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@xxxxxx>
Signed-off-by: Stefano Brivio <sbrivio@xxxxxxxxxx>
Signed-off-by: Pablo Neira Ayuso <pablo@xxxxxxxxxxxxx>
---
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 38c680f28f15..d11f1a74d43c 100644
--- a/net/netfilter/nf_tables_api.c
+++ b/net/netfilter/nf_tables_api.c
@@ -5082,6 +5082,11 @@ 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 err_element_clash;
}
--
2.11.0
