From: Arvind Sankar <nivedita@alum.mit.edu>
Date: Mon, 18 May 2020 19:07:05 +0000 (-0400)
Subject: efi/printf: Handle null string input
X-Git-Tag: v5.10.7~2527^2~1^2~16
X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=fb031937a86874e6d663542bdbd83e310c13610e;p=platform%2Fkernel%2Flinux-rpi.git

efi/printf: Handle null string input

Print "(null)" for 's' if the input is a NULL pointer.

Signed-off-by: Arvind Sankar <nivedita@alum.mit.edu>
Link: https://lore.kernel.org/r/20200518190716.751506-14-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 27685c7..d427a7b 100644
--- a/drivers/firmware/efi/libstub/vsprintf.c
+++ b/drivers/firmware/efi/libstub/vsprintf.c
@@ -14,6 +14,7 @@
 
 #include <linux/compiler.h>
 #include <linux/ctype.h>
+#include <linux/limits.h>
 #include <linux/string.h>
 
 static int skip_atoi(const char **s)
@@ -356,7 +357,11 @@ int vsprintf(char *buf, const char *fmt, va_list ap)
 			continue;
 
 		case 's':
+			if (precision < 0)
+				precision = INT_MAX;
 			s = va_arg(args, char *);
+			if (!s)
+				s = precision < 6 ? "" : "(null)";
 			len = strnlen(s, precision);
 
 			if (!(flags & LEFT))