From: Pablo Neira Ayuso <pablo@netfilter.org>
Date: Thu, 17 Mar 2022 11:59:26 +0100
Subject: netfilter: nf_tables: validate registers coming from userspace.
Patch-mainline: v5.18-rc1
Git-commit: 6e1acfa387b9ff82cfc7db8cc3b6959221a95851
References: CVE-2022-1015 bsc#1197227
Bail out in case userspace uses unsupported registers.
Fixes: 49499c3e6e18 ("netfilter: nf_tables: switch registers to 32 bit addressing")
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Acked-by: Michal Kubecek <mkubecek@suse.cz>
---
net/netfilter/nf_tables_api.c | 22 +++++++++++++++++-----
1 file changed, 17 insertions(+), 5 deletions(-)
--- a/net/netfilter/nf_tables_api.c
+++ b/net/netfilter/nf_tables_api.c
@@ -9203,17 +9203,23 @@ int nft_parse_u32_check(const struct nlattr *attr, int max, u32 *dest)
}
EXPORT_SYMBOL_GPL(nft_parse_u32_check);
-static unsigned int nft_parse_register(const struct nlattr *attr)
+static unsigned 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;
}
/**
@@ -9255,7 +9261,10 @@ 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, ®);
+ if (err < 0)
+ return err;
+
err = nft_validate_register_load(reg, len);
if (err < 0)
return err;
@@ -9310,7 +9319,10 @@ int nft_parse_register_store(const struct nft_ctx *ctx,
int err;
u32 reg;
- reg = nft_parse_register(attr);
+ err = nft_parse_register(attr, ®);
+ if (err < 0)
+ return err;
+
err = nft_validate_register_store(ctx, reg, data, type, len);
if (err < 0)
return err;