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 [ Upstream fixed this in a different way as parts of the commits:
   9         8d987e5c7510 (net: avoid limits overflow)
  10         a9febbb4bd13 (sysctl: min/max bounds are optional)
  11         27b3d80a7b6a (sysctl: fix min/max handling in __do_proc_doulongvec_minmax())
  12  -DaveM ]
  13
  14 On a 16TB x86_64 machine, sysctl_tcp_mem[2], sysctl_udp_mem[2], and
  15 sysctl_sctp_mem[2] can integer overflow.  Set limit such that they are
  16 maximized without overflowing.
  17
  18 Signed-off-by: Robin Holt <holt@sgi.com>
  19 To: "David S. Miller" <davem@davemloft.net>
  20 Cc: Willy Tarreau <w@1wt.eu>
  21 Cc: linux-kernel@vger.kernel.org
  22 Cc: netdev@vger.kernel.org
  23 Cc: linux-sctp@vger.kernel.org
  24 Cc: Alexey Kuznetsov <kuznet@ms2.inr.ac.ru>
  25 Cc: "Pekka Savola (ipv6)" <pekkas@netcore.fi>
  26 Cc: James Morris <jmorris@namei.org>
  27 Cc: Hideaki YOSHIFUJI <yoshfuji@linux-ipv6.org>
  28 Cc: Patrick McHardy <kaber@trash.net>
  29 Cc: Vlad Yasevich <vladislav.yasevich@hp.com>
  30 Cc: Sridhar Samudrala <sri@us.ibm.com>
  31 Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
  32 ---
  33  net/ipv4/tcp.c      |    4 +++-
  34  net/ipv4/udp.c      |    4 +++-
  35  net/sctp/protocol.c |    4 +++-
  36  3 files changed, 9 insertions(+), 3 deletions(-)
  37
  38 --- a/net/ipv4/tcp.c
  39 +++ b/net/ipv4/tcp.c
  40 @@ -2754,12 +2754,14 @@ void __init tcp_init(void)
  41
  42         /* Set the pressure threshold to be a fraction of global memory that
  43          * is up to 1/2 at 256 MB, decreasing toward zero with the amount of
  44 -        * memory, with a floor of 128 pages.
  45 +        * memory, with a floor of 128 pages, and a ceiling that prevents an
  46 +        * integer overflow.
  47          */
  48         nr_pages = totalram_pages - totalhigh_pages;
  49         limit = min(nr_pages, 1UL<<(28-PAGE_SHIFT)) >> (20-PAGE_SHIFT);
  50         limit = (limit * (nr_pages >> (20-PAGE_SHIFT))) >> (PAGE_SHIFT-11);
  51         limit = max(limit, 128UL);
  52 +       limit = min(limit, INT_MAX * 4UL / 3 / 2);
  53         sysctl_tcp_mem[0] = limit / 4 * 3;
  54         sysctl_tcp_mem[1] = limit;
  55         sysctl_tcp_mem[2] = sysctl_tcp_mem[0] * 2;
  56 --- a/net/ipv4/udp.c
  57 +++ b/net/ipv4/udp.c
  58 @@ -1722,11 +1722,13 @@ void __init udp_init(void)
  59
  60         /* Set the pressure threshold up by the same strategy of TCP. It is a
  61          * fraction of global memory that is up to 1/2 at 256 MB, decreasing
  62 -        * toward zero with the amount of memory, with a floor of 128 pages.
  63 +        * toward zero with the amount of memory, with a floor of 128 pages,
  64 +        * and a ceiling that prevents an integer overflow.
  65          */
  66         limit = min(nr_all_pages, 1UL<<(28-PAGE_SHIFT)) >> (20-PAGE_SHIFT);
  67         limit = (limit * (nr_all_pages >> (20-PAGE_SHIFT))) >> (PAGE_SHIFT-11);
  68         limit = max(limit, 128UL);
  69 +       limit = min(limit, INT_MAX * 4UL / 3 / 2);
  70         sysctl_udp_mem[0] = limit / 4 * 3;
  71         sysctl_udp_mem[1] = limit;
  72         sysctl_udp_mem[2] = sysctl_udp_mem[0] * 2;
  73 --- a/net/sctp/protocol.c
  74 +++ b/net/sctp/protocol.c
  75 @@ -1179,7 +1179,8 @@ SCTP_STATIC __init int sctp_init(void)
  76
  77         /* Set the pressure threshold to be a fraction of global memory that
  78          * is up to 1/2 at 256 MB, decreasing toward zero with the amount of
  79 -        * memory, with a floor of 128 pages.
  80 +        * memory, with a floor of 128 pages, and a ceiling that prevents an
  81 +        * integer overflow.
  82          * Note this initalizes the data in sctpv6_prot too
  83          * Unabashedly stolen from tcp_init
  84          */
  85 @@ -1187,6 +1188,7 @@ SCTP_STATIC __init int sctp_init(void)
  86         limit = min(nr_pages, 1UL<<(28-PAGE_SHIFT)) >> (20-PAGE_SHIFT);
  87         limit = (limit * (nr_pages >> (20-PAGE_SHIFT))) >> (PAGE_SHIFT-11);
  88         limit = max(limit, 128UL);
  89 +       limit = min(limit, INT_MAX * 4UL / 3 / 2);
  90         sysctl_sctp_mem[0] = limit / 4 * 3;
  91         sysctl_sctp_mem[1] = limit;
  92         sysctl_sctp_mem[2] = sysctl_sctp_mem[0] * 2;