Do not assume that the tcph->doff field is correct when parsing for TCP
options, skb_header_pointer() might fail to fetch these bits.
Fixes: 11eeef41d5 ("netfilter: passive OS fingerprint xtables match")
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Add a new structure to reduce callback footprint and to facilite
extensions of the nfnetlink callback interface in the future.
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
gcc-10 points out that a code path exists where a pointer to a stack
variable may be passed back to the caller:
net/netfilter/nfnetlink_osf.c: In function 'nf_osf_hdr_ctx_init':
cc1: warning: function may return address of local variable [-Wreturn-local-addr]
net/netfilter/nfnetlink_osf.c:171:16: note: declared here
171 | struct tcphdr _tcph;
| ^~~~~
I am not sure whether this can happen in practice, but moving the
variable declaration into the callers avoids the problem.
Fixes: 31a9c29210 ("netfilter: nf_osf: add struct nf_osf_hdr_ctx")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Netfilter hooks are always running under rcu read lock, use
the new iterator macro so sparse won't complain once we add
proper __rcu annotations.
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: David S. Miller <davem@davemloft.net>
Add SPDX license identifiers to all files which:
- Have no license information of any form
- Have MODULE_LICENCE("GPL*") inside which was used in the initial
scan/conversion to ignore the file
These files fall under the project license, GPL v2 only. The resulting SPDX
license identifier is:
GPL-2.0-only
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Add version option support to the nftables "osf" expression.
Signed-off-by: Fernando Fernandez Mancera <ffmancera@riseup.net>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
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: 11eeef41d5 ("netfilter: passive OS fingerprint xtables match")
Signed-off-by: Fernando Fernandez Mancera <ffmancera@riseup.net>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Add ttl option support to the nftables "osf" expression.
Signed-off-by: Fernando Fernandez Mancera <ffmancera@riseup.net>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Fixes the following sparse warning:
net/netfilter/nfnetlink_osf.c:274:24: warning:
Using plain integer as NULL pointer
Signed-off-by: Wei Yongjun <weiyongjun1@huawei.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
The first client of the nf_osf.h userspace header is nft_osf, coming in
this batch, rename it to nfnetlink_osf.h as there are no userspace
clients for this yet, hence this looks consistent with other nfnetlink
subsystem.
Suggested-by: Jan Engelhardt <jengelh@inai.de>
Signed-off-by: Fernando Fernandez Mancera <ffmancera@riseup.net>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Move nfnetlink osf subsystem from xt_osf.c to standalone module so we can
reuse it from the new nft_ost extension.
Signed-off-by: Fernando Fernandez Mancera <ffmancera@riseup.net>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Rename nf_osf.c to nfnetlink_osf.c as we introduce nfnetlink_osf which is
the OSF infraestructure.
Signed-off-by: Fernando Fernandez Mancera <ffmancera@riseup.net>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Pablo Neira Ayuso