mirror of https://gitee.com/openkylin/linux.git
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: Florian Westphal <fw@strlen.de> Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
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@ -44,49 +44,24 @@ void __nf_ct_ext_destroy(struct nf_conn *ct)
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}
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EXPORT_SYMBOL(__nf_ct_ext_destroy);
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static void *
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nf_ct_ext_create(struct nf_ct_ext **ext, enum nf_ct_ext_id id, gfp_t gfp)
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{
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unsigned int off, len, alloc;
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struct nf_ct_ext_type *t;
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rcu_read_lock();
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t = rcu_dereference(nf_ct_ext_types[id]);
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if (!t) {
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rcu_read_unlock();
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return NULL;
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}
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off = ALIGN(sizeof(struct nf_ct_ext), t->align);
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len = off + t->len;
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rcu_read_unlock();
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alloc = max(len, NF_CT_EXT_PREALLOC);
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*ext = kzalloc(alloc, gfp);
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if (!*ext)
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return NULL;
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(*ext)->offset[id] = off;
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(*ext)->len = len;
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return (void *)(*ext) + off;
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}
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void *nf_ct_ext_add(struct nf_conn *ct, enum nf_ct_ext_id id, gfp_t gfp)
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{
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unsigned int newlen, newoff, oldlen, alloc;
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struct nf_ct_ext *old, *new;
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int newlen, newoff;
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struct nf_ct_ext_type *t;
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/* Conntrack must not be confirmed to avoid races on reallocation. */
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NF_CT_ASSERT(!nf_ct_is_confirmed(ct));
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old = ct->ext;
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if (!old)
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return nf_ct_ext_create(&ct->ext, id, gfp);
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if (__nf_ct_ext_exist(old, id))
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return NULL;
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if (old) {
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if (__nf_ct_ext_exist(old, id))
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return NULL;
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oldlen = old->len;
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} else {
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oldlen = sizeof(*new);
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}
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rcu_read_lock();
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t = rcu_dereference(nf_ct_ext_types[id]);
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@ -95,15 +70,19 @@ void *nf_ct_ext_add(struct nf_conn *ct, enum nf_ct_ext_id id, gfp_t gfp)
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return NULL;
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}
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newoff = ALIGN(old->len, t->align);
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newoff = ALIGN(oldlen, t->align);
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newlen = newoff + t->len;
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rcu_read_unlock();
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new = __krealloc(old, newlen, gfp);
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alloc = max(newlen, NF_CT_EXT_PREALLOC);
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new = __krealloc(old, alloc, gfp);
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if (!new)
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return NULL;
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if (new != old) {
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if (!old) {
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memset(new->offset, 0, sizeof(new->offset));
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ct->ext = new;
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} else if (new != old) {
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kfree_rcu(old, rcu);
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rcu_assign_pointer(ct->ext, new);
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}
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