1 files changed, 23 insertions, 0 deletions

diff --git a/src/firejail/util.c b/src/firejail/util.c
index b35225620..8c3a13fb8 100644
--- a/src/firejail/util.c
+++ b/src/firejail/util.c
@@ -1448,6 +1448,29 @@ static int has_link(const char *dir) {
         return 0;
 }
 
+// allow strict ASCII letters and numbers; names with only numbers are rejected; spaces are rejected
+int invalid_name(const char *name) {
+        const char *c = name;
+
+        int only_numbers = 1;
+        while (*c) {
+                if (!isalnum(*c))
+                        return 1;
+                if (!isdigit(*c))
+                        only_numbers = 0;
+                ++c;
+        }
+        if (only_numbers)
+                return 1;
+
+        // restrict name to 64 chars max
+        if (strlen(name) > 64)
+                return 1;
+
+        return 0;
+}
+
+
 void check_homedir(const char *dir) {
         assert(dir);
         if (dir[0] != '/') {