SKF_AD_NLATTR allows us to find the first matching attribute in a
stream of netlink attributes from one offset to the end of the
netlink message. This is not suitable to look for a specific
matching inside a set of nested attributes.
For example, in ctnetlink messages, if we look for the CTA_V6_SRC
attribute in a message that talks about an IPv4 connection,
SKF_AD_NLATTR returns the offset of CTA_STATUS which has the same
value of CTA_V6_SRC but outside the nest. To differenciate
CTA_STATUS and CTA_V6_SRC, we would have to make assumptions on the
size of the attribute and the usual offset, resulting in horrible
BSF code.
This patch adds SKF_AD_NLATTR_NEST, which is a variant of
SKF_AD_NLATTR, that looks for an attribute inside the limits of
a nested attributes, but not further.
This patch validates that we have enough room to look for the
nested attributes - based on a suggestion from Patrick McHardy.
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Acked-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
SKF_ADF_NLATTR searches for a netlink attribute, which avoids manually
parsing and walking attributes. It takes the offset at which to start
searching in the 'A' register and the attribute type in the 'X' register
and returns the offset in the 'A' register. When the attribute is not
found it returns zero.
A top-level attribute can be located using a filter like this
(example for nfnetlink, using struct nfgenmsg):
...
{
/* A = offset of first attribute */
.code = BPF_LD | BPF_IMM,
.k = sizeof(struct nlmsghdr) + sizeof(struct nfgenmsg)
},
{
/* X = CTA_PROTOINFO */
.code = BPF_LDX | BPF_IMM,
.k = CTA_PROTOINFO,
},
{
/* A = netlink attribute offset */
.code = BPF_LD | BPF_B | BPF_ABS,
.k = SKF_AD_OFF + SKF_AD_NLATTR
},
{
/* Exit if not found */
.code = BPF_JMP | BPF_JEQ | BPF_K,
.k = 0,
.jt = <error>
},
...
A nested attribute below the CTA_PROTOINFO attribute would then
be parsed like this:
...
{
/* A += sizeof(struct nlattr) */
.code = BPF_ALU | BPF_ADD | BPF_K,
.k = sizeof(struct nlattr),
},
{
/* X = CTA_PROTOINFO_TCP */
.code = BPF_LDX | BPF_IMM,
.k = CTA_PROTOINFO_TCP,
},
{
/* A = netlink attribute offset */
.code = BPF_LD | BPF_B | BPF_ABS,
.k = SKF_AD_OFF + SKF_AD_NLATTR
},
...
The data of an attribute can be loaded into 'A' like this:
...
{
/* X = A (attribute offset) */
.code = BPF_MISC | BPF_TAX,
},
{
/* A = skb->data[X + k] */
.code = BPF_LD | BPF_B | BPF_IND,
.k = sizeof(struct nlattr),
},
...
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
The sk_filter function is too big to be inlined. This saves 2296 bytes
of text on allyesconfig.
Signed-off-by: Stephen Hemminger <shemminger@vyatta.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Some minor style cleanups:
* Move __KERNEL__ definitions to one place in filter.h
* Use const for sk_filter_len
* Line wrapping
* Put EXPORT_SYMBOL next to function definition
Signed-off-by: Stephen Hemminger <shemminger@vyatta.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Looks like this might be causing problems, at least for me on ppc. This
happened during a normal boot, right around first interface config/dhcp
run..
cpu 0x0: Vector: 300 (Data Access) at [c00000000147b820]
pc: c000000000435e5c: .sk_filter_delayed_uncharge+0x1c/0x60
lr: c0000000004360d0: .sk_attach_filter+0x170/0x180
sp: c00000000147baa0
msr: 9000000000009032
dar: 4
dsisr: 40000000
current = 0xc000000004780fa0
paca = 0xc000000000650480
pid = 1295, comm = dhclient3
0:mon> t
[c00000000147bb20] c0000000004360d0 .sk_attach_filter+0x170/0x180
[c00000000147bbd0] c000000000418988 .sock_setsockopt+0x788/0x7f0
[c00000000147bcb0] c000000000438a74 .compat_sys_setsockopt+0x4e4/0x5a0
[c00000000147bd90] c00000000043955c .compat_sys_socketcall+0x25c/0x2b0
[c00000000147be30] c000000000007508 syscall_exit+0x0/0x40
--- Exception: c01 (System Call) at 000000000ff618d8
SP (fffdf040) is in userspace
0:mon>
I.e. null pointer deref at sk_filter_delayed_uncharge+0x1c:
0:mon> di $.sk_filter_delayed_uncharge
c000000000435e40 7c0802a6 mflr r0
c000000000435e44 fbc1fff0 std r30,-16(r1)
c000000000435e48 7c8b2378 mr r11,r4
c000000000435e4c ebc2cdd0 ld r30,-12848(r2)
c000000000435e50 f8010010 std r0,16(r1)
c000000000435e54 f821ff81 stdu r1,-128(r1)
c000000000435e58 380300a4 addi r0,r3,164
c000000000435e5c 81240004 lwz r9,4(r4)
That's the deref of fp:
static void sk_filter_delayed_uncharge(struct sock *sk, struct sk_filter *fp)
{
unsigned int size = sk_filter_len(fp);
...
That is called from sk_attach_filter():
...
rcu_read_lock_bh();
old_fp = rcu_dereference(sk->sk_filter);
rcu_assign_pointer(sk->sk_filter, fp);
rcu_read_unlock_bh();
sk_filter_delayed_uncharge(sk, old_fp);
return 0;
...
So, looks like rcu_dereference() returned NULL. I don't know the
filter code at all, but it seems like it might be a valid case?
sk_detach_filter() seems to handle a NULL sk_filter, at least.
So, this needs review by someone who knows the filter, but it fixes the
problem for me:
Signed-off-by: Olof Johansson <olof@lixom.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
The proposed fix is to delay the reference counter decrement
until the quiescent state pass. This will give sk_clone() a
chance to get the reference on the cloned filter.
Regular sk_filter_uncharge can happen from the sk_free() only
and there's no need in delaying the put - the socket is dead
anyway and is to be release itself.
Signed-off-by: Pavel Emelyanov <xemul@openvz.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
The sk_filter_uncharge is called for error handling and
for releasing the former filter, but this will have to
be done in a bit different manner, so cleanup the error
path a bit.
Signed-off-by: Pavel Emelyanov <xemul@openvz.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
This is done merely as a preparation for the fix.
The sk_filter_uncharge() unaccounts the filter memory and calls
the sk_filter_release(), which in turn decrements the refcount
anf frees the filter.
The latter function will be required separately.
Signed-off-by: Pavel Emelyanov <xemul@openvz.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Filter is attached in a separate function, so do the
same for filter detaching.
This also removes one variable sock_setsockopt().
Signed-off-by: Pavel Emelyanov <xemul@openvz.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
So that it is also an offset from skb->head, reduces its size from 8 to 4 bytes
on 64bit architectures, allowing us to combine the 4 bytes hole left by the
layer headers conversion, reducing struct sk_buff size to 256 bytes, i.e. 4
64byte cachelines, and since the sk_buff slab cache is SLAB_HWCACHE_ALIGN...
:-)
Many calculations that previously required that skb->{transport,network,
mac}_header be first converted to a pointer now can be done directly, being
meaningful as offsets or pointers.
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
For the places where we need a pointer to the network header, it is still legal
to touch skb->nh.raw directly if just adding to, subtracting from or setting it
to another layer header.
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
For the places where we need a pointer to the mac header, it is still legal to
touch skb->mac.raw directly if just adding to, subtracting from or setting it
to another layer header.
This one also converts some more cases to skb_reset_mac_header() that my
regex missed as it had no spaces before nor after '=', ugh.
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
After Al Viro (finally) succeeded in removing the sched.h #include in module.h
recently, it makes sense again to remove other superfluous sched.h includes.
There are quite a lot of files which include it but don't actually need
anything defined in there. Presumably these includes were once needed for
macros that used to live in sched.h, but moved to other header files in the
course of cleaning it up.
To ease the pain, this time I did not fiddle with any header files and only
removed #includes from .c-files, which tend to cause less trouble.
Compile tested against 2.6.20-rc2 and 2.6.20-rc2-mm2 (with offsets) on alpha,
arm, i386, ia64, mips, powerpc, and x86_64 with allnoconfig, defconfig,
allmodconfig, and allyesconfig as well as a few randconfigs on x86_64 and all
configs in arch/arm/configs on arm. I also checked that no new warnings were
introduced by the patch (actually, some warnings are removed that were emitted
by unnecessarily included header files).
Signed-off-by: Tim Schmielau <tim@physik3.uni-rostock.de>
Acked-by: Russell King <rmk+kernel@arm.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Function sk_filter() is called from tcp_v{4,6}_rcv() functions with arg
needlock = 0, while socket is not locked at that moment. In order to avoid
this and similar issues in the future, use rcu for sk->sk_filter field read
protection.
Signed-off-by: Dmitry Mishin <dim@openvz.org>
Signed-off-by: Alexey Kuznetsov <kuznet@ms2.inr.ac.ru>
Signed-off-by: Kirill Korotaev <dev@openvz.org>
This patch fixes unaligned access warnings noticed on IA64
in sk_run_filter(). 'ptr' can be unaligned.
Signed-off-By: Dmitry Mishin <dim@openvz.org>
Signed-off-By: Kirill Korotaev <dev@openvz.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
This fixes some whitespace issues in net/core/filter.c
Signed-off-by: Kris Katterjohn <kjak@users.sourceforge.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
This fixes some whitespace issues in net/core/filter.c
Signed-off-by: Kris Katterjohn <kjak@users.sourceforge.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
This removes redundant comments, and moves one comment to a better
location.
Signed-off-by: Kris Katterjohn <kjak@users.sourceforge.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
It should return an unsigned value, and fix sk_filter() as well.
Signed-off-by: Kris Katterjohn <kjak@ispwest.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Currently the checks are scattered all over and this leads
to inconsistencies and even cases where the check is not made.
Based upon a patch from Kris Katterjohn.
Signed-off-by: David S. Miller <davem@davemloft.net>
This way we don't have to check it in sk_run_filter().
Signed-off-by: Kris Katterjohn <kjak@users.sourceforge.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
Patrick McHardy says:
Never mind, I got it, we never fall through to the second switch
statement anymore. I think we could simply break when load_pointer
returns NULL. The switch statement will fall through to the default
case and return 0 for all cases but 0 > k >= SKF_AD_OFF.
Here's a patch to do just that.
I left BPF_MSH alone because it's really a hack to calculate the IP
header length, which makes no sense when applied to the special data.
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
As suggested by Herbert Xu:
Since we don't require anything to be in the linear packet range
anymore make len cover the entire packet.
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
skb_header_pointer handles linear and non-linear data, no need to handle
linear data again.
Signed-off-by: Patrick McHardy <kaber@trash.net>
Acked-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.
Let it rip!
Pablo Neira Ayuso