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authorPatrick McHardy <kaber@trash.net>2015-03-03 20:04:20 +0000
committerPablo Neira Ayuso <pablo@netfilter.org>2015-03-04 18:46:06 +0100
commit86f1ec32318159a24de349f0a38e79b9d2b3131a (patch)
tree6533fb1a3354201a635cf4dfdeaa143e2d3de12a /net
parent9889840f5988ecfd43b00c9abb83c1804e21406b (diff)
netfilter: nf_tables: fix userdata length overflow
The NFT_USERDATA_MAXLEN is defined to 256, however we only have a u8 to store its size. Introduce a struct nft_userdata which contains a length field and indicate its presence using a single bit in the rule. The length field of struct nft_userdata is also a u8, however we don't store zero sized data, so the actual length is udata->len + 1. Signed-off-by: Patrick McHardy <kaber@trash.net> Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Diffstat (limited to 'net')
-rw-r--r--net/netfilter/nf_tables_api.c28
1 files changed, 19 insertions, 9 deletions
diff --git a/net/netfilter/nf_tables_api.c b/net/netfilter/nf_tables_api.c
index 7baafd5ab520..74e4b876c96e 100644
--- a/net/netfilter/nf_tables_api.c
+++ b/net/netfilter/nf_tables_api.c
@@ -1711,9 +1711,12 @@ static int nf_tables_fill_rule_info(struct sk_buff *skb, struct net *net,
}
nla_nest_end(skb, list);
- if (rule->ulen &&
- nla_put(skb, NFTA_RULE_USERDATA, rule->ulen, nft_userdata(rule)))
- goto nla_put_failure;
+ if (rule->udata) {
+ struct nft_userdata *udata = nft_userdata(rule);
+ if (nla_put(skb, NFTA_RULE_USERDATA, udata->len + 1,
+ udata->data) < 0)
+ goto nla_put_failure;
+ }
nlmsg_end(skb, nlh);
return 0;
@@ -1896,11 +1899,12 @@ static int nf_tables_newrule(struct sock *nlsk, struct sk_buff *skb,
struct nft_table *table;
struct nft_chain *chain;
struct nft_rule *rule, *old_rule = NULL;
+ struct nft_userdata *udata;
struct nft_trans *trans = NULL;
struct nft_expr *expr;
struct nft_ctx ctx;
struct nlattr *tmp;
- unsigned int size, i, n, ulen = 0;
+ unsigned int size, i, n, ulen = 0, usize = 0;
int err, rem;
bool create;
u64 handle, pos_handle;
@@ -1973,11 +1977,14 @@ static int nf_tables_newrule(struct sock *nlsk, struct sk_buff *skb,
if (size >= 1 << 12)
goto err1;
- if (nla[NFTA_RULE_USERDATA])
+ if (nla[NFTA_RULE_USERDATA]) {
ulen = nla_len(nla[NFTA_RULE_USERDATA]);
+ if (ulen > 0)
+ usize = sizeof(struct nft_userdata) + ulen;
+ }
err = -ENOMEM;
- rule = kzalloc(sizeof(*rule) + size + ulen, GFP_KERNEL);
+ rule = kzalloc(sizeof(*rule) + size + usize, GFP_KERNEL);
if (rule == NULL)
goto err1;
@@ -1985,10 +1992,13 @@ static int nf_tables_newrule(struct sock *nlsk, struct sk_buff *skb,
rule->handle = handle;
rule->dlen = size;
- rule->ulen = ulen;
+ rule->udata = ulen ? 1 : 0;
- if (ulen)
- nla_memcpy(nft_userdata(rule), nla[NFTA_RULE_USERDATA], ulen);
+ if (ulen) {
+ udata = nft_userdata(rule);
+ udata->len = ulen - 1;
+ nla_memcpy(udata->data, nla[NFTA_RULE_USERDATA], ulen);
+ }
expr = nft_expr_first(rule);
for (i = 0; i < n; i++) {