git.ipfire.org Git - thirdparty/kernel/stable-queue.git/blob

   1 From 92988de9edaa8e54456640dbcd866e74c558c911 Mon Sep 17 00:00:00 2001
   2 From: Robin Holt <holt@sgi.com>
   3 Date: Wed, 20 Oct 2010 02:03:37 +0000
   4 Subject: Limit sysctl_tcp_mem and sysctl_udp_mem initializers to prevent integer overflows.
   5
   6 From: Robin Holt <holt@sgi.com>
   7
   8 [ Problem was fixed differently upstream. -DaveM ]
   9
  10 On a 16TB x86_64 machine, sysctl_tcp_mem[2], sysctl_udp_mem[2], and
  11 sysctl_sctp_mem[2] can integer overflow.  Set limit such that they are
  12 maximized without overflowing.
  13
  14 Signed-off-by: Robin Holt <holt@sgi.com>
  15 To: "David S. Miller" <davem@davemloft.net>
  16 Cc: Willy Tarreau <w@1wt.eu>
  17 Cc: linux-kernel@vger.kernel.org
  18 Cc: netdev@vger.kernel.org
  19 Cc: linux-sctp@vger.kernel.org
  20 Cc: Alexey Kuznetsov <kuznet@ms2.inr.ac.ru>
  21 Cc: "Pekka Savola (ipv6)" <pekkas@netcore.fi>
  22 Cc: James Morris <jmorris@namei.org>
  23 Cc: Hideaki YOSHIFUJI <yoshfuji@linux-ipv6.org>
  24 Cc: Patrick McHardy <kaber@trash.net>
  25 Cc: Vlad Yasevich <vladislav.yasevich@hp.com>
  26 Cc: Sridhar Samudrala <sri@us.ibm.com>
  27 Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
  28 ---
  29  net/ipv4/tcp.c      |    4 +++-
  30  net/ipv4/udp.c      |    4 +++-
  31  net/sctp/protocol.c |    4 +++-
  32  3 files changed, 9 insertions(+), 3 deletions(-)
  33
  34 --- a/net/ipv4/tcp.c
  35 +++ b/net/ipv4/tcp.c
  36 @@ -2754,12 +2754,14 @@ void __init tcp_init(void)
  37
  38         /* Set the pressure threshold to be a fraction of global memory that
  39          * is up to 1/2 at 256 MB, decreasing toward zero with the amount of
  40 -        * memory, with a floor of 128 pages.
  41 +        * memory, with a floor of 128 pages, and a ceiling that prevents an
  42 +        * integer overflow.
  43          */
  44         nr_pages = totalram_pages - totalhigh_pages;
  45         limit = min(nr_pages, 1UL<<(28-PAGE_SHIFT)) >> (20-PAGE_SHIFT);
  46         limit = (limit * (nr_pages >> (20-PAGE_SHIFT))) >> (PAGE_SHIFT-11);
  47         limit = max(limit, 128UL);
  48 +       limit = min(limit, INT_MAX * 4UL / 3 / 2);
  49         sysctl_tcp_mem[0] = limit / 4 * 3;
  50         sysctl_tcp_mem[1] = limit;
  51         sysctl_tcp_mem[2] = sysctl_tcp_mem[0] * 2;
  52 --- a/net/ipv4/udp.c
  53 +++ b/net/ipv4/udp.c
  54 @@ -1722,11 +1722,13 @@ void __init udp_init(void)
  55
  56         /* Set the pressure threshold up by the same strategy of TCP. It is a
  57          * fraction of global memory that is up to 1/2 at 256 MB, decreasing
  58 -        * toward zero with the amount of memory, with a floor of 128 pages.
  59 +        * toward zero with the amount of memory, with a floor of 128 pages,
  60 +        * and a ceiling that prevents an integer overflow.
  61          */
  62         limit = min(nr_all_pages, 1UL<<(28-PAGE_SHIFT)) >> (20-PAGE_SHIFT);
  63         limit = (limit * (nr_all_pages >> (20-PAGE_SHIFT))) >> (PAGE_SHIFT-11);
  64         limit = max(limit, 128UL);
  65 +       limit = min(limit, INT_MAX * 4UL / 3 / 2);
  66         sysctl_udp_mem[0] = limit / 4 * 3;
  67         sysctl_udp_mem[1] = limit;
  68         sysctl_udp_mem[2] = sysctl_udp_mem[0] * 2;
  69 --- a/net/sctp/protocol.c
  70 +++ b/net/sctp/protocol.c
  71 @@ -1179,7 +1179,8 @@ SCTP_STATIC __init int sctp_init(void)
  72
  73         /* Set the pressure threshold to be a fraction of global memory that
  74          * is up to 1/2 at 256 MB, decreasing toward zero with the amount of
  75 -        * memory, with a floor of 128 pages.
  76 +        * memory, with a floor of 128 pages, and a ceiling that prevents an
  77 +        * integer overflow.
  78          * Note this initalizes the data in sctpv6_prot too
  79          * Unabashedly stolen from tcp_init
  80          */
  81 @@ -1187,6 +1188,7 @@ SCTP_STATIC __init int sctp_init(void)
  82         limit = min(nr_pages, 1UL<<(28-PAGE_SHIFT)) >> (20-PAGE_SHIFT);
  83         limit = (limit * (nr_pages >> (20-PAGE_SHIFT))) >> (PAGE_SHIFT-11);
  84         limit = max(limit, 128UL);
  85 +       limit = min(limit, INT_MAX * 4UL / 3 / 2);
  86         sysctl_sctp_mem[0] = limit / 4 * 3;
  87         sysctl_sctp_mem[1] = limit;
  88         sysctl_sctp_mem[2] = sysctl_sctp_mem[0] * 2;