initial commit

Makefile

@@ -0,0 +1,10 @@
+PREFIX ?= $(DESTDIR)/usr
+BINDIR ?= $(PREFIX)/bin
+LIBDIR ?= $(PREFIX)/lib/x86_64-linux-gnu
+
+CFLAGS ?= -g -Wall -Werror -Wshadow -O2 -pipe -fno-strict-aliasing
+LDLIBS=$(LIBDIR)/libsepol.a 
+
+all: sepolicy-inject
+
+sepolicy-inject: sepolicy-inject.c

README.txt

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+Injects allow rules into binary SELinux kernel policies
+
+joshua@QuarkZilla:~/sepolicy-inject$ ./sepolicy-inject -s shell -t system -c file -p read -P sepolicy -o sepolicy2                                   
+libsepol.policydb_index_others: security:  1 users, 2 roles, 518 types, 14 bools
+libsepol.policydb_index_others: security: 1 sens, 1024 cats
+libsepol.policydb_index_others: security:  84 classes, 4539 rules, 162 cond rules
+
+joshua@QuarkZilla:~/sepolicy-inject$ sesearch -A -s shell -t system -c file sepolicy
+Found 1 semantic av rules:
+   allow appdomain domain : file { ioctl read getattr lock open } ; 
+
+joshua@QuarkZilla:~/sepolicy-inject$ sesearch -A -s shell -t system -c file sepolicy2
+Found 2 semantic av rules:
+   allow shell system : file read ; 
+   allow appdomain domain : file { ioctl read getattr lock open } ; 
+

sepolicy-inject.c

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+#include <getopt.h>
+#include <unistd.h>
+#include <stdlib.h>
+#include <sys/mman.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+#include <stdio.h>
+#include <sepol/policydb/policydb.h>
+#include <sepol/policydb/services.h>
+
+void usage(char *arg0) {
+	fprintf(stderr, "%s -s <source type> -t <target type> -c <class> -p <perm> -P <policy file> -o <output file>\n", arg0);
+	exit(1);
+}
+
+void *cmalloc(size_t s) {
+	void *t = malloc(s);
+	if (t == NULL) {
+		fprintf(stderr, "Out of memory\n");
+		exit(1);
+	}
+	return t;
+}
+
+int add_rule(char *s, char *t, char *c, char *p, policydb_t *policy) {
+	type_datum_t *src, *tgt;
+	class_datum_t *cls;
+	perm_datum_t *perm;
+	avtab_datum_t *av;
+	avtab_key_t key;
+	
+	src = hashtab_search(policy->p_types.table, s);
+	if (src == NULL) {
+		fprintf(stderr, "source type %s does not exist\n", s);
+		return 1;
+	}
+	tgt = hashtab_search(policy->p_types.table, t);
+	if (tgt == NULL) {
+		fprintf(stderr, "target type %s does not exist\n", t);
+		return 1;
+	}
+	cls = hashtab_search(policy->p_classes.table, c);
+	if (cls == NULL) {
+		fprintf(stderr, "class %s does not exist\n", c);
+		return 1;
+	}
+	perm = hashtab_search(cls->permissions.table, p);
+	if (perm == NULL) {
+		if (cls->comdatum == NULL) {
+			fprintf(stderr, "perm %s does not exist in class %s\n", p, c);
+			return 1;
+		}
+		perm = hashtab_search(cls->comdatum->permissions.table, p);
+		if (perm == NULL) {
+			fprintf(stderr, "perm %s does not exist in class %s\n", p, c);
+			return 1;
+		}
+	}
+
+	// See if there is already a rule
+	key.source_type = src->s.value;
+	key.target_type = tgt->s.value;
+	key.target_class = cls->s.value;
+	key.specified = AVTAB_ALLOWED;
+	av = avtab_search(&policy->te_avtab, &key);
+
+	if (av == NULL) {
+		av = cmalloc(sizeof av);
+		av->data |= 1U << (perm->s.value - 1);
+		int ret = avtab_insert(&policy->te_avtab, &key, av);
+		if (ret) {
+			fprintf(stderr, "Error inserting into avtab\n");
+			return 1;
+		}	
+	}
+
+	av->data |= 1U << (perm->s.value - 1);
+
+	return 0;
+}
+	
+
+int load_policy(char *filename, policydb_t *policydb, struct policy_file *pf) {
+	int fd;
+	struct stat sb;
+	void *map;
+	int ret;
+
+	fd = open(filename, O_RDONLY);
+	if (fd < 0) {
+		fprintf(stderr, "Can't open '%s':  %s\n",
+				filename, strerror(errno));
+		return 1;
+	}
+	if (fstat(fd, &sb) < 0) {
+		fprintf(stderr, "Can't stat '%s':  %s\n",
+				filename, strerror(errno));
+		return 1;
+	}
+	map = mmap(NULL, sb.st_size, PROT_READ | PROT_WRITE, MAP_PRIVATE,
+				fd, 0);
+	if (map == MAP_FAILED) {
+		fprintf(stderr, "Can't mmap '%s':  %s\n",
+				filename, strerror(errno));
+		return 1;
+	}
+
+	policy_file_init(pf);
+	pf->type = PF_USE_MEMORY;
+	pf->data = map;
+	pf->len = sb.st_size;
+	if (policydb_init(policydb)) {
+		fprintf(stderr, "policydb_init: Out of memory!\n");
+		return 1;
+	}
+	ret = policydb_read(policydb, pf, 1);
+	if (ret) {
+		fprintf(stderr, "error(s) encountered while parsing configuration\n");
+		return 1;
+	}
+
+	return 0;
+}
+	
+
+int main(int argc, char **argv)
+{
+	char *policy = NULL, *source = NULL, *target = NULL, *class = NULL, *perm = NULL, *outfile = NULL;
+	policydb_t policydb;
+	struct policy_file pf, outpf;
+	sidtab_t sidtab;
+	char ch;
+	FILE *fp;
+	
+	
+        struct option long_options[] = {
+                {"source", required_argument, NULL, 's'},
+                {"target", required_argument, NULL, 't'},
+                {"class", required_argument, NULL, 'c'},
+                {"perm", required_argument, NULL, 'p'},
+                {"policy", required_argument, NULL, 'P'},
+                {"output", required_argument, NULL, 'o'},
+                {NULL, 0, NULL, 0}
+        };
+
+        while ((ch = getopt_long(argc, argv, "s:t:c:p:P:o:", long_options, NULL)) != -1) {
+                switch (ch) {
+                case 's':
+                        source = optarg;
+                        break;
+                case 't':
+                        target = optarg;
+                        break;
+                case 'c':
+                        class = optarg;
+                        break;
+                case 'p':
+                        perm = optarg;
+                        break;
+                case 'P':
+                        policy = optarg;
+                        break;
+		case 'o':
+			outfile = optarg;
+			break;
+		default:
+			usage(argv[0]);
+		}
+	}
+
+	if (!source || !target || !class || !perm || !policy)
+		usage(argv[0]);
+
+	sepol_set_policydb(&policydb);
+        sepol_set_sidtab(&sidtab);
+
+	if (load_policy(policy, &policydb, &pf)) {
+		fprintf(stderr, "Could not load policy\n");
+		return 1;
+	}
+
+        if (policydb_load_isids(&policydb, &sidtab))
+		return 1;
+
+	if (add_rule(source, target, class, perm, &policydb)) {
+		fprintf(stderr, "Could not add rule\n");
+		return 1;
+	}
+
+	fp = fopen(outfile, "w");
+	if (!fp) {
+		fprintf(stderr, "Could not open outfile\n");
+		return 1;
+	}
+	
+	policy_file_init(&outpf);
+	outpf.type = PF_USE_STDIO;
+	outpf.fp = fp;
+	
+
+	if (policydb_write(&policydb, &outpf)) {
+		fprintf(stderr, "Could not write policy\n");
+		return 1;
+	}
+	
+	policydb_destroy(&policydb);
+	fclose(fp);
+	
+	return 0;
+}