[PATCH v2] libsemanage: Use umask(0077) for fopen() write operations

[Petr Lautrbach <plautrba@redhat.com>]

When a calling process uses umask(0) some files in the SELinux module
store can be created to be world writeable. With this patch, libsemanage
sets umask(0077) before fopen() operations and restores the original
umask value when it's done.

Fixes:
drwx------. /var/lib/selinux/targeted/active
-rw-rw-rw-. /var/lib/selinux/targeted/active/booleans.local
-rw-rw-rw-. /var/lib/selinux/targeted/active/policy.linked
-rw-rw-rw-. /var/lib/selinux/targeted/active/seusers.local

drwx------. /var/lib/selinux/targeted/active/modules/400/permissive_sshd_t
-rw-rw-rw-. /var/lib/selinux/targeted/active/modules/400/permissive_sshd_t/cil
-rw-rw-rw-. /var/lib/selinux/targeted/active/modules/400/permissive_sshd_t/lang_ext
drwx------. /var/lib/selinux/targeted/active/modules/disabled
-rw-rw-rw-. /var/lib/selinux/targeted/active/modules/disabled/zosremote

Signed-off-by: Petr Lautrbach <plautrba@redhat.com>
---
 libsemanage/src/database_file.c  | 3 +++
 libsemanage/src/direct_api.c     | 8 ++++++++
 libsemanage/src/semanage_store.c | 2 ++
 3 files changed, 13 insertions(+)

diff --git a/libsemanage/src/database_file.c b/libsemanage/src/database_file.c
index a21b3eeb..a51269e7 100644
--- a/libsemanage/src/database_file.c
+++ b/libsemanage/src/database_file.c
@@ -119,13 +119,16 @@ static int dbase_file_flush(semanage_handle_t * handle, dbase_file_t * dbase)
 	cache_entry_t *ptr;
 	const char *fname = NULL;
 	FILE *str = NULL;
+	mode_t mask;
 
 	if (!dbase_llist_is_modified(&dbase->llist))
 		return STATUS_SUCCESS;
 
 	fname = dbase->path[handle->is_in_transaction];
 
+	mask = umask(0077);
 	str = fopen(fname, "w");
+	umask(mask);
 	if (!str) {
 		ERR(handle, "could not open %s for writing: %s",
 		    fname, strerror(errno));
diff --git a/libsemanage/src/direct_api.c b/libsemanage/src/direct_api.c
index 00ad8201..a455612f 100644
--- a/libsemanage/src/direct_api.c
+++ b/libsemanage/src/direct_api.c
@@ -1176,6 +1176,7 @@ static int semanage_direct_commit(semanage_handle_t * sh)
 	sepol_policydb_t *out = NULL;
 	struct cil_db *cildb = NULL;
 	semanage_module_info_t *modinfos = NULL;
+	mode_t mask = umask(0077);
 
 	int do_rebuild, do_write_kernel, do_install;
 	int fcontexts_modified, ports_modified, seusers_modified,
@@ -1645,6 +1646,8 @@ cleanup:
 	semanage_remove_directory(semanage_final_path
 				  (SEMANAGE_FINAL_TMP,
 				   SEMANAGE_FINAL_TOPLEVEL));
+	umask(mask);
+
 	return retval;
 }
 
@@ -2016,6 +2019,7 @@ static int semanage_direct_set_enabled(semanage_handle_t *sh,
 	const char *path = NULL;
 	FILE *fp = NULL;
 	semanage_module_info_t *modinfo = NULL;
+	mode_t mask;
 
 	/* check transaction */
 	if (!sh->is_in_transaction) {
@@ -2076,7 +2080,9 @@ static int semanage_direct_set_enabled(semanage_handle_t *sh,
 
 	switch (enabled) {
 		case 0: /* disable the module */
+			mask = umask(0077);
 			fp = fopen(fn, "w");
+			umask(mask);
 
 			if (fp == NULL) {
 				ERR(sh,
@@ -2722,6 +2728,7 @@ static int semanage_direct_install_info(semanage_handle_t *sh,
 	int type;
 
 	char path[PATH_MAX];
+	mode_t mask = umask(0077);
 
 	semanage_module_info_t *higher_info = NULL;
 	semanage_module_key_t higher_key;
@@ -2833,6 +2840,7 @@ cleanup:
 	semanage_module_key_destroy(sh, &higher_key);
 	semanage_module_info_destroy(sh, higher_info);
 	free(higher_info);
+	umask(mask);
 
 	return status;
 }
diff --git a/libsemanage/src/semanage_store.c b/libsemanage/src/semanage_store.c
index 63c80b04..37ff5ace 100644
--- a/libsemanage/src/semanage_store.c
+++ b/libsemanage/src/semanage_store.c
@@ -2099,6 +2099,7 @@ int semanage_write_policydb(semanage_handle_t * sh, sepol_policydb_t * out,
 	const char *kernel_filename = NULL;
 	struct sepol_policy_file *pf = NULL;
 	FILE *outfile = NULL;
+	mode_t mask = umask(0077);
 
 	if ((kernel_filename =
 	     semanage_path(SEMANAGE_TMP, file)) == NULL) {
@@ -2127,6 +2128,7 @@ int semanage_write_policydb(semanage_handle_t * sh, sepol_policydb_t * out,
 	if (outfile != NULL) {
 		fclose(outfile);
 	}
+	umask(mask);
 	sepol_policy_file_free(pf);
 	return retval;
 }
-- 
2.15.0