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Subject[PATCH] netlink: fix memory leak of dump
Date
1) if netlink_dump_start start fail, the memory of c->data will leak.
so free manually after netlink_dump_start return error.

2) In netlink_dump_start, ignore the return of netlink_dump.
Because if cb_running is set to true, cb->dump will be call in anyway.
so if netlink_dump_start start successfully, just return -EINTR.

Signed-off-by: Shaochun Chen <cscnull@gmail.com>
---
net/netfilter/nf_conntrack_netlink.c | 8 ++++--
net/netfilter/nf_tables_api.c | 41 ++++++++++++++++++++--------
net/netfilter/nfnetlink_acct.c | 8 ++++--
net/netlink/af_netlink.c | 5 +---
4 files changed, 41 insertions(+), 21 deletions(-)

diff --git a/net/netfilter/nf_conntrack_netlink.c b/net/netfilter/nf_conntrack_netlink.c
index 20a2e37c76d1..31db758bdb7a 100644
--- a/net/netfilter/nf_conntrack_netlink.c
+++ b/net/netfilter/nf_conntrack_netlink.c
@@ -1243,17 +1243,19 @@ static int ctnetlink_get_conntrack(struct net *net, struct sock *ctnl,
.dump = ctnetlink_dump_table,
.done = ctnetlink_done,
};
+ struct ctnetlink_filter *filter = NULL;

if (cda[CTA_MARK] && cda[CTA_MARK_MASK]) {
- struct ctnetlink_filter *filter;
-
filter = ctnetlink_alloc_filter(cda);
if (IS_ERR(filter))
return PTR_ERR(filter);

c.data = filter;
}
- return netlink_dump_start(ctnl, skb, nlh, &c);
+ err = netlink_dump_start(ctnl, skb, nlh, &c);
+ if (err != -EINTR && filter)
+ kfree(filter);
+ return err;
}

err = ctnetlink_parse_zone(cda[CTA_ZONE], &zone);
diff --git a/net/netfilter/nf_tables_api.c b/net/netfilter/nf_tables_api.c
index 896d4a36081d..4635a841f5f2 100644
--- a/net/netfilter/nf_tables_api.c
+++ b/net/netfilter/nf_tables_api.c
@@ -2287,10 +2287,9 @@ static int nf_tables_getrule(struct net *net, struct sock *nlsk,
.done = nf_tables_dump_rules_done,
.module = THIS_MODULE,
};
+ struct nft_rule_dump_ctx *ctx = NULL;

if (nla[NFTA_RULE_TABLE] || nla[NFTA_RULE_CHAIN]) {
- struct nft_rule_dump_ctx *ctx;
-
ctx = kzalloc(sizeof(*ctx), GFP_ATOMIC);
if (!ctx)
return -ENOMEM;
@@ -2315,7 +2314,13 @@ static int nf_tables_getrule(struct net *net, struct sock *nlsk,
c.data = ctx;
}

- return nft_netlink_dump_start_rcu(nlsk, skb, nlh, &c);
+ err = nft_netlink_dump_start_rcu(nlsk, skb, nlh, &c);
+ if (err != -EINTR && ctx) {
+ kfree(ctx->table);
+ kfree(ctx->chain);
+ kfree(ctx);
+ }
+ return err;
}

table = nft_table_lookup(net, nla[NFTA_RULE_TABLE], family, genmask);
@@ -3201,7 +3206,10 @@ static int nf_tables_getset(struct net *net, struct sock *nlsk,
*ctx_dump = ctx;
c.data = ctx_dump;

- return nft_netlink_dump_start_rcu(nlsk, skb, nlh, &c);
+ err = nft_netlink_dump_start_rcu(nlsk, skb, nlh, &c);
+ if (err != -EINTR)
+ kfree(ctx_dump);
+ return err;
}

/* Only accept unspec with dump */
@@ -4016,7 +4024,10 @@ static int nf_tables_getsetelem(struct net *net, struct sock *nlsk,
dump_ctx->ctx = ctx;

c.data = dump_ctx;
- return nft_netlink_dump_start_rcu(nlsk, skb, nlh, &c);
+ err = nft_netlink_dump_start_rcu(nlsk, skb, nlh, &c);
+ if (err != -EINTR)
+ kfree(dump_ctx);
+ return err;
}

if (!nla[NFTA_SET_ELEM_LIST_ELEMENTS])
@@ -5031,18 +5042,22 @@ static int nf_tables_getobj(struct net *net, struct sock *nlsk,
.done = nf_tables_dump_obj_done,
.module = THIS_MODULE,
};
+ struct nft_obj_filter *filter = NULL;

if (nla[NFTA_OBJ_TABLE] ||
nla[NFTA_OBJ_TYPE]) {
- struct nft_obj_filter *filter;
-
filter = nft_obj_filter_alloc(nla);
if (IS_ERR(filter))
return -ENOMEM;

c.data = filter;
}
- return nft_netlink_dump_start_rcu(nlsk, skb, nlh, &c);
+ err = nft_netlink_dump_start_rcu(nlsk, skb, nlh, &c);
+ if (err != -EINTR && filter) {
+ kfree(filter->table);
+ kfree(filter);
+ }
+ return err;
}

if (!nla[NFTA_OBJ_NAME] ||
@@ -5704,17 +5719,21 @@ static int nf_tables_getflowtable(struct net *net, struct sock *nlsk,
.done = nf_tables_dump_flowtable_done,
.module = THIS_MODULE,
};
+ struct nft_flowtable_filter *filter = NULL;

if (nla[NFTA_FLOWTABLE_TABLE]) {
- struct nft_flowtable_filter *filter;
-
filter = nft_flowtable_filter_alloc(nla);
if (IS_ERR(filter))
return -ENOMEM;

c.data = filter;
}
- return nft_netlink_dump_start_rcu(nlsk, skb, nlh, &c);
+ err = nft_netlink_dump_start_rcu(nlsk, skb, nlh, &c);
+ if (err != -EINTR && filter) {
+ kfree(filter->table);
+ kfree(filter);
+ }
+ return err;
}

if (!nla[NFTA_FLOWTABLE_NAME])
diff --git a/net/netfilter/nfnetlink_acct.c b/net/netfilter/nfnetlink_acct.c
index a0e5adf0b3b6..aecdb9cc1c5d 100644
--- a/net/netfilter/nfnetlink_acct.c
+++ b/net/netfilter/nfnetlink_acct.c
@@ -277,17 +277,19 @@ static int nfnl_acct_get(struct net *net, struct sock *nfnl,
.dump = nfnl_acct_dump,
.done = nfnl_acct_done,
};
+ struct nfacct_filter *filter = NULL;

if (tb[NFACCT_FILTER]) {
- struct nfacct_filter *filter;
-
filter = nfacct_filter_alloc(tb[NFACCT_FILTER]);
if (IS_ERR(filter))
return PTR_ERR(filter);

c.data = filter;
}
- return netlink_dump_start(nfnl, skb, nlh, &c);
+ ret = netlink_dump_start(nfnl, skb, nlh, &c);
+ if (ret != -EINTR && filter)
+ kfree(filter);
+ return ret;
}

if (!tb[NFACCT_NAME])
diff --git a/net/netlink/af_netlink.c b/net/netlink/af_netlink.c
index 393573a99a5a..61450461378c 100644
--- a/net/netlink/af_netlink.c
+++ b/net/netlink/af_netlink.c
@@ -2320,13 +2320,10 @@ int __netlink_dump_start(struct sock *ssk, struct sk_buff *skb,

mutex_unlock(nlk->cb_mutex);

- ret = netlink_dump(sk);
+ netlink_dump(sk);

sock_put(sk);

- if (ret)
- return ret;
-
/* We successfully started a dump, by returning -EINTR we
* signal not to send ACK even if it was requested.
*/
--
2.17.1
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