[PATCH 3.16 072/245] netfilter: nf_tables: validate NFT_DATA_VALUE after nft_data_init()

Ben Hutchings
2020-04-23T23:21:13Z

From: Pablo Neira Ayuso <pablo@netfilter.org>

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>
---
--- a/net/netfilter/nft_bitwise.c
+++ b/net/netfilter/nft_bitwise.c
@@ -86,7 +86,7 @@ static int nft_bitwise_init(const struct
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
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;
}
--- a/net/netfilter/nft_cmp.c
+++ b/net/netfilter/nft_cmp.c
@@ -84,6 +84,12 @@ static int nft_cmp_init(const struct nft
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;
}