Re: Patch "netfilter: x_tables: introduce and use xt_copy_counters_from_user" has been added to the 4.4-stable tree

[Luis Henriques <luis.henriques@canonical.com>]

On Wed, Jun 22, 2016 at 09:47:17PM -0700, Greg Kroah-Hartman wrote:
> 
> This is a note to let you know that I've just added the patch titled
> 
>     netfilter: x_tables: introduce and use xt_copy_counters_from_user
> 
> to the 4.4-stable tree which can be found at:
>     http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
> 
> The filename of the patch is:
>      netfilter-x_tables-introduce-and-use-xt_copy_counters_from_user.patch
> and it can be found in the queue-4.4 subdirectory.
> 
> If you, or anyone else, feels it should not be added to the stable tree,
> please let <stable@vger.kernel.org> know about it.
>

This patch is not queued for the 3.14 kernel; was this on purpose, or is
there a good reason for that?  It looks like it's a clean cherry-pick.

Cheers,
--
Lu�s


> 
> From d7591f0c41ce3e67600a982bab6989ef0f07b3ce Mon Sep 17 00:00:00 2001
> From: Florian Westphal <fw@strlen.de>
> Date: Fri, 1 Apr 2016 15:37:59 +0200
> Subject: netfilter: x_tables: introduce and use xt_copy_counters_from_user
> 
> From: Florian Westphal <fw@strlen.de>
> 
> commit d7591f0c41ce3e67600a982bab6989ef0f07b3ce upstream.
> 
> The three variants use same copy&pasted code, condense this into a
> helper and use that.
> 
> Make sure info.name is 0-terminated.
> 
> Signed-off-by: Florian Westphal <fw@strlen.de>
> Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> 
> ---
>  include/linux/netfilter/x_tables.h |    3 +
>  net/ipv4/netfilter/arp_tables.c    |   48 ++----------------------
>  net/ipv4/netfilter/ip_tables.c     |   48 ++----------------------
>  net/ipv6/netfilter/ip6_tables.c    |   49 ++----------------------
>  net/netfilter/x_tables.c           |   74 +++++++++++++++++++++++++++++++++++++
>  5 files changed, 92 insertions(+), 130 deletions(-)
> 
> --- a/include/linux/netfilter/x_tables.h
> +++ b/include/linux/netfilter/x_tables.h
> @@ -248,6 +248,9 @@ int xt_check_match(struct xt_mtchk_param
>  int xt_check_target(struct xt_tgchk_param *, unsigned int size, u_int8_t proto,
>  		    bool inv_proto);
>  
> +void *xt_copy_counters_from_user(const void __user *user, unsigned int len,
> +				 struct xt_counters_info *info, bool compat);
> +
>  struct xt_table *xt_register_table(struct net *net,
>  				   const struct xt_table *table,
>  				   struct xt_table_info *bootstrap,
> --- a/net/ipv4/netfilter/arp_tables.c
> +++ b/net/ipv4/netfilter/arp_tables.c
> @@ -1130,55 +1130,17 @@ static int do_add_counters(struct net *n
>  	unsigned int i;
>  	struct xt_counters_info tmp;
>  	struct xt_counters *paddc;
> -	unsigned int num_counters;
> -	const char *name;
> -	int size;
> -	void *ptmp;
>  	struct xt_table *t;
>  	const struct xt_table_info *private;
>  	int ret = 0;
>  	struct arpt_entry *iter;
>  	unsigned int addend;
> -#ifdef CONFIG_COMPAT
> -	struct compat_xt_counters_info compat_tmp;
>  
> -	if (compat) {
> -		ptmp = &compat_tmp;
> -		size = sizeof(struct compat_xt_counters_info);
> -	} else
> -#endif
> -	{
> -		ptmp = &tmp;
> -		size = sizeof(struct xt_counters_info);
> -	}
> -
> -	if (copy_from_user(ptmp, user, size) != 0)
> -		return -EFAULT;
> -
> -#ifdef CONFIG_COMPAT
> -	if (compat) {
> -		num_counters = compat_tmp.num_counters;
> -		name = compat_tmp.name;
> -	} else
> -#endif
> -	{
> -		num_counters = tmp.num_counters;
> -		name = tmp.name;
> -	}
> -
> -	if (len != size + num_counters * sizeof(struct xt_counters))
> -		return -EINVAL;
> -
> -	paddc = vmalloc(len - size);
> -	if (!paddc)
> -		return -ENOMEM;
> -
> -	if (copy_from_user(paddc, user + size, len - size) != 0) {
> -		ret = -EFAULT;
> -		goto free;
> -	}
> +	paddc = xt_copy_counters_from_user(user, len, &tmp, compat);
> +	if (IS_ERR(paddc))
> +		return PTR_ERR(paddc);
>  
> -	t = xt_find_table_lock(net, NFPROTO_ARP, name);
> +	t = xt_find_table_lock(net, NFPROTO_ARP, tmp.name);
>  	if (IS_ERR_OR_NULL(t)) {
>  		ret = t ? PTR_ERR(t) : -ENOENT;
>  		goto free;
> @@ -1186,7 +1148,7 @@ static int do_add_counters(struct net *n
>  
>  	local_bh_disable();
>  	private = t->private;
> -	if (private->number != num_counters) {
> +	if (private->number != tmp.num_counters) {
>  		ret = -EINVAL;
>  		goto unlock_up_free;
>  	}
> --- a/net/ipv4/netfilter/ip_tables.c
> +++ b/net/ipv4/netfilter/ip_tables.c
> @@ -1313,55 +1313,17 @@ do_add_counters(struct net *net, const v
>  	unsigned int i;
>  	struct xt_counters_info tmp;
>  	struct xt_counters *paddc;
> -	unsigned int num_counters;
> -	const char *name;
> -	int size;
> -	void *ptmp;
>  	struct xt_table *t;
>  	const struct xt_table_info *private;
>  	int ret = 0;
>  	struct ipt_entry *iter;
>  	unsigned int addend;
> -#ifdef CONFIG_COMPAT
> -	struct compat_xt_counters_info compat_tmp;
>  
> -	if (compat) {
> -		ptmp = &compat_tmp;
> -		size = sizeof(struct compat_xt_counters_info);
> -	} else
> -#endif
> -	{
> -		ptmp = &tmp;
> -		size = sizeof(struct xt_counters_info);
> -	}
> -
> -	if (copy_from_user(ptmp, user, size) != 0)
> -		return -EFAULT;
> -
> -#ifdef CONFIG_COMPAT
> -	if (compat) {
> -		num_counters = compat_tmp.num_counters;
> -		name = compat_tmp.name;
> -	} else
> -#endif
> -	{
> -		num_counters = tmp.num_counters;
> -		name = tmp.name;
> -	}
> -
> -	if (len != size + num_counters * sizeof(struct xt_counters))
> -		return -EINVAL;
> -
> -	paddc = vmalloc(len - size);
> -	if (!paddc)
> -		return -ENOMEM;
> -
> -	if (copy_from_user(paddc, user + size, len - size) != 0) {
> -		ret = -EFAULT;
> -		goto free;
> -	}
> +	paddc = xt_copy_counters_from_user(user, len, &tmp, compat);
> +	if (IS_ERR(paddc))
> +		return PTR_ERR(paddc);
>  
> -	t = xt_find_table_lock(net, AF_INET, name);
> +	t = xt_find_table_lock(net, AF_INET, tmp.name);
>  	if (IS_ERR_OR_NULL(t)) {
>  		ret = t ? PTR_ERR(t) : -ENOENT;
>  		goto free;
> @@ -1369,7 +1331,7 @@ do_add_counters(struct net *net, const v
>  
>  	local_bh_disable();
>  	private = t->private;
> -	if (private->number != num_counters) {
> +	if (private->number != tmp.num_counters) {
>  		ret = -EINVAL;
>  		goto unlock_up_free;
>  	}
> --- a/net/ipv6/netfilter/ip6_tables.c
> +++ b/net/ipv6/netfilter/ip6_tables.c
> @@ -1325,55 +1325,16 @@ do_add_counters(struct net *net, const v
>  	unsigned int i;
>  	struct xt_counters_info tmp;
>  	struct xt_counters *paddc;
> -	unsigned int num_counters;
> -	char *name;
> -	int size;
> -	void *ptmp;
>  	struct xt_table *t;
>  	const struct xt_table_info *private;
>  	int ret = 0;
>  	struct ip6t_entry *iter;
>  	unsigned int addend;
> -#ifdef CONFIG_COMPAT
> -	struct compat_xt_counters_info compat_tmp;
>  
> -	if (compat) {
> -		ptmp = &compat_tmp;
> -		size = sizeof(struct compat_xt_counters_info);
> -	} else
> -#endif
> -	{
> -		ptmp = &tmp;
> -		size = sizeof(struct xt_counters_info);
> -	}
> -
> -	if (copy_from_user(ptmp, user, size) != 0)
> -		return -EFAULT;
> -
> -#ifdef CONFIG_COMPAT
> -	if (compat) {
> -		num_counters = compat_tmp.num_counters;
> -		name = compat_tmp.name;
> -	} else
> -#endif
> -	{
> -		num_counters = tmp.num_counters;
> -		name = tmp.name;
> -	}
> -
> -	if (len != size + num_counters * sizeof(struct xt_counters))
> -		return -EINVAL;
> -
> -	paddc = vmalloc(len - size);
> -	if (!paddc)
> -		return -ENOMEM;
> -
> -	if (copy_from_user(paddc, user + size, len - size) != 0) {
> -		ret = -EFAULT;
> -		goto free;
> -	}
> -
> -	t = xt_find_table_lock(net, AF_INET6, name);
> +	paddc = xt_copy_counters_from_user(user, len, &tmp, compat);
> +	if (IS_ERR(paddc))
> +		return PTR_ERR(paddc);
> +	t = xt_find_table_lock(net, AF_INET6, tmp.name);
>  	if (IS_ERR_OR_NULL(t)) {
>  		ret = t ? PTR_ERR(t) : -ENOENT;
>  		goto free;
> @@ -1381,7 +1342,7 @@ do_add_counters(struct net *net, const v
>  
>  	local_bh_disable();
>  	private = t->private;
> -	if (private->number != num_counters) {
> +	if (private->number != tmp.num_counters) {
>  		ret = -EINVAL;
>  		goto unlock_up_free;
>  	}
> --- a/net/netfilter/x_tables.c
> +++ b/net/netfilter/x_tables.c
> @@ -751,6 +751,80 @@ int xt_check_target(struct xt_tgchk_para
>  }
>  EXPORT_SYMBOL_GPL(xt_check_target);
>  
> +/**
> + * xt_copy_counters_from_user - copy counters and metadata from userspace
> + *
> + * @user: src pointer to userspace memory
> + * @len: alleged size of userspace memory
> + * @info: where to store the xt_counters_info metadata
> + * @compat: true if we setsockopt call is done by 32bit task on 64bit kernel
> + *
> + * Copies counter meta data from @user and stores it in @info.
> + *
> + * vmallocs memory to hold the counters, then copies the counter data
> + * from @user to the new memory and returns a pointer to it.
> + *
> + * If @compat is true, @info gets converted automatically to the 64bit
> + * representation.
> + *
> + * The metadata associated with the counters is stored in @info.
> + *
> + * Return: returns pointer that caller has to test via IS_ERR().
> + * If IS_ERR is false, caller has to vfree the pointer.
> + */
> +void *xt_copy_counters_from_user(const void __user *user, unsigned int len,
> +				 struct xt_counters_info *info, bool compat)
> +{
> +	void *mem;
> +	u64 size;
> +
> +#ifdef CONFIG_COMPAT
> +	if (compat) {
> +		/* structures only differ in size due to alignment */
> +		struct compat_xt_counters_info compat_tmp;
> +
> +		if (len <= sizeof(compat_tmp))
> +			return ERR_PTR(-EINVAL);
> +
> +		len -= sizeof(compat_tmp);
> +		if (copy_from_user(&compat_tmp, user, sizeof(compat_tmp)) != 0)
> +			return ERR_PTR(-EFAULT);
> +
> +		strlcpy(info->name, compat_tmp.name, sizeof(info->name));
> +		info->num_counters = compat_tmp.num_counters;
> +		user += sizeof(compat_tmp);
> +	} else
> +#endif
> +	{
> +		if (len <= sizeof(*info))
> +			return ERR_PTR(-EINVAL);
> +
> +		len -= sizeof(*info);
> +		if (copy_from_user(info, user, sizeof(*info)) != 0)
> +			return ERR_PTR(-EFAULT);
> +
> +		info->name[sizeof(info->name) - 1] = '\0';
> +		user += sizeof(*info);
> +	}
> +
> +	size = sizeof(struct xt_counters);
> +	size *= info->num_counters;
> +
> +	if (size != (u64)len)
> +		return ERR_PTR(-EINVAL);
> +
> +	mem = vmalloc(len);
> +	if (!mem)
> +		return ERR_PTR(-ENOMEM);
> +
> +	if (copy_from_user(mem, user, len) == 0)
> +		return mem;
> +
> +	vfree(mem);
> +	return ERR_PTR(-EFAULT);
> +}
> +EXPORT_SYMBOL_GPL(xt_copy_counters_from_user);
> +
>  #ifdef CONFIG_COMPAT
>  int xt_compat_target_offset(const struct xt_target *target)
>  {
> 
> 
> Patches currently in stable-queue which might be from fw@strlen.de are
> 
> queue-4.4/netfilter-x_tables-validate-targets-of-jumps.patch
> queue-4.4/netfilter-x_tables-introduce-and-use-xt_copy_counters_from_user.patch
> queue-4.4/netfilter-arp_tables-simplify-translate_compat_table-args.patch
> queue-4.4/netfilter-x_tables-validate-e-target_offset-early.patch
> queue-4.4/netfilter-x_tables-assert-minimum-target-size.patch
> queue-4.4/netfilter-ip6_tables-simplify-translate_compat_table-args.patch
> queue-4.4/netfilter-x_tables-check-for-bogus-target-offset.patch
> queue-4.4/netfilter-x_tables-add-compat-version-of-xt_check_entry_offsets.patch
> queue-4.4/netfilter-x_tables-don-t-reject-valid-target-size-on-some-architectures.patch
> queue-4.4/netfilter-x_tables-check-standard-target-size-too.patch
> queue-4.4/netfilter-x_tables-xt_compat_match_from_user-doesn-t-need-a-retval.patch
> queue-4.4/netfilter-x_tables-do-compat-validation-via-translate_table.patch
> queue-4.4/netfilter-x_tables-add-and-use-xt_check_entry_offsets.patch
> queue-4.4/netfilter-x_tables-don-t-move-to-non-existent-next-rule.patch
> queue-4.4/netfilter-x_tables-kill-check_entry-helper.patch
> queue-4.4/netfilter-x_tables-validate-all-offsets-and-sizes-in-a-rule.patch
> queue-4.4/netfilter-x_tables-make-sure-e-next_offset-covers-remaining-blob-size.patch
> queue-4.4/netfilter-ip_tables-simplify-translate_compat_table-args.patch
> queue-4.4/netfilter-x_tables-fix-unconditional-helper.patch
> --
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