netfilter: nf_tables: validate NFT_DATA_VALUE after nft_data_init()

commit 0d2c96af797ba149e559c5875c0151384ab6dd14 upstream.

Userspace might bogusly sent NFT_DATA_VERDICT in several netlink
attributes that assume NFT_DATA_VALUE. Moreover, make sure that error
path invokes nft_data_release() to decrement the reference count on the
chain object.

Fixes: 96518518cc41 ("netfilter: add nftables")
Fixes: 0f3cd9b36977 ("netfilter: nf_tables: add range expression")
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
[bwh: Backported to 3.16:
 - Drop changes in nft_get_set_elem(), nft_range
 - Call nft_data_uninit() instead of nft_data_release()
 - Adjust context]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

diff --git a/net/netfilter/nft_bitwise.c b/net/netfilter/nft_bitwise.c
index 8f2b5aae1d503d78719bcd01b5b6ce38d64e49ff..4ee55017cd58f23229d56821e672a9270acd328b 100644 (file)
--- a/net/netfilter/nft_bitwise.c
+++ b/net/netfilter/nft_bitwise.c
@@ -86,7 +86,7 @@ static int nft_bitwise_init(const struct nft_ctx *ctx,
        err = nft_data_init(NULL, &priv->mask, &d1, tb[NFTA_BITWISE_MASK]);
        if (err < 0)
                return err;
-       if (d1.len != priv->len) {
+       if (d1.type != NFT_DATA_VALUE || d1.len != priv->len) {
                err = -EINVAL;
                goto err1;
        }
@@ -94,7 +94,7 @@ static int nft_bitwise_init(const struct nft_ctx *ctx,
        err = nft_data_init(NULL, &priv->xor, &d2, tb[NFTA_BITWISE_XOR]);
        if (err < 0)
                goto err1;
-       if (d2.len != priv->len) {
+       if (d2.type != NFT_DATA_VALUE || d2.len != priv->len) {
                err = -EINVAL;
                goto err2;
        }

diff --git a/net/netfilter/nft_cmp.c b/net/netfilter/nft_cmp.c
index 8ad2f2d9870b29c0b139ae4180b049b4df57d5b8..109793a93ec901d524473b581ee4690800b29f7f 100644 (file)
--- a/net/netfilter/nft_cmp.c
+++ b/net/netfilter/nft_cmp.c
@@ -84,6 +84,12 @@ static int nft_cmp_init(const struct nft_ctx *ctx, const struct nft_expr *expr,
        if (desc.len > U8_MAX)
                return -ERANGE;
 
+       if (desc.type != NFT_DATA_VALUE) {
+               err = -EINVAL;
+               nft_data_uninit(&priv->data, desc.type);
+               return err;
+       }
+
        priv->len = desc.len;
        return 0;
 }