From 22c7652cdaa8cd33ce78bacceb4e826a3f795873 Mon Sep 17 00:00:00 2001 From: Fernando Fernandez Mancera Date: Wed, 27 Mar 2019 11:36:26 +0100 Subject: [PATCH] netfilter: nft_osf: Add version option support Add version option support to the nftables "osf" expression. Signed-off-by: Fernando Fernandez Mancera Signed-off-by: Pablo Neira Ayuso --- include/linux/netfilter/nfnetlink_osf.h | 11 ++++++++--- include/uapi/linux/netfilter/nf_tables.h | 6 ++++++ net/netfilter/nfnetlink_osf.c | 14 +++++++------- net/netfilter/nft_osf.c | 30 +++++++++++++++++++++++++----- 4 files changed, 46 insertions(+), 15 deletions(-) diff --git a/include/linux/netfilter/nfnetlink_osf.h b/include/linux/netfilter/nfnetlink_osf.h index c600004..788613f3 100644 --- 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 --- 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 --- 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 --- 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 = ®s->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; -- 2.7.4