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From: Phil Sutter <phil@nwl.cc>
To: Florian Westphal <fw@strlen.de>
Cc: netfilter-devel <netfilter-devel@vger.kernel.org>
Subject: Re: [PATCH v3 iptables-nft 1/3] xlate: get rid of escape_quotes
Date: Wed, 30 Nov 2022 13:35:08 +0100	[thread overview]
Message-ID: <Y4dN/NLxE2miZaFZ@orbyte.nwl.cc> (raw)
In-Reply-To: <20221130093154.29004-2-fw@strlen.de>

On Wed, Nov 30, 2022 at 10:31:52AM +0100, Florian Westphal wrote:
> Its not necessary to escape " characters, we can let xtables-translate
> print the entire translation/command enclosed in '' chracters, i.e. nft
> 'add rule ...', this also takes care of [, { and other special characters
> that some shells might parse otherwise (when copy-pasting translated output).
> 
> The escape_quotes struct member is retained to avoid an ABI breakage.
> 
> This breaks all xlate test cases, fixup in followup patches.
> 
> v3: no need to escape ', replace strcmp(x, "") with x[0] (Phil Sutter)
> 
> Signed-off-by: Florian Westphal <fw@strlen.de>
> ---
>  extensions/libebt_log.c         |  8 ++------
>  extensions/libebt_nflog.c       |  8 ++------
>  extensions/libxt_LOG.c          | 10 +++-------
>  extensions/libxt_NFLOG.c        | 12 ++++--------
>  extensions/libxt_comment.c      |  7 +------
>  extensions/libxt_helper.c       |  8 ++------
>  include/xtables.h               |  4 ++--
>  iptables/nft-bridge.c           |  2 --
>  iptables/xtables-eb-translate.c | 12 ++++++------
>  iptables/xtables-translate.c    | 22 ++++++++++------------
>  10 files changed, 32 insertions(+), 61 deletions(-)
> 
> diff --git a/extensions/libebt_log.c b/extensions/libebt_log.c
> index 13c7fafecb11..045062196d20 100644
> --- a/extensions/libebt_log.c
> +++ b/extensions/libebt_log.c
> @@ -181,12 +181,8 @@ static int brlog_xlate(struct xt_xlate *xl,
>  	const struct ebt_log_info *loginfo = (const void *)params->target->data;
>  
>  	xt_xlate_add(xl, "log");
> -	if (loginfo->prefix[0]) {
> -		if (params->escape_quotes)
> -			xt_xlate_add(xl, " prefix \\\"%s\\\"", loginfo->prefix);
> -		else
> -			xt_xlate_add(xl, " prefix \"%s\"", loginfo->prefix);
> -	}
> +	if (loginfo->prefix[0])
> +		xt_xlate_add(xl, " prefix \"%s\"", loginfo->prefix);
>  
>  	if (loginfo->loglevel != LOG_DEFAULT_LEVEL)
>  		xt_xlate_add(xl, " level %s", eight_priority[loginfo->loglevel].c_name);
> diff --git a/extensions/libebt_nflog.c b/extensions/libebt_nflog.c
> index 9801f358c81b..115e15da4584 100644
> --- a/extensions/libebt_nflog.c
> +++ b/extensions/libebt_nflog.c
> @@ -130,12 +130,8 @@ static int brnflog_xlate(struct xt_xlate *xl,
>  	const struct ebt_nflog_info *info = (void *)params->target->data;
>  
>  	xt_xlate_add(xl, "log ");
> -	if (info->prefix[0] != '\0') {
> -		if (params->escape_quotes)
> -			xt_xlate_add(xl, "prefix \\\"%s\\\" ", info->prefix);
> -		else
> -			xt_xlate_add(xl, "prefix \"%s\" ", info->prefix);
> -	}
> +	if (info->prefix[0] != '\0')
> +		xt_xlate_add(xl, "prefix \"%s\" ", info->prefix);
>  
>  	xt_xlate_add(xl, "group %u ", info->group);
>  
> diff --git a/extensions/libxt_LOG.c b/extensions/libxt_LOG.c
> index e3f4290ba003..cfde0c7bca6a 100644
> --- a/extensions/libxt_LOG.c
> +++ b/extensions/libxt_LOG.c
> @@ -116,7 +116,7 @@ static void LOG_print(const void *ip, const struct xt_entry_target *target,
>  			printf(" unknown-flags");
>  	}
>  
> -	if (strcmp(loginfo->prefix, "") != 0)
> +	if (loginfo->prefix[0] != 0)
>  		printf(" prefix \"%s\"", loginfo->prefix);
>  }
>  

Wrong spot? Because:

> @@ -151,12 +151,8 @@ static int LOG_xlate(struct xt_xlate *xl,
>  	const char *pname = priority2name(loginfo->level);
>  
>  	xt_xlate_add(xl, "log");
> -	if (strcmp(loginfo->prefix, "") != 0) {
> -		if (params->escape_quotes)
> -			xt_xlate_add(xl, " prefix \\\"%s\\\"", loginfo->prefix);
> -		else
> -			xt_xlate_add(xl, " prefix \"%s\"", loginfo->prefix);
> -	}
> +	if (strcmp(loginfo->prefix, "") != 0)
> +		xt_xlate_add(xl, " prefix \"%s\"", loginfo->prefix);
>  
>  	if (loginfo->level != LOG_DEFAULT_LEVEL && pname)
>  		xt_xlate_add(xl, " level %s", pname);

Here's still strcmp(). Since it doesn't make a difference in the binary
though, I'm fine with leaving the strcmp() calls as-is.

[...]
> diff --git a/iptables/xtables-translate.c b/iptables/xtables-translate.c
> index 4e8db4bedff8..1f16e726d3a7 100644
> --- a/iptables/xtables-translate.c
> +++ b/iptables/xtables-translate.c
[...]
> @@ -150,6 +148,7 @@ static int nft_rule_xlate_add(struct nft_handle *h,
>  			      bool append)
>  {
>  	struct xt_xlate *xl = xt_xlate_alloc(10240);
> +	const char *tick = cs->restore ? "" : "\'";

Left-over tick escaping here.

Thanks, Phil

  reply	other threads:[~2022-11-30 12:35 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-11-30  9:31 [PATCH v3 iptables-nft 0/3] remove escape_quotes support Florian Westphal
2022-11-30  9:31 ` [PATCH v3 iptables-nft 1/3] xlate: get rid of escape_quotes Florian Westphal
2022-11-30 12:35   ` Phil Sutter [this message]
2022-11-30  9:31 ` [PATCH v3 iptables-nft 2/3] extensions: change expected output for new format Florian Westphal
2022-11-30  9:31 ` [PATCH v3 iptables-nft 3/3] xlate-test: avoid shell entanglements Florian Westphal
2022-11-30 19:37 ` [PATCH v3 iptables-nft 0/3] remove escape_quotes support Phil Sutter

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