Commit 22d4536d authored by Florian Westphal's avatar Florian Westphal Committed by Pablo Neira Ayuso
Browse files

netfilter: conntrack: handle initial extension alloc via krealloc 



krealloc(NULL, ..) is same as kmalloc(), so we can avoid special-casing
the initial allocation after the prealloc removal (we had to use
->alloc_len as the initial allocation size).

This also means we do not zero the preallocated memory anymore; only
offsets[].  Existing code makes sure the new (used) extension space gets
zeroed out.

Signed-off-by: default avatarFlorian Westphal <fw@strlen.de>
Signed-off-by: default avatarPablo Neira Ayuso <pablo@netfilter.org>
parent 23f671a1

net/netfilter/nf_conntrack_extend.c

+15 −36
Original line number Diff line number Diff line
@@ -44,49 +44,24 @@ void __nf_ct_ext_destroy(struct nf_conn *ct) 
}

EXPORT_SYMBOL(__nf_ct_ext_destroy);



static void *

nf_ct_ext_create(struct nf_ct_ext **ext, enum nf_ct_ext_id id, gfp_t gfp)

{

	unsigned int off, len, alloc;

	struct nf_ct_ext_type *t;



	rcu_read_lock();

	t = rcu_dereference(nf_ct_ext_types[id]);

	if (!t) {

		rcu_read_unlock();

		return NULL;

	}



	off = ALIGN(sizeof(struct nf_ct_ext), t->align);

	len = off + t->len;

	rcu_read_unlock();



	alloc = max(len, NF_CT_EXT_PREALLOC);

	*ext = kzalloc(alloc, gfp);

	if (!*ext)

		return NULL;



	(*ext)->offset[id] = off;

	(*ext)->len = len;



	return (void *)(*ext) + off;

}



void *nf_ct_ext_add(struct nf_conn *ct, enum nf_ct_ext_id id, gfp_t gfp)

{

	unsigned int newlen, newoff, oldlen, alloc;

	struct nf_ct_ext *old, *new;

	int newlen, newoff;

	struct nf_ct_ext_type *t;



	/* Conntrack must not be confirmed to avoid races on reallocation. */

	NF_CT_ASSERT(!nf_ct_is_confirmed(ct));



	old = ct->ext;

	if (!old)

		return nf_ct_ext_create(&ct->ext, id, gfp);



	if (old) {

		if (__nf_ct_ext_exist(old, id))

			return NULL;

		oldlen = old->len;

	} else {

		oldlen = sizeof(*new);

	}



	rcu_read_lock();

	t = rcu_dereference(nf_ct_ext_types[id]);
@@ -95,15 +70,19 @@ void *nf_ct_ext_add(struct nf_conn *ct, enum nf_ct_ext_id id, gfp_t gfp) 
		return NULL;

	}



	newoff = ALIGN(old->len, t->align);

	newoff = ALIGN(oldlen, t->align);

	newlen = newoff + t->len;

	rcu_read_unlock();



	new = __krealloc(old, newlen, gfp);

	alloc = max(newlen, NF_CT_EXT_PREALLOC);

	new = __krealloc(old, alloc, gfp);

	if (!new)

		return NULL;



	if (new != old) {

	if (!old) {

		memset(new->offset, 0, sizeof(new->offset));

		ct->ext = new;

	} else if (new != old) {

		kfree_rcu(old, rcu);

		rcu_assign_pointer(ct->ext, new);

	}

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