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authorJohannes Berg <johannes.berg@intel.com>2018-09-17 12:57:29 +0300
committerDavid S. Miller <davem@davemloft.net>2018-09-19 05:51:29 +0300
commitb60b87fc2996240e298529a46e122ef62ef9c27f (patch)
treea39a2b84798368f1c53b412586eff77e6e3b1673 /include
parent568b742a9d9888aca876b6ad9fa45490f18bee0a (diff)
downloadlinux-b60b87fc2996240e298529a46e122ef62ef9c27f.tar.xz
netlink: add ethernet address policy types
Commonly, ethernet addresses are just using a policy of { .len = ETH_ALEN } which leaves userspace free to send more data than it should, which may hide bugs. Introduce NLA_EXACT_LEN which checks for exact size, rejecting the attribute if it's not exactly that length. Also add NLA_EXACT_LEN_WARN which requires the minimum length and will warn on longer attributes, for backward compatibility. Use these to define NLA_POLICY_ETH_ADDR (new strict policy) and NLA_POLICY_ETH_ADDR_COMPAT (compatible policy with warning); these are used like this: static const struct nla_policy <name>[...] = { [NL_ATTR_NAME] = NLA_POLICY_ETH_ADDR, ... }; Signed-off-by: Johannes Berg <johannes.berg@intel.com> Reviewed-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'include')
-rw-r--r--include/net/netlink.h13
1 files changed, 13 insertions, 0 deletions
diff --git a/include/net/netlink.h b/include/net/netlink.h
index b318b0a9f6c3..318b1ded3833 100644
--- a/include/net/netlink.h
+++ b/include/net/netlink.h
@@ -181,6 +181,8 @@ enum {
NLA_S64,
NLA_BITFIELD32,
NLA_REJECT,
+ NLA_EXACT_LEN,
+ NLA_EXACT_LEN_WARN,
__NLA_TYPE_MAX,
};
@@ -211,6 +213,10 @@ enum {
* just like "All other"
* NLA_BITFIELD32 Unused
* NLA_REJECT Unused
+ * NLA_EXACT_LEN Attribute must have exactly this length, otherwise
+ * it is rejected.
+ * NLA_EXACT_LEN_WARN Attribute should have exactly this length, a warning
+ * is logged if it is longer, shorter is rejected.
* All other Minimum length of attribute payload
*
* Meaning of `validation_data' field:
@@ -236,6 +242,13 @@ struct nla_policy {
void *validation_data;
};
+#define NLA_POLICY_EXACT_LEN(_len) { .type = NLA_EXACT_LEN, .len = _len }
+#define NLA_POLICY_EXACT_LEN_WARN(_len) { .type = NLA_EXACT_LEN_WARN, \
+ .len = _len }
+
+#define NLA_POLICY_ETH_ADDR NLA_POLICY_EXACT_LEN(ETH_ALEN)
+#define NLA_POLICY_ETH_ADDR_COMPAT NLA_POLICY_EXACT_LEN_WARN(ETH_ALEN)
+
/**
* struct nl_info - netlink source information
* @nlh: Netlink message header of original request