PERFORCE change 34051 for review
Robert Watson
rwatson at FreeBSD.org
Thu Jul 3 20:17:27 PDT 2003
http://perforce.freebsd.org/chv.cgi?CH=34051
Change 34051 by rwatson at rwatson_paprika on 2003/07/03 20:16:31
As new objects begin to support new labels, start to generalize
the default label support in /etc/mac.conf. Rather than maintain
each default label type in an explicit global variable in mac.c,
keep a list of defaults loaded from the configuration file.
Generalize the parsing so that we support both the older:
default_file_labels foo
default_ifnet_labels foo
default_process_labels foo
And also a new:
default_labels file foo
default_labels ifnet foo
default_labels process foo
We now accept arbitrary object classes in the first argument. If
the same object is specified more than once, we discard the
earlier definition in favor of the later one.
Add a new API, mac_prepare_type(), which accepts a mac_t to
prepare, as well as an object name in the second argument, which
will pull a default label set for the object out of the
configuration loaded by mac_init_internal(). This permits the libc
to adapt to new objects known about by applications but not by libc
at compile-time.
Also liberalize the error handling a bit: if we're using implicit
initialization (i.e., the application didn't explicitly initialize
the MAC code), ignore syntax errors and only use valid lines. In
the future, we may want to add explicit warnings and do this a
bit more consistently.
While here, add support for a MAC_CONFFILE environmental variable,
which may be used to specify an alternative mac.conf configuration
file if the application isn't running with modified privilege
(issetugid()).
Affected files ...
.. //depot/projects/trustedbsd/mac/lib/libc/posix1e/mac.c#10 edit
Differences ...
==== //depot/projects/trustedbsd/mac/lib/libc/posix1e/mac.c#10 (text+ko) ====
@@ -1,6 +1,6 @@
/*
* Copyright (c) 1999, 2000, 2001, 2002 Robert N. M. Watson
- * Copyright (c) 2002 Networks Associates Technology, Inc.
+ * Copyright (c) 2002, 2003 Networks Associates Technology, Inc.
* All rights reserved.
*
* This software was developed by Robert Watson for the TrustedBSD Project.
@@ -49,123 +49,211 @@
static int internal_initialized;
-/* Default sets of labels for various query operations. */
-static char *default_file_labels;
-static char *default_ifnet_labels;
-static char *default_process_labels;
+/*
+ * Maintain a list of default label preparations for various object
+ * types. Each name will appear only once in the list.
+ *
+ * XXXMAC: Not thread-safe.
+ */
+LIST_HEAD(, label_default) label_default_head;
+struct label_default {
+ char *ld_name;
+ char *ld_labels;
+ LIST_ENTRY(label_default) ld_entries;
+};
static void
mac_destroy_labels(void)
{
+ struct label_default *ld;
+
+ while ((ld = LIST_FIRST(&label_default_head))) {
+ free(ld->ld_name);
+ free(ld->ld_labels);
+ LIST_REMOVE(ld, ld_entries);
+ free(ld);
+ }
+}
- if (default_file_labels != NULL) {
- free(default_file_labels);
- default_file_labels = NULL;
+static void
+mac_destroy_internal(void)
+{
+
+ mac_destroy_labels();
+
+ internal_initialized = 0;
+}
+
+static int
+mac_add_type(const char *name, const char *labels)
+{
+ struct label_default *ld, *ld_new;
+ char *name_dup, *labels_dup;
+
+ /*
+ * Speculatively allocate all the memory now to avoid allocating
+ * later when we will someday hold a mutex.
+ */
+ name_dup = strdup(name);
+ if (name_dup == NULL) {
+ errno = ENOMEM;
+ return (-1);
+ }
+ labels_dup = strdup(labels);
+ if (labels_dup == NULL) {
+ free(name_dup);
+ errno = ENOMEM;
+ return (-1);
+ }
+ ld_new = malloc(sizeof(*ld));
+ if (ld_new == NULL) {
+ free(name_dup);
+ free(labels_dup);
+ errno = ENOMEM;
+ return (-1);
}
- if (default_ifnet_labels != NULL) {
- free(default_ifnet_labels);
- default_ifnet_labels = NULL;
+ /*
+ * If the type is already present, replace the current entry
+ * rather than add a new instance.
+ */
+ for (ld = LIST_FIRST(&label_default_head); ld != NULL;
+ ld = LIST_NEXT(ld, ld_entries)) {
+ if (strcmp(name, ld->ld_name) == 0)
+ break;
}
- if (default_process_labels != NULL) {
- free(default_process_labels);
- default_process_labels = NULL;
+ if (ld != NULL) {
+ free(ld->ld_labels);
+ ld->ld_labels = labels_dup;
+ labels_dup = NULL;
+ } else {
+ ld = ld_new;
+ ld->ld_name = name_dup;
+ ld->ld_labels = labels_dup;
+
+ ld_new = NULL;
+ name_dup = NULL;
+ labels_dup = NULL;
+
+ LIST_INSERT_HEAD(&label_default_head, ld, ld_entries);
}
+
+ if (name_dup != NULL)
+ free(name_dup);
+ if (labels_dup != NULL)
+ free(labels_dup);
+ if (ld_new != NULL)
+ free(ld_new);
+
+ return (0);
}
-static void
-mac_destroy_internal(void)
+static char *
+next_token(char **string)
{
+ char *token;
- mac_destroy_labels();
+ token = strsep(string, " \t");
+ while (token != NULL && *token == '\0')
+ token = strsep(string, " \t");
- internal_initialized = 0;
+ return (token);
}
static int
-mac_init_internal(void)
+mac_init_internal(int ignore_errors)
{
+ const char *filename;
+ char line[LINE_MAX];
FILE *file;
- char line[LINE_MAX];
int error;
error = 0;
- file = fopen(MAC_CONFFILE, "r");
+ LIST_INIT(&label_default_head);
+
+ if (!issetugid() && getenv("MAC_CONFFILE") != NULL)
+ filename = getenv("MAC_CONFFILE");
+ else
+ filename = MAC_CONFFILE;
+ file = fopen(filename, "r");
if (file == NULL)
return (0);
while (fgets(line, LINE_MAX, file)) {
- char *arg, *parse, *statement;
+ char *arg, *comment, *parse, *statement;
if (line[strlen(line)-1] == '\n')
line[strlen(line)-1] = '\0';
else {
+ if (ignore_errors)
+ continue;
fclose(file);
error = EINVAL;
goto just_return;
}
- parse = line;
- statement = "";
- while (parse && statement[0] == '\0')
- statement = strsep(&parse, " \t");
+ /* Remove any comment. */
+ comment = line;
+ parse = strsep(&comment, "#");
- /* Blank lines ok. */
- if (strlen(statement) == 0)
+ /* Blank lines OK. */
+ statement = next_token(&parse);
+ if (statement == NULL)
continue;
- /* Lines that consist only of comments ok. */
- if (statement[0] == '#')
- continue;
+ if (strcmp(statement, "default_labels") == 0) {
+ char *name, *labels;
- if (strcmp(statement, "default_file_labels") == 0) {
- if (default_file_labels != NULL) {
- free(default_file_labels);
- default_file_labels = NULL;
+ name = next_token(&parse);
+ labels = next_token(&parse);
+ if (name == NULL || labels == NULL ||
+ next_token(&parse) != NULL) {
+ if (ignore_errors)
+ continue;
+ error = EINVAL;
+ fclose(file);
+ goto just_return;
}
- arg = strsep(&parse, "# \t");
- if (arg != NULL && arg[0] != '\0') {
- default_file_labels = strdup(arg);
- if (default_file_labels == NULL) {
- error = ENOMEM;
- fclose(file);
- goto just_return;
- }
+ if (mac_add_type(name, labels) == -1) {
+ if (ignore_errors)
+ continue;
+ fclose(file);
+ goto just_return;
}
- } else if (strcmp(statement, "default_ifnet_labels") == 0) {
- if (default_ifnet_labels != NULL) {
- free(default_ifnet_labels);
- default_ifnet_labels = NULL;
- }
+ } else if (strcmp(statement, "default_ifnet_labels") == 0 ||
+ strcmp(statement, "default_file_labels") == 0 ||
+ strcmp(statement, "default_process_labels") == 0) {
+ char *labels, *type;
+
+ if (strcmp(statement, "default_ifnet_labels") == 0)
+ type = "ifnet";
+ else if (strcmp(statement, "default_file_labels") == 0)
+ type = "file";
+ else if (strcmp(statement, "default_process_labels") ==
+ 0)
+ type = "process";
- arg = strsep(&parse, "# \t");
- if (arg != NULL && arg[0] != '\0') {
- default_ifnet_labels = strdup(arg);
- if (default_ifnet_labels == NULL) {
- error = ENOMEM;
- fclose(file);
- goto just_return;
- }
+ labels = next_token(&parse);
+ if (labels == NULL || next_token(&parse) != NULL) {
+ if (ignore_errors)
+ continue;
+ error = EINVAL;
+ fclose(file);
+ goto just_return;
}
- } else if (strcmp(statement, "default_process_labels") == 0) {
- if (default_process_labels != NULL) {
- free(default_process_labels);
- default_process_labels = NULL;
- }
- arg = strsep(&parse, "# \t");
- if (arg != NULL && arg[0] != '\0') {
- default_process_labels = strdup(arg);
- if (default_process_labels == NULL) {
- error = ENOMEM;
- fclose(file);
- goto just_return;
- }
+ if (mac_add_type(type, labels) == -1) {
+ if (ignore_errors)
+ continue;
+ fclose(file);
+ goto just_return;
}
} else {
+ if (ignore_errors)
+ continue;
fclose(file);
error = EINVAL;
goto just_return;
@@ -187,7 +275,7 @@
{
if (!internal_initialized)
- return (mac_init_internal());
+ return (mac_init_internal(1));
else
return (0);
}
@@ -198,7 +286,7 @@
if (internal_initialized)
mac_destroy_internal();
- return (mac_init_internal());
+ return (mac_init_internal(0));
}
int
@@ -267,6 +355,32 @@
}
int
+mac_prepare_type(struct mac **mac, const char *name)
+{
+ struct label_default *ld;
+
+ for (ld = LIST_FIRST(&label_default_head); ld != NULL;
+ ld = LIST_NEXT(ld, ld_entries)) {
+ if (strcmp(name, ld->ld_name) == 0)
+ return (mac_prepare(mac, ld->ld_labels));
+ }
+
+ return (ENOENT); /* XXXMAC: ENOLABEL */
+}
+
+int
+mac_prepare_ifnet_label(struct mac **mac)
+{
+ int error;
+
+ error = mac_maybe_init_internal();
+ if (error != 0)
+ return (error);
+
+ return (mac_prepare_type(mac, "ifnet"));
+}
+
+int
mac_prepare_file_label(struct mac **mac)
{
int error;
@@ -275,14 +389,11 @@
if (error != 0)
return (error);
- if (default_file_labels == NULL)
- return (mac_prepare(mac, ""));
-
- return (mac_prepare(mac, default_file_labels));
+ return (mac_prepare_type(mac, "file"));
}
int
-mac_prepare_ifnet_label(struct mac **mac)
+mac_prepare_packet_label(struct mac **mac)
{
int error;
@@ -290,11 +401,9 @@
if (error != 0)
return (error);
- if (default_ifnet_labels == NULL)
- return (mac_prepare(mac, ""));
+ return (mac_prepare_type(mac, "packet"));
+}
- return (mac_prepare(mac, default_ifnet_labels));
-}
int
mac_prepare_process_label(struct mac **mac)
{
@@ -304,10 +413,7 @@
if (error != 0)
return (error);
- if (default_process_labels == NULL)
- return (mac_prepare(mac, ""));
-
- return (mac_prepare(mac, default_process_labels));
+ return (mac_prepare_type(mac, "process"));
}
/*
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