releases/4.19.35/openvswitch-fix-flow-actions-reallocation.patch

   1 From 14051a86b37caa6112d12b69391cdd4aea9bf3f8 Mon Sep 17 00:00:00 2001
   2 From: Andrea Righi <andrea.righi@canonical.com>
   3 Date: Thu, 28 Mar 2019 07:36:00 +0100
   4 Subject: openvswitch: fix flow actions reallocation
   5
   6 [ Upstream commit f28cd2af22a0c134e4aa1c64a70f70d815d473fb ]
   7
   8 The flow action buffer can be resized if it's not big enough to contain
   9 all the requested flow actions. However, this resize doesn't take into
  10 account the new requested size, the buffer is only increased by a factor
  11 of 2x. This might be not enough to contain the new data, causing a
  12 buffer overflow, for example:
  13
  14 [   42.044472] =============================================================================
  15 [   42.045608] BUG kmalloc-96 (Not tainted): Redzone overwritten
  16 [   42.046415] -----------------------------------------------------------------------------
  17
  18 [   42.047715] Disabling lock debugging due to kernel taint
  19 [   42.047716] INFO: 0x8bf2c4a5-0x720c0928. First byte 0x0 instead of 0xcc
  20 [   42.048677] INFO: Slab 0xbc6d2040 objects=29 used=18 fp=0xdc07dec4 flags=0x2808101
  21 [   42.049743] INFO: Object 0xd53a3464 @offset=2528 fp=0xccdcdebb
  22
  23 [   42.050747] Redzone 76f1b237: cc cc cc cc cc cc cc cc                          ........
  24 [   42.051839] Object d53a3464: 6b 6b 6b 6b 6b 6b 6b 6b 0c 00 00 00 6c 00 00 00  kkkkkkkk....l...
  25 [   42.053015] Object f49a30cc: 6c 00 0c 00 00 00 00 00 00 00 00 03 78 a3 15 f6  l...........x...
  26 [   42.054203] Object acfe4220: 20 00 02 00 ff ff ff ff 00 00 00 00 00 00 00 00   ...............
  27 [   42.055370] Object 21024e91: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
  28 [   42.056541] Object 070e04c3: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
  29 [   42.057797] Object 948a777a: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
  30 [   42.059061] Redzone 8bf2c4a5: 00 00 00 00                                      ....
  31 [   42.060189] Padding a681b46e: 5a 5a 5a 5a 5a 5a 5a 5a                          ZZZZZZZZ
  32
  33 Fix by making sure the new buffer is properly resized to contain all the
  34 requested data.
  35
  36 BugLink: https://bugs.launchpad.net/bugs/1813244
  37 Signed-off-by: Andrea Righi <andrea.righi@canonical.com>
  38 Acked-by: Pravin B Shelar <pshelar@ovn.org>
  39 Signed-off-by: David S. Miller <davem@davemloft.net>
  40 Signed-off-by: Sasha Levin <sashal@kernel.org>
  41 ---
  42  net/openvswitch/flow_netlink.c | 4 ++--
  43  1 file changed, 2 insertions(+), 2 deletions(-)
  44
  45 diff --git a/net/openvswitch/flow_netlink.c b/net/openvswitch/flow_netlink.c
  46 index c7b6010b2c09..eab5e8eaddaa 100644
  47 --- a/net/openvswitch/flow_netlink.c
  48 +++ b/net/openvswitch/flow_netlink.c
  49 @@ -2306,14 +2306,14 @@ static struct nlattr *reserve_sfa_size(struct sw_flow_actions **sfa,
  50
  51         struct sw_flow_actions *acts;
  52         int new_acts_size;
  53 -       int req_size = NLA_ALIGN(attr_len);
  54 +       size_t req_size = NLA_ALIGN(attr_len);
  55         int next_offset = offsetof(struct sw_flow_actions, actions) +
  56                                         (*sfa)->actions_len;
  57
  58         if (req_size <= (ksize(*sfa) - next_offset))
  59                 goto out;
  60
  61 -       new_acts_size = ksize(*sfa) * 2;
  62 +       new_acts_size = max(next_offset + req_size, ksize(*sfa) * 2);
  63
  64         if (new_acts_size > MAX_ACTIONS_BUFSIZE) {
  65                 if ((MAX_ACTIONS_BUFSIZE - next_offset) < req_size) {
  66 --
  67 2.19.1
  68