1 files changed, 14 insertions, 4 deletions

diff --git a/lib/libc/net/getnameinfo.c b/lib/libc/net/getnameinfo.c
index 5ca6140b0da0..42f7906ee9f9 100644
--- a/lib/libc/net/getnameinfo.c
+++ b/lib/libc/net/getnameinfo.c
@@ -189,14 +189,24 @@ getnameinfo(sa, salen, host, hostlen, serv, servlen, flags)
 				unsigned int ifindex =
 					((struct sockaddr_in6 *)sa)->sin6_scope_id;
 				char ifname[IF_NAMESIZE * 2 /* for safety */];
+				int scopelen, numaddrlen;
 
 				if ((if_indextoname(ifindex, ifname)) == NULL)
 					return ENI_SYSTEM;
-				if (strlen(host) + 1 /* SCOPE_DELIMITER */
-				    + strlen(ifname) > hostlen)
+				scopelen = strlen(ifname);
+				numaddrlen = strlen(host);
+				if (numaddrlen + 1 /* SCOPE_DELIMITER */
+				    + scopelen > hostlen)
 					return ENI_MEMORY;
-				*ep = SCOPE_DELIMITER;
-				strcpy(ep + 1, ifname);
+				/*
+				 * Shift the host string to allocate
+				 * space for the scope ID part.
+				 */
+				memmove(host + scopelen + 1, host, numaddrlen);
+				/* copy the scope ID and the delimiter */
+				memcpy(host, ifname, scopelen);
+				host[scopelen] = SCOPE_DELIMITER;
+				host[scopelen + 1 + numaddrlen] = '\0';
 			}
 		}
 #endif /* INET6 */