src/patches/dnsmasq/007-Fix_logic_error_in_Linux_netlink_code.patch

   1 From 1d07667ac77c55b9de56b1b2c385167e0e0ec27a Mon Sep 17 00:00:00 2001
   2 From: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
   3 Date: Mon, 11 Jul 2016 18:36:05 +0100
   4 Subject: [PATCH] Fix logic error in Linux netlink code.
   5
   6 This could cause dnsmasq to enter a tight loop on systems
   7 with a very large number of network interfaces.
   8 ---
   9  CHANGELOG     |    6 ++++++
  10  src/netlink.c |    8 +++++++-
  11  2 files changed, 13 insertions(+), 1 deletion(-)
  12
  13 diff --git a/CHANGELOG b/CHANGELOG
  14 index 0559a6f..59c9c49 100644
  15 --- a/CHANGELOG
  16 +++ b/CHANGELOG
  17 @@ -11,6 +11,12 @@ version 2.77
  18             Thanks to Mozilla for funding the security audit
  19             which spotted this bug.
  20
  21 +           Fix logic error in Linux netlink code. This could
  22 +           cause dnsmasq to enter a tight loop on systems
  23 +           with a very large number of network interfaces.
  24 +           Thanks to Ivan Kokshaysky for the diagnosis and
  25 +           patch.
  26 +
  27
  28  version 2.76
  29              Include 0.0.0.0/8 in DNS rebind checks. This range
  30 diff --git a/src/netlink.c b/src/netlink.c
  31 index 049247b..8cd51af 100644
  32 --- a/src/netlink.c
  33 +++ b/src/netlink.c
  34 @@ -188,11 +188,17 @@ int iface_enumerate(int family, void *parm, int (*callback)())
  35         }
  36
  37        for (h = (struct nlmsghdr *)iov.iov_base; NLMSG_OK(h, (size_t)len); h = NLMSG_NEXT(h, len))
  38 -       if (h->nlmsg_seq != seq || h->nlmsg_pid != netlink_pid || h->nlmsg_type == NLMSG_ERROR)
  39 +       if (h->nlmsg_pid != netlink_pid || h->nlmsg_type == NLMSG_ERROR)
  40           {
  41             /* May be multicast arriving async */
  42             nl_async(h);
  43           }
  44 +       else if (h->nlmsg_seq != seq)
  45 +         {
  46 +           /* May be part of incomplete response to previous request after
  47 +              ENOBUFS. Drop it. */
  48 +           continue;
  49 +         }
  50         else if (h->nlmsg_type == NLMSG_DONE)
  51           return callback_ok;
  52         else if (h->nlmsg_type == RTM_NEWADDR && family != AF_UNSPEC && family != AF_LOCAL)
  53 --
  54 1.7.10.4
  55