[hurd, commited] hurd: Make readlinkat check bogus length returned by translator (BZ 34504)

[Samuel Thibault]

---
 sysdeps/mach/hurd/readlinkat.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/sysdeps/mach/hurd/readlinkat.c b/sysdeps/mach/hurd/readlinkat.c
index e0b1458f6c..d35922c605 100644
--- a/sysdeps/mach/hurd/readlinkat.c
+++ b/sysdeps/mach/hurd/readlinkat.c
@@ -65,7 +65,13 @@ __readlinkat (int fd, const char *file_name, char *buf, 
size_t len)
   if (err)
     goto out;
 
+  if (__glibc_unlikely (nread > len))  /* Sanity check for bogus server.       
*/
+    {
+      err = EGRATUITOUS;
+      goto out;
+    }
   len = nread;
+
   if (rbuf != buf)
     {
       memcpy (buf, rbuf, len);
-- 
2.53.0