Change in coreboot[master]: arch/x86/smbios: Consider conner case of Part Number

[Lijian Zhao (Code Review)]

Lijian Zhao has uploaded this change for review. ( https://review.coreboot.org/25377

Change subject: arch/x86/smbios: Consider conner case of Part Number
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arch/x86/smbios: Consider conner case of Part Number

In case of all DMI Type 17 could be all empty, the strip trailing
whitespace code will have a zero length Part Number entry, which will
cause exception when using (len - 1) where len is zero. Add extra code
to cover this corner case.

BUG=None
TEST=Boot up fine with moowth platform, without this patch system will
stuck at "Create SMBIOS type 17".

Change-Id: Id870c983584771dc1b60b1c99e95bbe7c0d25c4c
Signed-off-by: Lijian Zhao 
---
M src/arch/x86/smbios.c
1 file changed, 8 insertions(+), 4 deletions(-)

git pull ssh://review.coreboot.org:29418/coreboot refs/changes/77/25377/1

diff --git a/src/arch/x86/smbios.c b/src/arch/x86/smbios.c
index 7079374..c14c231 100644
--- a/src/arch/x86/smbios.c
+++ b/src/arch/x86/smbios.c
@@ -232,10 +232,14 @@
    len = strlen(trimmed_part_number);

invalid = 0; /* assume valid */
-	for (i = 0; i < len - 1; i++) {
-		if (trimmed_part_number[i] < ' ') {
-			invalid = 1;
-			trimmed_part_number[i] = '*';
+	if (len == 0)
+		invalid = 1;
+	else {
+		for (i = 0; i < len - 1; i++) {
+			if (trimmed_part_number[i] < ' ') {
+				invalid = 1;
+				trimmed_part_number[i] = '*';
+			}
    	}
    }