From: Pablo Neira Ayuso pablo@netfilter.org
[ Upstream commit 8c2d45b2b65ca1f215244be1c600236e83f9815f ]
Currently, the -EEXIST return code of ->insert() callbacks is ambiguous: it might indicate that a given element (including intervals) already exists as such, or that the new element would clash with existing ones.
If identical elements already exist, the front-end is ignoring this without returning error, in case NLM_F_EXCL is not set. However, if the new element can't be inserted due an overlap, we should report this to the user.
To this purpose, allow set back-ends to return -ENOTEMPTY on collision with existing elements, translate that to -EEXIST, and return that to userspace, no matter if NLM_F_EXCL was set.
Reported-by: Phil Sutter phil@nwl.cc Signed-off-by: Stefano Brivio sbrivio@redhat.com Signed-off-by: Pablo Neira Ayuso pablo@netfilter.org Signed-off-by: Sasha Levin sashal@kernel.org --- net/netfilter/nf_tables_api.c | 5 +++++ 1 file changed, 5 insertions(+)
diff --git a/net/netfilter/nf_tables_api.c b/net/netfilter/nf_tables_api.c index 068daff41f6e6..ddaaf5e535d58 100644 --- a/net/netfilter/nf_tables_api.c +++ b/net/netfilter/nf_tables_api.c @@ -4689,6 +4689,11 @@ static int nft_add_set_elem(struct nft_ctx *ctx, struct nft_set *set, err = -EBUSY; else if (!(nlmsg_flags & NLM_F_EXCL)) err = 0; + } else if (err == -ENOTEMPTY) { + /* ENOTEMPTY reports overlapping between this element + * and an existing one. + */ + err = -EEXIST; } goto err5; }