syscall: add some paranoia in Linux's Accept4

Fixes #7428

LGTM=r
R=r
CC=golang-codereviews
https://golang.org/cl/69530044

diff --git a/src/pkg/syscall/syscall_linux.go b/src/pkg/syscall/syscall_linux.go
index 400fe50ddeb17d8ef671e86ef70ee967b057d401..704c4ffa6cc6f20025f1792cc9b46971eeeee46f 100644 (file)
--- a/src/pkg/syscall/syscall_linux.go
+++ b/src/pkg/syscall/syscall_linux.go
@@ -420,6 +420,9 @@ func Accept4(fd int, flags int) (nfd int, sa Sockaddr, err error) {
        if err != nil {
                return
        }
+       if len > SizeofSockaddrAny {
+               panic("RawSockaddrAny too small")
+       }
        sa, err = anyToSockaddr(&rsa)
        if err != nil {
                Close(nfd)