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9354405a GKH |
1 | From foo@baz Mon Apr 15 07:47:06 CEST 2019 |
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 | From: Andrea Righi <andrea.righi@canonical.com> | |
7 | ||
8 | [ Upstream commit f28cd2af22a0c134e4aa1c64a70f70d815d473fb ] | |
9 | ||
10 | The flow action buffer can be resized if it's not big enough to contain | |
11 | all the requested flow actions. However, this resize doesn't take into | |
12 | account the new requested size, the buffer is only increased by a factor | |
13 | of 2x. This might be not enough to contain the new data, causing a | |
14 | buffer overflow, for example: | |
15 | ||
16 | [ 42.044472] ============================================================================= | |
17 | [ 42.045608] BUG kmalloc-96 (Not tainted): Redzone overwritten | |
18 | [ 42.046415] ----------------------------------------------------------------------------- | |
19 | ||
20 | [ 42.047715] Disabling lock debugging due to kernel taint | |
21 | [ 42.047716] INFO: 0x8bf2c4a5-0x720c0928. First byte 0x0 instead of 0xcc | |
22 | [ 42.048677] INFO: Slab 0xbc6d2040 objects=29 used=18 fp=0xdc07dec4 flags=0x2808101 | |
23 | [ 42.049743] INFO: Object 0xd53a3464 @offset=2528 fp=0xccdcdebb | |
24 | ||
25 | [ 42.050747] Redzone 76f1b237: cc cc cc cc cc cc cc cc ........ | |
26 | [ 42.051839] Object d53a3464: 6b 6b 6b 6b 6b 6b 6b 6b 0c 00 00 00 6c 00 00 00 kkkkkkkk....l... | |
27 | [ 42.053015] Object f49a30cc: 6c 00 0c 00 00 00 00 00 00 00 00 03 78 a3 15 f6 l...........x... | |
28 | [ 42.054203] Object acfe4220: 20 00 02 00 ff ff ff ff 00 00 00 00 00 00 00 00 ............... | |
29 | [ 42.055370] Object 21024e91: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ | |
30 | [ 42.056541] Object 070e04c3: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ | |
31 | [ 42.057797] Object 948a777a: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ | |
32 | [ 42.059061] Redzone 8bf2c4a5: 00 00 00 00 .... | |
33 | [ 42.060189] Padding a681b46e: 5a 5a 5a 5a 5a 5a 5a 5a ZZZZZZZZ | |
34 | ||
35 | Fix by making sure the new buffer is properly resized to contain all the | |
36 | requested data. | |
37 | ||
38 | BugLink: https://bugs.launchpad.net/bugs/1813244 | |
39 | Signed-off-by: Andrea Righi <andrea.righi@canonical.com> | |
40 | Acked-by: Pravin B Shelar <pshelar@ovn.org> | |
41 | Signed-off-by: David S. Miller <davem@davemloft.net> | |
42 | Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> | |
43 | --- | |
44 | net/openvswitch/flow_netlink.c | 4 ++-- | |
45 | 1 file changed, 2 insertions(+), 2 deletions(-) | |
46 | ||
47 | --- a/net/openvswitch/flow_netlink.c | |
48 | +++ b/net/openvswitch/flow_netlink.c | |
49 | @@ -1967,14 +1967,14 @@ static struct nlattr *reserve_sfa_size(s | |
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) { |