add patch series

1 files changed, 364 insertions, 0 deletions

diff --git a/debian/patches/0025-libports-use-protected-payloads-to-optimize-the-obje.patch b/debian/patches/0025-libports-use-protected-payloads-to-optimize-the-obje.patch
new file mode 100644
index 00000000..dafb7841
--- /dev/null
+++ b/debian/patches/0025-libports-use-protected-payloads-to-optimize-the-obje.patch
@@ -0,0 +1,364 @@
+From 17a4eebe9b0de469be71b931601dbde49f8fa9cd Mon Sep 17 00:00:00 2001
+From: Justus Winter <4winter@informatik.uni-hamburg.de>
+Date: Sat, 23 Nov 2013 16:12:55 +0100
+Subject: [PATCH hurd 25/27] libports: use protected payloads to optimize the
+ object lookup
+
+* libports/create-internal.c (_ports_create_port_internal): Set the
+protected payload to the objects address.
+* libports/import-port.c (ports_import_port): Likewise.
+* libports/reallocate-from-external.c (ports_reallocate_from_external):
+Likewise.
+* libports/reallocate-port.c (ports_reallocate_port): Likewise.
+* libports/transfer-right.c (ports_transfer_right): Likewise.
+* libports/manage-multithread.c (ports_manage_port_operations_multithread):
+Use the protected payload as the objects address if provided.
+* libports/manage-one-thread.c (ports_manage_port_operations_one_thread):
+Likewise.
+* libports/destroy-right.c (ports_destroy_right): Defer the
+dereferencing of outstanding send rights to avoid a port_info
+use-after-free if a no-senders notification is dispatched.
+(struct deferred_dereference, gc_loop, start_gc, defer_dereferencing):
+Simple generational garbage collection of outstanding send rights.
+---
+ libports/complete-deallocate.c      |   2 +-
+ libports/create-internal.c          |   6 +-
+ libports/destroy-right.c            | 133 ++++++++++++++++++++++++++++++++++--
+ libports/import-port.c              |   6 +-
+ libports/manage-multithread.c       |  22 +++++-
+ libports/manage-one-thread.c        |  22 +++++-
+ libports/reallocate-from-external.c |   4 ++
+ libports/reallocate-port.c          |   4 ++
+ libports/transfer-right.c           |   3 +
+ 9 files changed, 193 insertions(+), 9 deletions(-)
+
+diff --git a/libports/complete-deallocate.c b/libports/complete-deallocate.c
+index 0d852f5..6799dfd 100644
+--- a/libports/complete-deallocate.c
++++ b/libports/complete-deallocate.c
+@@ -27,7 +27,7 @@ _ports_complete_deallocate (struct port_info *pi)
+ {
+   assert ((pi->flags & PORT_HAS_SENDRIGHTS) == 0);
+ 
+-  if (pi->port_right)
++  if (MACH_PORT_VALID (pi->port_right))
+     {
+       struct references result;
+ 
+diff --git a/libports/create-internal.c b/libports/create-internal.c
+index 2d85931..d79dc78 100644
+--- a/libports/create-internal.c
++++ b/libports/create-internal.c
+@@ -99,7 +99,11 @@ _ports_create_port_internal (struct port_class *class,
+   bucket->count++;
+   class->count++;
+   pthread_mutex_unlock (&_ports_lock);
+-  
++
++  /* This is an optimization.  It may fail.  */
++  mach_port_set_protected_payload (mach_task_self (), port,
++				   (unsigned long) pi);
++
+   if (install)
+     {
+       err = mach_port_move_member (mach_task_self (), pi->port_right,
+diff --git a/libports/destroy-right.c b/libports/destroy-right.c
+index 448b379..c229d77 100644
+--- a/libports/destroy-right.c
++++ b/libports/destroy-right.c
+@@ -1,5 +1,5 @@
+ /*
+-   Copyright (C) 1995, 1996, 1999 Free Software Foundation, Inc.
++   Copyright (C) 1995, 1996, 1999, 2014 Free Software Foundation, Inc.
+    Written by Michael I. Bushnell.
+ 
+    This file is part of the GNU Hurd.
+@@ -22,30 +22,155 @@
+ #include <hurd/ihash.h>
+ #include <assert.h>
+ 
++#include <pthread.h>
++#include <error.h>
++#include <time.h>
++#include <unistd.h>
++
++/* To prevent protected payloads from becoming stale, we defer the
++   derefercing of port_info objects.  Consumes PI.  */
++static error_t defer_dereferencing (struct port_info *pi);
++
+ error_t
+ ports_destroy_right (void *portstruct)
+ {
+   struct port_info *pi = portstruct;
+   error_t err;
+ 
++  mach_port_clear_protected_payload (mach_task_self (),
++				     pi->port_right);
++
++  pthread_mutex_lock (&_ports_lock);
+   if (pi->port_right != MACH_PORT_NULL)
+     {
+       pthread_rwlock_wrlock (&_ports_htable_lock);
+       hurd_ihash_locp_remove (&_ports_htable, pi->ports_htable_entry);
+       hurd_ihash_locp_remove (&pi->bucket->htable, pi->hentry);
+       pthread_rwlock_unlock (&_ports_htable_lock);
++
+       err = mach_port_mod_refs (mach_task_self (), pi->port_right,
+ 				MACH_PORT_RIGHT_RECEIVE, -1);
+       assert_perror (err);
+ 
+-      pi->port_right = MACH_PORT_NULL;
+-
+       if (pi->flags & PORT_HAS_SENDRIGHTS)
+ 	{
+ 	  pi->flags &= ~PORT_HAS_SENDRIGHTS;
+-	  ports_port_deref (pi);
++
++	  /* There are outstanding send rights, so we might get a
++	     no-senders notification.  Attached to the notification
++	     is a reference to the port_info object.  Of course we
++	     destroyed the receive right these were send to above, but
++	     the message could already have been send and dequeued.
++
++	     Previously, those messages would have carried an stale
++	     name, which would have caused a hash table lookup
++	     failure.  However, stale payloads results in port_info
++	     use-after-free.  Therefore, we cannot release the
++	     reference here, but defer that instead.  */
++	  defer_dereferencing (pi);
+ 	}
++
++      pi->port_right = MACH_PORT_DEAD;
+     }
++  pthread_mutex_unlock (&_ports_lock);
++
++  return 0;
++}
++
++/* Simple lock-less generational garbage collection.  */
++
++/* We maintain three lists of objects.	Producers add objects to the
++   current generation G using defer_dereferencing.  G-1 holds old
++   objects, G-2 holds garbage.	*/
++static struct deferred_dereference
++{
++  struct deferred_dereference *next;
++  struct port_info *pi;	/* We hold a reference for these objects.  */
++} *generations[3];	/* Must be accessed using atomic
++			   operations.	*/
++
++/* The current generation.  Must be accessed using atomic operations.  */
++static int generation;
++
++/* The garbage collection thread.  Does not return.  */
++static void *
++gc_loop (void *arg)
++{
++  while (1)
++    {
++      int old, garbage;
++      struct deferred_dereference *d;
++
++      sleep (5);
++
++      /* We are the only one updating generation, so this is safe.  */
++      old = generation;
++
++      /* Update generation.  */
++      __atomic_store_n (&generation, (old + 1) % 3, __ATOMIC_RELAXED);
++
++      /* This is the garbage generation.  As all writers are long
++	 gone, we do not need to bother with atomic operations.	 */
++      garbage = (old + 2) % 3;
++      d = generations[garbage];
++      generations[garbage] = NULL;
++      while (d != NULL)
++	{
++	  struct deferred_dereference *next = d->next;
++
++	  /* Get rid of our reference.	*/
++	  ports_port_deref (d->pi);
++
++	  free (d);
++	  d = next;
++	}
++    }
++
++  assert (! "reached");
++  return NULL;
++}
++
++/* Start the gc thread.  */
++static void
++start_gc (void)
++{
++  error_t err;
++  pthread_attr_t attr;
++  pthread_t thread;
++
++  pthread_attr_init (&attr);
++#define STACK_SIZE (64 * 1024)
++  pthread_attr_setstacksize (&attr, STACK_SIZE);
++#undef STACK_SIZE
++
++  err = pthread_create (&thread, &attr, gc_loop, NULL);
++  assert_perror (err);
++  err = pthread_detach (thread);
++  assert_perror (err);
++}
++
++/* Defer the derefercing of port_info objects.  Consumes PI.  */
++static error_t
++defer_dereferencing (struct port_info *pi)
++{
++  static pthread_once_t once = PTHREAD_ONCE_INIT;
++  int g;
++  struct deferred_dereference *d;
++  pthread_once (&once, start_gc);
++
++  d = malloc (sizeof *d);
++  if (d == NULL)
++    return ENOMEM;
++  d->pi = pi;
++
++ retry:
++  /* Append to the current generation.	*/
++  g = __atomic_load_n (&generation, __ATOMIC_RELAXED);
++
++  d->next = __atomic_load_n (&generations[g], __ATOMIC_RELAXED);
++  if (! __atomic_compare_exchange_n (&generations[g], &d->next, d,
++				     0, __ATOMIC_RELAXED, __ATOMIC_RELAXED))
++    goto retry;
+ 
+   return 0;
+ }
+diff --git a/libports/import-port.c b/libports/import-port.c
+index c337c85..2c638e1 100644
+--- a/libports/import-port.c
++++ b/libports/import-port.c
+@@ -93,7 +93,11 @@ ports_import_port (struct port_class *class, struct port_bucket *bucket,
+   bucket->count++;
+   class->count++;
+   pthread_mutex_unlock (&_ports_lock);
+-  
++
++  /* This is an optimization.  It may fail.  */
++  mach_port_set_protected_payload (mach_task_self (), port,
++				   (unsigned long) pi);
++
+   mach_port_move_member (mach_task_self (), port, bucket->portset);
+ 
+   if (stat.mps_srights)
+diff --git a/libports/manage-multithread.c b/libports/manage-multithread.c
+index 2067cba..90b3044 100644
+--- a/libports/manage-multithread.c
++++ b/libports/manage-multithread.c
+@@ -162,7 +162,27 @@ ports_manage_port_operations_multithread (struct port_bucket *bucket,
+       outp->RetCodeType = RetCodeType;
+       outp->RetCode = MIG_BAD_ID;
+ 
+-      pi = ports_lookup_port (bucket, inp->msgh_local_port, 0);
++      if (MACH_MSGH_BITS_LOCAL (inp->msgh_bits) ==
++	  MACH_MSG_TYPE_PROTECTED_PAYLOAD)
++	{
++	  pi = (struct port_info *) inp->msgh_protected_payload;
++	  if (pi && pi->bucket == bucket)
++	    ports_port_ref (pi);
++	  else
++	    pi = NULL;
++	}
++      else
++	{
++	  pi = ports_lookup_port (bucket, inp->msgh_local_port, 0);
++	  if (pi)
++	    {
++	      inp->msgh_bits = MACH_MSGH_BITS (
++		MACH_MSGH_BITS_REMOTE (inp->msgh_bits),
++		MACH_MSG_TYPE_PROTECTED_PAYLOAD);
++	      inp->msgh_protected_payload = (unsigned long) pi;
++	    }
++	}
++
+       if (pi)
+ 	{
+ 	  error_t err = ports_begin_rpc (pi, inp->msgh_id, &link);
+diff --git a/libports/manage-one-thread.c b/libports/manage-one-thread.c
+index cbd2df7..58c0f36 100644
+--- a/libports/manage-one-thread.c
++++ b/libports/manage-one-thread.c
+@@ -57,7 +57,27 @@ ports_manage_port_operations_one_thread (struct port_bucket *bucket,
+       outp->RetCodeType = RetCodeType;
+       outp->RetCode = MIG_BAD_ID;
+ 
+-      pi = ports_lookup_port (bucket, inp->msgh_local_port, 0);
++      if (MACH_MSGH_BITS_LOCAL (inp->msgh_bits) ==
++	  MACH_MSG_TYPE_PROTECTED_PAYLOAD)
++	{
++	  pi = (struct port_info *) inp->msgh_protected_payload;
++	  if (pi && pi->bucket == bucket)
++	    ports_port_ref (pi);
++	  else
++	    pi = NULL;
++	}
++      else
++	{
++	  pi = ports_lookup_port (bucket, inp->msgh_local_port, 0);
++	  if (pi)
++	    {
++	      inp->msgh_bits = MACH_MSGH_BITS (
++		MACH_MSGH_BITS_REMOTE (inp->msgh_bits),
++		MACH_MSG_TYPE_PROTECTED_PAYLOAD);
++	      inp->msgh_protected_payload = (unsigned long) pi;
++	    }
++	}
++
+       if (pi)
+ 	{
+ 	  err = ports_begin_rpc (pi, inp->msgh_id, &link);
+diff --git a/libports/reallocate-from-external.c b/libports/reallocate-from-external.c
+index 7205bd9..d0fae1a 100644
+--- a/libports/reallocate-from-external.c
++++ b/libports/reallocate-from-external.c
+@@ -71,6 +71,10 @@ ports_reallocate_from_external (void *portstruct, mach_port_t receive)
+   pthread_mutex_unlock (&_ports_lock);
+   assert_perror (err);
+ 
++  /* This is an optimization.  It may fail.  */
++  mach_port_set_protected_payload (mach_task_self (), pi->port_right,
++				   (unsigned long) pi);
++
+   mach_port_move_member (mach_task_self (), receive, pi->bucket->portset);
+   
+   if (stat.mps_srights)
+diff --git a/libports/reallocate-port.c b/libports/reallocate-port.c
+index cc534eb..4e859a1 100644
+--- a/libports/reallocate-port.c
++++ b/libports/reallocate-port.c
+@@ -59,6 +59,10 @@ ports_reallocate_port (void *portstruct)
+   pthread_mutex_unlock (&_ports_lock);
+   assert_perror (err);
+ 
++  /* This is an optimization.  It may fail.  */
++  mach_port_set_protected_payload (mach_task_self (), pi->port_right,
++				   (unsigned long) pi);
++
+   err = mach_port_move_member (mach_task_self (), pi->port_right, 
+ 			       pi->bucket->portset);
+   assert_perror (err);
+diff --git a/libports/transfer-right.c b/libports/transfer-right.c
+index 776a8d2..64de7f7 100644
+--- a/libports/transfer-right.c
++++ b/libports/transfer-right.c
+@@ -91,6 +91,9 @@ ports_transfer_right (void *tostruct,
+       err = hurd_ihash_add (&topi->bucket->htable, port, topi);
+       pthread_rwlock_unlock (&_ports_htable_lock);
+       assert_perror (err);
++      /* This is an optimization.  It may fail.  */
++      mach_port_set_protected_payload (mach_task_self (), port,
++				       (unsigned long) topi);
+       if (topi->bucket != frompi->bucket)
+         {
+ 	  err = mach_port_move_member (mach_task_self (), port,
+-- 
+2.1.3
+