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netfilter: nf_tables: fix memory leak during stateful obj update

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stateful objects can be updated from the control plane.
The transaction logic allocates a temporary object for this purpose.

The ->init function was called for this object, so plain kfree() leaks
resources. We must call ->destroy function of the object.

nft_obj_destroy does this, but it also decrements the module refcount,
but the update path doesn't increment it.

To avoid special-casing the update object release, do module_get for
the update case too and release it via nft_obj_destroy().

Fixes: d62d0ba97b ("netfilter: nf_tables: Introduce stateful object update operation")
Cc: Fernando Fernandez Mancera <ffmancera@riseup.net>
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
This commit is contained in:
Florian Westphal 2022-02-21 13:31:49 +01:00 committed by Pablo Neira Ayuso
parent 1a58f84ea5
commit dad3bdeef4
1 changed files with 9 additions and 4 deletions
repo.diff.show_diff_stats Download patch file Download diff file Expand all files Collapse all files

13
net/netfilter/nf_tables_api.c
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@ -6551,12 +6551,15 @@ static int nf_tables_updobj(const struct nft_ctx *ctx,
{ {
struct nft_object *newobj; struct nft_object *newobj;
struct nft_trans *trans; struct nft_trans *trans;
int err; int err = -ENOMEM;
if (!try_module_get(type->owner))
return -ENOENT;
trans = nft_trans_alloc(ctx, NFT_MSG_NEWOBJ, trans = nft_trans_alloc(ctx, NFT_MSG_NEWOBJ,
sizeof(struct nft_trans_obj)); sizeof(struct nft_trans_obj));
if (!trans) if (!trans)
return -ENOMEM; goto err_trans;
newobj = nft_obj_init(ctx, type, attr); newobj = nft_obj_init(ctx, type, attr);
if (IS_ERR(newobj)) { if (IS_ERR(newobj)) {
@ -6573,6 +6576,8 @@ static int nf_tables_updobj(const struct nft_ctx *ctx,
err_free_trans: err_free_trans:
kfree(trans); kfree(trans);
err_trans:
module_put(type->owner);
return err; return err;
} }
@ -8185,7 +8190,7 @@ static void nft_obj_commit_update(struct nft_trans *trans)
if (obj->ops->update) if (obj->ops->update)
obj->ops->update(obj, newobj); obj->ops->update(obj, newobj);
kfree(newobj); nft_obj_destroy(&trans->ctx, newobj);
} }
static void nft_commit_release(struct nft_trans *trans) static void nft_commit_release(struct nft_trans *trans)
@ -8976,7 +8981,7 @@ static int __nf_tables_abort(struct net *net, enum nfnl_abort_action action)
break; break;
case NFT_MSG_NEWOBJ: case NFT_MSG_NEWOBJ:
if (nft_trans_obj_update(trans)) { if (nft_trans_obj_update(trans)) {
kfree(nft_trans_obj_newobj(trans)); nft_obj_destroy(&trans->ctx, nft_trans_obj_newobj(trans));
nft_trans_destroy(trans); nft_trans_destroy(trans);
} else { } else {
trans->ctx.table->use--; trans->ctx.table->use--;