[PATCH][next] netfilter: nftables: fix incorrect increment of loop counter

From: Colin King
Date: Mon Dec 14 2020 - 18:41:40 EST


From: Colin Ian King <colin.king@xxxxxxxxxxxxx>

The intention of the err_expr cleanup path is to iterate over the
allocated expr_array objects and free them, starting from i - 1 and
working down to the start of the array. Currently the loop counter
is being incremented instead of decremented and also the index i is
being used instead of k, repeatedly destroying the same expr_array
element. Fix this by decrementing k and using k as the index into
expr_array.

Addresses-Coverity: ("Infinite loop")
Fixes: 8cfd9b0f8515 ("netfilter: nftables: generalize set expressions support")
Signed-off-by: Colin Ian King <colin.king@xxxxxxxxxxxxx>
---
net/netfilter/nf_tables_api.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/net/netfilter/nf_tables_api.c b/net/netfilter/nf_tables_api.c
index 8d5aa0ac45f4..4186b1e52d58 100644
--- a/net/netfilter/nf_tables_api.c
+++ b/net/netfilter/nf_tables_api.c
@@ -5254,8 +5254,8 @@ static int nft_set_elem_expr_clone(const struct nft_ctx *ctx,
return 0;

err_expr:
- for (k = i - 1; k >= 0; k++)
- nft_expr_destroy(ctx, expr_array[i]);
+ for (k = i - 1; k >= 0; k--)
+ nft_expr_destroy(ctx, expr_array[k]);

return -ENOMEM;
}
--
2.29.2