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FAILED: patch "[PATCH] netfilter: nf_tables: upfront validation of data via" failed to apply to 5.10-stable tree

PATCH [email protected] 1 participant 1 message Aug 13, 2022

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The patch below does not apply to the 5.10-stable tree.
If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <[email protected]>.

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From 341b6941608762d8235f3fd1e45e4d7114ed8c2c Mon Sep 17 00:00:00 2001
From: Pablo Neira Ayuso <[email protected]>
Date: Mon, 8 Aug 2022 19:30:06 +0200
Subject: [PATCH] netfilter: nf_tables: upfront validation of data via
nft_data_init()

Instead of parsing the data and then validate that type and length are correct, pass a description of the expected data so it can be validated upfront before parsing it to bail out earlier.

This patch adds a new .size field to specify the maximum size of the data area. The .len field is optional and it is used as an input/output field, it provides the specific length of the expected data in the input path. If then .len field is not specified, then obtained length from the netlink attribute is stored. This is required by cmp, bitwise, range and immediate, which provide no netlink attribute that describes the data length. The immediate expression uses the destination register type to infer the expected data type.

Relying on opencoded validation of the expected data might lead to subtle bugs as described in 7e6bc1f6cabc ("netfilter: nf_tables:
stricter validation of element data").

Signed-off-by Pablo Neira Ayuso <[email protected]>
include/net/netfilter/nf_tables.h +2 -2
index 7ece4fd0cf66..1554f1e7215b 100644
@@ -223,11 +223,11 @@ struct nft_ctx {
 
 struct nft_data_desc {
 	enum nft_data_types		type;
+	unsigned int			size;
 	unsigned int			len;
 };
 
-int nft_data_init(const struct nft_ctx *ctx,
-		  struct nft_data *data, unsigned int size,
+int nft_data_init(const struct nft_ctx *ctx, struct nft_data *data,
 		  struct nft_data_desc *desc, const struct nlattr *nla);
 void nft_data_hold(const struct nft_data *data, enum nft_data_types type);
 void nft_data_release(const struct nft_data *data, enum nft_data_types type);
net/netfilter/nf_tables_api.c +40 -38

141 lines not on this page · raw message

net/netfilter/nft_bitwise.c +33 -33

112 lines not on this page · raw message

net/netfilter/nft_cmp.c +20 -24

94 lines not on this page · raw message

net/netfilter/nft_immediate.c +19 -3
index b80f7b507349..5f28b21abc7d 100644
@@ -29,20 +29,36 @@ static const struct nla_policy nft_immediate_policy[NFTA_IMMEDIATE_MAX + 1] = {
 	[NFTA_IMMEDIATE_DATA]	= { .type = NLA_NESTED },
 };
 
+static enum nft_data_types nft_reg_to_type(const struct nlattr *nla)
+{
+	enum nft_data_types type;
+	u8 reg;
+
+	reg = ntohl(nla_get_be32(nla));
+	if (reg == NFT_REG_VERDICT)
+		type = NFT_DATA_VERDICT;
+	else
+		type = NFT_DATA_VALUE;
+
+	return type;
+}
+
 static int nft_immediate_init(const struct nft_ctx *ctx,
 			      const struct nft_expr *expr,
 			      const struct nlattr * const tb[])
 {
 	struct nft_immediate_expr *priv = nft_expr_priv(expr);
-	struct nft_data_desc desc;
+	struct nft_data_desc desc = {
+		.size	= sizeof(priv->data),
+	};
 	int err;
 
 	if (tb[NFTA_IMMEDIATE_DREG] == NULL ||
 	    tb[NFTA_IMMEDIATE_DATA] == NULL)
 		return -EINVAL;
 
-	err = nft_data_init(ctx, &priv->data, sizeof(priv->data), &desc,
-			    tb[NFTA_IMMEDIATE_DATA]);
+	desc.type = nft_reg_to_type(tb[NFTA_IMMEDIATE_DREG]);
+	err = nft_data_init(ctx, &priv->data, &desc, tb[NFTA_IMMEDIATE_DATA]);
 	if (err < 0)
 		return err;
net/netfilter/nft_range.c +12 -15
index 66f77484c227..832f0d725a9e 100644
@@ -51,7 +51,14 @@ static int nft_range_init(const struct nft_ctx *ctx, const struct nft_expr *expr
 			const struct nlattr * const tb[])
 {
 	struct nft_range_expr *priv = nft_expr_priv(expr);
-	struct nft_data_desc desc_from, desc_to;
+	struct nft_data_desc desc_from = {
+		.type	= NFT_DATA_VALUE,
+		.size	= sizeof(priv->data_from),
+	};
+	struct nft_data_desc desc_to = {
+		.type	= NFT_DATA_VALUE,
+		.size	= sizeof(priv->data_to),
+	};
 	int err;
 	u32 op;
 

@@ -61,26 +68,16 @@ static int nft_range_init(const struct nft_ctx *ctx, const struct nft_expr *expr
 	    !tb[NFTA_RANGE_TO_DATA])
 		return -EINVAL;
 
-	err = nft_data_init(NULL, &priv->data_from, sizeof(priv->data_from),
-			    &desc_from, tb[NFTA_RANGE_FROM_DATA]);
+	err = nft_data_init(NULL, &priv->data_from, &desc_from,
+			    tb[NFTA_RANGE_FROM_DATA]);
 	if (err < 0)
 		return err;
 
-	if (desc_from.type != NFT_DATA_VALUE) {
-		err = -EINVAL;
-		goto err1;
-	}
-
-	err = nft_data_init(NULL, &priv->data_to, sizeof(priv->data_to),
-			    &desc_to, tb[NFTA_RANGE_TO_DATA]);
+	err = nft_data_init(NULL, &priv->data_to, &desc_to,
+			    tb[NFTA_RANGE_TO_DATA]);
 	if (err < 0)
 		goto err1;
 
-	if (desc_to.type != NFT_DATA_VALUE) {
-		err = -EINVAL;
-		goto err2;
-	}
-
 	if (desc_from.len != desc_to.len) {
 		err = -EINVAL;
 		goto err2;