netfilter: nft_compat: check match/targetinfo attr size

We copy according to ->target|matchsize, so check that the netlink attribute
(which can include padding and might be larger) contains enough data.

Reported-by: Julia Lawall <Julia.Lawall@lip6.fr>
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

diff --git a/net/netfilter/nft_compat.c b/net/netfilter/nft_compat.c
index 454841baa4d07f3312a09dd397257ad66b41c412..6228c422c766e26dc4766e01635b538e4fd4d194 100644 (file)
--- a/net/netfilter/nft_compat.c
+++ b/net/netfilter/nft_compat.c
@@ -660,6 +660,9 @@ nft_match_select_ops(const struct nft_ctx *ctx,
        if (IS_ERR(match))
                return ERR_PTR(-ENOENT);
 
+       if (match->matchsize > nla_len(tb[NFTA_MATCH_INFO]))
+               return ERR_PTR(-EINVAL);
+
        /* This is the first time we use this match, allocate operations */
        nft_match = kzalloc(sizeof(struct nft_xt), GFP_KERNEL);
        if (nft_match == NULL)
@@ -740,6 +743,9 @@ nft_target_select_ops(const struct nft_ctx *ctx,
        if (IS_ERR(target))
                return ERR_PTR(-ENOENT);
 
+       if (target->targetsize > nla_len(tb[NFTA_TARGET_INFO]))
+               return ERR_PTR(-EINVAL);
+
        /* This is the first time we use this target, allocate operations */
        nft_target = kzalloc(sizeof(struct nft_xt), GFP_KERNEL);
        if (nft_target == NULL)