patches/kernel/0268-userns-prevent-speculative-execution.patch

   1 From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
   2 From: Elena Reshetova <elena.reshetova@intel.com>
   3 Date: Mon, 4 Sep 2017 13:11:52 +0300
   4 Subject: [PATCH] userns: prevent speculative execution
   5 MIME-Version: 1.0
   6 Content-Type: text/plain; charset=UTF-8
   7 Content-Transfer-Encoding: 8bit
   8
   9 CVE-2017-5753
  10 CVE-2017-5715
  11
  12 Real commit text tbd
  13
  14 Signed-off-by: Elena Reshetova <elena.reshetova@intel.com>
  15 Signed-off-by: Tim Chen <tim.c.chen@linux.intel.com>
  16 Signed-off-by: Andy Whitcroft <apw@canonical.com>
  17 Signed-off-by: Kleber Sacilotto de Souza <kleber.souza@canonical.com>
  18 (cherry picked from commit 1410678db6238e625775f7108c68a9e5b8d439a1)
  19 Signed-off-by: Fabian Grünbichler <f.gruenbichler@proxmox.com>
  20 ---
  21  kernel/user_namespace.c | 4 +++-
  22  1 file changed, 3 insertions(+), 1 deletion(-)
  23
  24 diff --git a/kernel/user_namespace.c b/kernel/user_namespace.c
  25 index 4eacf186f5bc..684cc69d431c 100644
  26 --- a/kernel/user_namespace.c
  27 +++ b/kernel/user_namespace.c
  28 @@ -549,8 +549,10 @@ static void *m_start(struct seq_file *seq, loff_t *ppos,
  29         struct uid_gid_extent *extent = NULL;
  30         loff_t pos = *ppos;
  31
  32 -       if (pos < map->nr_extents)
  33 +       if (pos < map->nr_extents) {
  34 +               gmb();
  35                 extent = &map->extent[pos];
  36 +       }
  37
  38         return extent;
  39  }
  40 --
  41 2.14.2
  42