end key should be equal to start unless NFT_SET_EXT_KEY_END is present.
Its possible to add elements that only have a start key
("{ 1.0.0.0 . 2.0.0.0 }") without an internval end.
Insertion treats this via:
if (nft_set_ext_exists(ext, NFT_SET_EXT_KEY_END))
end = (const u8 *)nft_set_ext_key_end(ext)->data;
else
end = start;
but removal side always uses nft_set_ext_key_end().
This is wrong and leads to garbage remaining in the set after removal
next lookup/insert attempt will give:
BUG: KASAN: slab-use-after-free in pipapo_get+0x8eb/0xb90
Read of size 1 at addr ffff888100d50586 by task nft-pipapo_uaf_/1399
Call Trace:
kasan_report+0x105/0x140
pipapo_get+0x8eb/0xb90
nft_pipapo_insert+0x1dc/0x1710
nf_tables_newsetelem+0x31f5/0x4e00
..
Fixes: 3c4287f62044 ("nf_tables: Add set type for arbitrary concatenation of ranges")
Reported-by: lonial con <kongln9170@xxxxxxxxx>
Reviewed-by: Stefano Brivio <sbrivio@xxxxxxxxxx>
Signed-off-by: Florian Westphal <fw@xxxxxxxxx>
---
net/netfilter/nft_set_pipapo.c | 6 +++++-
1 file changed, 5 insertions(+), 1 deletion(-)
diff --git a/net/netfilter/nft_set_pipapo.c b/net/netfilter/nft_set_pipapo.c
index db526cb7a485..49915a2a58eb 100644
--- a/net/netfilter/nft_set_pipapo.c
+++ b/net/netfilter/nft_set_pipapo.c
@@ -1929,7 +1929,11 @@ static void nft_pipapo_remove(const struct net *net, const struct nft_set *set,
int i, start, rules_fx;
match_start = data;
- match_end = (const u8 *)nft_set_ext_key_end(&e->ext)->data;
+
+ if (nft_set_ext_exists(&e->ext, NFT_SET_EXT_KEY_END))
+ match_end = (const u8 *)nft_set_ext_key_end(&e->ext)->data;
+ else
+ match_end = data;
start = first_rule;
rules_fx = rules_f0;
--
2.41.0
