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    Subject[PATCH 5.17 21/39] netfilter: nf_tables: validate registers coming from userspace.
    Date
    From: Pablo Neira Ayuso <pablo@netfilter.org>

    commit 6e1acfa387b9ff82cfc7db8cc3b6959221a95851 upstream.

    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>
    Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
    ---
    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
    @@ -9275,17 +9275,23 @@ int nft_parse_u32_check(const struct nla
    }
    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;
    }

    /**
    @@ -9327,7 +9333,10 @@ int nft_parse_register_load(const struct
    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;
    @@ -9382,7 +9391,10 @@ int nft_parse_register_store(const struc
    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;

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