| From c219cea7d51ea1701e8173f8822fa303b425080d Mon Sep 17 00:00:00 2001 |
| From: Andrea Righi <andrea.righi@canonical.com> |
| Date: Thu, 28 Mar 2019 07:36:00 +0100 |
| Subject: openvswitch: fix flow actions reallocation |
| |
| [ Upstream commit f28cd2af22a0c134e4aa1c64a70f70d815d473fb ] |
| |
| The flow action buffer can be resized if it's not big enough to contain |
| all the requested flow actions. However, this resize doesn't take into |
| account the new requested size, the buffer is only increased by a factor |
| of 2x. This might be not enough to contain the new data, causing a |
| buffer overflow, for example: |
| |
| [ 42.044472] ============================================================================= |
| [ 42.045608] BUG kmalloc-96 (Not tainted): Redzone overwritten |
| [ 42.046415] ----------------------------------------------------------------------------- |
| |
| [ 42.047715] Disabling lock debugging due to kernel taint |
| [ 42.047716] INFO: 0x8bf2c4a5-0x720c0928. First byte 0x0 instead of 0xcc |
| [ 42.048677] INFO: Slab 0xbc6d2040 objects=29 used=18 fp=0xdc07dec4 flags=0x2808101 |
| [ 42.049743] INFO: Object 0xd53a3464 @offset=2528 fp=0xccdcdebb |
| |
| [ 42.050747] Redzone 76f1b237: cc cc cc cc cc cc cc cc ........ |
| [ 42.051839] Object d53a3464: 6b 6b 6b 6b 6b 6b 6b 6b 0c 00 00 00 6c 00 00 00 kkkkkkkk....l... |
| [ 42.053015] Object f49a30cc: 6c 00 0c 00 00 00 00 00 00 00 00 03 78 a3 15 f6 l...........x... |
| [ 42.054203] Object acfe4220: 20 00 02 00 ff ff ff ff 00 00 00 00 00 00 00 00 ............... |
| [ 42.055370] Object 21024e91: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ |
| [ 42.056541] Object 070e04c3: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ |
| [ 42.057797] Object 948a777a: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ |
| [ 42.059061] Redzone 8bf2c4a5: 00 00 00 00 .... |
| [ 42.060189] Padding a681b46e: 5a 5a 5a 5a 5a 5a 5a 5a ZZZZZZZZ |
| |
| Fix by making sure the new buffer is properly resized to contain all the |
| requested data. |
| |
| BugLink: https://bugs.launchpad.net/bugs/1813244 |
| Signed-off-by: Andrea Righi <andrea.righi@canonical.com> |
| Acked-by: Pravin B Shelar <pshelar@ovn.org> |
| Signed-off-by: David S. Miller <davem@davemloft.net> |
| Signed-off-by: Sasha Levin <sashal@kernel.org> |
| --- |
| net/openvswitch/flow_netlink.c | 4 ++-- |
| 1 file changed, 2 insertions(+), 2 deletions(-) |
| |
| diff --git a/net/openvswitch/flow_netlink.c b/net/openvswitch/flow_netlink.c |
| index 691da853bef5..4bdf5e3ac208 100644 |
| --- a/net/openvswitch/flow_netlink.c |
| +++ b/net/openvswitch/flow_netlink.c |
| @@ -2306,14 +2306,14 @@ static struct nlattr *reserve_sfa_size(struct sw_flow_actions **sfa, |
| |
| struct sw_flow_actions *acts; |
| int new_acts_size; |
| - int req_size = NLA_ALIGN(attr_len); |
| + size_t req_size = NLA_ALIGN(attr_len); |
| int next_offset = offsetof(struct sw_flow_actions, actions) + |
| (*sfa)->actions_len; |
| |
| if (req_size <= (ksize(*sfa) - next_offset)) |
| goto out; |
| |
| - new_acts_size = ksize(*sfa) * 2; |
| + new_acts_size = max(next_offset + req_size, ksize(*sfa) * 2); |
| |
| if (new_acts_size > MAX_ACTIONS_BUFSIZE) { |
| if ((MAX_ACTIONS_BUFSIZE - next_offset) < req_size) { |
| -- |
| 2.19.1 |
| |