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netfilter: nf_tables: fix null deref due to zeroed list head
In nf_tables_updtable, if nf_tables_table_enable returns an error,
nft_trans_destroy is called to free the transaction object.

nft_trans_destroy() calls list_del(), but the transaction was never
placed on a list -- the list head is all zeroes, this results in
a null dereference:

BUG: KASAN: null-ptr-deref in nft_trans_destroy+0x26/0x59
Call Trace:
 nft_trans_destroy+0x26/0x59
 nf_tables_newtable+0x4bc/0x9bc
 [..]

Its sane to assume that nft_trans_destroy() can be called
on the transaction object returned by nft_trans_alloc(), so
make sure the list head is initialised.

Fixes: 55dd6f9 ("netfilter: nf_tables: use new transaction infrastructure to handle table")
Reported-by: mingi cho <mgcho.minic@gmail.com>
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
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Florian Westphal authored and ummakynes committed Aug 9, 2022
1 parent f323ef3 commit 5800778
Showing 1 changed file with 1 addition and 0 deletions.
1 change: 1 addition & 0 deletions net/netfilter/nf_tables_api.c
Expand Up @@ -153,6 +153,7 @@ static struct nft_trans *nft_trans_alloc_gfp(const struct nft_ctx *ctx,
if (trans == NULL)
return NULL;

INIT_LIST_HEAD(&trans->list);
trans->msg_type = msg_type;
trans->ctx = *ctx;

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