netfilter: nf_tables: fix set->nelems counting with no NLM_F_EXCL

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[ Upstream commit 35d0ac9070 ]

If the element exists and no NLM_F_EXCL is specified, do not bump
set->nelems, otherwise we leak one set element slot. This problem
amplifies if the set is full since the abort path always decrements the
counter for the -ENFILE case too, giving one spare extra slot.

Fix this by moving set->nelems update to nft_add_set_elem() after
successful element insertion. Moreover, remove the element if the set is
full so there is no need to rely on the abort path to undo things
anymore.

Fixes: c016c7e45d ("netfilter: nf_tables: honor NLM_F_EXCL flag in set element insertion")
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Sasha Levin <alexander.levin@verizon.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

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Pablo Neira Ayuso 2017-01-24 00:51:32 +01:00 • committed by Greg Kroah-Hartman

parent f68a45776a

commit fefdd79403

1 changed files with 9 additions and 7 deletions

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net/netfilter/nf_tables_api.c

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