From: Sasha Levin <sashal@kernel.org>
To: linux-kernel@vger.kernel.org, stable@vger.kernel.org
Cc: Fernando Fernandez Mancera <ffmancera@riseup.net>,
Pablo Neira Ayuso <pablo@netfilter.org>,
Sasha Levin <sashal@kernel.org>,
netfilter-devel@vger.kernel.org, coreteam@netfilter.org,
netdev@vger.kernel.org
Subject: [PATCH AUTOSEL 4.20 38/72] netfilter: nfnetlink_osf: add missing fmatch check
Date: Sat, 23 Feb 2019 16:03:48 -0500 [thread overview]
Message-ID: <20190223210422.199966-38-sashal@kernel.org> (raw)
In-Reply-To: <20190223210422.199966-1-sashal@kernel.org>
From: Fernando Fernandez Mancera <ffmancera@riseup.net>
[ Upstream commit 1a6a0951fc009f6d9fe8ebea2d2417d80d54097b ]
When we check the tcp options of a packet and it doesn't match the current
fingerprint, the tcp packet option pointer must be restored to its initial
value in order to do the proper tcp options check for the next fingerprint.
Here we can see an example.
Assumming the following fingerprint base with two lines:
S10:64:1:60:M*,S,T,N,W6: Linux:3.0::Linux 3.0
S20:64:1:60:M*,S,T,N,W7: Linux:4.19:arch:Linux 4.1
Where TCP options are the last field in the OS signature, all of them overlap
except by the last one, ie. 'W6' versus 'W7'.
In case a packet for Linux 4.19 kicks in, the osf finds no matching because the
TCP options pointer is updated after checking for the TCP options in the first
line.
Therefore, reset pointer back to where it should be.
Fixes: 11eeef41d5f6 ("netfilter: passive OS fingerprint xtables match")
Signed-off-by: Fernando Fernandez Mancera <ffmancera@riseup.net>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
net/netfilter/nfnetlink_osf.c | 4 ++++
1 file changed, 4 insertions(+)
diff --git a/net/netfilter/nfnetlink_osf.c b/net/netfilter/nfnetlink_osf.c
index 6f41dd74729d9..1f1d90c1716b5 100644
--- a/net/netfilter/nfnetlink_osf.c
+++ b/net/netfilter/nfnetlink_osf.c
@@ -66,6 +66,7 @@ static bool nf_osf_match_one(const struct sk_buff *skb,
int ttl_check,
struct nf_osf_hdr_ctx *ctx)
{
+ const __u8 *optpinit = ctx->optp;
unsigned int check_WSS = 0;
int fmatch = FMATCH_WRONG;
int foptsize, optnum;
@@ -155,6 +156,9 @@ static bool nf_osf_match_one(const struct sk_buff *skb,
}
}
+ if (fmatch != FMATCH_OK)
+ ctx->optp = optpinit;
+
return fmatch == FMATCH_OK;
}
--
2.19.1
next prev parent reply other threads:[~2019-02-23 21:32 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-02-23 21:03 [PATCH AUTOSEL 4.20 01/72] vti4: Fix a ipip packet processing bug in 'IPCOMP' virtual tunnel Sasha Levin
2019-02-23 21:03 ` [PATCH AUTOSEL 4.20 02/72] xfrm: refine validation of template and selector families Sasha Levin
2019-02-23 21:03 ` [PATCH AUTOSEL 4.20 03/72] xfrm: Make set-mark default behavior backward compatible Sasha Levin
2019-02-23 21:03 ` [PATCH AUTOSEL 4.20 05/72] netfilter: nft_compat: use refcnt_t type for nft_xt reference count Sasha Levin
2019-02-23 21:03 ` [PATCH AUTOSEL 4.20 06/72] netfilter: nft_compat: make lists per netns Sasha Levin
2019-02-23 21:03 ` [PATCH AUTOSEL 4.20 07/72] netfilter: nft_compat: destroy function must not have side effects Sasha Levin
2019-02-23 21:03 ` [PATCH AUTOSEL 4.20 17/72] ipvs: Fix signed integer overflow when setsockopt timeout Sasha Levin
2019-02-23 21:03 ` [PATCH AUTOSEL 4.20 32/72] net: altera_tse: fix msgdma_tx_completion on non-zero fill_level case Sasha Levin
2019-02-23 21:03 ` [PATCH AUTOSEL 4.20 33/72] net: hns: Fix for missing of_node_put() after of_parse_phandle() Sasha Levin
2019-02-23 21:03 ` [PATCH AUTOSEL 4.20 34/72] net: hns: Restart autoneg need return failed when autoneg off Sasha Levin
2019-02-23 21:03 ` [PATCH AUTOSEL 4.20 35/72] net: hns: Fix wrong read accesses via Clause 45 MDIO protocol Sasha Levin
2019-02-23 21:03 ` [PATCH AUTOSEL 4.20 36/72] net: stmmac: dwmac-rk: fix error handling in rk_gmac_powerup() Sasha Levin
2019-02-23 21:03 ` [PATCH AUTOSEL 4.20 37/72] netfilter: ebtables: compat: un-break 32bit setsockopt when no rules are present Sasha Levin
2019-02-23 21:03 ` Sasha Levin [this message]
2019-02-23 21:03 ` [PATCH AUTOSEL 4.20 40/72] selftests: net: use LDLIBS instead of LDFLAGS Sasha Levin
2019-02-23 21:03 ` [PATCH AUTOSEL 4.20 43/72] qed: Fix bug in tx promiscuous mode settings Sasha Levin
2019-02-23 21:03 ` [PATCH AUTOSEL 4.20 44/72] qed: Fix LACP pdu drops for VFs Sasha Levin
2019-02-23 21:03 ` [PATCH AUTOSEL 4.20 45/72] qed: Fix VF probe failure while FLR Sasha Levin
2019-02-23 21:03 ` [PATCH AUTOSEL 4.20 46/72] qed: Fix system crash in ll2 xmit Sasha Levin
2019-02-23 21:03 ` [PATCH AUTOSEL 4.20 47/72] qed: Fix stack out of bounds bug Sasha Levin
2019-02-23 21:04 ` [PATCH AUTOSEL 4.20 55/72] net: macb: Apply RXUBR workaround only to versions with errata Sasha Levin
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