Index: lib/sanitizer_common/sanitizer_common_interceptors.inc
===================================================================
--- lib/sanitizer_common/sanitizer_common_interceptors.inc
+++ lib/sanitizer_common/sanitizer_common_interceptors.inc
@@ -3077,17 +3077,28 @@
 #endif
 
 #if SANITIZER_INTERCEPT_GETPEERNAME
-INTERCEPTOR(int, getpeername, int sockfd, void *addr, unsigned *addrlen) {
+INTERCEPTOR(int, getpeername, int sockfd, void *addr,
+  __sanitizer_socklen_t *addrlen) {
   void *ctx;
   COMMON_INTERCEPTOR_ENTER(ctx, getpeername, sockfd, addr, addrlen);
-  unsigned addr_sz;
-  if (addrlen) addr_sz = *addrlen;
-  // FIXME: under ASan the call below may write to freed memory and corrupt
-  // its metadata. See
-  // https://github.com/google/sanitizers/issues/321.
-  int res = REAL(getpeername)(sockfd, addr, addrlen);
-  if (!res && addr && addrlen)
-    COMMON_INTERCEPTOR_WRITE_RANGE(ctx, addr, Min(addr_sz, *addrlen));
+  __sanitizer_socklen_t taddrlen;
+  if (addrlen)
+    taddrlen = *addrlen;
+  else
+    taddrlen = 0;
+  __sanitizer_sockaddr_storage taddr;
+  int res = REAL(getpeername)(sockfd, addr ? &taddr : 0,
+                              addrlen ? &taddrlen : 0);
+  if (!res) {
+    if (addr && addrlen)
+      COMMON_INTERCEPTOR_WRITE_RANGE(ctx, addr, taddrlen);
+    if (addrlen)
+      COMMON_INTERCEPTOR_WRITE_RANGE(ctx, addrlen, sizeof(*addrlen));
+  }
+  if (addr && addrlen)
+    memcpy(addr, &taddr, taddrlen);
+  if (addrlen)
+    *addrlen = taddrlen;
   return res;
 }
 #define INIT_GETPEERNAME COMMON_INTERCEPT_FUNCTION(getpeername);