* [PATCH] netfilter: nft_hash: Add hash offset value
@ 2016-09-05 8:36 Laura Garcia Liebana
2016-09-05 9:10 ` Pablo Neira Ayuso
0 siblings, 1 reply; 4+ messages in thread
From: Laura Garcia Liebana @ 2016-09-05 8:36 UTC (permalink / raw)
To: netfilter-devel
Add support to pass through an offset to the hash value. With this
feature, the sysadmin is able to generate a hash with a given
offset value.
Example:
meta mark set jhash ip saddr mod 2 seed 0xabcd sum 100
This option generates marks according to the source address from 100 to
101.
Signed-off-by: Laura Garcia Liebana <nevola@gmail.com>
---
include/uapi/linux/netfilter/nf_tables.h | 2 ++
net/netfilter/nft_hash.c | 13 +++++++++++--
2 files changed, 13 insertions(+), 2 deletions(-)
diff --git a/include/uapi/linux/netfilter/nf_tables.h b/include/uapi/linux/netfilter/nf_tables.h
index 4dbeeed..8026684 100644
--- a/include/uapi/linux/netfilter/nf_tables.h
+++ b/include/uapi/linux/netfilter/nf_tables.h
@@ -764,6 +764,7 @@ enum nft_meta_keys {
* @NFTA_HASH_LEN: source data length (NLA_U32)
* @NFTA_HASH_MODULUS: modulus value (NLA_U32)
* @NFTA_HASH_SEED: seed value (NLA_U32)
+ * @NFTA_HASH_SUM: Hash offset value (NLA_U32)
*/
enum nft_hash_attributes {
NFTA_HASH_UNSPEC,
@@ -772,6 +773,7 @@ enum nft_hash_attributes {
NFTA_HASH_LEN,
NFTA_HASH_MODULUS,
NFTA_HASH_SEED,
+ NFTA_HASH_SUM,
__NFTA_HASH_MAX,
};
#define NFTA_HASH_MAX (__NFTA_HASH_MAX - 1)
diff --git a/net/netfilter/nft_hash.c b/net/netfilter/nft_hash.c
index b7e3b40..8ab04d9 100644
--- a/net/netfilter/nft_hash.c
+++ b/net/netfilter/nft_hash.c
@@ -23,6 +23,7 @@ struct nft_hash {
u8 len;
u32 modulus;
u32 seed;
+ u32 sum;
};
static void nft_hash_eval(const struct nft_expr *expr,
@@ -35,7 +36,7 @@ static void nft_hash_eval(const struct nft_expr *expr,
h = reciprocal_scale(jhash(data, priv->len, priv->seed), priv->modulus);
- regs->data[priv->dreg] = h;
+ regs->data[priv->dreg] = priv->sum + h;
}
const struct nla_policy nft_hash_policy[NFTA_HASH_MAX + 1] = {
@@ -44,6 +45,7 @@ const struct nla_policy nft_hash_policy[NFTA_HASH_MAX + 1] = {
[NFTA_HASH_LEN] = { .type = NLA_U32 },
[NFTA_HASH_MODULUS] = { .type = NLA_U32 },
[NFTA_HASH_SEED] = { .type = NLA_U32 },
+ [NFTA_HASH_SUM] = { .type = NLA_U32 },
};
static int nft_hash_init(const struct nft_ctx *ctx,
@@ -60,6 +62,11 @@ static int nft_hash_init(const struct nft_ctx *ctx,
!tb[NFTA_HASH_MODULUS])
return -EINVAL;
+ if (tb[NFTA_HASH_SUM])
+ priv->sum = ntohl(nla_get_be32(tb[NFTA_HASH_SUM]));
+ else
+ priv->sum = 0;
+
priv->sreg = nft_parse_register(tb[NFTA_HASH_SREG]);
if (priv->sreg < 0)
return -ERANGE;
@@ -99,7 +106,9 @@ static int nft_hash_dump(struct sk_buff *skb,
goto nla_put_failure;
if (nft_dump_register(skb, NFTA_HASH_SEED, priv->seed))
goto nla_put_failure;
-
+ if (priv->sum != 0)
+ if (nft_dump_register(skb, NFTA_HASH_SUM, priv->sum))
+ goto nla_put_failure;
return 0;
nla_put_failure:
--
2.8.1
^ permalink raw reply related [flat|nested] 4+ messages in thread* Re: [PATCH] netfilter: nft_hash: Add hash offset value
2016-09-05 8:36 [PATCH] netfilter: nft_hash: Add hash offset value Laura Garcia Liebana
@ 2016-09-05 9:10 ` Pablo Neira Ayuso
2016-09-05 9:58 ` Laura Garcia
0 siblings, 1 reply; 4+ messages in thread
From: Pablo Neira Ayuso @ 2016-09-05 9:10 UTC (permalink / raw)
To: Laura Garcia Liebana; +Cc: netfilter-devel
On Mon, Sep 05, 2016 at 10:36:57AM +0200, Laura Garcia Liebana wrote:
> Add support to pass through an offset to the hash value. With this
> feature, the sysadmin is able to generate a hash with a given
> offset value.
>
> Example:
>
> meta mark set jhash ip saddr mod 2 seed 0xabcd sum 100
>
> This option generates marks according to the source address from 100 to
> 101.
>
> Signed-off-by: Laura Garcia Liebana <nevola@gmail.com>
> ---
> include/uapi/linux/netfilter/nf_tables.h | 2 ++
> net/netfilter/nft_hash.c | 13 +++++++++++--
> 2 files changed, 13 insertions(+), 2 deletions(-)
>
> diff --git a/include/uapi/linux/netfilter/nf_tables.h b/include/uapi/linux/netfilter/nf_tables.h
> index 4dbeeed..8026684 100644
> --- a/include/uapi/linux/netfilter/nf_tables.h
> +++ b/include/uapi/linux/netfilter/nf_tables.h
> @@ -764,6 +764,7 @@ enum nft_meta_keys {
> * @NFTA_HASH_LEN: source data length (NLA_U32)
> * @NFTA_HASH_MODULUS: modulus value (NLA_U32)
> * @NFTA_HASH_SEED: seed value (NLA_U32)
> + * @NFTA_HASH_SUM: Hash offset value (NLA_U32)
> */
> enum nft_hash_attributes {
> NFTA_HASH_UNSPEC,
> @@ -772,6 +773,7 @@ enum nft_hash_attributes {
> NFTA_HASH_LEN,
> NFTA_HASH_MODULUS,
> NFTA_HASH_SEED,
> + NFTA_HASH_SUM,
> __NFTA_HASH_MAX,
> };
> #define NFTA_HASH_MAX (__NFTA_HASH_MAX - 1)
> diff --git a/net/netfilter/nft_hash.c b/net/netfilter/nft_hash.c
> index b7e3b40..8ab04d9 100644
> --- a/net/netfilter/nft_hash.c
> +++ b/net/netfilter/nft_hash.c
> @@ -23,6 +23,7 @@ struct nft_hash {
> u8 len;
> u32 modulus;
> u32 seed;
> + u32 sum;
> };
>
> static void nft_hash_eval(const struct nft_expr *expr,
> @@ -35,7 +36,7 @@ static void nft_hash_eval(const struct nft_expr *expr,
>
> h = reciprocal_scale(jhash(data, priv->len, priv->seed), priv->modulus);
>
> - regs->data[priv->dreg] = h;
> + regs->data[priv->dreg] = priv->sum + h;
> }
>
> const struct nla_policy nft_hash_policy[NFTA_HASH_MAX + 1] = {
> @@ -44,6 +45,7 @@ const struct nla_policy nft_hash_policy[NFTA_HASH_MAX + 1] = {
> [NFTA_HASH_LEN] = { .type = NLA_U32 },
> [NFTA_HASH_MODULUS] = { .type = NLA_U32 },
> [NFTA_HASH_SEED] = { .type = NLA_U32 },
> + [NFTA_HASH_SUM] = { .type = NLA_U32 },
> };
>
> static int nft_hash_init(const struct nft_ctx *ctx,
> @@ -60,6 +62,11 @@ static int nft_hash_init(const struct nft_ctx *ctx,
> !tb[NFTA_HASH_MODULUS])
> return -EINVAL;
>
> + if (tb[NFTA_HASH_SUM])
> + priv->sum = ntohl(nla_get_be32(tb[NFTA_HASH_SUM]));
> + else
> + priv->sum = 0;
There is a corner case that we should reject from the kernel, I think
this is:
if (priv->sum + priv->modulus - 1 < priv->sum)
return -EOVERFLOW;
We'll handle this from userspace anyway too, but I think it's easy to
reject this crazy this.
^ permalink raw reply [flat|nested] 4+ messages in thread* Re: [PATCH] netfilter: nft_hash: Add hash offset value
2016-09-05 9:10 ` Pablo Neira Ayuso
@ 2016-09-05 9:58 ` Laura Garcia
2016-09-05 10:09 ` Pablo Neira Ayuso
0 siblings, 1 reply; 4+ messages in thread
From: Laura Garcia @ 2016-09-05 9:58 UTC (permalink / raw)
To: Pablo Neira Ayuso; +Cc: netfilter-devel
On Mon, Sep 05, 2016 at 11:10:28AM +0200, Pablo Neira Ayuso wrote:
> On Mon, Sep 05, 2016 at 10:36:57AM +0200, Laura Garcia Liebana wrote:
> > Add support to pass through an offset to the hash value. With this
> > feature, the sysadmin is able to generate a hash with a given
> > offset value.
> >
> > Example:
> >
> > meta mark set jhash ip saddr mod 2 seed 0xabcd sum 100
> >
> > This option generates marks according to the source address from 100 to
> > 101.
> >
> > Signed-off-by: Laura Garcia Liebana <nevola@gmail.com>
> > ---
> > include/uapi/linux/netfilter/nf_tables.h | 2 ++
> > net/netfilter/nft_hash.c | 13 +++++++++++--
> > 2 files changed, 13 insertions(+), 2 deletions(-)
> >
> > diff --git a/include/uapi/linux/netfilter/nf_tables.h b/include/uapi/linux/netfilter/nf_tables.h
> > index 4dbeeed..8026684 100644
> > --- a/include/uapi/linux/netfilter/nf_tables.h
> > +++ b/include/uapi/linux/netfilter/nf_tables.h
> > @@ -764,6 +764,7 @@ enum nft_meta_keys {
> > * @NFTA_HASH_LEN: source data length (NLA_U32)
> > * @NFTA_HASH_MODULUS: modulus value (NLA_U32)
> > * @NFTA_HASH_SEED: seed value (NLA_U32)
> > + * @NFTA_HASH_SUM: Hash offset value (NLA_U32)
> > */
> > enum nft_hash_attributes {
> > NFTA_HASH_UNSPEC,
> > @@ -772,6 +773,7 @@ enum nft_hash_attributes {
> > NFTA_HASH_LEN,
> > NFTA_HASH_MODULUS,
> > NFTA_HASH_SEED,
> > + NFTA_HASH_SUM,
> > __NFTA_HASH_MAX,
> > };
> > #define NFTA_HASH_MAX (__NFTA_HASH_MAX - 1)
> > diff --git a/net/netfilter/nft_hash.c b/net/netfilter/nft_hash.c
> > index b7e3b40..8ab04d9 100644
> > --- a/net/netfilter/nft_hash.c
> > +++ b/net/netfilter/nft_hash.c
> > @@ -23,6 +23,7 @@ struct nft_hash {
> > u8 len;
> > u32 modulus;
> > u32 seed;
> > + u32 sum;
> > };
> >
> > static void nft_hash_eval(const struct nft_expr *expr,
> > @@ -35,7 +36,7 @@ static void nft_hash_eval(const struct nft_expr *expr,
> >
> > h = reciprocal_scale(jhash(data, priv->len, priv->seed), priv->modulus);
> >
> > - regs->data[priv->dreg] = h;
> > + regs->data[priv->dreg] = priv->sum + h;
> > }
> >
> > const struct nla_policy nft_hash_policy[NFTA_HASH_MAX + 1] = {
> > @@ -44,6 +45,7 @@ const struct nla_policy nft_hash_policy[NFTA_HASH_MAX + 1] = {
> > [NFTA_HASH_LEN] = { .type = NLA_U32 },
> > [NFTA_HASH_MODULUS] = { .type = NLA_U32 },
> > [NFTA_HASH_SEED] = { .type = NLA_U32 },
> > + [NFTA_HASH_SUM] = { .type = NLA_U32 },
> > };
> >
> > static int nft_hash_init(const struct nft_ctx *ctx,
> > @@ -60,6 +62,11 @@ static int nft_hash_init(const struct nft_ctx *ctx,
> > !tb[NFTA_HASH_MODULUS])
> > return -EINVAL;
> >
> > + if (tb[NFTA_HASH_SUM])
> > + priv->sum = ntohl(nla_get_be32(tb[NFTA_HASH_SUM]));
> > + else
> > + priv->sum = 0;
>
> There is a corner case that we should reject from the kernel, I think
> this is:
>
> if (priv->sum + priv->modulus - 1 < priv->sum)
> return -EOVERFLOW;
>
> We'll handle this from userspace anyway too, but I think it's easy to
> reject this crazy this.
Such case shouldn't happen cause the modulus must be > 1. The init()
provides:
priv->modulus = ntohl(nla_get_be32(tb[NFTA_HASH_MODULUS]));
if (priv->modulus <= 1)
return -ERANGE;
^ permalink raw reply [flat|nested] 4+ messages in thread* Re: [PATCH] netfilter: nft_hash: Add hash offset value
2016-09-05 9:58 ` Laura Garcia
@ 2016-09-05 10:09 ` Pablo Neira Ayuso
0 siblings, 0 replies; 4+ messages in thread
From: Pablo Neira Ayuso @ 2016-09-05 10:09 UTC (permalink / raw)
To: Laura Garcia; +Cc: netfilter-devel
On Mon, Sep 05, 2016 at 11:58:24AM +0200, Laura Garcia wrote:
> On Mon, Sep 05, 2016 at 11:10:28AM +0200, Pablo Neira Ayuso wrote:
> > On Mon, Sep 05, 2016 at 10:36:57AM +0200, Laura Garcia Liebana wrote:
> > > Add support to pass through an offset to the hash value. With this
> > > feature, the sysadmin is able to generate a hash with a given
> > > offset value.
> > >
> > > Example:
> > >
> > > meta mark set jhash ip saddr mod 2 seed 0xabcd sum 100
> > >
> > > This option generates marks according to the source address from 100 to
> > > 101.
> > >
> > > Signed-off-by: Laura Garcia Liebana <nevola@gmail.com>
> > > ---
> > > include/uapi/linux/netfilter/nf_tables.h | 2 ++
> > > net/netfilter/nft_hash.c | 13 +++++++++++--
> > > 2 files changed, 13 insertions(+), 2 deletions(-)
> > >
> > > diff --git a/include/uapi/linux/netfilter/nf_tables.h b/include/uapi/linux/netfilter/nf_tables.h
> > > index 4dbeeed..8026684 100644
> > > --- a/include/uapi/linux/netfilter/nf_tables.h
> > > +++ b/include/uapi/linux/netfilter/nf_tables.h
> > > @@ -764,6 +764,7 @@ enum nft_meta_keys {
> > > * @NFTA_HASH_LEN: source data length (NLA_U32)
> > > * @NFTA_HASH_MODULUS: modulus value (NLA_U32)
> > > * @NFTA_HASH_SEED: seed value (NLA_U32)
> > > + * @NFTA_HASH_SUM: Hash offset value (NLA_U32)
> > > */
> > > enum nft_hash_attributes {
> > > NFTA_HASH_UNSPEC,
> > > @@ -772,6 +773,7 @@ enum nft_hash_attributes {
> > > NFTA_HASH_LEN,
> > > NFTA_HASH_MODULUS,
> > > NFTA_HASH_SEED,
> > > + NFTA_HASH_SUM,
> > > __NFTA_HASH_MAX,
> > > };
> > > #define NFTA_HASH_MAX (__NFTA_HASH_MAX - 1)
> > > diff --git a/net/netfilter/nft_hash.c b/net/netfilter/nft_hash.c
> > > index b7e3b40..8ab04d9 100644
> > > --- a/net/netfilter/nft_hash.c
> > > +++ b/net/netfilter/nft_hash.c
> > > @@ -23,6 +23,7 @@ struct nft_hash {
> > > u8 len;
> > > u32 modulus;
> > > u32 seed;
> > > + u32 sum;
> > > };
> > >
> > > static void nft_hash_eval(const struct nft_expr *expr,
> > > @@ -35,7 +36,7 @@ static void nft_hash_eval(const struct nft_expr *expr,
> > >
> > > h = reciprocal_scale(jhash(data, priv->len, priv->seed), priv->modulus);
> > >
> > > - regs->data[priv->dreg] = h;
> > > + regs->data[priv->dreg] = priv->sum + h;
> > > }
> > >
> > > const struct nla_policy nft_hash_policy[NFTA_HASH_MAX + 1] = {
> > > @@ -44,6 +45,7 @@ const struct nla_policy nft_hash_policy[NFTA_HASH_MAX + 1] = {
> > > [NFTA_HASH_LEN] = { .type = NLA_U32 },
> > > [NFTA_HASH_MODULUS] = { .type = NLA_U32 },
> > > [NFTA_HASH_SEED] = { .type = NLA_U32 },
> > > + [NFTA_HASH_SUM] = { .type = NLA_U32 },
> > > };
> > >
> > > static int nft_hash_init(const struct nft_ctx *ctx,
> > > @@ -60,6 +62,11 @@ static int nft_hash_init(const struct nft_ctx *ctx,
> > > !tb[NFTA_HASH_MODULUS])
> > > return -EINVAL;
> > >
> > > + if (tb[NFTA_HASH_SUM])
> > > + priv->sum = ntohl(nla_get_be32(tb[NFTA_HASH_SUM]));
> > > + else
> > > + priv->sum = 0;
> >
> > There is a corner case that we should reject from the kernel, I think
> > this is:
> >
> > if (priv->sum + priv->modulus - 1 < priv->sum)
> > return -EOVERFLOW;
> >
> > We'll handle this from userspace anyway too, but I think it's easy to
> > reject this crazy this.
>
> Such case shouldn't happen cause the modulus must be > 1. The init()
> provides:
>
> priv->modulus = ntohl(nla_get_be32(tb[NFTA_HASH_MODULUS]));
> if (priv->modulus <= 1)
> return -ERANGE;
I don't see how this is preventing an overflow of hash(x) + sum.
^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2016-09-05 10:09 UTC | newest]
Thread overview: 4+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2016-09-05 8:36 [PATCH] netfilter: nft_hash: Add hash offset value Laura Garcia Liebana
2016-09-05 9:10 ` Pablo Neira Ayuso
2016-09-05 9:58 ` Laura Garcia
2016-09-05 10:09 ` Pablo Neira Ayuso
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).