patches/kernel/0020-mm-mempolicy-fix-memory-leak-in-set_mempolicy_home_n.patch

   1 From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
   2 From: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
   3 Date: Thu, 15 Dec 2022 14:46:21 -0500
   4 Subject: [PATCH] mm/mempolicy: fix memory leak in set_mempolicy_home_node
   5  system call
   6
   7 commit 38ce7c9bdfc228c14d7621ba36d3eebedd9d4f76 upstream.
   8
   9 When encountering any vma in the range with policy other than MPOL_BIND or
  10 MPOL_PREFERRED_MANY, an error is returned without issuing a mpol_put on
  11 the policy just allocated with mpol_dup().
  12
  13 This allows arbitrary users to leak kernel memory.
  14
  15 Link: https://lkml.kernel.org/r/20221215194621.202816-1-mathieu.desnoyers@efficios.com
  16 Fixes: c6018b4b2549 ("mm/mempolicy: add set_mempolicy_home_node syscall")
  17 Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
  18 Reviewed-by: Randy Dunlap <rdunlap@infradead.org>
  19 Reviewed-by: "Huang, Ying" <ying.huang@intel.com>
  20 Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
  21 Acked-by: Michal Hocko <mhocko@suse.com>
  22 Cc: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
  23 Cc: Dave Hansen <dave.hansen@linux.intel.com>
  24 Cc: Feng Tang <feng.tang@intel.com>
  25 Cc: Michal Hocko <mhocko@kernel.org>
  26 Cc: Andrea Arcangeli <aarcange@redhat.com>
  27 Cc: Mel Gorman <mgorman@techsingularity.net>
  28 Cc: Mike Kravetz <mike.kravetz@oracle.com>
  29 Cc: Randy Dunlap <rdunlap@infradead.org>
  30 Cc: Vlastimil Babka <vbabka@suse.cz>
  31 Cc: Andi Kleen <ak@linux.intel.com>
  32 Cc: Dan Williams <dan.j.williams@intel.com>
  33 Cc: Huang Ying <ying.huang@intel.com>
  34 Cc: <stable@vger.kernel.org>    [5.17+]
  35 Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
  36 Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
  37 (cherry picked from commit 0ce4cc6d269ddc448a825955b495f662f5d9e153)
  38 Signed-off-by: Thomas Lamprecht <t.lamprecht@proxmox.com>
  39 ---
  40  mm/mempolicy.c | 1 +
  41  1 file changed, 1 insertion(+)
  42
  43 diff --git a/mm/mempolicy.c b/mm/mempolicy.c
  44 index 61aa9aedb728..02c8a712282f 100644
  45 --- a/mm/mempolicy.c
  46 +++ b/mm/mempolicy.c
  47 @@ -1540,6 +1540,7 @@ SYSCALL_DEFINE4(set_mempolicy_home_node, unsigned long, start, unsigned long, le
  48                  * the home node for vmas we already updated before.
  49                  */
  50                 if (new->mode != MPOL_BIND && new->mode != MPOL_PREFERRED_MANY) {
  51 +                       mpol_put(new);
  52                         err = -EOPNOTSUPP;
  53                         break;
  54                 }