Fix strncpy from padding past the actual max size

In the padding portion of strncpy an array was used on a
pointer that was incremented N times. Resulting in padding
N bytes past the max

Change-Id: Icb075a234f456f9763c9712e1d6c78c947efdce1
Reviewed-on: http://ralgit01.raleigh.ibm.com/gerrit1/50001
Reviewed-by: Martin Gloff <mgloff@us.ibm.com>
Tested-by: Jenkins Server <pfd-jenkins+hostboot@us.ibm.com>
Tested-by: Jenkins OP Build CI <op-jenkins+hostboot@us.ibm.com>
Tested-by: Jenkins OP HW <op-hw-jenkins+hostboot@us.ibm.com>
Tested-by: FSP CI Jenkins <fsp-CI-jenkins+hostboot@us.ibm.com>
Reviewed-by: Michael Baiocchi <mbaiocch@us.ibm.com>
Reviewed-by: Nicholas E. Bofferding <bofferdn@us.ibm.com>
Reviewed-by: Daniel M. Crowell <dcrowell@us.ibm.com>

1 files changed, 7 insertions, 10 deletions

diff --git a/src/lib/string_utils.C b/src/lib/string_utils.C
index 27d9228fb..6e7bcd804 100644
--- a/src/lib/string_utils.C
+++ b/src/lib/string_utils.C
@@ -159,20 +159,17 @@ extern "C" int strncmp(const char* a, const char* b, size_t l)
 extern "C" char* strncpy(char* d, const char* s, size_t l)
 {
     char* d1 = d;
-    size_t len = 0;
-
-    do
+    while ( (l > 0) && (*s != '\0') )
     {
-        if (len++ >= l) break;
-        *d1 = *s;
-        if (*s == '\0') break;
-        d1++; s++;
-    } while(1);
+        *d1++ = *s++;
+        --l;
+    }
 
     // pad the remainder
-    while( len < l )
+    while (l > 0)
     {
-        d1[len++] = '\0';
+        *d1++ = '\0';
+        --l;
     }
 
     return d;