From: Florian Westphal fw@strlen.de
[ Upstream commit 87b5a5c209405cb6b57424cdfa226a6dbd349232 ]
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@gmail.com Reviewed-by: Stefano Brivio sbrivio@redhat.com Signed-off-by: Florian Westphal fw@strlen.de Signed-off-by: Sasha Levin sashal@kernel.org --- 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 0452ee586c1cc..a81829c10feab 100644 --- a/net/netfilter/nft_set_pipapo.c +++ b/net/netfilter/nft_set_pipapo.c @@ -1930,7 +1930,11 @@ 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;