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authorAndrea Righi <andrea.righi@canonical.com>2019-03-28 07:36:00 +0100
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2019-04-17 08:36:44 +0200
commit12ff23da758517d5c618b6f59f5818e9ad6d8542 (patch)
treef7279e7f119dd6679b0da9a19960163c685f1edc
parenta1aa69beac4d88dfb892a95ee04fe6f932803952 (diff)
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: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-rw-r--r--net/openvswitch/flow_netlink.c4
1 files changed, 2 insertions, 2 deletions
diff --git a/net/openvswitch/flow_netlink.c b/net/openvswitch/flow_netlink.c
index 3bd4d5d0c346..50ea76180afa 100644
--- a/net/openvswitch/flow_netlink.c
+++ b/net/openvswitch/flow_netlink.c
@@ -1853,14 +1853,14 @@ 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) {