod(log, history, now, rp)) {
return 1;
}
while (**rp == ',') {
(*rp)++;
if (matchperiod(log, history, now, rp)) {
return 1;
}
}
return 0;
}
static int check_clause(log_context *log, const char **rp,
const char *user, const char *service,
AuthState *history, time_t now) {
int inv = 0;
if (**rp == '!') {
inv = 1;
(*rp)++;
}
if (!(inv ^ matchnames(log, user, service, rp))) {
return 0;
}
log_debug(log, "Name matched, next char is '%c'", **rp);
/* The name part matches so now check the trigger clauses */
if (**rp != ':') {
return 0;
}
(*rp)++;
return rule_matchperiods(log, history, now, rp);
}
BlockState rule_test(log_context *log, const char *rule,
const char *user, const char *service,
AuthState *history, time_t now) {
if (!rule)
return CLEAR;
const char *rp = rule;
while (*rp != '\0') {
if (check_clause(log, &rp, user, service, history, now)) {
return BLOCKED;
}
while (*rp != '\0' && !isspace(*rp)) {
rp++;
}
while (isspace(*rp)) {
rp++;
}
}
return CLEAR;
}
|