[PATCH AUTOSEL 5.7 55/61] netfilter: nf_tables: report EEXIST on overlaps

From: Sasha Levin
Date: Fri Aug 21 2020 - 13:12:20 EST


From: Pablo Neira Ayuso <pablo@xxxxxxxxxxxxx>

[ Upstream commit 77a92189ecfd061616ad531d386639aab7baaad9 ]

Replace EBUSY by EEXIST in the following cases:

- If the user adds a chain with a different configuration such as different
type, hook and priority.

- If the user adds a non-base chain that clashes with an existing basechain.

- If the user adds a { key : value } mapping element and the key exists
but the value differs.

- If the device already belongs to an existing flowtable.

User describe that this error reporting is confusing:

- https://bugzilla.netfilter.org/show_bug.cgi?id=1176
- https://bugzilla.netfilter.org/show_bug.cgi?id=1413

Signed-off-by: Pablo Neira Ayuso <pablo@xxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
net/netfilter/nf_tables_api.c | 16 +++++++---------
1 file changed, 7 insertions(+), 9 deletions(-)

diff --git a/net/netfilter/nf_tables_api.c b/net/netfilter/nf_tables_api.c
index e1d678af8749b..4d6ed763e5dd4 100644
--- a/net/netfilter/nf_tables_api.c
+++ b/net/netfilter/nf_tables_api.c
@@ -2035,7 +2035,7 @@ static int nf_tables_updchain(struct nft_ctx *ctx, u8 genmask, u8 policy,

if (nla[NFTA_CHAIN_HOOK]) {
if (!nft_is_base_chain(chain))
- return -EBUSY;
+ return -EEXIST;

err = nft_chain_parse_hook(ctx->net, nla, &hook, ctx->family,
false);
@@ -2045,21 +2045,21 @@ static int nf_tables_updchain(struct nft_ctx *ctx, u8 genmask, u8 policy,
basechain = nft_base_chain(chain);
if (basechain->type != hook.type) {
nft_chain_release_hook(&hook);
- return -EBUSY;
+ return -EEXIST;
}

if (ctx->family == NFPROTO_NETDEV) {
if (!nft_hook_list_equal(&basechain->hook_list,
&hook.list)) {
nft_chain_release_hook(&hook);
- return -EBUSY;
+ return -EEXIST;
}
} else {
ops = &basechain->ops;
if (ops->hooknum != hook.num ||
ops->priority != hook.priority) {
nft_chain_release_hook(&hook);
- return -EBUSY;
+ return -EEXIST;
}
}
nft_chain_release_hook(&hook);
@@ -5144,10 +5144,8 @@ static int nft_add_set_elem(struct nft_ctx *ctx, struct nft_set *set,
if (nft_set_ext_exists(ext, NFT_SET_EXT_DATA) ^
nft_set_ext_exists(ext2, NFT_SET_EXT_DATA) ||
nft_set_ext_exists(ext, NFT_SET_EXT_OBJREF) ^
- nft_set_ext_exists(ext2, NFT_SET_EXT_OBJREF)) {
- err = -EBUSY;
+ nft_set_ext_exists(ext2, NFT_SET_EXT_OBJREF))
goto err_element_clash;
- }
if ((nft_set_ext_exists(ext, NFT_SET_EXT_DATA) &&
nft_set_ext_exists(ext2, NFT_SET_EXT_DATA) &&
memcmp(nft_set_ext_data(ext),
@@ -5155,7 +5153,7 @@ static int nft_add_set_elem(struct nft_ctx *ctx, struct nft_set *set,
(nft_set_ext_exists(ext, NFT_SET_EXT_OBJREF) &&
nft_set_ext_exists(ext2, NFT_SET_EXT_OBJREF) &&
*nft_set_ext_obj(ext) != *nft_set_ext_obj(ext2)))
- err = -EBUSY;
+ goto err_element_clash;
else if (!(nlmsg_flags & NLM_F_EXCL))
err = 0;
} else if (err == -ENOTEMPTY) {
@@ -6264,7 +6262,7 @@ static int nft_register_flowtable_net_hooks(struct net *net,
list_for_each_entry(hook2, &ft->hook_list, list) {
if (hook->ops.dev == hook2->ops.dev &&
hook->ops.pf == hook2->ops.pf) {
- err = -EBUSY;
+ err = -EEXIST;
goto err_unregister_net_hooks;
}
}
--
2.25.1