list_option_mask(): return 0 (empty mask) for < '0'

Missing limit check at the bottom of the ASCII range.

Signed-off-by: H. Peter Anvin <hpa@zytor.com>

1 files changed, 2 insertions, 0 deletions

diff --git a/asm/listing.h b/asm/listing.h
index 19cdbb48..21c46775 100644
--- a/asm/listing.h
+++ b/asm/listing.h
@@ -149,6 +149,8 @@ static inline const_func uint64_t list_option_mask(unsigned char x)
         if (x > '9')
             return 0;
         x = x - '0' + 26*2;
+    } else {
+        return 0;
     }
 
     return UINT64_C(1) << x;