| 1 |
Mailman security is in part enforced by requiring it execute |
| 2 |
SGID. When the mail process or the web server attempts to execute a |
| 3 |
mailman script a C program is invoked to verify the group |
| 4 |
permission. Mailman as it is shipped only allows one group to be |
| 5 |
specified at build time. For users who build and install on their own |
| 6 |
machine this is not a limitation. However, when making a binary |
| 7 |
package to be installed on an arbitrary machine it is hard to predict |
| 8 |
the correct group to use for that installation. Therefore this patch |
| 9 |
allows us to specify at build time a list of groups that will be |
| 10 |
iterated over, if the mailman process is executing as any of one of |
| 11 |
the group in the set of groups then the permission check passes. Since |
| 12 |
the groups we build with are limited to a small number of safe groups |
| 13 |
this does not lower the security much while at the same time provides |
| 14 |
a much more friendly way to package a binary installation that will |
| 15 |
run in a wider range of installations. |
| 16 |
|
| 17 |
It was necessary to add the macro MM_FIND_GROUP_LIST to the |
| 18 |
configure.in file replacing the original use of MM_FIND_GROUP_NAME, |
| 19 |
the former operates on a list of group names while the later on a |
| 20 |
single name. MM_FIND_GROUP_LIST includes a filter parameter that was |
| 21 |
added with the notion of supporting the with-permcheck option. If |
| 22 |
filter is true then only group names that exist on the build machine |
| 23 |
are permitted in the list, otherwise all names are permitted. However, |
| 24 |
note that whenever MM_FIND_GROUP_LIST is invoked it is currently |
| 25 |
hardcoded to disable filtering and is not tied to with-permcheck, this |
| 26 |
was done because of the observation that if one is passing a list of |
| 27 |
groups it is likely one is doing so to support installations that have |
| 28 |
a group not present on the build machine, but one might still want to |
| 29 |
take advantage of the other with-permcheck functionality. |
| 30 |
|
| 31 |
diff -u mailman-2.1.2/configure.in.orig mailman-2.1.2/configure.in |
| 32 |
--- mailman-2.1.2/configure.in.orig 2003-04-21 23:34:51.000000000 -0400 |
| 33 |
+++ mailman-2.1.2/configure.in 2003-05-02 16:32:45.000000000 -0400 |
| 34 |
@@ -208,26 +208,101 @@ |
| 35 |
fi |
| 36 |
|
| 37 |
# new macro for finding group names |
| 38 |
-AC_DEFUN(MM_FIND_GROUP_NAME, [ |
| 39 |
+# returns a comma separated list of quoted group names |
| 40 |
+# the list is returned in the same order as specified with any duplicates removed |
| 41 |
+# the filter flag must be "yes" or "no", e.g. this is permcheck |
| 42 |
+# "no" ==> none existing groups are not filtered out |
| 43 |
+# "yes" ==> only those groups that are in the group database are included |
| 44 |
+# in the list |
| 45 |
+AC_DEFUN(MM_FIND_GROUP_LIST, [ |
| 46 |
# $1 == variable name |
| 47 |
-# $2 == user id to check for |
| 48 |
+# $2 == white space separated list of groups to check, |
| 49 |
+# list may contain mix of id's and names |
| 50 |
+# $3 == filter, if == 'yes' then remove any non-existing groups |
| 51 |
AC_SUBST($1) |
| 52 |
changequote(,) |
| 53 |
if test -z "$$1" |
| 54 |
then |
| 55 |
cat > conftest.py <<EOF |
| 56 |
import grp |
| 57 |
-gid = '' |
| 58 |
+group_names = [] |
| 59 |
+seen = {} |
| 60 |
+filter = "$3" |
| 61 |
+ |
| 62 |
for group in "$2".split(): |
| 63 |
try: |
| 64 |
+ gid = int(group) |
| 65 |
+ try: |
| 66 |
+ gname = grp.getgrgid(gid)[0] |
| 67 |
+ except KeyError: |
| 68 |
+ gname = '' |
| 69 |
+ except ValueError: |
| 70 |
try: |
| 71 |
- gname = grp.getgrgid(int(group))[0] |
| 72 |
- break |
| 73 |
- except ValueError: |
| 74 |
gname = grp.getgrnam(group)[0] |
| 75 |
+ except KeyError: |
| 76 |
+ if filter == "yes": |
| 77 |
+ gname = '' |
| 78 |
+ else: |
| 79 |
+ gname = group |
| 80 |
+ if gname: |
| 81 |
+ if gname not in seen: |
| 82 |
+ seen[gname] = 1 |
| 83 |
+ group_names.append(gname) |
| 84 |
+ |
| 85 |
+if group_names: |
| 86 |
+ val = '"' + '", "'.join(group_names) + '"' |
| 87 |
+ #val = "'"+val+"'" |
| 88 |
+else: |
| 89 |
+ val = '' |
| 90 |
+ |
| 91 |
+fp = open("conftest.out", "w") |
| 92 |
+fp.write("%s\n" % val) |
| 93 |
+fp.close() |
| 94 |
+EOF |
| 95 |
+ $PYTHON conftest.py |
| 96 |
+ $1=`cat conftest.out` |
| 97 |
+fi |
| 98 |
+changequote([, ]) |
| 99 |
+rm -f conftest.out conftest.py]) |
| 100 |
+ |
| 101 |
+ |
| 102 |
+# new macro for finding group names |
| 103 |
+AC_DEFUN(MM_FIND_GROUP_NAME, [ |
| 104 |
+# Given a list of tokens, either a name or a number (gid) |
| 105 |
+# return the first one in the list that is found in the |
| 106 |
+# group database. The return value is always a name, possibly |
| 107 |
+# translated from a gid. If permcheck is "no" then the group |
| 108 |
+# database is not checked, instead the first token in the list |
| 109 |
+# which is a name is returned (e.g. the default value). If permcheck |
| 110 |
+# is no and only gid's are in the list then the null string is returned. |
| 111 |
+# $1 == variable name |
| 112 |
+# $2 == group id to check for |
| 113 |
+# $3 == permcheck, either "yes" or "no" |
| 114 |
+AC_SUBST($1) |
| 115 |
+changequote(,) |
| 116 |
+if test -z "$$1" |
| 117 |
+then |
| 118 |
+ cat > conftest.py <<EOF |
| 119 |
+import grp |
| 120 |
+gname='' |
| 121 |
+if "$3" == "yes": |
| 122 |
+ for group in "$2".split(): |
| 123 |
+ try: |
| 124 |
+ try: |
| 125 |
+ gname = grp.getgrgid(int(group))[0] |
| 126 |
+ break |
| 127 |
+ except ValueError: |
| 128 |
+ gname = grp.getgrnam(group)[0] |
| 129 |
+ break |
| 130 |
+ except KeyError: |
| 131 |
+ gname = '' |
| 132 |
+else: |
| 133 |
+ for group in "$2".split(): |
| 134 |
+ try: |
| 135 |
+ int(group) |
| 136 |
+ except ValueError: |
| 137 |
+ gname = group |
| 138 |
break |
| 139 |
- except KeyError: |
| 140 |
- gname = '' |
| 141 |
fp = open("conftest.out", "w") |
| 142 |
fp.write("%s\n" % gname) |
| 143 |
fp.close() |
| 144 |
@@ -241,25 +316,41 @@ |
| 145 |
|
| 146 |
# new macro for finding UIDs |
| 147 |
AC_DEFUN(MM_FIND_USER_NAME, [ |
| 148 |
+# Given a list of tokens, either a name or a number (uid) |
| 149 |
+# return the first one in the list that is found in the |
| 150 |
+# password database. The return value is always a name, possibly |
| 151 |
+# translated from a uid. If permcheck is "no" then the password |
| 152 |
+# database is not checked, instead the first token in the list |
| 153 |
+# which is a name is returned (e.g. the default value). If permcheck |
| 154 |
+# is no and only uid's are in the list then the null string is returned. |
| 155 |
# $1 == variable name |
| 156 |
# $2 == user id to check for |
| 157 |
+# $3 == permcheck, either "yes" or "no" |
| 158 |
AC_SUBST($1) |
| 159 |
changequote(,) |
| 160 |
if test -z "$$1" |
| 161 |
then |
| 162 |
cat > conftest.py <<EOF |
| 163 |
import pwd |
| 164 |
-uid = '' |
| 165 |
-for user in "$2".split(): |
| 166 |
- try: |
| 167 |
+uname='' |
| 168 |
+if "$3" == "yes": |
| 169 |
+ for user in "$2".split(): |
| 170 |
try: |
| 171 |
- uname = pwd.getpwuid(int(user))[0] |
| 172 |
- break |
| 173 |
+ try: |
| 174 |
+ uname = pwd.getpwuid(int(user))[0] |
| 175 |
+ break |
| 176 |
+ except ValueError: |
| 177 |
+ uname = pwd.getpwnam(user)[0] |
| 178 |
+ break |
| 179 |
+ except KeyError: |
| 180 |
+ uname = '' |
| 181 |
+else: |
| 182 |
+ for user in "$2".split(): |
| 183 |
+ try: |
| 184 |
+ int(user) |
| 185 |
except ValueError: |
| 186 |
- uname = pwd.getpwnam(user)[0] |
| 187 |
+ uname = user |
| 188 |
break |
| 189 |
- except KeyError: |
| 190 |
- uname = '' |
| 191 |
fp = open("conftest.out", "w") |
| 192 |
fp.write("%s\n" % uname) |
| 193 |
fp.close() |
| 194 |
@@ -285,7 +376,7 @@ |
| 195 |
# User `mailman' must exist |
| 196 |
AC_SUBST(MAILMAN_USER) |
| 197 |
AC_MSG_CHECKING(for user name \"$USERNAME\") |
| 198 |
-MM_FIND_USER_NAME(MAILMAN_USER, $USERNAME) |
| 199 |
+MM_FIND_USER_NAME(MAILMAN_USER, $USERNAME, $with_permcheck) |
| 200 |
if test -z "$MAILMAN_USER" |
| 201 |
then |
| 202 |
if test "$with_permcheck" = "yes" |
| 203 |
@@ -316,7 +407,7 @@ |
| 204 |
# Target group must exist |
| 205 |
AC_SUBST(MAILMAN_GROUP) |
| 206 |
AC_MSG_CHECKING(for group name \"$GROUPNAME\") |
| 207 |
-MM_FIND_GROUP_NAME(MAILMAN_GROUP, $GROUPNAME) |
| 208 |
+MM_FIND_GROUP_NAME(MAILMAN_GROUP, $GROUPNAME, $with_permcheck) |
| 209 |
if test -z "$MAILMAN_GROUP" |
| 210 |
then |
| 211 |
if test "$with_permcheck" = "yes" |
| 212 |
@@ -339,11 +430,11 @@ |
| 213 |
prefix = "$prefixcheck" |
| 214 |
groupname = "$GROUPNAME" |
| 215 |
mailmangroup = "$MAILMAN_GROUP" |
| 216 |
-try: |
| 217 |
- mailmangid = grp.getgrnam(mailmangroup)[2] |
| 218 |
-except KeyError: |
| 219 |
- mailmangid = -1 |
| 220 |
problems = [] |
| 221 |
+try: mailmangid = grp.getgrnam(mailmangroup)[2] |
| 222 |
+except KeyError: |
| 223 |
+ problems.append("group doesn't exist: " + mailmangroup) |
| 224 |
+ mailmangid = 41 |
| 225 |
try: statdata = os.stat(prefix) |
| 226 |
except OSError: |
| 227 |
problems.append("Directory doesn't exist: " + prefix) |
| 228 |
@@ -393,7 +484,7 @@ |
| 229 |
then |
| 230 |
with_mail_gid="mailman other mail daemon" |
| 231 |
fi |
| 232 |
-MM_FIND_GROUP_NAME(MAIL_GROUP, $with_mail_gid) |
| 233 |
+MM_FIND_GROUP_LIST(MAIL_GROUP, $with_mail_gid, $with_permcheck) |
| 234 |
if test -z "$MAIL_GROUP" |
| 235 |
then |
| 236 |
if test "$with_permcheck" = "yes" |
| 237 |
@@ -420,7 +511,7 @@ |
| 238 |
with_cgi_gid="www www-data nobody" |
| 239 |
fi |
| 240 |
|
| 241 |
-MM_FIND_GROUP_NAME(CGI_GROUP, $with_cgi_gid) |
| 242 |
+MM_FIND_GROUP_LIST(CGI_GROUP, $with_cgi_gid, $with_permcheck) |
| 243 |
if test -z "$CGI_GROUP" |
| 244 |
then |
| 245 |
if test "$with_permcheck" = "yes" |
| 246 |
diff -u mailman-2.1.2/src/cgi-wrapper.c.orig mailman-2.1.2/src/cgi-wrapper.c |
| 247 |
--- mailman-2.1.2/src/cgi-wrapper.c.orig 2002-08-23 16:39:47.000000000 -0400 |
| 248 |
+++ mailman-2.1.2/src/cgi-wrapper.c 2003-05-02 16:28:11.000000000 -0400 |
| 249 |
@@ -28,11 +28,11 @@ |
| 250 |
/* Group name that CGI scripts run as. See your web server's documentation |
| 251 |
* for details. |
| 252 |
*/ |
| 253 |
-#define LEGAL_PARENT_GROUP CGI_GROUP |
| 254 |
+#define LEGAL_PARENT_GROUPS CGI_GROUP |
| 255 |
|
| 256 |
const char* logident = LOG_IDENT; |
| 257 |
char* script = SCRIPTNAME; |
| 258 |
-const char* parentgroup = LEGAL_PARENT_GROUP; |
| 259 |
+const char* parentgroups[] = {LEGAL_PARENT_GROUPS}; |
| 260 |
|
| 261 |
|
| 262 |
int |
| 263 |
@@ -42,7 +42,7 @@ |
| 264 |
char* fake_argv[3]; |
| 265 |
|
| 266 |
running_as_cgi = 1; |
| 267 |
- check_caller(logident, parentgroup); |
| 268 |
+ check_caller(logident, parentgroups, sizeof(parentgroups) / sizeof(parentgroups[0])); |
| 269 |
|
| 270 |
/* For these CGI programs, we can ignore argc and argv since they |
| 271 |
* don't contain anything useful. `script' will always be the driver |
| 272 |
diff -u mailman-2.1.2/src/common.c.orig mailman-2.1.2/src/common.c |
| 273 |
--- mailman-2.1.2/src/common.c.orig 2002-09-04 21:29:57.000000000 -0400 |
| 274 |
+++ mailman-2.1.2/src/common.c 2003-05-02 16:28:11.000000000 -0400 |
| 275 |
@@ -116,13 +116,14 @@ |
| 276 |
/* Is the parent process allowed to call us? |
| 277 |
*/ |
| 278 |
void |
| 279 |
-check_caller(const char* ident, const char* parentgroup) |
| 280 |
+check_caller(const char* ident, const char** parentgroups, size_t numgroups) |
| 281 |
{ |
| 282 |
GID_T mygid = getgid(); |
| 283 |
struct group *mygroup = getgrgid(mygid); |
| 284 |
char* option; |
| 285 |
char* server; |
| 286 |
char* wrapper; |
| 287 |
+ int i; |
| 288 |
|
| 289 |
if (running_as_cgi) { |
| 290 |
option = "--with-cgi-gid"; |
| 291 |
@@ -136,22 +137,45 @@ |
| 292 |
} |
| 293 |
|
| 294 |
if (!mygroup) |
| 295 |
- fatal(ident, GROUP_NAME_NOT_FOUND, |
| 296 |
- "Failure to find group name %s. Try adding this group\n" |
| 297 |
- "to your system, or re-run configure, providing an\n" |
| 298 |
- "existing group name with the command line option %s.", |
| 299 |
- parentgroup, option); |
| 300 |
+ fatal(ident, GROUP_ID_NOT_FOUND, |
| 301 |
+ "Failure to lookup via getgrgid() the group info for group id %d that this Mailman %s wrapper is executing under.\n" |
| 302 |
+ "This is probably due to an incorrectly configured system and is not a Mailman problem", |
| 303 |
+ mygid, wrapper); |
| 304 |
+ |
| 305 |
+ for (i = 0; i < numgroups; i++) { |
| 306 |
+ if (strcmp(parentgroups[i], mygroup->gr_name) == 0) break; |
| 307 |
+ } |
| 308 |
+ |
| 309 |
+ if (i >= numgroups) { |
| 310 |
+ char *groupset = NULL; |
| 311 |
+ size_t size = 0; |
| 312 |
+ |
| 313 |
+ for (i = 0; i < numgroups; i++) { |
| 314 |
+ size += strlen(parentgroups[i]) + 2; |
| 315 |
+ } |
| 316 |
+ |
| 317 |
+ groupset = malloc(size); |
| 318 |
+ |
| 319 |
+ if (groupset) { |
| 320 |
+ groupset[0] = 0; |
| 321 |
+ for (i = 0; i < numgroups; i++) { |
| 322 |
+ strcat(groupset, parentgroups[i]); |
| 323 |
+ if (i < numgroups-1) strcat(groupset, ", "); |
| 324 |
+ } |
| 325 |
+ } |
| 326 |
|
| 327 |
- if (strcmp(parentgroup, mygroup->gr_name)) |
| 328 |
fatal(ident, GROUP_MISMATCH, |
| 329 |
- "Group mismatch error. Mailman expected the %s\n" |
| 330 |
- "wrapper script to be executed as group \"%s\", but\n" |
| 331 |
- "the system's %s server executed the %s script as\n" |
| 332 |
- "group \"%s\". Try tweaking the %s server to run the\n" |
| 333 |
- "script as group \"%s\", or re-run configure, \n" |
| 334 |
- "providing the command line option `%s=%s'.", |
| 335 |
- wrapper, parentgroup, server, wrapper, mygroup->gr_name, |
| 336 |
- server, parentgroup, option, mygroup->gr_name); |
| 337 |
+ "Group mismatch error. Mailman expected the %s wrapper script to be\n" |
| 338 |
+ "executed as one of the following groups:\n" |
| 339 |
+ "[%s],\n" |
| 340 |
+ "but the system's %s server executed the %s script as group: \"%s\".\n" |
| 341 |
+ "Try tweaking the %s server to run the script as one of these groups:\n" |
| 342 |
+ "[%s],\n" |
| 343 |
+ "or re-run configure providing the command line option:\n" |
| 344 |
+ "'%s=%s'.", |
| 345 |
+ wrapper, groupset, server, wrapper, mygroup->gr_name, |
| 346 |
+ server, groupset, option, mygroup->gr_name); |
| 347 |
+ } |
| 348 |
} |
| 349 |
|
| 350 |
|
| 351 |
diff -u mailman-2.1.2/src/common.h.orig mailman-2.1.2/src/common.h |
| 352 |
--- mailman-2.1.2/src/common.h.orig 2002-10-21 14:48:03.000000000 -0400 |
| 353 |
+++ mailman-2.1.2/src/common.h 2003-05-02 16:28:11.000000000 -0400 |
| 354 |
@@ -33,7 +33,7 @@ |
| 355 |
#define GID_T GETGROUPS_T |
| 356 |
|
| 357 |
extern void fatal(const char*, int, char*, ...); |
| 358 |
-extern void check_caller(const char*, const char*); |
| 359 |
+extern void check_caller(const char* ident, const char**, size_t); |
| 360 |
extern int run_script(const char*, int, char**, char**); |
| 361 |
|
| 362 |
/* Global variable used as a flag. */ |
| 363 |
@@ -51,7 +51,7 @@ |
| 364 |
#define MAIL_USAGE_ERROR 5 |
| 365 |
#define MAIL_ILLEGAL_COMMAND 6 |
| 366 |
#define ADDALIAS_USAGE_ERROR 7 |
| 367 |
-#define GROUP_NAME_NOT_FOUND 8 |
| 368 |
+#define GROUP_ID_NOT_FOUND 8 |
| 369 |
|
| 370 |
|
| 371 |
/* |
| 372 |
diff -u mailman-2.1.2/src/mail-wrapper.c.orig mailman-2.1.2/src/mail-wrapper.c |
| 373 |
--- mailman-2.1.2/src/mail-wrapper.c.orig 2002-08-23 16:40:27.000000000 -0400 |
| 374 |
+++ mailman-2.1.2/src/mail-wrapper.c 2003-05-02 16:28:11.000000000 -0400 |
| 375 |
@@ -23,9 +23,9 @@ |
| 376 |
/* Group name that your mail programs run as. See your mail server's |
| 377 |
* documentation for details. |
| 378 |
*/ |
| 379 |
-#define LEGAL_PARENT_GROUP MAIL_GROUP |
| 380 |
+#define LEGAL_PARENT_GROUPS MAIL_GROUP |
| 381 |
|
| 382 |
-const char* parentgroup = LEGAL_PARENT_GROUP; |
| 383 |
+const char* parentgroups[] = {LEGAL_PARENT_GROUPS}; |
| 384 |
const char* logident = "Mailman mail-wrapper"; |
| 385 |
|
| 386 |
|
| 387 |
@@ -74,7 +74,7 @@ |
| 388 |
fatal(logident, MAIL_ILLEGAL_COMMAND, |
| 389 |
"Illegal command: %s", argv[1]); |
| 390 |
|
| 391 |
- check_caller(logident, parentgroup); |
| 392 |
+ check_caller(logident, parentgroups, sizeof(parentgroups) / sizeof(parentgroups[0])); |
| 393 |
|
| 394 |
/* If we got here, everything must be OK */ |
| 395 |
status = run_script(argv[1], argc, argv, env); |
| 396 |
diff -u mailman-2.1.2/src/Makefile.in.orig mailman-2.1.2/src/Makefile.in |
| 397 |
--- mailman-2.1.2/src/Makefile.in.orig 2003-03-31 14:27:14.000000000 -0500 |
| 398 |
+++ mailman-2.1.2/src/Makefile.in 2003-05-02 16:28:11.000000000 -0400 |
| 399 |
@@ -49,9 +49,9 @@ |
| 400 |
|
| 401 |
SHELL= /bin/sh |
| 402 |
|
| 403 |
-MAIL_FLAGS= -DMAIL_GROUP="\"$(MAIL_GROUP)\"" |
| 404 |
+MAIL_FLAGS= -DMAIL_GROUP='$(MAIL_GROUP)' |
| 405 |
|
| 406 |
-CGI_FLAGS= -DCGI_GROUP="\"$(CGI_GROUP)\"" |
| 407 |
+CGI_FLAGS= -DCGI_GROUP='$(CGI_GROUP)' |
| 408 |
|
| 409 |
HELPFUL= -DHELPFUL |
| 410 |
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