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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>
This commit is contained in:
Fernando Fernandez Mancera 2019-03-27 11:36:26 +01:00 committed by Pablo Neira Ayuso
parent 6978cdb129
commit 22c7652cda
4 changed files with 46 additions and 15 deletions
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11
include/linux/netfilter/nfnetlink_osf.h
View File

@ -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 */

6
include/uapi/linux/netfilter/nf_tables.h
View File

@ -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
*

14
net/netfilter/nfnetlink_osf.c
View File

@ -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);

30
net/netfilter/nft_osf.c
View File

@ -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;