Re: [PATCH 4.19 233/422] netfilter: nf_tables: avoid BUG_ON usage

From: Pavel Machek
Date: Thu Nov 21 2019 - 15:16:38 EST


Hi!

> From: Florian Westphal <fw@xxxxxxxxx>
>
> [ Upstream commit fa5950e498e7face21a1761f327e6c1152f778c3 ]
>
> None of these spots really needs to crash the kernel.
> In one two cases we can jsut report error to userspace, in the other
> cases we can just use WARN_ON (and leak memory instead).

Do these conditions trigger for someone, to warrant -stable patch?

> +++ b/net/netfilter/nft_cmp.c
> @@ -79,7 +79,8 @@ static int nft_cmp_init(const struct nft_ctx *ctx, const struct nft_expr *expr,
>
> err = nft_data_init(NULL, &priv->data, sizeof(priv->data), &desc,
> tb[NFTA_CMP_DATA]);
> - BUG_ON(err < 0);
> + if (err < 0)
> + return err;
>
> priv->sreg = nft_parse_register(tb[NFTA_CMP_SREG]);
> err = nft_validate_register_load(priv->sreg, desc.len);
> @@ -129,7 +130,8 @@ static int nft_cmp_fast_init(const struct nft_ctx *ctx,
>
> err = nft_data_init(NULL, &data, sizeof(data), &desc,
> tb[NFTA_CMP_DATA]);
> - BUG_ON(err < 0);
> + if (err < 0)
> + return err;
>
> priv->sreg = nft_parse_register(tb[NFTA_CMP_SREG]);
> err = nft_validate_register_load(priv->sreg, desc.len);

This goes from "kill kernel with backtrace" to "silently return
failure". Should WARN_ON() be preserved here?

Best regards,
Pavel

--
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html

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