From: Florian Westphal <fw@strlen.de>
To: Pablo Neira Ayuso <pablo@netfilter.org>
Cc: netfilter-devel@vger.kernel.org
Subject: Re: [PATCH nf 1/2] netfilter: nf_tables: registers should not go over NFT_REG32_NUM
Date: Thu, 17 Mar 2022 13:53:13 +0100 [thread overview]
Message-ID: <20220317125313.GB9722@breakpoint.cc> (raw)
In-Reply-To: <20220317123937.21345-1-pablo@netfilter.org>
Pablo Neira Ayuso <pablo@netfilter.org> wrote:
> Bail out in case userspace uses registers over maximum number of register.
>
> Fixes: 49499c3e6e18 ("netfilter: nf_tables: switch registers to 32 bit addressing")
> Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
> ---
> net/netfilter/nf_tables_api.c | 23 ++++++++++++++++++-----
> 1 file changed, 18 insertions(+), 5 deletions(-)
>
> diff --git a/net/netfilter/nf_tables_api.c b/net/netfilter/nf_tables_api.c
> index d71a33ae39b3..829ecd310ae6 100644
> --- a/net/netfilter/nf_tables_api.c
> +++ b/net/netfilter/nf_tables_api.c
> @@ -9275,17 +9275,24 @@ 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));
> + if (reg >= NFT_REG32_NUM)
> + return -ERANGE;
> +
This breaks userspace.
NFT_REG32_00 is 8, so this makes NFT_REG32_13, 14 and 15 invalid.
next prev parent reply other threads:[~2022-03-17 12:53 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-03-17 12:39 [PATCH nf 1/2] netfilter: nf_tables: registers should not go over NFT_REG32_NUM Pablo Neira Ayuso
2022-03-17 12:39 ` [PATCH nf 2/2] netfilter: nf_tables: initialize registers in nft_do_chain() Pablo Neira Ayuso
2022-03-17 12:53 ` Florian Westphal [this message]
2022-03-17 13:08 ` [PATCH nf 1/2] netfilter: nf_tables: registers should not go over NFT_REG32_NUM Pablo Neira Ayuso
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