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| author |   Johannes Berg <johannes.berg@intel.com> | 2018-09-17 11:57:29 +0200 |
|---|---|---|
| committer |   David S. Miller <davem@davemloft.net> | 2018-09-18 19:51:29 -0700 |
| commit | b60b87fc2996240e298529a46e122ef62ef9c27f (patch) | |
| tree | a39a2b84798368f1c53b412586eff77e6e3b1673 /lib | |
| parent | netlink: add NLA_REJECT policy type (diff) | |
| download | linux-dev-b60b87fc2996240e298529a46e122ef62ef9c27f.tar.xz linux-dev-b60b87fc2996240e298529a46e122ef62ef9c27f.zip | |
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 'lib')
| -rw-r--r-- | lib/nlattr.c | 8 |
1 files changed, 7 insertions, 1 deletions
diff --git a/lib/nlattr.c b/lib/nlattr.c index 36d74b079151..bb6fe5ed4ecf 100644 --- a/lib/nlattr.c +++ b/lib/nlattr.c @@ -82,12 +82,18 @@ static int validate_nla(const struct nlattr *nla, int maxtype, BUG_ON(pt->type > NLA_TYPE_MAX); - if (nla_attr_len[pt->type] && attrlen != nla_attr_len[pt->type]) { + if ((nla_attr_len[pt->type] && attrlen != nla_attr_len[pt->type]) || + (pt->type == NLA_EXACT_LEN_WARN && attrlen != pt->len)) { pr_warn_ratelimited("netlink: '%s': attribute type %d has an invalid length.\n", current->comm, type); } switch (pt->type) { + case NLA_EXACT_LEN: + if (attrlen != pt->len) + return -ERANGE; + break; + case NLA_REJECT: if (pt->validation_data && error_msg) *error_msg = pt->validation_data; |