netfilter: nft_compat: use .release_ops and remove list of extension
Add .release_ops, that is called in case of error at a later stage in the expression initialization path, ie. .select_ops() has been already set up operations and that needs to be undone. This allows us to unwind .select_ops from the error path, ie. release the dynamic operations for this extension. Moreover, allocate one single operation instead of recycling them, this comes at the cost of consuming a bit more memory per rule, but it simplifies the infrastructure. Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
This commit is contained in:
Pablo Neira Ayuso
Родитель
ff8285f818
Коммит
b8e2040063
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@ -690,10 +690,12 @@ static inline void nft_set_gc_batch_add(struct nft_set_gc_batch *gcb,
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gcb->elems[gcb->head.cnt++] = elem;
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}
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struct nft_expr_ops;
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/**
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* struct nft_expr_type - nf_tables expression type
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*
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* @select_ops: function to select nft_expr_ops
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* @release_ops: release nft_expr_ops
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* @ops: default ops, used when no select_ops functions is present
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* @list: used internally
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* @name: Identifier
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@ -706,6 +708,7 @@ static inline void nft_set_gc_batch_add(struct nft_set_gc_batch *gcb,
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struct nft_expr_type {
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const struct nft_expr_ops *(*select_ops)(const struct nft_ctx *,
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const struct nlattr * const tb[]);
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void (*release_ops)(const struct nft_expr_ops *ops);
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const struct nft_expr_ops *ops;
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struct list_head list;
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const char *name;
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@ -2172,6 +2172,7 @@ struct nft_expr *nft_expr_init(const struct nft_ctx *ctx,
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{
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struct nft_expr_info info;
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struct nft_expr *expr;
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struct module *owner;
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int err;
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err = nf_tables_expr_parse(ctx, nla, &info);
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@ -2191,7 +2192,11 @@ struct nft_expr *nft_expr_init(const struct nft_ctx *ctx,
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err3:
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kfree(expr);
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err2:
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module_put(info.ops->type->owner);
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owner = info.ops->type->owner;
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if (info.ops->type->release_ops)
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info.ops->type->release_ops(info.ops);
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module_put(owner);
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err1:
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return ERR_PTR(err);
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}
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@ -22,23 +22,6 @@
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#include <linux/netfilter_bridge/ebtables.h>
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#include <linux/netfilter_arp/arp_tables.h>
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#include <net/netfilter/nf_tables.h>
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#include <net/netns/generic.h>
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struct nft_xt {
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struct list_head head;
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struct nft_expr_ops ops;
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refcount_t refcnt;
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/* used only when transaction mutex is locked */
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unsigned int listcnt;
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/* Unlike other expressions, ops doesn't have static storage duration.
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* nft core assumes they do. We use kfree_rcu so that nft core can
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* can check expr->ops->size even after nft_compat->destroy() frees
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* the nft_xt struct that holds the ops structure.
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*/
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struct rcu_head rcu_head;
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};
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/* Used for matches where *info is larger than X byte */
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#define NFT_MATCH_LARGE_THRESH 192
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@ -47,46 +30,6 @@ struct nft_xt_match_priv {
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void *info;
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};
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struct nft_compat_net {
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struct list_head nft_target_list;
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struct list_head nft_match_list;
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};
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static unsigned int nft_compat_net_id __read_mostly;
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static struct nft_expr_type nft_match_type;
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static struct nft_expr_type nft_target_type;
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static struct nft_compat_net *nft_compat_pernet(struct net *net)
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{
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return net_generic(net, nft_compat_net_id);
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}
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static void nft_xt_get(struct nft_xt *xt)
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{
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/* refcount_inc() warns on 0 -> 1 transition, but we can't
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* init the reference count to 1 in .select_ops -- we can't
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* undo such an increase when another expression inside the same
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* rule fails afterwards.
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*/
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if (xt->listcnt == 0)
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refcount_set(&xt->refcnt, 1);
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else
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refcount_inc(&xt->refcnt);
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xt->listcnt++;
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}
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static bool nft_xt_put(struct nft_xt *xt)
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{
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if (refcount_dec_and_test(&xt->refcnt)) {
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WARN_ON_ONCE(!list_empty(&xt->head));
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kfree_rcu(xt, rcu_head);
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return true;
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}
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return false;
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}
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static int nft_compat_chain_validate_dependency(const struct nft_ctx *ctx,
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const char *tablename)
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{
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@ -281,7 +224,6 @@ nft_target_init(const struct nft_ctx *ctx, const struct nft_expr *expr,
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struct xt_target *target = expr->ops->data;
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struct xt_tgchk_param par;
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size_t size = XT_ALIGN(nla_len(tb[NFTA_TARGET_INFO]));
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struct nft_xt *nft_xt;
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u16 proto = 0;
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bool inv = false;
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union nft_entry e = {};
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@ -305,8 +247,6 @@ nft_target_init(const struct nft_ctx *ctx, const struct nft_expr *expr,
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if (!target->target)
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return -EINVAL;
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nft_xt = container_of(expr->ops, struct nft_xt, ops);
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nft_xt_get(nft_xt);
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return 0;
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}
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@ -325,8 +265,8 @@ nft_target_destroy(const struct nft_ctx *ctx, const struct nft_expr *expr)
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if (par.target->destroy != NULL)
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par.target->destroy(&par);
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if (nft_xt_put(container_of(expr->ops, struct nft_xt, ops)))
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module_put(me);
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kfree(expr->ops);
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}
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static int nft_extension_dump_info(struct sk_buff *skb, int attr,
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@ -499,7 +439,6 @@ __nft_match_init(const struct nft_ctx *ctx, const struct nft_expr *expr,
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struct xt_match *match = expr->ops->data;
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struct xt_mtchk_param par;
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size_t size = XT_ALIGN(nla_len(tb[NFTA_MATCH_INFO]));
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struct nft_xt *nft_xt;
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u16 proto = 0;
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bool inv = false;
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union nft_entry e = {};
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@ -515,13 +454,7 @@ __nft_match_init(const struct nft_ctx *ctx, const struct nft_expr *expr,
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nft_match_set_mtchk_param(&par, ctx, match, info, &e, proto, inv);
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ret = xt_check_match(&par, size, proto, inv);
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if (ret < 0)
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return ret;
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nft_xt = container_of(expr->ops, struct nft_xt, ops);
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nft_xt_get(nft_xt);
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return 0;
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return xt_check_match(&par, size, proto, inv);
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}
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static int
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@ -564,8 +497,8 @@ __nft_match_destroy(const struct nft_ctx *ctx, const struct nft_expr *expr,
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if (par.match->destroy != NULL)
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par.match->destroy(&par);
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if (nft_xt_put(container_of(expr->ops, struct nft_xt, ops)))
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module_put(me);
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kfree(expr->ops);
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}
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static void
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@ -574,18 +507,6 @@ nft_match_destroy(const struct nft_ctx *ctx, const struct nft_expr *expr)
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__nft_match_destroy(ctx, expr, nft_expr_priv(expr));
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}
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static void nft_compat_deactivate(const struct nft_ctx *ctx,
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const struct nft_expr *expr,
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enum nft_trans_phase phase)
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{
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struct nft_xt *xt = container_of(expr->ops, struct nft_xt, ops);
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if (phase == NFT_TRANS_ABORT || phase == NFT_TRANS_COMMIT) {
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if (--xt->listcnt == 0)
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list_del_init(&xt->head);
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}
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}
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static void
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nft_match_large_destroy(const struct nft_ctx *ctx, const struct nft_expr *expr)
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{
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@ -780,19 +701,13 @@ static const struct nfnetlink_subsystem nfnl_compat_subsys = {
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.cb = nfnl_nft_compat_cb,
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};
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static bool nft_match_cmp(const struct xt_match *match,
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const char *name, u32 rev, u32 family)
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{
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return strcmp(match->name, name) == 0 && match->revision == rev &&
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(match->family == NFPROTO_UNSPEC || match->family == family);
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}
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static struct nft_expr_type nft_match_type;
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static const struct nft_expr_ops *
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nft_match_select_ops(const struct nft_ctx *ctx,
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const struct nlattr * const tb[])
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{
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struct nft_compat_net *cn;
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struct nft_xt *nft_match;
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struct nft_expr_ops *ops;
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struct xt_match *match;
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unsigned int matchsize;
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char *mt_name;
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@ -808,16 +723,6 @@ nft_match_select_ops(const struct nft_ctx *ctx,
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rev = ntohl(nla_get_be32(tb[NFTA_MATCH_REV]));
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family = ctx->family;
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cn = nft_compat_pernet(ctx->net);
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/* Re-use the existing match if it's already loaded. */
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list_for_each_entry(nft_match, &cn->nft_match_list, head) {
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struct xt_match *match = nft_match->ops.data;
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if (nft_match_cmp(match, mt_name, rev, family))
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return &nft_match->ops;
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}
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match = xt_request_find_match(family, mt_name, rev);
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if (IS_ERR(match))
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return ERR_PTR(-ENOENT);
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@ -827,65 +732,62 @@ nft_match_select_ops(const struct nft_ctx *ctx,
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goto err;
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}
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/* This is the first time we use this match, allocate operations */
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nft_match = kzalloc(sizeof(struct nft_xt), GFP_KERNEL);
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if (nft_match == NULL) {
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ops = kzalloc(sizeof(struct nft_expr_ops), GFP_KERNEL);
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if (!ops) {
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err = -ENOMEM;
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goto err;
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}
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refcount_set(&nft_match->refcnt, 0);
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nft_match->ops.type = &nft_match_type;
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nft_match->ops.eval = nft_match_eval;
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nft_match->ops.init = nft_match_init;
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nft_match->ops.destroy = nft_match_destroy;
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nft_match->ops.deactivate = nft_compat_deactivate;
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nft_match->ops.dump = nft_match_dump;
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nft_match->ops.validate = nft_match_validate;
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nft_match->ops.data = match;
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ops->type = &nft_match_type;
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ops->eval = nft_match_eval;
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ops->init = nft_match_init;
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ops->destroy = nft_match_destroy;
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ops->dump = nft_match_dump;
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ops->validate = nft_match_validate;
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ops->data = match;
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matchsize = NFT_EXPR_SIZE(XT_ALIGN(match->matchsize));
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if (matchsize > NFT_MATCH_LARGE_THRESH) {
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matchsize = NFT_EXPR_SIZE(sizeof(struct nft_xt_match_priv));
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nft_match->ops.eval = nft_match_large_eval;
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nft_match->ops.init = nft_match_large_init;
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nft_match->ops.destroy = nft_match_large_destroy;
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nft_match->ops.dump = nft_match_large_dump;
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ops->eval = nft_match_large_eval;
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ops->init = nft_match_large_init;
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ops->destroy = nft_match_large_destroy;
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ops->dump = nft_match_large_dump;
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}
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nft_match->ops.size = matchsize;
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ops->size = matchsize;
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nft_match->listcnt = 0;
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list_add(&nft_match->head, &cn->nft_match_list);
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return &nft_match->ops;
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return ops;
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err:
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module_put(match->me);
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return ERR_PTR(err);
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}
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static void nft_match_release_ops(const struct nft_expr_ops *ops)
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{
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struct xt_match *match = ops->data;
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module_put(match->me);
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kfree(ops);
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}
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static struct nft_expr_type nft_match_type __read_mostly = {
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.name = "match",
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.select_ops = nft_match_select_ops,
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.release_ops = nft_match_release_ops,
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.policy = nft_match_policy,
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.maxattr = NFTA_MATCH_MAX,
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.owner = THIS_MODULE,
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};
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static bool nft_target_cmp(const struct xt_target *tg,
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const char *name, u32 rev, u32 family)
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{
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return strcmp(tg->name, name) == 0 && tg->revision == rev &&
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(tg->family == NFPROTO_UNSPEC || tg->family == family);
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}
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static struct nft_expr_type nft_target_type;
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static const struct nft_expr_ops *
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nft_target_select_ops(const struct nft_ctx *ctx,
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const struct nlattr * const tb[])
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{
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struct nft_compat_net *cn;
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struct nft_xt *nft_target;
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struct nft_expr_ops *ops;
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struct xt_target *target;
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char *tg_name;
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u32 rev, family;
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@ -905,18 +807,6 @@ nft_target_select_ops(const struct nft_ctx *ctx,
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strcmp(tg_name, "standard") == 0)
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return ERR_PTR(-EINVAL);
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cn = nft_compat_pernet(ctx->net);
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/* Re-use the existing target if it's already loaded. */
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list_for_each_entry(nft_target, &cn->nft_target_list, head) {
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struct xt_target *target = nft_target->ops.data;
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if (!target->target)
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continue;
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if (nft_target_cmp(target, tg_name, rev, family))
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return &nft_target->ops;
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}
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target = xt_request_find_target(family, tg_name, rev);
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if (IS_ERR(target))
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return ERR_PTR(-ENOENT);
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@ -931,113 +821,55 @@ nft_target_select_ops(const struct nft_ctx *ctx,
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goto err;
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}
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/* This is the first time we use this target, allocate operations */
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nft_target = kzalloc(sizeof(struct nft_xt), GFP_KERNEL);
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if (nft_target == NULL) {
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ops = kzalloc(sizeof(struct nft_expr_ops), GFP_KERNEL);
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if (!ops) {
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err = -ENOMEM;
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goto err;
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}
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refcount_set(&nft_target->refcnt, 0);
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nft_target->ops.type = &nft_target_type;
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nft_target->ops.size = NFT_EXPR_SIZE(XT_ALIGN(target->targetsize));
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nft_target->ops.init = nft_target_init;
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nft_target->ops.destroy = nft_target_destroy;
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nft_target->ops.deactivate = nft_compat_deactivate;
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nft_target->ops.dump = nft_target_dump;
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nft_target->ops.validate = nft_target_validate;
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nft_target->ops.data = target;
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ops->type = &nft_target_type;
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ops->size = NFT_EXPR_SIZE(XT_ALIGN(target->targetsize));
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ops->init = nft_target_init;
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ops->destroy = nft_target_destroy;
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ops->dump = nft_target_dump;
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ops->validate = nft_target_validate;
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ops->data = target;
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if (family == NFPROTO_BRIDGE)
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nft_target->ops.eval = nft_target_eval_bridge;
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ops->eval = nft_target_eval_bridge;
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else
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nft_target->ops.eval = nft_target_eval_xt;
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ops->eval = nft_target_eval_xt;
|
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nft_target->listcnt = 0;
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list_add(&nft_target->head, &cn->nft_target_list);
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return &nft_target->ops;
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return ops;
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err:
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module_put(target->me);
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return ERR_PTR(err);
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}
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static void nft_target_release_ops(const struct nft_expr_ops *ops)
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{
|
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struct xt_target *target = ops->data;
|
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|
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module_put(target->me);
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kfree(ops);
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}
|
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static struct nft_expr_type nft_target_type __read_mostly = {
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.name = "target",
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.select_ops = nft_target_select_ops,
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.release_ops = nft_target_release_ops,
|
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.policy = nft_target_policy,
|
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.maxattr = NFTA_TARGET_MAX,
|
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.owner = THIS_MODULE,
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};
|
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|
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static int __net_init nft_compat_init_net(struct net *net)
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{
|
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struct nft_compat_net *cn = nft_compat_pernet(net);
|
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INIT_LIST_HEAD(&cn->nft_target_list);
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INIT_LIST_HEAD(&cn->nft_match_list);
|
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|
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return 0;
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}
|
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|
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static void __net_exit nft_compat_exit_net(struct net *net)
|
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{
|
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struct nft_compat_net *cn = nft_compat_pernet(net);
|
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struct nft_xt *xt, *next;
|
||||
|
||||
if (list_empty(&cn->nft_match_list) &&
|
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list_empty(&cn->nft_target_list))
|
||||
return;
|
||||
|
||||
/* If there was an error that caused nft_xt expr to not be initialized
|
||||
* fully and noone else requested the same expression later, the lists
|
||||
* contain 0-refcount entries that still hold module reference.
|
||||
*
|
||||
* Clean them here.
|
||||
*/
|
||||
mutex_lock(&net->nft.commit_mutex);
|
||||
list_for_each_entry_safe(xt, next, &cn->nft_target_list, head) {
|
||||
struct xt_target *target = xt->ops.data;
|
||||
|
||||
list_del_init(&xt->head);
|
||||
|
||||
if (refcount_read(&xt->refcnt))
|
||||
continue;
|
||||
module_put(target->me);
|
||||
kfree(xt);
|
||||
}
|
||||
|
||||
list_for_each_entry_safe(xt, next, &cn->nft_match_list, head) {
|
||||
struct xt_match *match = xt->ops.data;
|
||||
|
||||
list_del_init(&xt->head);
|
||||
|
||||
if (refcount_read(&xt->refcnt))
|
||||
continue;
|
||||
module_put(match->me);
|
||||
kfree(xt);
|
||||
}
|
||||
mutex_unlock(&net->nft.commit_mutex);
|
||||
}
|
||||
|
||||
static struct pernet_operations nft_compat_net_ops = {
|
||||
.init = nft_compat_init_net,
|
||||
.exit = nft_compat_exit_net,
|
||||
.id = &nft_compat_net_id,
|
||||
.size = sizeof(struct nft_compat_net),
|
||||
};
|
||||
|
||||
static int __init nft_compat_module_init(void)
|
||||
{
|
||||
int ret;
|
||||
|
||||
ret = register_pernet_subsys(&nft_compat_net_ops);
|
||||
if (ret < 0)
|
||||
goto err_target;
|
||||
|
||||
ret = nft_register_expr(&nft_match_type);
|
||||
if (ret < 0)
|
||||
goto err_pernet;
|
||||
return ret;
|
||||
|
||||
ret = nft_register_expr(&nft_target_type);
|
||||
if (ret < 0)
|
||||
|
|
@ -1054,8 +886,6 @@ err_target:
|
|||
nft_unregister_expr(&nft_target_type);
|
||||
err_match:
|
||||
nft_unregister_expr(&nft_match_type);
|
||||
err_pernet:
|
||||
unregister_pernet_subsys(&nft_compat_net_ops);
|
||||
return ret;
|
||||
}
|
||||
|
||||
|
|
@ -1064,7 +894,6 @@ static void __exit nft_compat_module_exit(void)
|
|||
nfnetlink_subsys_unregister(&nfnl_compat_subsys);
|
||||
nft_unregister_expr(&nft_target_type);
|
||||
nft_unregister_expr(&nft_match_type);
|
||||
unregister_pernet_subsys(&nft_compat_net_ops);
|
||||
}
|
||||
|
||||
MODULE_ALIAS_NFNL_SUBSYS(NFNL_SUBSYS_NFT_COMPAT);
|
||||
|
|
|
|||
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