Allocate all table names dynamically to allow for arbitrary lengths but
introduce NFT_NAME_MAXLEN as an upper sanity boundary. It's value was
chosen to allow using a domain name as per RFC 1035.
Signed-off-by: Phil Sutter <phil@xxxxxx>
---
Changes since v1:
- Introduce NFT_NAME_MAXLEN as an upper boundary to restrict overly long
names but still allow to use e.g. domain names.
- Adjust commit messages accordingly.
Changes since v2:
- Adjust commit summary - length is not really unlimited.
- Don't drop NFT_TABLE_MAXNAMELEN macro since it's UAPI.
- Keep using NFT_TABLE_MAXNAMELEN in netlink policies to reduce patch
size.
- Add size of chain's table name unconditionally to nlmsg size in
nft_trace_notify() since info->chain should always be present.
---
include/net/netfilter/nf_tables.h | 2 +-
include/uapi/linux/netfilter/nf_tables.h | 3 +-
net/netfilter/nf_tables_api.c | 49 +++++++++++++++++++++++---------
net/netfilter/nf_tables_trace.c | 2 +-
4 files changed, 40 insertions(+), 16 deletions(-)
diff --git a/include/net/netfilter/nf_tables.h b/include/net/netfilter/nf_tables.h
index bd5be0d691d51..05ecf78ec0787 100644
--- a/include/net/netfilter/nf_tables.h
+++ b/include/net/netfilter/nf_tables.h
@@ -957,7 +957,7 @@ struct nft_table {
u32 use;
u16 flags:14,
genmask:2;
- char name[NFT_TABLE_MAXNAMELEN];
+ char *name;
};
enum nft_af_flags {
diff --git a/include/uapi/linux/netfilter/nf_tables.h b/include/uapi/linux/netfilter/nf_tables.h
index 683f6f88fcace..f796da401672b 100644
--- a/include/uapi/linux/netfilter/nf_tables.h
+++ b/include/uapi/linux/netfilter/nf_tables.h
@@ -1,7 +1,8 @@
#ifndef _LINUX_NF_TABLES_H
#define _LINUX_NF_TABLES_H
-#define NFT_TABLE_MAXNAMELEN 32
+#define NFT_NAME_MAXLEN 256
+#define NFT_TABLE_MAXNAMELEN NFT_NAME_MAXLEN
#define NFT_CHAIN_MAXNAMELEN 32
#define NFT_SET_MAXNAMELEN 32
#define NFT_OBJ_MAXNAMELEN 32
diff --git a/net/netfilter/nf_tables_api.c b/net/netfilter/nf_tables_api.c
index 7843efa33c598..dd824def0a182 100644
--- a/net/netfilter/nf_tables_api.c
+++ b/net/netfilter/nf_tables_api.c
@@ -726,7 +726,10 @@ static int nf_tables_newtable(struct net *net, struct sock *nlsk,
if (table == NULL)
goto err2;
- nla_strlcpy(table->name, name, NFT_TABLE_MAXNAMELEN);
+ table->name = nla_strdup(name, GFP_KERNEL);
+ if (table->name == NULL)
+ goto err3;
+
INIT_LIST_HEAD(&table->chains);
INIT_LIST_HEAD(&table->sets);
INIT_LIST_HEAD(&table->objects);
@@ -735,10 +738,12 @@ static int nf_tables_newtable(struct net *net, struct sock *nlsk,
nft_ctx_init(&ctx, net, skb, nlh, afi, table, NULL, nla);
err = nft_trans_table_add(&ctx, NFT_MSG_NEWTABLE);
if (err < 0)
- goto err3;
+ goto err4;
list_add_tail_rcu(&table->list, &afi->tables);
return 0;
+err4:
+ kfree(table->name);
err3:
kfree(table);
err2:
@@ -865,6 +870,7 @@ static void nf_tables_table_destroy(struct nft_ctx *ctx)
{
BUG_ON(ctx->table->use > 0);
+ kfree(ctx->table->name);
kfree(ctx->table);
module_put(ctx->afi->owner);
}
@@ -1977,7 +1983,7 @@ static void nf_tables_rule_notify(const struct nft_ctx *ctx,
}
struct nft_rule_dump_ctx {
- char table[NFT_TABLE_MAXNAMELEN];
+ char *table;
char chain[NFT_CHAIN_MAXNAMELEN];
};
@@ -2002,7 +2008,7 @@ static int nf_tables_dump_rules(struct sk_buff *skb,
continue;
list_for_each_entry_rcu(table, &afi->tables, list) {
- if (ctx && ctx->table[0] &&
+ if (ctx && ctx->table &&
strcmp(ctx->table, table->name) != 0)
continue;
@@ -2042,7 +2048,12 @@ static int nf_tables_dump_rules(struct sk_buff *skb,
static int nf_tables_dump_rules_done(struct netlink_callback *cb)
{
- kfree(cb->data);
+ struct nft_rule_dump_ctx *ctx = cb->data;
+
+ if (ctx) {
+ kfree(ctx->table);
+ kfree(ctx);
+ }
return 0;
}
@@ -2074,9 +2085,14 @@ static int nf_tables_getrule(struct net *net, struct sock *nlsk,
if (!ctx)
return -ENOMEM;
- if (nla[NFTA_RULE_TABLE])
- nla_strlcpy(ctx->table, nla[NFTA_RULE_TABLE],
- sizeof(ctx->table));
+ if (nla[NFTA_RULE_TABLE]) {
+ ctx->table = nla_strdup(nla[NFTA_RULE_TABLE],
+ GFP_KERNEL);
+ if (!ctx->table) {
+ kfree(ctx);
+ return -ENOMEM;
+ }
+ }
if (nla[NFTA_RULE_CHAIN])
nla_strlcpy(ctx->chain, nla[NFTA_RULE_CHAIN],
sizeof(ctx->chain));
@@ -4415,7 +4431,7 @@ static int nf_tables_fill_obj_info(struct sk_buff *skb, struct net *net,
}
struct nft_obj_filter {
- char table[NFT_OBJ_MAXNAMELEN];
+ char *table;
u32 type;
};
@@ -4480,7 +4496,10 @@ static int nf_tables_dump_obj(struct sk_buff *skb, struct netlink_callback *cb)
static int nf_tables_dump_obj_done(struct netlink_callback *cb)
{
- kfree(cb->data);
+ struct nft_obj_filter *filter = cb->data;
+
+ kfree(filter->table);
+ kfree(filter);
return 0;
}
@@ -4494,9 +4513,13 @@ nft_obj_filter_alloc(const struct nlattr * const nla[])
if (!filter)
return ERR_PTR(-ENOMEM);
- if (nla[NFTA_OBJ_TABLE])
- nla_strlcpy(filter->table, nla[NFTA_OBJ_TABLE],
- NFT_TABLE_MAXNAMELEN);
+ if (nla[NFTA_OBJ_TABLE]) {
+ filter->table = nla_strdup(nla[NFTA_OBJ_TABLE], GFP_KERNEL);
+ if (!filter->table) {
+ kfree(filter);
+ return ERR_PTR(-ENOMEM);
+ }
+ }
if (nla[NFTA_OBJ_TYPE])
filter->type = ntohl(nla_get_be32(nla[NFTA_OBJ_TYPE]));
diff --git a/net/netfilter/nf_tables_trace.c b/net/netfilter/nf_tables_trace.c
index 0c3a0049e4aa2..62787d985e9d3 100644
--- a/net/netfilter/nf_tables_trace.c
+++ b/net/netfilter/nf_tables_trace.c
@@ -175,7 +175,7 @@ void nft_trace_notify(struct nft_traceinfo *info)
return;
size = nlmsg_total_size(sizeof(struct nfgenmsg)) +
- nla_total_size(NFT_TABLE_MAXNAMELEN) +
+ nla_total_size(strlen(info->chain->table->name)) +
nla_total_size(NFT_CHAIN_MAXNAMELEN) +
nla_total_size_64bit(sizeof(__be64)) + /* rule handle */
nla_total_size(sizeof(__be32)) + /* trace type */
--
2.13.1
--
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