selinux: generate flask headers during kernel build

Add a simple utility (scripts/selinux/genheaders) and invoke it to
generate the kernel-private class and permission indices in flask.h
and av_permissions.h automatically during the kernel build from the
security class mapping definitions in classmap.h.  Adding new kernel
classes and permissions can then be done just by adding them to classmap.h.

Signed-off-by:  Stephen Smalley <[email protected]>
Signed-off-by: James Morris <[email protected]>

scripts/selinux/Makefile

@@ -1,2 +1,2 @@
-subdir-y := mdp
-subdir-	+= mdp
+subdir-y := mdp genheaders
+subdir-	+= mdp genheaders

scripts/selinux/genheaders/Makefile

@@ -0,0 +1,5 @@
+hostprogs-y	:= genheaders
+HOST_EXTRACFLAGS += -Isecurity/selinux/include
+
+always		:= $(hostprogs-y)
+clean-files	:= $(hostprogs-y)

scripts/selinux/genheaders/genheaders.c

@@ -0,0 +1,118 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <string.h>
+#include <errno.h>
+#include <ctype.h>
+
+struct security_class_mapping {
+	const char *name;
+	const char *perms[sizeof(unsigned) * 8 + 1];
+};
+
+#include "classmap.h"
+#include "initial_sid_to_string.h"
+
+#define max(x, y) ((x > y) ? x : y)
+
+const char *progname;
+
+void usage(void)
+{
+	printf("usage: %s flask.h av_permissions.h\n", progname);
+	exit(1);
+}
+
+char *stoupperx(const char *s)
+{
+	char *s2 = strdup(s);
+	char *p;
+
+	if (!s2) {
+		fprintf(stderr, "%s:  out of memory\n", progname);
+		exit(3);
+	}
+
+	for (p = s2; *p; p++)
+		*p = toupper(*p);
+	return s2;
+}
+
+int main(int argc, char *argv[])
+{
+	int i, j, k;
+	int isids_len;
+	FILE *fout;
+
+	progname = argv[0];
+
+	if (argc < 3)
+		usage();
+
+	fout = fopen(argv[1], "w");
+	if (!fout) {
+		fprintf(stderr, "Could not open %s for writing:  %s\n",
+			argv[1], strerror(errno));
+		exit(2);
+	}
+
+	for (i = 0; secclass_map[i].name; i++) {
+		struct security_class_mapping *map = &secclass_map[i];
+		map->name = stoupperx(map->name);
+		for (j = 0; map->perms[j]; j++)
+			map->perms[j] = stoupperx(map->perms[j]);
+	}
+
+	isids_len = sizeof(initial_sid_to_string) / sizeof (char *);
+	for (i = 1; i < isids_len; i++)
+		initial_sid_to_string[i] = stoupperx(initial_sid_to_string[i]);
+
+	fprintf(fout, "/* This file is automatically generated.  Do not edit. */\n");
+	fprintf(fout, "#ifndef _SELINUX_FLASK_H_\n#define _SELINUX_FLASK_H_\n\n");
+
+	for (i = 0; secclass_map[i].name; i++) {
+		struct security_class_mapping *map = &secclass_map[i];
+		fprintf(fout, "#define SECCLASS_%s", map->name);
+		for (j = 0; j < max(1, 40 - strlen(map->name)); j++)
+			fprintf(fout, " ");
+		fprintf(fout, "%2d\n", i+1);
+	}
+
+	fprintf(fout, "\n");
+
+	for (i = 1; i < isids_len; i++) {
+		char *s = initial_sid_to_string[i];
+		fprintf(fout, "#define SECINITSID_%s", s);
+		for (j = 0; j < max(1, 40 - strlen(s)); j++)
+			fprintf(fout, " ");
+		fprintf(fout, "%2d\n", i);
+	}
+	fprintf(fout, "\n#define SECINITSID_NUM %d\n", i-1);
+	fprintf(fout, "\n#endif\n");
+	fclose(fout);
+
+	fout = fopen(argv[2], "w");
+	if (!fout) {
+		fprintf(stderr, "Could not open %s for writing:  %s\n",
+			argv[2], strerror(errno));
+		exit(4);
+	}
+
+	fprintf(fout, "/* This file is automatically generated.  Do not edit. */\n");
+	fprintf(fout, "#ifndef _SELINUX_AV_PERMISSIONS_H_\n#define _SELINUX_AV_PERMISSIONS_H_\n\n");
+
+	for (i = 0; secclass_map[i].name; i++) {
+		struct security_class_mapping *map = &secclass_map[i];
+		for (j = 0; map->perms[j]; j++) {
+			fprintf(fout, "#define %s__%s", map->name,
+				map->perms[j]);
+			for (k = 0; k < max(1, 40 - strlen(map->name) - strlen(map->perms[j])); k++)
+				fprintf(fout, " ");
+			fprintf(fout, "0x%08xUL\n", (1<<j));
+		}
+	}
+
+	fprintf(fout, "\n#endif\n");
+	fclose(fout);
+	exit(0);
+}

security/selinux/Makefile

@@ -18,5 +18,13 @@ selinux-$(CONFIG_SECURITY_NETWORK_XFRM) += xfrm.o
 
 selinux-$(CONFIG_NETLABEL) += netlabel.o
 
-EXTRA_CFLAGS += -Isecurity/selinux/include
+EXTRA_CFLAGS += -Isecurity/selinux -Isecurity/selinux/include
 
+$(obj)/avc.o: $(obj)/flask.h
+
+quiet_cmd_flask = GEN     $(obj)/flask.h $(obj)/av_permissions.h
+      cmd_flask = scripts/selinux/genheaders/genheaders $(obj)/flask.h $(obj)/av_permissions.h
+
+targets += flask.h
+$(obj)/flask.h: $(src)/include/classmap.h FORCE
+	$(call if_changed,flask)