Handle out-of-memory case in svc_tcp.c/svc_unix.c:rendezvous_request.

If glibc is build with -O3 on at least 390 (-m31) or x86 (-m32),
gcc 11 dumps this warning:
svc_tcp.c: In function 'rendezvous_request':
svc_tcp.c:274:3: error: 'memcpy' offset [0, 15] is out of the bounds [0, 0] [-Werror=array-bounds]
  274 |   memcpy (&xprt->xp_raddr, &addr, sizeof (addr));
      |   ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
cc1: all warnings being treated as errors

In out-of-memory case, if one of the mallocs in makefd_xprt function
returns NULL, a message is dumped, makefd_xprt returns NULL
and the subsequent memcpy would copy to NULL.

Instead of a segfaulting, we delay a bit (see also __svc_accept_failed
and Bug 14889 (CVE-2011-4609) - svc_run() produces high cpu usage when
accept() fails with EMFILE (CVE-2011-4609).

The same applies to svc_unix.c.
Reviewed-by: Adhemerval Zanella  <adhemerval.zanella@linaro.org>

1 files changed, 8 insertions, 2 deletions

diff --git a/sunrpc/svc.c b/sunrpc/svc.c
index 917e9a3..3ed6cee 100644
--- a/sunrpc/svc.c
+++ b/sunrpc/svc.c
@@ -545,6 +545,13 @@ svc_getreq_common (const int fd)
 }
 libc_hidden_nolink_sunrpc (svc_getreq_common, GLIBC_2_2)
 
+void
+__svc_wait_on_error (void)
+{
+  struct timespec ts = { .tv_sec = 0, .tv_nsec = 50000000 };
+  __nanosleep (&ts, NULL);
+}
+
 /* If there are no file descriptors available, then accept will fail.
    We want to delay here so the connection request can be dequeued;
    otherwise we can bounce between polling and accepting, never giving the
@@ -555,8 +562,7 @@ __svc_accept_failed (void)
 {
   if (errno == EMFILE)
     {
-      struct timespec ts = { .tv_sec = 0, .tv_nsec = 50000000 };
-      __nanosleep (&ts, NULL);
+      __svc_wait_on_error ();
     }
 }