Stephen Suryaputra 666d1d1a05 netfilter: nf_tables: nft_exthdr: the presence return value should be little-endian
[ Upstream commit b428336676dbca363262cc134b6218205df4f530 ]

On big-endian machine, the returned register data when the exthdr is
present is not being compared correctly because little-endian is
assumed. The function nft_cmp_fast_mask(), called by nft_cmp_fast_eval()
and nft_cmp_fast_init(), calls cpu_to_le32().

The following dump also shows that little endian is assumed:

$ nft --debug=netlink add rule ip recordroute forward ip option rr exists counter
ip
  [ exthdr load ipv4 1b @ 7 + 0 present => reg 1 ]
  [ cmp eq reg 1 0x01000000 ]
  [ counter pkts 0 bytes 0 ]

Lastly, debug print in nft_cmp_fast_init() and nft_cmp_fast_eval() when
RR option exists in the packet shows that the comparison fails because
the assumption:

nft_cmp_fast_init:189 priv->sreg=4 desc.len=8 mask=0xff000000 data.data[0]=0x10003e0
nft_cmp_fast_eval:57 regs->data[priv->sreg=4]=0x1 mask=0xff000000 priv->data=0x1000000

v2: use nft_reg_store8() instead (Florian Westphal). Also to avoid the
    warnings reported by kernel test robot.

Fixes: dbb5281a1f84 ("netfilter: nf_tables: add support for matching IPv4 options")
Fixes: c078ca3b0c5b ("netfilter: nft_exthdr: Add support for existence check")
Signed-off-by: Stephen Suryaputra <ssuryaextr@gmail.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2020-08-26 10:40:59 +02:00
..
2020-08-11 15:33:36 +02:00
2019-09-26 08:56:17 +02:00
2020-05-20 08:20:08 +02:00
2020-07-22 09:32:46 +02:00
2019-12-04 22:30:54 +01:00
2019-10-24 14:53:48 -07:00
2020-08-19 08:16:23 +02:00
2020-01-17 19:48:52 +01:00
2020-06-24 17:50:44 +02:00