From: Pablo Neira Ayuso <pablo@netfilter.org>
Date: Tue, 16 May 2023 14:44:30 +0000 (+0200)
Subject: netfilter: nf_tables: validate registers coming from userspace.
X-Git-Tag: baikal/aarch64/sdk5.10~56
X-Git-Url: https://git.baikalelectronics.ru/sdk/?a=commitdiff_plain;h=a60661352d5a05ade59567d1562b12d6a0121853;p=kernel.git

netfilter: nf_tables: validate registers coming from userspace.

[ bfcfe6b3cdd49aec05edc762572828e0e1d9c7e3 ]

Bail out in case userspace uses unsupported registers.

Fixes: 73590c994412 ("netfilter: nf_tables: switch registers to 32 bit addressing")
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---

diff --git a/net/netfilter/nf_tables_api.c b/net/netfilter/nf_tables_api.c
index 8a0095664e619..a90bf82ea1435 100644
--- a/net/netfilter/nf_tables_api.c
+++ b/net/netfilter/nf_tables_api.c
@@ -7384,26 +7384,23 @@ int nft_parse_u32_check(const struct nlattr *attr, int max, u32 *dest)
 }
 EXPORT_SYMBOL_GPL(nft_parse_u32_check);
 
-/**
- *	nft_parse_register - parse a register value from a netlink attribute
- *
- *	@attr: netlink attribute
- *
- *	Parse and translate a register value from a netlink attribute.
- *	Registers used to be 128 bit wide, these register numbers will be
- *	mapped to the corresponding 32 bit register numbers.
- */
-static unsigned int nft_parse_register(const struct nlattr *attr)
+static int nft_parse_register(const struct nlattr *attr, u32 *preg)
 {
 	unsigned int reg;
 
 	reg = ntohl(nla_get_be32(attr));
 	switch (reg) {
 	case NFT_REG_VERDICT...NFT_REG_4:
-		return reg * NFT_REG_SIZE / NFT_REG32_SIZE;
+		*preg = reg * NFT_REG_SIZE / NFT_REG32_SIZE;
+		break;
+	case NFT_REG32_00...NFT_REG32_15:
+		*preg = reg + NFT_REG_SIZE / NFT_REG32_SIZE - NFT_REG32_00;
+		break;
 	default:
-		return reg + NFT_REG_SIZE / NFT_REG32_SIZE - NFT_REG32_00;
+		return -ERANGE;
 	}
+
+	return 0;
 }
 
 /**
@@ -7454,7 +7451,10 @@ int nft_parse_register_load(const struct nlattr *attr, u8 *sreg, u32 len)
 	u32 reg;
 	int err;
 
-	reg = nft_parse_register(attr);
+	err = nft_parse_register(attr, &reg);
+	if (err < 0)
+		return err;
+
 	err = nft_validate_register_load(reg, len);
 	if (err < 0)
 		return err;
@@ -7523,7 +7523,10 @@ int nft_parse_register_store(const struct nft_ctx *ctx,
 	int err;
 	u32 reg;
 
-	reg = nft_parse_register(attr);
+	err = nft_parse_register(attr, &reg);
+	if (err < 0)
+		return err;
+
 	err = nft_validate_register_store(ctx, reg, data, type, len);
 	if (err < 0)
 		return err;