diff -Nru glibc-2.24/debian/changelog glibc-2.24/debian/changelog
--- glibc-2.24/debian/changelog	2016-12-05 07:36:48.000000000 -0500
+++ glibc-2.24/debian/changelog	2017-03-02 15:22:01.000000000 -0500
@@ -1,3 +1,11 @@
+glibc (2.24-7ubuntu3) zesty; urgency=medium
+
+  * Fix ttyname inside containers (LP: #1669578)
+    - ubuntu/submitted-ttyname-enodev.diff
+    - ubuntu/local-ttyname-return-symlink.diff
+
+ -- Stéphane Graber <stgraber@ubuntu.com>  Thu, 02 Mar 2017 15:22:01 -0500
+
 glibc (2.24-7ubuntu2) zesty; urgency=medium
 
   * Disable lock-elision on all targets to avoid regressions (LP: #1642390)
diff -Nru glibc-2.24/debian/patches/series glibc-2.24/debian/patches/series
--- glibc-2.24/debian/patches/series	2016-11-30 11:57:20.000000000 -0500
+++ glibc-2.24/debian/patches/series	2017-03-02 15:21:09.000000000 -0500
@@ -230,3 +230,5 @@
 ubuntu/localedata/pt_BR-d_fmt.diff
 ubuntu/localedata/sd_PK.diff
 ubuntu/localedata/ug_CN@latin.diff
+ubuntu/submitted-ttyname-enodev.diff
+ubuntu/local-ttyname-return-symlink.diff
diff -Nru glibc-2.24/debian/patches/ubuntu/local-ttyname-return-symlink.diff glibc-2.24/debian/patches/ubuntu/local-ttyname-return-symlink.diff
--- glibc-2.24/debian/patches/ubuntu/local-ttyname-return-symlink.diff	1969-12-31 19:00:00.000000000 -0500
+++ glibc-2.24/debian/patches/ubuntu/local-ttyname-return-symlink.diff	2017-03-02 15:18:05.000000000 -0500
@@ -0,0 +1,71 @@
+From 93f44707175c22633633ddc66427b258286f5d89 Mon Sep 17 00:00:00 2001
+From: Christian Brauner <christian.brauner@canonical.com>
+Date: Fri, 24 Feb 2017 02:02:36 +0100
+Subject: [PATCH 2/2] linux ttyname and ttyname_r: return symlink
+
+Return the symbolic link /proc/self/fd/<n> instead of /dev/pts/<n> or NULL in
+two case:
+
+- when the /dev/pts/<n> link exists but it exists in a different namespace
+- when the /dev/pts/<n> link does not exist in the current namespace
+
+In both case the previous patch ensures that ENODEV is set. This will allow
+allow programs like e.g. tmux to behave correctly when run in a container that
+allocates a pty file descriptor from another namespace:
+
+ubuntu@edfu:~/glibc_build$ lxc exec xen1 -- bash
+root@xen1:~# tty
+/proc/self/fd/0
+
+Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>
+Acked-by: Serge Hallyn <serge@hallyn.com>
+---
+ sysdeps/unix/sysv/linux/ttyname.c   | 10 ++++++++--
+ sysdeps/unix/sysv/linux/ttyname_r.c | 10 ++++++++--
+ 2 files changed, 16 insertions(+), 4 deletions(-)
+
+diff --git a/sysdeps/unix/sysv/linux/ttyname.c b/sysdeps/unix/sysv/linux/ttyname.c
+index 5909cb7..44c4941 100644
+--- a/sysdeps/unix/sysv/linux/ttyname.c
++++ b/sysdeps/unix/sysv/linux/ttyname.c
+@@ -181,8 +181,14 @@ ttyname (int fd)
+ 	 namespace. */
+       if (is_pty (&st))
+ 	{
+-	  __set_errno (ENODEV);
+-	  return NULL;
++	  if (strlen (procname) < (buflen - 1))
++	    {
++	      strcpy(ttyname_buf, procname);
++	      __set_errno (ENODEV);
++	      return ttyname_buf;
++	    }
++	      __set_errno (ENODEV);
++	      return NULL;
+ 	}
+     }
+ 
+diff --git a/sysdeps/unix/sysv/linux/ttyname_r.c b/sysdeps/unix/sysv/linux/ttyname_r.c
+index dc86352..a081a11 100644
+--- a/sysdeps/unix/sysv/linux/ttyname_r.c
++++ b/sysdeps/unix/sysv/linux/ttyname_r.c
+@@ -164,8 +164,14 @@ __ttyname_r (int fd, char *buf, size_t buflen)
+        */
+       if (is_pty (&st))
+ 	{
+-	  __set_errno (ENODEV);
+-	  return ENODEV;
++	  if (strlen (procname) < (buflen - 1))
++	    {
++	      strcpy(buf, procname);
++	      __set_errno (ENODEV);
++	      return 0;
++	    }
++	      __set_errno (ENODEV);
++	      return ENODEV;
+ 	}
+     }
+ 
+-- 
+2.10.2
+
diff -Nru glibc-2.24/debian/patches/ubuntu/submitted-ttyname-enodev.diff glibc-2.24/debian/patches/ubuntu/submitted-ttyname-enodev.diff
--- glibc-2.24/debian/patches/ubuntu/submitted-ttyname-enodev.diff	1969-12-31 19:00:00.000000000 -0500
+++ glibc-2.24/debian/patches/ubuntu/submitted-ttyname-enodev.diff	2017-03-02 15:18:05.000000000 -0500
@@ -0,0 +1,139 @@
+From c3a1fb13917857c03d83dcdd3f2ccf44aa765af2 Mon Sep 17 00:00:00 2001
+From: Christian Brauner <christian.brauner@canonical.com>
+Date: Fri, 24 Feb 2017 02:02:35 +0100
+Subject: [PATCH 1/2] linux ttyname and ttyname_r: do not return wrong results
+
+If a link (say /proc/self/fd/0) pointing to a device, say /dev/pts/2, in a
+parent mount namespace is passed to ttyname, and a /dev/pts/2 exists (in a
+different devpts) in the current namespace, then it returns /dev/pts/2. But
+/dev/pts/2 is NOT the current tty, it is a different file and device.
+
+Detect this case and return ENODEV. Userspace can choose to take this as a hint
+that the fd points to a tty device but to act on the fd rather than the link.
+
+Signed-off-by: Serge Hallyn <serge@hallyn.com>
+Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>
+---
+ sysdeps/unix/sysv/linux/ttyname.c   | 16 ++++++++++++----
+ sysdeps/unix/sysv/linux/ttyname.h   | 35 +++++++++++++++++++++++++++++++++++
+ sysdeps/unix/sysv/linux/ttyname_r.c | 17 +++++++++++++----
+ 3 files changed, 60 insertions(+), 8 deletions(-)
+ create mode 100644 sysdeps/unix/sysv/linux/ttyname.h
+
+diff --git a/sysdeps/unix/sysv/linux/ttyname.c b/sysdeps/unix/sysv/linux/ttyname.c
+index e2686b5..5909cb7 100644
+--- a/sysdeps/unix/sysv/linux/ttyname.c
++++ b/sysdeps/unix/sysv/linux/ttyname.c
+@@ -28,6 +28,8 @@
+ 
+ #include <_itoa.h>
+ 
++#include "ttyname.h"
++
+ #if 0
+ /* Is this used anywhere?  It is not exported.  */
+ char *__ttyname;
+@@ -170,12 +172,18 @@ ttyname (int fd)
+ #ifdef _STATBUF_ST_RDEV
+ 	  && S_ISCHR (st1.st_mode)
+ 	  && st1.st_rdev == st.st_rdev
+-#else
+-	  && st1.st_ino == st.st_ino
+-	  && st1.st_dev == st.st_dev
+ #endif
+-	  )
++	  && st1.st_ino == st.st_ino
++	  && st1.st_dev == st.st_dev)
+ 	return ttyname_buf;
++
++      /* If the link doesn't exist, then it points to a device in another
++	 namespace. */
++      if (is_pty (&st))
++	{
++	  __set_errno (ENODEV);
++	  return NULL;
++	}
+     }
+ 
+   if (__xstat64 (_STAT_VER, "/dev/pts", &st1) == 0 && S_ISDIR (st1.st_mode))
+diff --git a/sysdeps/unix/sysv/linux/ttyname.h b/sysdeps/unix/sysv/linux/ttyname.h
+new file mode 100644
+index 0000000..a1aa314
+--- /dev/null
++++ b/sysdeps/unix/sysv/linux/ttyname.h
+@@ -0,0 +1,35 @@
++/* Copyright (C) 2016 Free Software Foundation, Inc.
++   This file is part of the GNU C Library.
++
++   The GNU C Library is free software; you can redistribute it and/or
++   modify it under the terms of the GNU Lesser General Public License as
++   published by the Free Software Foundation; either version 2.1 of the
++   License, or (at your option) any later version.
++
++   The GNU C Library is distributed in the hope that it will be useful,
++   but WITHOUT ANY WARRANTY; without even the implied warranty of
++   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
++   Lesser General Public License for more details.
++
++   You should have received a copy of the GNU Lesser General Public
++   License along with the GNU C Library; see the file COPYING.LIB.  If
++   not, see <http://www.gnu.org/licenses/>.  */
++
++#include <unistd.h>
++#include <sys/sysmacros.h>
++#include <sys/types.h>
++#include <sys/stat.h>
++
++/* Return true if this is a UNIX98 pty device, as defined in
++   linux/Documentation/devices.txt.  */
++static inline int
++is_pty (struct stat64 *sb)
++{
++#ifdef _STATBUF_ST_RDEV
++  int m = major (sb->st_rdev);
++  return (136 <= m && m <= 143);
++#else
++  return false;
++#endif
++}
++
+diff --git a/sysdeps/unix/sysv/linux/ttyname_r.c b/sysdeps/unix/sysv/linux/ttyname_r.c
+index 10b170a..dc86352 100644
+--- a/sysdeps/unix/sysv/linux/ttyname_r.c
++++ b/sysdeps/unix/sysv/linux/ttyname_r.c
+@@ -28,6 +28,8 @@
+ 
+ #include <_itoa.h>
+ 
++#include "ttyname.h"
++
+ static int getttyname_r (char *buf, size_t buflen,
+ 			 dev_t mydev, ino64_t myino, int save,
+ 			 int *dostat) internal_function;
+@@ -152,12 +154,19 @@ __ttyname_r (int fd, char *buf, size_t buflen)
+ #ifdef _STATBUF_ST_RDEV
+ 	  && S_ISCHR (st1.st_mode)
+ 	  && st1.st_rdev == st.st_rdev
+-#else
+-	  && st1.st_ino == st.st_ino
+-	  && st1.st_dev == st.st_dev
+ #endif
+-	  )
++	  && st1.st_ino == st.st_ino
++	  && st1.st_dev == st.st_dev)
+ 	return 0;
++
++      /* If the link doesn't exist, then it points to a device in another
++       * namespace.
++       */
++      if (is_pty (&st))
++	{
++	  __set_errno (ENODEV);
++	  return ENODEV;
++	}
+     }
+ 
+   /* Prepare the result buffer.  */
+-- 
+2.10.2
+