replace control characters and print rejected filenames

1 files changed, 28 insertions, 4 deletions

diff --git a/src/firejail/macros.c b/src/firejail/macros.c
index ccd201956..3dbc910a4 100644
--- a/src/firejail/macros.c
+++ b/src/firejail/macros.c
@@ -258,6 +258,28 @@ char *expand_macros(const char *path) {
         return rv;
 }
 
+// replace control characters with a '?'
+static char *fix_control_chars(const char *fname) {
+        assert(fname);
+
+        size_t len = strlen(fname);
+        char *rv = malloc(len + 1);
+        if (!rv)
+                errExit("malloc");
+
+        size_t i = 0;
+        while (fname[i] != '\0') {
+                if (iscntrl((unsigned char) fname[i]))
+                        rv[i] = '?';
+                else
+                        rv[i] = fname[i];
+                i++;
+        }
+        rv[i] = '\0';
+
+        return rv;
+}
+
 void invalid_filename(const char *fname, int globbing) {
 //      EUID_ASSERT();
         assert(fname);
@@ -275,12 +297,14 @@ void invalid_filename(const char *fname, int globbing) {
                         return;
         }
 
-        size_t i;
-        for (i = 0; ptr[i]; i++) {
+        size_t i = 0;
+        while (ptr[i] != '\0') {
                 if (iscntrl((unsigned char) ptr[i])) {
-                        fprintf(stderr, "Error: invalid filename: contains a control character\n");
+                        fprintf(stderr, "Error: \"%s\" is an invalid filename: no control characters allowed\n",
+                                fix_control_chars(fname));
                         exit(1);
                 }
+                i++;
         }
         
         char *reject;
@@ -290,7 +314,7 @@ void invalid_filename(const char *fname, int globbing) {
                 reject = "\\&!?\"'<>%^(){};,*[]";
         char *c = strpbrk(ptr, reject);
         if (c) {
-                fprintf(stderr, "Error: \"%s\" is an invalid filename: rejected character: \"%c\"\n", ptr, *c);
+                fprintf(stderr, "Error: \"%s\" is an invalid filename: rejected character: \"%c\"\n", fname, *c);
                 exit(1);
         }
 }