libsmack: check in accesses_apply() that rule has short labels

Check rule has short labels when only 'load' is available.

Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>

diff --git a/libsmack/libsmack.c b/libsmack/libsmack.c
index 9116422..f7ce313 100644 (file)
--- a/libsmack/libsmack.c
+++ b/libsmack/libsmack.c
@@ -33,6 +33,7 @@
 #include <limits.h>
 #include <sys/xattr.h>
 
+#define SHORT_LABEL_LEN 23
 #define ACC_LEN 5
 #define LOAD_LEN (2 * (SMACK_LABEL_LEN + 1) + 2 * ACC_LEN + 1)
 
@@ -63,6 +64,8 @@ extern char *smackfs_mnt;
 struct smack_rule {
        char subject[SMACK_LABEL_LEN + 1];
        char object[SMACK_LABEL_LEN + 1];
+       int subject_len;
+       int object_len;
        int allow_code;
        int deny_code;
        struct smack_rule *next;
@@ -186,8 +189,9 @@ int smack_accesses_add(struct smack_accesses *handle, const char *subject,
        if (rule == NULL)
                return -1;
 
-       if (get_label(rule->subject, subject) < 0 ||
-           get_label(rule->object, object) < 0) {
+       rule->subject_len = get_label(rule->subject, subject);
+       rule->object_len = get_label(rule->object, object);
+       if (rule->subject_len < 0 || rule->object_len < 0) {
                free(rule);
                return -1;
        }
@@ -221,8 +225,9 @@ int smack_accesses_add_modify(struct smack_accesses *handle,
        if (rule == NULL)
                return -1;
 
-       if (get_label(rule->subject, subject) < 0 ||
-           get_label(rule->object, object) < 0) {
+       rule->subject_len = get_label(rule->subject, subject);
+       rule->object_len = get_label(rule->object, object);
+       if (rule->subject_len < 0 || rule->object_len < 0) {
                free(rule);
                return -1;
        }
@@ -697,10 +702,17 @@ static int accesses_apply(struct smack_accesses *handle, int clear)
                                ret = snprintf(buf, LOAD_LEN + 1, KERNEL_LONG_FORMAT,
                                               rule->subject, rule->object,
                                               allow_str);
-                       else
+                       else {
+                               if (rule->subject_len > SHORT_LABEL_LEN ||
+                                   rule->object_len > SHORT_LABEL_LEN) {
+                                       ret = -1;
+                                       goto err_out;
+                               }
+
                                ret = snprintf(buf, LOAD_LEN + 1, KERNEL_SHORT_FORMAT,
                                               rule->subject, rule->object,
                                               allow_str);
+                       }
                }
 
                if (ret < 0) {