Bug 1643557 - Make pk11_MatchString accept a size_t length rather tha…

…n an int length (consistent with all callers), and reformulate its internals to avoid a signed-unsigned comparison. r=kjacobs

Depends on D78450

Differential Revision: https://phabricator.services.mozilla.com/D78451

--HG--
extra : moz-landing-system : lando

lib/pk11wrap/pk11priv.h

@@ -3,6 +3,9 @@
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 #ifndef _PK11PRIV_H_
 #define _PK11PRIV_H_
+
+#include <stddef.h>
+
 #include "plarena.h"
 #include "seccomon.h"
 #include "secoidt.h"
@@ -48,7 +51,7 @@ CK_ULONG PK11_ReadULongAttribute(PK11SlotInfo *slot, CK_OBJECT_HANDLE id,
 char *PK11_MakeString(PLArenaPool *arena, char *space, char *staticSring,
                       int stringLen);
 PRBool pk11_MatchString(const char *string,
-                        const char *staticString, int staticStringLen);
+                        const char *staticString, size_t staticStringLen);
 int PK11_MapError(CK_RV error);
 CK_SESSION_HANDLE PK11_GetRWSession(PK11SlotInfo *slot);
 void PK11_RestoreROSession(PK11SlotInfo *slot, CK_SESSION_HANDLE rwsession);

lib/pk11wrap/pk11slot.c

@@ -1102,16 +1102,16 @@ PK11_MakeString(PLArenaPool *arena, char *space,
  */
 PRBool
 pk11_MatchString(const char *string,
-                 const char *staticString, int staticStringLen)
+                 const char *staticString, size_t staticStringLen)
 {
-    int i;
+    size_t i = staticStringLen;
 
-    for (i = (staticStringLen - 1); i >= 0; i--) {
-        if (staticString[i] != ' ')
+    /* move i to point to the last space */
+    while (i > 0) {
+        if (staticString[i - 1] != ' ')
             break;
+        i--;
     }
-    /* move i to point to the last space */
-    i++;
 
     if (strlen(string) == i && memcmp(string, staticString, i) == 0) {
         return PR_TRUE;