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Date: Fri, 11 Sep 2015 18:38:28 -0700
From: Jesse Gross <jesse@...ira.com>
To: David Miller <davem@...emloft.net>
Cc: netdev@...r.kernel.org
Subject: [PATCH net v2] openvswitch: Fix mask generation for nested attributes.
Masks were added to OVS flows in a way that was backwards compatible
with userspace programs that did not generate masks. As a result, it is
possible that we may receive flows that do not have a mask and we need
to synthesize one.
Generating a mask requires iterating over attributes and descending into
nested attributes. For each level we need to know the size to generate the
correct mask. We do this with a linked table of attribute types.
Although the logic to handle these nested attributes was there in concept,
there are a number of bugs in practice. Examples include incomplete links
between tables, variable length attributes being treated as nested and
missing sanity checks.
Signed-off-by: Jesse Gross <jesse@...ira.com>
---
v2: Fix whitespace errors.
Add check for unknown bytes in VXLAN extensions.
Factor out check for nested or variable attributes.
---
net/openvswitch/flow_netlink.c | 82 ++++++++++++++++++++++++++++++------------
1 file changed, 59 insertions(+), 23 deletions(-)
diff --git a/net/openvswitch/flow_netlink.c b/net/openvswitch/flow_netlink.c
index c92d6a2..5c030a4 100644
--- a/net/openvswitch/flow_netlink.c
+++ b/net/openvswitch/flow_netlink.c
@@ -57,6 +57,7 @@ struct ovs_len_tbl {
};
#define OVS_ATTR_NESTED -1
+#define OVS_ATTR_VARIABLE -2
static void update_range(struct sw_flow_match *match,
size_t offset, size_t size, bool is_mask)
@@ -304,6 +305,10 @@ size_t ovs_key_attr_size(void)
+ nla_total_size(28); /* OVS_KEY_ATTR_ND */
}
+static const struct ovs_len_tbl ovs_vxlan_ext_key_lens[OVS_VXLAN_EXT_MAX + 1] = {
+ [OVS_VXLAN_EXT_GBP] = { .len = sizeof(u32) },
+};
+
static const struct ovs_len_tbl ovs_tunnel_key_lens[OVS_TUNNEL_KEY_ATTR_MAX + 1] = {
[OVS_TUNNEL_KEY_ATTR_ID] = { .len = sizeof(u64) },
[OVS_TUNNEL_KEY_ATTR_IPV4_SRC] = { .len = sizeof(u32) },
@@ -315,8 +320,9 @@ static const struct ovs_len_tbl ovs_tunnel_key_lens[OVS_TUNNEL_KEY_ATTR_MAX + 1]
[OVS_TUNNEL_KEY_ATTR_TP_SRC] = { .len = sizeof(u16) },
[OVS_TUNNEL_KEY_ATTR_TP_DST] = { .len = sizeof(u16) },
[OVS_TUNNEL_KEY_ATTR_OAM] = { .len = 0 },
- [OVS_TUNNEL_KEY_ATTR_GENEVE_OPTS] = { .len = OVS_ATTR_NESTED },
- [OVS_TUNNEL_KEY_ATTR_VXLAN_OPTS] = { .len = OVS_ATTR_NESTED },
+ [OVS_TUNNEL_KEY_ATTR_GENEVE_OPTS] = { .len = OVS_ATTR_VARIABLE },
+ [OVS_TUNNEL_KEY_ATTR_VXLAN_OPTS] = { .len = OVS_ATTR_NESTED,
+ .next = ovs_vxlan_ext_key_lens },
};
/* The size of the argument for each %OVS_KEY_ATTR_* Netlink attribute. */
@@ -349,6 +355,13 @@ static const struct ovs_len_tbl ovs_key_lens[OVS_KEY_ATTR_MAX + 1] = {
[OVS_KEY_ATTR_CT_LABEL] = { .len = sizeof(struct ovs_key_ct_label) },
};
+static bool check_attr_len(unsigned int attr_len, unsigned int expected_len)
+{
+ return expected_len == attr_len ||
+ expected_len == OVS_ATTR_NESTED ||
+ expected_len == OVS_ATTR_VARIABLE;
+}
+
static bool is_all_zero(const u8 *fp, size_t size)
{
int i;
@@ -388,7 +401,7 @@ static int __parse_flow_nlattrs(const struct nlattr *attr,
}
expected_len = ovs_key_lens[type].len;
- if (nla_len(nla) != expected_len && expected_len != OVS_ATTR_NESTED) {
+ if (!check_attr_len(nla_len(nla), expected_len)) {
OVS_NLERR(log, "Key %d has unexpected len %d expected %d",
type, nla_len(nla), expected_len);
return -EINVAL;
@@ -473,29 +486,50 @@ static int genev_tun_opt_from_nlattr(const struct nlattr *a,
return 0;
}
-static const struct nla_policy vxlan_opt_policy[OVS_VXLAN_EXT_MAX + 1] = {
- [OVS_VXLAN_EXT_GBP] = { .type = NLA_U32 },
-};
-
-static int vxlan_tun_opt_from_nlattr(const struct nlattr *a,
+static int vxlan_tun_opt_from_nlattr(const struct nlattr *attr,
struct sw_flow_match *match, bool is_mask,
bool log)
{
- struct nlattr *tb[OVS_VXLAN_EXT_MAX+1];
+ struct nlattr *a;
+ int rem;
unsigned long opt_key_offset;
struct vxlan_metadata opts;
- int err;
BUILD_BUG_ON(sizeof(opts) > sizeof(match->key->tun_opts));
- err = nla_parse_nested(tb, OVS_VXLAN_EXT_MAX, a, vxlan_opt_policy);
- if (err < 0)
- return err;
-
memset(&opts, 0, sizeof(opts));
+ nla_for_each_nested(a, attr, rem) {
+ int type = nla_type(a);
- if (tb[OVS_VXLAN_EXT_GBP])
- opts.gbp = nla_get_u32(tb[OVS_VXLAN_EXT_GBP]);
+ if (type > OVS_VXLAN_EXT_MAX) {
+ OVS_NLERR(log, "VXLAN extension %d out of range max %d",
+ type, OVS_VXLAN_EXT_MAX);
+ return -EINVAL;
+ }
+
+ if (!check_attr_len(nla_len(a),
+ ovs_vxlan_ext_key_lens[type].len)) {
+ OVS_NLERR(log, "VXLAN extension %d has unexpected len %d expected %d",
+ type, nla_len(a),
+ ovs_vxlan_ext_key_lens[type].len);
+ return -EINVAL;
+ }
+
+ switch (type) {
+ case OVS_VXLAN_EXT_GBP:
+ opts.gbp = nla_get_u32(a);
+ break;
+ default:
+ OVS_NLERR(log, "Unknown VXLAN extension attribute %d",
+ type);
+ return -EINVAL;
+ }
+ }
+ if (rem) {
+ OVS_NLERR(log, "VXLAN extension message has %d unknown bytes.",
+ rem);
+ return -EINVAL;
+ }
if (!is_mask)
SW_FLOW_KEY_PUT(match, tun_opts_len, sizeof(opts), false);
@@ -528,8 +562,8 @@ static int ipv4_tun_from_nlattr(const struct nlattr *attr,
return -EINVAL;
}
- if (ovs_tunnel_key_lens[type].len != nla_len(a) &&
- ovs_tunnel_key_lens[type].len != OVS_ATTR_NESTED) {
+ if (!check_attr_len(nla_len(a),
+ ovs_tunnel_key_lens[type].len)) {
OVS_NLERR(log, "Tunnel attr %d has unexpected len %d expected %d",
type, nla_len(a), ovs_tunnel_key_lens[type].len);
return -EINVAL;
@@ -1052,10 +1086,13 @@ static void nlattr_set(struct nlattr *attr, u8 val,
/* The nlattr stream should already have been validated */
nla_for_each_nested(nla, attr, rem) {
- if (tbl && tbl[nla_type(nla)].len == OVS_ATTR_NESTED)
- nlattr_set(nla, val, tbl[nla_type(nla)].next);
- else
+ if (tbl[nla_type(nla)].len == OVS_ATTR_NESTED) {
+ if (tbl[nla_type(nla)].next)
+ tbl = tbl[nla_type(nla)].next;
+ nlattr_set(nla, val, tbl);
+ } else {
memset(nla_data(nla), val, nla_len(nla));
+ }
}
}
@@ -1922,8 +1959,7 @@ static int validate_set(const struct nlattr *a,
key_len /= 2;
if (key_type > OVS_KEY_ATTR_MAX ||
- (ovs_key_lens[key_type].len != key_len &&
- ovs_key_lens[key_type].len != OVS_ATTR_NESTED))
+ !check_attr_len(key_len, ovs_key_lens[key_type].len))
return -EINVAL;
if (masked && !validate_masked(nla_data(ovs_key), key_len))
--
2.1.4
--
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