netfilter: nft_osf: Add version option support

Add version 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>

diff --git a/include/linux/netfilter/nfnetlink_osf.h b/include/linux/netfilter/nfnetlink_osf.h
index c600004..788613f 100644 (file)
--- a/include/linux/netfilter/nfnetlink_osf.h
+++ b/include/linux/netfilter/nfnetlink_osf.h
@@ -21,13 +21,18 @@ struct nf_osf_finger {
        struct nf_osf_user_finger       finger;
 };
 
+struct nf_osf_data {
+       const char *genre;
+       const char *version;
+};
+
 bool nf_osf_match(const struct sk_buff *skb, u_int8_t family,
                  int hooknum, struct net_device *in, struct net_device *out,
                  const struct nf_osf_info *info, struct net *net,
                  const struct list_head *nf_osf_fingers);
 
-const char *nf_osf_find(const struct sk_buff *skb,
-                       const struct list_head *nf_osf_fingers,
-                       const int ttl_check);
+bool nf_osf_find(const struct sk_buff *skb,
+                const struct list_head *nf_osf_fingers,
+                const int ttl_check, struct nf_osf_data *data);
 
 #endif /* _NFOSF_H */

diff --git a/include/uapi/linux/netfilter/nf_tables.h b/include/uapi/linux/netfilter/nf_tables.h
index a66c8de..061bb3e 100644 (file)
--- a/include/uapi/linux/netfilter/nf_tables.h
+++ b/include/uapi/linux/netfilter/nf_tables.h
@@ -1522,15 +1522,21 @@ enum nft_flowtable_hook_attributes {
  *
  * @NFTA_OSF_DREG: destination register (NLA_U32: nft_registers)
  * @NFTA_OSF_TTL: Value of the TTL osf option (NLA_U8)
+ * @NFTA_OSF_FLAGS: flags (NLA_U32)
  */
 enum nft_osf_attributes {
        NFTA_OSF_UNSPEC,
        NFTA_OSF_DREG,
        NFTA_OSF_TTL,
+       NFTA_OSF_FLAGS,
        __NFTA_OSF_MAX,
 };
 #define NFTA_OSF_MAX (__NFTA_OSF_MAX - 1)
 
+enum nft_osf_flags {
+       NFT_OSF_F_VERSION = (1 << 0),
+};
+
 /**
  * enum nft_device_attributes - nf_tables device netlink attributes
  *

diff --git a/net/netfilter/nfnetlink_osf.c b/net/netfilter/nfnetlink_osf.c
index 1f1d90c..7b827bc 100644 (file)
--- a/net/netfilter/nfnetlink_osf.c
+++ b/net/netfilter/nfnetlink_osf.c
@@ -255,9 +255,9 @@ 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 int ttl_check)
+bool nf_osf_find(const struct sk_buff *skb,
+                const struct list_head *nf_osf_fingers,
+                const int ttl_check, struct nf_osf_data *data)
 {
        const struct iphdr *ip = ip_hdr(skb);
        const struct nf_osf_user_finger *f;
@@ -265,24 +265,24 @@ const char *nf_osf_find(const struct sk_buff *skb,
        const struct nf_osf_finger *kf;
        struct nf_osf_hdr_ctx ctx;
        const struct tcphdr *tcp;
-       const char *genre = NULL;
 
        memset(&ctx, 0, sizeof(ctx));
 
        tcp = nf_osf_hdr_ctx_init(&ctx, skb, ip, opts);
        if (!tcp)
-               return NULL;
+               return false;
 
        list_for_each_entry_rcu(kf, &nf_osf_fingers[ctx.df], finger_entry) {
                f = &kf->finger;
                if (!nf_osf_match_one(skb, f, ttl_check, &ctx))
                        continue;
 
-               genre = f->genre;
+               data->genre = f->genre;
+               data->version = f->version;
                break;
        }
 
-       return genre;
+       return true;
 }
 EXPORT_SYMBOL_GPL(nf_osf_find);
 

diff --git a/net/netfilter/nft_osf.c b/net/netfilter/nft_osf.c
index b13618c..87b60d6 100644 (file)
--- a/net/netfilter/nft_osf.c
+++ b/net/netfilter/nft_osf.c
@@ -7,11 +7,13 @@
 struct nft_osf {
        enum nft_registers      dreg:8;
        u8                      ttl;
+       u32                     flags;
 };
 
 static const struct nla_policy nft_osf_policy[NFTA_OSF_MAX + 1] = {
        [NFTA_OSF_DREG]         = { .type = NLA_U32 },
        [NFTA_OSF_TTL]          = { .type = NLA_U8 },
+       [NFTA_OSF_FLAGS]        = { .type = NLA_U32 },
 };
 
 static void nft_osf_eval(const struct nft_expr *expr, struct nft_regs *regs,
@@ -20,9 +22,10 @@ static void nft_osf_eval(const struct nft_expr *expr, struct nft_regs *regs,
        struct nft_osf *priv = nft_expr_priv(expr);
        u32 *dest = &regs->data[priv->dreg];
        struct sk_buff *skb = pkt->skb;
+       char os_match[NFT_OSF_MAXGENRELEN + 1];
        const struct tcphdr *tcp;
+       struct nf_osf_data data;
        struct tcphdr _tcph;
-       const char *os_name;
 
        tcp = skb_header_pointer(skb, ip_hdrlen(skb),
                                 sizeof(struct tcphdr), &_tcph);
@@ -35,11 +38,17 @@ static void nft_osf_eval(const struct nft_expr *expr, struct nft_regs *regs,
                return;
        }
 
-       os_name = nf_osf_find(skb, nf_osf_fingers, priv->ttl);
-       if (!os_name)
+       if (!nf_osf_find(skb, nf_osf_fingers, priv->ttl, &data)) {
                strncpy((char *)dest, "unknown", NFT_OSF_MAXGENRELEN);
-       else
-               strncpy((char *)dest, os_name, NFT_OSF_MAXGENRELEN);
+       } else {
+               if (priv->flags & NFT_OSF_F_VERSION)
+                       snprintf(os_match, NFT_OSF_MAXGENRELEN, "%s:%s",
+                                data.genre, data.version);
+               else
+                       strlcpy(os_match, data.genre, NFT_OSF_MAXGENRELEN);
+
+               strncpy((char *)dest, os_match, NFT_OSF_MAXGENRELEN);
+       }
 }
 
 static int nft_osf_init(const struct nft_ctx *ctx,
@@ -47,6 +56,7 @@ static int nft_osf_init(const struct nft_ctx *ctx,
                        const struct nlattr * const tb[])
 {
        struct nft_osf *priv = nft_expr_priv(expr);
+       u32 flags;
        int err;
        u8 ttl;
 
@@ -57,6 +67,13 @@ static int nft_osf_init(const struct nft_ctx *ctx,
                priv->ttl = ttl;
        }
 
+       if (tb[NFTA_OSF_FLAGS]) {
+               flags = ntohl(nla_get_be32(tb[NFTA_OSF_FLAGS]));
+               if (flags != NFT_OSF_F_VERSION)
+                       return -EINVAL;
+               priv->flags = flags;
+       }
+
        priv->dreg = nft_parse_register(tb[NFTA_OSF_DREG]);
        err = nft_validate_register_store(ctx, priv->dreg, NULL,
                                          NFT_DATA_VALUE, NFT_OSF_MAXGENRELEN);
@@ -73,6 +90,9 @@ static int nft_osf_dump(struct sk_buff *skb, const struct nft_expr *expr)
        if (nla_put_u8(skb, NFTA_OSF_TTL, priv->ttl))
                goto nla_put_failure;
 
+       if (nla_put_be32(skb, NFTA_OSF_FLAGS, ntohl(priv->flags)))
+               goto nla_put_failure;
+
        if (nft_dump_register(skb, NFTA_OSF_DREG, priv->dreg))
                goto nla_put_failure;