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authorFernando Fernandez Mancera <ffmancera@riseup.net>2018-10-10 09:57:13 +0200
committerPablo Neira Ayuso <pablo@netfilter.org>2018-10-16 10:01:48 +0200
commita218dc82f0b5c6c8ad3d58c9870ed69e26c08b3e (patch)
treeb5b7b92c1a6399f4da8dadffe3f261ba763cf081 /net/netfilter
parentea9cf2a55a7bb84ba862a0fc13044a4311c9bbfe (diff)
netfilter: nft_osf: Add ttl option support
Add ttl option support to the nftables "osf" expression. Signed-off-by: Fernando Fernandez Mancera <ffmancera@riseup.net> Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Diffstat (limited to 'net/netfilter')
-rw-r--r--net/netfilter/nfnetlink_osf.c46
-rw-r--r--net/netfilter/nft_osf.c15
2 files changed, 35 insertions, 26 deletions
diff --git a/net/netfilter/nfnetlink_osf.c b/net/netfilter/nfnetlink_osf.c
index 00db27dfd2ff..6f41dd74729d 100644
--- a/net/netfilter/nfnetlink_osf.c
+++ b/net/netfilter/nfnetlink_osf.c
@@ -30,32 +30,27 @@ EXPORT_SYMBOL_GPL(nf_osf_fingers);
static inline int nf_osf_ttl(const struct sk_buff *skb,
int ttl_check, unsigned char f_ttl)
{
+ struct in_device *in_dev = __in_dev_get_rcu(skb->dev);
const struct iphdr *ip = ip_hdr(skb);
-
- if (ttl_check != -1) {
- if (ttl_check == NF_OSF_TTL_TRUE)
- return ip->ttl == f_ttl;
- if (ttl_check == NF_OSF_TTL_NOCHECK)
- return 1;
- else if (ip->ttl <= f_ttl)
- return 1;
- else {
- struct in_device *in_dev = __in_dev_get_rcu(skb->dev);
- int ret = 0;
-
- for_ifa(in_dev) {
- if (inet_ifa_match(ip->saddr, ifa)) {
- ret = (ip->ttl == f_ttl);
- break;
- }
- }
- endfor_ifa(in_dev);
-
- return ret;
+ int ret = 0;
+
+ if (ttl_check == NF_OSF_TTL_TRUE)
+ return ip->ttl == f_ttl;
+ if (ttl_check == NF_OSF_TTL_NOCHECK)
+ return 1;
+ else if (ip->ttl <= f_ttl)
+ return 1;
+
+ for_ifa(in_dev) {
+ if (inet_ifa_match(ip->saddr, ifa)) {
+ ret = (ip->ttl == f_ttl);
+ break;
}
}
- return ip->ttl == f_ttl;
+ endfor_ifa(in_dev);
+
+ return ret;
}
struct nf_osf_hdr_ctx {
@@ -213,7 +208,7 @@ nf_osf_match(const struct sk_buff *skb, u_int8_t family,
if (!tcp)
return false;
- ttl_check = (info->flags & NF_OSF_TTL) ? info->ttl : -1;
+ ttl_check = (info->flags & NF_OSF_TTL) ? info->ttl : 0;
list_for_each_entry_rcu(kf, &nf_osf_fingers[ctx.df], finger_entry) {
@@ -257,7 +252,8 @@ nf_osf_match(const struct sk_buff *skb, u_int8_t family,
EXPORT_SYMBOL_GPL(nf_osf_match);
const char *nf_osf_find(const struct sk_buff *skb,
- const struct list_head *nf_osf_fingers)
+ const struct list_head *nf_osf_fingers,
+ const int ttl_check)
{
const struct iphdr *ip = ip_hdr(skb);
const struct nf_osf_user_finger *f;
@@ -275,7 +271,7 @@ const char *nf_osf_find(const struct sk_buff *skb,
list_for_each_entry_rcu(kf, &nf_osf_fingers[ctx.df], finger_entry) {
f = &kf->finger;
- if (!nf_osf_match_one(skb, f, -1, &ctx))
+ if (!nf_osf_match_one(skb, f, ttl_check, &ctx))
continue;
genre = f->genre;
diff --git a/net/netfilter/nft_osf.c b/net/netfilter/nft_osf.c
index a35fb59ace73..0b452fd470c4 100644
--- a/net/netfilter/nft_osf.c
+++ b/net/netfilter/nft_osf.c
@@ -6,10 +6,12 @@
struct nft_osf {
enum nft_registers dreg:8;
+ u8 ttl;
};
static const struct nla_policy nft_osf_policy[NFTA_OSF_MAX + 1] = {
[NFTA_OSF_DREG] = { .type = NLA_U32 },
+ [NFTA_OSF_TTL] = { .type = NLA_U8 },
};
static void nft_osf_eval(const struct nft_expr *expr, struct nft_regs *regs,
@@ -33,7 +35,7 @@ static void nft_osf_eval(const struct nft_expr *expr, struct nft_regs *regs,
return;
}
- os_name = nf_osf_find(skb, nf_osf_fingers);
+ os_name = nf_osf_find(skb, nf_osf_fingers, priv->ttl);
if (!os_name)
strncpy((char *)dest, "unknown", NFT_OSF_MAXGENRELEN);
else
@@ -46,6 +48,14 @@ static int nft_osf_init(const struct nft_ctx *ctx,
{
struct nft_osf *priv = nft_expr_priv(expr);
int err;
+ u8 ttl;
+
+ if (nla_get_u8(tb[NFTA_OSF_TTL])) {
+ ttl = nla_get_u8(tb[NFTA_OSF_TTL]);
+ if (ttl > 2)
+ return -EINVAL;
+ priv->ttl = ttl;
+ }
priv->dreg = nft_parse_register(tb[NFTA_OSF_DREG]);
err = nft_validate_register_store(ctx, priv->dreg, NULL,
@@ -60,6 +70,9 @@ static int nft_osf_dump(struct sk_buff *skb, const struct nft_expr *expr)
{
const struct nft_osf *priv = nft_expr_priv(expr);
+ if (nla_put_u8(skb, NFTA_OSF_TTL, priv->ttl))
+ goto nla_put_failure;
+
if (nft_dump_register(skb, NFTA_OSF_DREG, priv->dreg))
goto nla_put_failure;