net: sunrpc: Fix off-by-one issues in 'rpc_ntop6'

Fix off-by-one issues in 'rpc_ntop6':
- 'snprintf' returns the number of characters which would have been written if enough space had been available, excluding the terminating null byte. Thus, a return value of 'sizeof(scopebuf)' means that the last character was dropped.
- 'strcat' adds a terminating null byte to the string, thus if len = buflen, the null byte is written past the end of the buffer.

---
 net/sunrpc/addr.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

index 8b4d72b..010dcb8 100644
@@ -82,11 +82,11 @@ static size_t rpc_ntop6(const struct sockaddr *sap,
 
 	rc = snprintf(scopebuf, sizeof(scopebuf), "%c%u",
 			IPV6_SCOPE_DELIMITER, sin6->sin6_scope_id);
-	if (unlikely((size_t)rc > sizeof(scopebuf)))
+	if (unlikely((size_t)rc >= sizeof(scopebuf)))
 		return 0;
 
 	len += rc;
-	if (unlikely(len > buflen))
+	if (unlikely(len >= buflen))
 		return 0;
 
 	strcat(buf, scopebuf);

2.7.4