File 0031-efi_loader-fix-off-by-one-bug-in-ef.patch of Package u-boot-mvebudb-88f3720.25181

From 1b38df0fe724f89453a697e0e50010dbdc77a69d Mon Sep 17 00:00:00 2001
From: Ivan Gorinov <ivan.gorinov@intel.com>
Date: Fri, 11 May 2018 13:18:25 -0700
Subject: [PATCH] efi_loader: fix off-by-one bug in efi_get_variable

efi_get_variable() always stores an extra zero byte after the output data.
When the returned data size matches the output buffer size, the extra zero
byte is stored past the end of the output buffer.

Signed-off-by: Ivan Gorinov <ivan.gorinov@intel.com>
Reviewed-by: Heinrich Schuchardt <xypron.glpk@gmx.de>
Signed-off-by: Alexander Graf <agraf@suse.de>
---
 lib/efi_loader/efi_variable.c | 40 ++++++++++++++---------------------
 1 file changed, 16 insertions(+), 24 deletions(-)

diff --git a/lib/efi_loader/efi_variable.c b/lib/efi_loader/efi_variable.c
index 6c177da3a6..9e7d3e62e9 100644
--- a/lib/efi_loader/efi_variable.c
+++ b/lib/efi_loader/efi_variable.c
@@ -50,7 +50,7 @@
 	(strlen("efi_xxxxxxxx-xxxx-xxxx-xxxxxxxxxxxxxxxx_") + \
 		(MAX_VAR_NAME * MAX_UTF8_PER_UTF16))
 
-static int hex(unsigned char ch)
+static int hex(int ch)
 {
 	if (ch >= 'a' && ch <= 'f')
 		return ch-'a'+10;
@@ -61,44 +61,32 @@ static int hex(unsigned char ch)
 	return -1;
 }
 
-static const char *hex2mem(u8 *mem, const char *hexstr, int count)
+static int hex2mem(u8 *mem, const char *hexstr, int size)
 {
-	memset(mem, 0, count/2);
+	int nibble;
+	int i;
 
-	do {
-		int nibble;
-
-		*mem = 0;
-
-		if (!count || !*hexstr)
+	for (i = 0; i < size; i++) {
+		if (*hexstr == '\0')
 			break;
 
 		nibble = hex(*hexstr);
 		if (nibble < 0)
-			break;
+			return -1;
 
 		*mem = nibble;
-		count--;
 		hexstr++;
 
-		if (!count || !*hexstr)
-			break;
-
 		nibble = hex(*hexstr);
 		if (nibble < 0)
-			break;
+			return -1;
 
 		*mem = (*mem << 4) | nibble;
-		count--;
 		hexstr++;
 		mem++;
+	}
 
-	} while (1);
-
-	if (*hexstr)
-		return hexstr;
-
-	return NULL;
+	return i;
 }
 
 static char *mem2hex(char *hexstr, const u8 *mem, int count)
@@ -210,8 +198,12 @@ efi_status_t EFIAPI efi_get_variable(s16 *variable_name,
 	if ((s = prefix(val, "(blob)"))) {
 		unsigned len = strlen(s);
 
+		/* number of hexadecimal digits must be even */
+		if (len & 1)
+			return EFI_EXIT(EFI_DEVICE_ERROR);
+
 		/* two characters per byte: */
-		len = DIV_ROUND_UP(len, 2);
+		len /= 2;
 		*data_size = len;
 
 		if (in_size < len)
@@ -220,7 +212,7 @@ efi_status_t EFIAPI efi_get_variable(s16 *variable_name,
 		if (!data)
 			return EFI_EXIT(EFI_INVALID_PARAMETER);
 
-		if (hex2mem(data, s, len * 2))
+		if (hex2mem(data, s, len) != len)
 			return EFI_EXIT(EFI_DEVICE_ERROR);
 
 		debug("%s: got value: \"%s\"\n", __func__, s);