1 files changed, 8 insertions, 3 deletions

diff --git a/fs/cifs/cifs_debug.c b/fs/cifs/cifs_debug.c
index 56c5d9126f50..73c4c419663c 100644
--- a/fs/cifs/cifs_debug.c
+++ b/fs/cifs/cifs_debug.c
@@ -879,11 +879,16 @@ security_flags_write(struct file *file, const char __user *buffer,
         if (count < 3) {
                 /* single char or single char followed by null */
                 c = flags_string[0];
-                if (c == '0' || c == 'n' || c == 'N')
+                if (c == '0' || c == 'n' || c == 'N') {
                         extended_security = CIFSSEC_DEF; /* default */
-                else if (c == '1' || c == 'y' || c == 'Y')
+                        return count;
+                } else if (c == '1' || c == 'y' || c == 'Y') {
                         extended_security = CIFSSEC_MAX;
-                return count;
+                        return count;
+                } else if (!isdigit(c)) {
+                        cERROR(1, ("invalid flag %c", c));
+                        return -EINVAL;
+                }
         }
         /* else we have a number */