1 files changed, 37 insertions, 17 deletions

diff --git a/net/netfilter/nft_numgen.c b/net/netfilter/nft_numgen.c
index 294745e..55bc5ab 100644
--- a/net/netfilter/nft_numgen.c
+++ b/net/netfilter/nft_numgen.c
@@ -21,8 +21,9 @@ static DEFINE_PER_CPU(struct rnd_state, nft_numgen_prandom_state);
 
 struct nft_ng_inc {
 	enum nft_registers      dreg:8;
-	u32			until;
+	u32			modulus;
 	atomic_t		counter;
+	u32			offset;
 };
 
 static void nft_ng_inc_eval(const struct nft_expr *expr,
@@ -34,16 +35,17 @@ static void nft_ng_inc_eval(const struct nft_expr *expr,
 
 	do {
 		oval = atomic_read(&priv->counter);
-		nval = (oval + 1 < priv->until) ? oval + 1 : 0;
+		nval = (oval + 1 < priv->modulus) ? oval + 1 : 0;
 	} while (atomic_cmpxchg(&priv->counter, oval, nval) != oval);
 
-	memcpy(&regs->data[priv->dreg], &priv->counter, sizeof(u32));
+	regs->data[priv->dreg] = nval + priv->offset;
 }
 
 static const struct nla_policy nft_ng_policy[NFTA_NG_MAX + 1] = {
 	[NFTA_NG_DREG]		= { .type = NLA_U32 },
-	[NFTA_NG_UNTIL]		= { .type = NLA_U32 },
+	[NFTA_NG_MODULUS]	= { .type = NLA_U32 },
 	[NFTA_NG_TYPE]		= { .type = NLA_U32 },
+	[NFTA_NG_OFFSET]	= { .type = NLA_U32 },
 };
 
 static int nft_ng_inc_init(const struct nft_ctx *ctx,
@@ -52,10 +54,16 @@ static int nft_ng_inc_init(const struct nft_ctx *ctx,
 {
 	struct nft_ng_inc *priv = nft_expr_priv(expr);
 
-	priv->until = ntohl(nla_get_be32(tb[NFTA_NG_UNTIL]));
-	if (priv->until == 0)
+	if (tb[NFTA_NG_OFFSET])
+		priv->offset = ntohl(nla_get_be32(tb[NFTA_NG_OFFSET]));
+
+	priv->modulus = ntohl(nla_get_be32(tb[NFTA_NG_MODULUS]));
+	if (priv->modulus == 0)
 		return -ERANGE;
 
+	if (priv->offset + priv->modulus - 1 < priv->offset)
+		return -EOVERFLOW;
+
 	priv->dreg = nft_parse_register(tb[NFTA_NG_DREG]);
 	atomic_set(&priv->counter, 0);
 
@@ -64,14 +72,16 @@ static int nft_ng_inc_init(const struct nft_ctx *ctx,
 }
 
 static int nft_ng_dump(struct sk_buff *skb, enum nft_registers dreg,
-		       u32 until, enum nft_ng_types type)
+		       u32 modulus, enum nft_ng_types type, u32 offset)
 {
 	if (nft_dump_register(skb, NFTA_NG_DREG, dreg))
 		goto nla_put_failure;
-	if (nla_put_be32(skb, NFTA_NG_UNTIL, htonl(until)))
+	if (nla_put_be32(skb, NFTA_NG_MODULUS, htonl(modulus)))
 		goto nla_put_failure;
 	if (nla_put_be32(skb, NFTA_NG_TYPE, htonl(type)))
 		goto nla_put_failure;
+	if (nla_put_be32(skb, NFTA_NG_OFFSET, htonl(offset)))
+		goto nla_put_failure;
 
 	return 0;
 
@@ -83,12 +93,14 @@ static int nft_ng_inc_dump(struct sk_buff *skb, const struct nft_expr *expr)
 {
 	const struct nft_ng_inc *priv = nft_expr_priv(expr);
 
-	return nft_ng_dump(skb, priv->dreg, priv->until, NFT_NG_INCREMENTAL);
+	return nft_ng_dump(skb, priv->dreg, priv->modulus, NFT_NG_INCREMENTAL,
+			   priv->offset);
 }
 
 struct nft_ng_random {
 	enum nft_registers      dreg:8;
-	u32			until;
+	u32			modulus;
+	u32			offset;
 };
 
 static void nft_ng_random_eval(const struct nft_expr *expr,
@@ -97,9 +109,10 @@ static void nft_ng_random_eval(const struct nft_expr *expr,
 {
 	struct nft_ng_random *priv = nft_expr_priv(expr);
 	struct rnd_state *state = this_cpu_ptr(&nft_numgen_prandom_state);
+	u32 val;
 
-	regs->data[priv->dreg] = reciprocal_scale(prandom_u32_state(state),
-						  priv->until);
+	val = reciprocal_scale(prandom_u32_state(state), priv->modulus);
+	regs->data[priv->dreg] = val + priv->offset;
 }
 
 static int nft_ng_random_init(const struct nft_ctx *ctx,
@@ -108,10 +121,16 @@ static int nft_ng_random_init(const struct nft_ctx *ctx,
 {
 	struct nft_ng_random *priv = nft_expr_priv(expr);
 
-	priv->until = ntohl(nla_get_be32(tb[NFTA_NG_UNTIL]));
-	if (priv->until == 0)
+	if (tb[NFTA_NG_OFFSET])
+		priv->offset = ntohl(nla_get_be32(tb[NFTA_NG_OFFSET]));
+
+	priv->modulus = ntohl(nla_get_be32(tb[NFTA_NG_MODULUS]));
+	if (priv->modulus == 0)
 		return -ERANGE;
 
+	if (priv->offset + priv->modulus - 1 < priv->offset)
+		return -EOVERFLOW;
+
 	prandom_init_once(&nft_numgen_prandom_state);
 
 	priv->dreg = nft_parse_register(tb[NFTA_NG_DREG]);
@@ -124,7 +143,8 @@ static int nft_ng_random_dump(struct sk_buff *skb, const struct nft_expr *expr)
 {
 	const struct nft_ng_random *priv = nft_expr_priv(expr);
 
-	return nft_ng_dump(skb, priv->dreg, priv->until, NFT_NG_RANDOM);
+	return nft_ng_dump(skb, priv->dreg, priv->modulus, NFT_NG_RANDOM,
+			   priv->offset);
 }
 
 static struct nft_expr_type nft_ng_type;
@@ -149,8 +169,8 @@ nft_ng_select_ops(const struct nft_ctx *ctx, const struct nlattr * const tb[])
 {
 	u32 type;
 
-	if (!tb[NFTA_NG_DREG]	||
-	    !tb[NFTA_NG_UNTIL]	||
+	if (!tb[NFTA_NG_DREG]	 ||
+	    !tb[NFTA_NG_MODULUS] ||
 	    !tb[NFTA_NG_TYPE])
 		return ERR_PTR(-EINVAL);