Patch "netfilter: nf_tables: fully validate NFT_DATA_VALUE on store to data registers" has been added to the 5.4-stable tree

[Sasha Levin <sashal@xxxxxxxxxx>]

This is a note to let you know that I've just added the patch titled

    netfilter: nf_tables: fully validate NFT_DATA_VALUE on store to data registers

to the 5.4-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     netfilter-nf_tables-fully-validate-nft_data_value-on.patch
and it can be found in the queue-5.4 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.



commit d1bbb2c6d766332914f313e9b2b90c1e88600f84
Author: Pablo Neira Ayuso <pablo@xxxxxxxxxxxxx>
Date:   Wed Jun 26 23:15:38 2024 +0200

    netfilter: nf_tables: fully validate NFT_DATA_VALUE on store to data registers
    
    [ Upstream commit 7931d32955e09d0a11b1fe0b6aac1bfa061c005c ]
    
    register store validation for NFT_DATA_VALUE is conditional, however,
    the datatype is always either NFT_DATA_VALUE or NFT_DATA_VERDICT. This
    only requires a new helper function to infer the register type from the
    set datatype so this conditional check can be removed. Otherwise,
    pointer to chain object can be leaked through the registers.
    
    Fixes: 96518518cc41 ("netfilter: add nftables")
    Reported-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxx>
    Signed-off-by: Pablo Neira Ayuso <pablo@xxxxxxxxxxxxx>
    Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>

diff --git a/include/net/netfilter/nf_tables.h b/include/net/netfilter/nf_tables.h
index cf314ce2fd178..4f77e2f8e1ca8 100644
--- a/include/net/netfilter/nf_tables.h
+++ b/include/net/netfilter/nf_tables.h
@@ -467,6 +467,11 @@ static inline void *nft_set_priv(const struct nft_set *set)
 	return (void *)set->data;
 }
 
+static inline enum nft_data_types nft_set_datatype(const struct nft_set *set)
+{
+	return set->dtype == NFT_DATA_VERDICT ? NFT_DATA_VERDICT : NFT_DATA_VALUE;
+}
+
 static inline bool nft_set_gc_is_pending(const struct nft_set *s)
 {
 	return refcount_read(&s->refs) != 1;
diff --git a/net/netfilter/nf_tables_api.c b/net/netfilter/nf_tables_api.c
index 44d4d97b45d13..ddbb0f4bff427 100644
--- a/net/netfilter/nf_tables_api.c
+++ b/net/netfilter/nf_tables_api.c
@@ -4301,8 +4301,7 @@ static int nf_tables_fill_setelem(struct sk_buff *skb,
 
 	if (nft_set_ext_exists(ext, NFT_SET_EXT_DATA) &&
 	    nft_data_dump(skb, NFTA_SET_ELEM_DATA, nft_set_ext_data(ext),
-			  set->dtype == NFT_DATA_VERDICT ? NFT_DATA_VERDICT : NFT_DATA_VALUE,
-			  set->dlen) < 0)
+			  nft_set_datatype(set), set->dlen) < 0)
 		goto nla_put_failure;
 
 	if (nft_set_ext_exists(ext, NFT_SET_EXT_EXPR) &&
@@ -8048,6 +8047,9 @@ static int nft_validate_register_store(const struct nft_ctx *ctx,
 
 		return 0;
 	default:
+		if (type != NFT_DATA_VALUE)
+			return -EINVAL;
+
 		if (reg < NFT_REG_1 * NFT_REG_SIZE / NFT_REG32_SIZE)
 			return -EINVAL;
 		if (len == 0)
@@ -8056,8 +8058,6 @@ static int nft_validate_register_store(const struct nft_ctx *ctx,
 		    FIELD_SIZEOF(struct nft_regs, data))
 			return -ERANGE;
 
-		if (data != NULL && type != NFT_DATA_VALUE)
-			return -EINVAL;
 		return 0;
 	}
 }
diff --git a/net/netfilter/nft_lookup.c b/net/netfilter/nft_lookup.c
index e0ffd463a1320..6d49b82d598ae 100644
--- a/net/netfilter/nft_lookup.c
+++ b/net/netfilter/nft_lookup.c
@@ -98,7 +98,8 @@ static int nft_lookup_init(const struct nft_ctx *ctx,
 			return -EINVAL;
 
 		err = nft_parse_register_store(ctx, tb[NFTA_LOOKUP_DREG],
-					       &priv->dreg, NULL, set->dtype,
+					       &priv->dreg, NULL,
+					       nft_set_datatype(set),
 					       set->dlen);
 		if (err < 0)
 			return err;