efi/printf: Fix minor bug in precision handling

A negative precision should be ignored completely, and the presence of a
valid precision should turn off the 0 flag.

Signed-off-by: Arvind Sankar <nivedita@alum.mit.edu>
Link: https://lore.kernel.org/r/20200518190716.751506-10-nivedita@alum.mit.edu
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>

diff --git a/drivers/firmware/efi/libstub/vsprintf.c b/drivers/firmware/efi/libstub/vsprintf.c
index fb9eb83..00123d5 100644 (file)
--- a/drivers/firmware/efi/libstub/vsprintf.c
+++ b/drivers/firmware/efi/libstub/vsprintf.c
@@ -279,9 +279,11 @@ int vsprintf(char *buf, const char *fmt, va_list args)
                                ++fmt;
                                /* it's the next argument */
                                precision = va_arg(args, int);
-                       }
-                       if (precision < 0)
+                       } else {
                                precision = 0;
+                       }
+                       if (precision >= 0)
+                               flags &= ~ZEROPAD;
                }
 
                /* get the conversion qualifier */