Commit graph

83 commits

Author SHA1 Message Date
Johannes Berg fceb6435e8 netlink: pass extended ACK struct to parsing functions
Pass the new extended ACK reporting struct to all of the generic
netlink parsing functions. For now, pass NULL in almost all callers
(except for some in the core.)

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2017-04-13 13:58:22 -04:00
Johannes Berg 2d4bc93368 netlink: extended ACK reporting
Add the base infrastructure and UAPI for netlink extended ACK
reporting. All "manual" calls to netlink_ack() pass NULL for now and
thus don't get extended ACK reporting.

Big thanks goes to Pablo Neira Ayuso for not only bringing up the
whole topic at netconf (again) but also coming up with the nlattr
passing trick and various other ideas.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Reviewed-by: David Ahern <dsa@cumulusnetworks.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2017-04-13 13:58:20 -04:00
David Ahern 3b1137fe74 net: ipv6: Change notifications for multipath add to RTA_MULTIPATH
Change ip6_route_multipath_add to send one notifciation with the full
route encoded with RTA_MULTIPATH instead of a series of individual routes.
This is done by adding a skip_notify flag to the nl_info struct. The
flag is used to skip sending of the notification in the fib code that
actually inserts the route. Once the full route has been added, a
notification is generated with all nexthops.

ip6_route_multipath_add handles 3 use cases: new routes, route replace,
and route append. The multipath notification generated needs to be
consistent with the order of the nexthops and it should be consistent
with the order in a FIB dump which means the route with the first nexthop
needs to be used as the route reference. For the first 2 cases (new and
replace), a reference to the route used to send the notification is
obtained by saving the first route added. For the append case, the last
route added is used to loop back to its first sibling route which is
the first nexthop in the multipath route.

Signed-off-by: David Ahern <dsa@cumulusnetworks.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2017-02-04 19:58:14 -05:00
Alexey Dobriyan 3e1ed981b7 netlink: revert broken, broken "2-clause nla_ok()"
Commit 4f7df337fe
"netlink: 2-clause nla_ok()" is BROKEN.

First clause tests if "->nla_len" could even be accessed at all,
it can not possibly be omitted.

Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2016-12-13 14:54:44 -05:00
Alexey Dobriyan 4f7df337fe netlink: 2-clause nla_ok()
nla_ok() consists of 3 clauses:

	1) int rem >= (int)sizeof(struct nlattr)

	2) u16 nla_len >= sizeof(struct nlattr)

	3) u16 nla_len <= int rem

The statement is that clause (1) is redundant.

What it does is ensuring that "rem" is a positive number,
so that in clause (3) positive number will be compared to positive number
with no problems.

However, "u16" fully fits into "int" and integers do not change value
when upcasting even to signed type. Negative integers will be rejected
by clause (3) just fine. Small positive integers will be rejected
by transitivity of comparison operator.

NOTE: all of the above DOES NOT apply to nlmsg_ok() where ->nlmsg_len is
u32(!), so 3 clauses AND A CAST TO INT are necessary.

Obligatory space savings report: -1.6 KB

	$ ./scripts/bloat-o-meter ../vmlinux-000* ../vmlinux-001*
	add/remove: 0/0 grow/shrink: 3/63 up/down: 35/-1692 (-1657)
	function                                     old     new   delta
	validate_scan_freqs                          142     155     +13
	tcf_em_tree_validate                         867     879     +12
	dcbnl_ieee_del                               328     338     +10
	netlbl_cipsov4_add_common.isra               218     215      -3
		...
	ovs_nla_put_actions                          888     806     -82
	netlbl_cipsov4_add_std                      1648    1566     -82
	nl80211_parse_sched_scan                    2889    2780    -109
	ip_tun_from_nlattr                          3086    2945    -141

Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2016-12-03 15:54:02 -05:00
Alexey Dobriyan 3b2c75d371 netlink: use "unsigned int" in nla_next()
->nla_len is unsigned entity (it's length after all) and u16,
thus it can't overflow when being aligned into int/unsigned int.

(nlmsg_next has the same code, but I didn't yet convince myself
it is correct to do so).

There is pointer arithmetic in this function and offset being
unsigned is better:

	add/remove: 0/0 grow/shrink: 1/64 up/down: 5/-309 (-304)
	function                                     old     new   delta
	nl80211_set_wiphy                           1444    1449      +5
	team_nl_cmd_options_set                      997     995      -2
	tcf_em_tree_validate                         872     870      -2
	switchdev_port_bridge_setlink                352     350      -2
	switchdev_port_br_afspec                     312     310      -2
	rtm_to_fib_config                            428     426      -2
	qla4xxx_sysfs_ddb_set_param                 2193    2191      -2
	qla4xxx_iface_set_param                     4470    4468      -2
	ovs_nla_free_flow_actions                    152     150      -2
	output_userspace                             518     516      -2
		...
	nl80211_set_reg                              654     649      -5
	validate_scan_freqs                          148     142      -6
	validate_linkmsg                             288     282      -6
	nl80211_parse_connkeys                       489     483      -6
	nlattr_set                                   231     224      -7
	nf_tables_delsetelem                         267     260      -7
	do_setlink                                  3416    3408      -8
	netlbl_cipsov4_add_std                      1672    1659     -13
	nl80211_parse_sched_scan                    2902    2888     -14
	nl80211_trigger_scan                        1738    1720     -18
	do_execute_actions                          2821    2738     -83
	Total: Before=154865355, After=154865051, chg -0.00%

Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2016-11-19 22:11:25 -05:00
Thomas Graf b15ca182ed netlink: Add nla_memdup() to wrap kmemdup() use on nlattr
Wrap several common instances of:
	kmemdup(nla_data(attr), nla_len(attr), GFP_KERNEL);

Signed-off-by: Thomas Graf <tgraf@suug.ch>
Acked-by: Johannes Berg <johannes@sipsolutions.net>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
2016-10-29 14:57:42 -04:00
Nicolas Dichtel 5022524308 netlink: kill nla_put_u64()
This function is not used anymore. nla_put_u64_64bit() should be used
instead.

Signed-off-by: Nicolas Dichtel <nicolas.dichtel@6wind.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2016-05-16 13:46:23 -04:00
Nicolas Dichtel 73520786b0 libnl: add nla_put_u64_64bit() helper
With this function, nla_data() is aligned on a 64-bit area.

Signed-off-by: Nicolas Dichtel <nicolas.dichtel@6wind.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2016-04-23 20:13:25 -04:00
Nicolas Dichtel 2175d87cc3 libnl: nla_put_msecs(): align on a 64-bit area
nla_data() is now aligned on a 64-bit area.

Signed-off-by: Nicolas Dichtel <nicolas.dichtel@6wind.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2016-04-23 20:13:24 -04:00
Nicolas Dichtel 756a2f59b7 libnl: nla_put_s64(): align on a 64-bit area
nla_data() is now aligned on a 64-bit area.
In fact, there is no user of this function.

Signed-off-by: Nicolas Dichtel <nicolas.dichtel@6wind.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2016-04-23 20:13:24 -04:00
Nicolas Dichtel e9bbe898cb libnl: nla_put_net64(): align on a 64-bit area
nla_data() is now aligned on a 64-bit area.

The temporary function nla_put_be64_32bit() is removed in this patch.

Signed-off-by: Nicolas Dichtel <nicolas.dichtel@6wind.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2016-04-23 20:13:24 -04:00
Nicolas Dichtel b46f6ded90 libnl: nla_put_be64(): align on a 64-bit area
nla_data() is now aligned on a 64-bit area.

A temporary version (nla_put_be64_32bit()) is added for nla_put_net64().
This function is removed in the next patch.

Signed-off-by: Nicolas Dichtel <nicolas.dichtel@6wind.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2016-04-23 20:13:24 -04:00
Nicolas Dichtel e7479122be libnl: nla_put_le64(): align on a 64-bit area
nla_data() is now aligned on a 64-bit area.

Signed-off-by: Nicolas Dichtel <nicolas.dichtel@6wind.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2016-04-23 20:13:24 -04:00
Nicolas Dichtel 089bf1a6a9 libnl: add more helpers to align attributes on 64-bit
Signed-off-by: Nicolas Dichtel <nicolas.dichtel@6wind.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2016-04-21 14:22:12 -04:00
David S. Miller e6f268ef36 net: nla_align_64bit() needs to test the right pointer.
Netlink messages are appended, one object at a time, to the end of
the SKB.  Therefore we need to test skb_tail_pointer() not skb->data
for alignment.

Fixes: 35c5845957 ("net: Add helpers for 64-bit aligning netlink attributes.")
Signed-off-by: David S. Miller <davem@davemloft.net>
2016-04-20 15:32:54 -04:00
Eric Dumazet cca1d81574 net: fix HAVE_EFFICIENT_UNALIGNED_ACCESS typos
HAVE_EFFICIENT_UNALIGNED_ACCESS needs CONFIG_ prefix.

Also add a comment in nla_align_64bit() explaining we have
to add a padding if current skb->data is aligned, as it
certainly can be confusing.

Fixes: 35c5845957 ("net: Add helpers for 64-bit aligning netlink attributes.")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2016-04-20 10:53:22 -04:00
David S. Miller 35c5845957 net: Add helpers for 64-bit aligning netlink attributes.
Suggested-by: Eric Dumazet <eric.dumazet@gmail.com>
Suggested-by: Nicolas Dichtel <nicolas.dichtel@6wind.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2016-04-19 19:49:29 -04:00
Alexander Aring c648a0138b netlink: add nla_get for le32 and le64
This patch adds missing inline wrappers for nla_get_le32 and
nla_get_le64. The 802.15.4 MAC byteorder is little endian and we keep
the byteorder for fields like address configuration in the same
byteorder as it comes from the MAC layer.

To provide these fields for nl802154 userspace applications, we need
these inline wrappers for netlink.

Cc: David S. Miller <davem@davemloft.net>
Signed-off-by: Alexander Aring <alex.aring@gmail.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
2015-09-30 13:16:44 +02:00
Jiri Benc 67b61f6c13 netlink: implement nla_get_in_addr and nla_get_in6_addr
Those are counterparts to nla_put_in_addr and nla_put_in6_addr.

Signed-off-by: Jiri Benc <jbenc@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2015-03-31 13:58:35 -04:00
Jiri Benc 930345ea63 netlink: implement nla_put_in_addr and nla_put_in6_addr
IP addresses are often stored in netlink attributes. Add generic functions
to do that.

For nla_put_in_addr, it would be nicer to pass struct in_addr but this is
not used universally throughout the kernel, in way too many places __be32 is
used to store IPv4 address.

Signed-off-by: Jiri Benc <jbenc@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2015-03-31 13:58:35 -04:00
Johannes Berg 053c095a82 netlink: make nlmsg_end() and genlmsg_end() void
Contrary to common expectations for an "int" return, these functions
return only a positive value -- if used correctly they cannot even
return 0 because the message header will necessarily be in the skb.

This makes the very common pattern of

  if (genlmsg_end(...) < 0) { ... }

be a whole bunch of dead code. Many places also simply do

  return nlmsg_end(...);

and the caller is expected to deal with it.

This also commonly (at least for me) causes errors, because it is very
common to write

  if (my_function(...))
    /* error condition */

and if my_function() does "return nlmsg_end()" this is of course wrong.

Additionally, there's not a single place in the kernel that actually
needs the message length returned, and if anyone needs it later then
it'll be very easy to just use skb->len there.

Remove this, and make the functions void. This removes a bunch of dead
code as described above. The patch adds lines because I did

-	return nlmsg_end(...);
+	nlmsg_end(...);
+	return 0;

I could have preserved all the function's return values by returning
skb->len, but instead I've audited all the places calling the affected
functions and found that none cared. A few places actually compared
the return value with <= 0 in dump functionality, but that could just
be changed to < 0 with no change in behaviour, so I opted for the more
efficient version.

One instance of the error I've made numerous times now is also present
in net/phonet/pn_netlink.c in the route_dumpit() function - it didn't
check for <0 or <=0 and thus broke out of the loop every single time.
I've preserved this since it will (I think) have caused the messages to
userspace to be formatted differently with just a single message for
every SKB returned to userspace. It's possible that this isn't needed
for the tools that actually use this, but I don't even know what they
are so couldn't test that changing this behaviour would be acceptable.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2015-01-18 01:03:45 -05:00
Thomas Graf 149118d893 netlink: Warn on unordered or illegal nla_nest_cancel() or nlmsg_cancel()
Calling nla_nest_cancel() in a different order as the nesting was
built up can lead to negative offsets being calculated which
results in skb_trim() being called with an underflowed unsigned
int. Warn if mark < skb->data as it's definitely a bug.

Signed-off-by: Thomas Graf <tgraf@suug.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>
2015-01-05 22:38:22 -05:00
Simon Horman 941d8ebcf7 datapath: Rename last_action() as nla_is_last() and move to netlink.h
The original motivation for this change was to allow the helper to be used
in files other than actions.c as part of work on an odp select group
action.

It was as pointed out by Thomas Graf that this helper would be best off
living in netlink.h. Furthermore, I think that the generic nature of this
helper means it is best off in netlink.h regardless of if it is used more
than one .c file or not. Thus, I would like it considered independent of
the work on an odp select group action.

Cc: Thomas Graf <tgraf@suug.ch>
Cc: Pravin Shelar <pshelar@nicira.com>
Cc: Andy Zhou <azhou@nicira.com>
Signed-off-by: Simon Horman <simon.horman@netronome.com>
Acked-by: Thomas Graf <tgraf@noironetworks.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2014-10-28 17:07:29 -04:00
Nicolas Dichtel 2c6ba4b15b netlink: fix description of portid
Avoid confusion between pid and portid.

Signed-off-by: Nicolas Dichtel <nicolas.dichtel@6wind.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2014-10-16 14:52:35 -04:00
Mark Rustad d87de1f3e9 netlink: Fix shadow warning on jiffies
Change formal parameter name to not shadow the global jiffies.

Signed-off-by: Mark Rustad <mark.d.rustad@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2014-07-28 17:20:43 -07:00
Joe Perches 4f69053b72 netevent/netlink.h: Remove extern from function prototypes
There are a mix of function prototypes with and without extern
in the kernel sources.  Standardize on not using extern for
function prototypes.

Function prototypes don't need to be written with extern.
extern is assumed by the compiler.  Its use is as unnecessary as
using auto to declare automatic/local variables in a block.

Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2013-09-21 14:01:39 -04:00
Eric W. Biederman 15e473046c netlink: Rename pid to portid to avoid confusion
It is a frequent mistake to confuse the netlink port identifier with a
process identifier.  Try to reduce this confusion by renaming fields
that hold port identifiers portid instead of pid.

I have carefully avoided changing the structures exported to
userspace to avoid changing the userspace API.

I have successfully built an allyesconfig kernel with this change.

Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Acked-by: Stephen Hemminger <shemminger@vyatta.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2012-09-10 15:30:41 -04:00
Jiri Pirko 4778e0be16 netlink: add signed types
Signed types might be needed in NL communication from time to time
(I need s32 in team driver), so add them.

Signed-off-by: Jiri Pirko <jiri@resnulli.us>
Signed-off-by: David S. Miller <davem@davemloft.net>
2012-08-03 20:40:11 -07:00
David S. Miller b3fe91c53a netlink: Delete all NLA_PUT*() macros.
They were error prone due to an embedded goto, and the entire tree has
been converted away from using them.

Signed-off-by: David S. Miller <davem@davemloft.net>
2012-04-02 04:33:45 -04:00
David S. Miller 24c410dce3 netlink: Add nla_put_le{16,32,64}() helpers.
Signed-off-by: David S. Miller <davem@davemloft.net>
2012-04-02 04:33:42 -04:00
David S. Miller 6c1dd3b6a3 netlink: Add nla_put_net{16,32,64}() helpers.
Signed-off-by: David S. Miller <davem@davemloft.net>
2012-04-02 04:33:41 -04:00
David S. Miller 569a8fc383 netlink: Add nla_put_be{16,32,64}() helpers.
Signed-off-by: David S. Miller <davem@davemloft.net>
2012-04-01 18:11:37 -04:00
Denys Vlasenko a46621a3a8 net: Deinline __nlmsg_put and genlmsg_put. -7k code on i386 defconfig.
text	   data	    bss	    dec	    hex	filename
8455963	 532732	1810804	10799499 a4c98b	vmlinux.o.before
8448899	 532732	1810804	10792435 a4adf3	vmlinux.o

This change also removes commented-out copy of __nlmsg_put
which was last touched in 2005 with "Enable once all users
have been converted" comment on top.

Changes in v2: rediffed against net-next.

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2012-01-30 15:22:06 -05:00
Johannes Berg 4b6cc7284d netlink: clarify attribute length check documentation
The documentation for how the length of attributes
is checked is wrong ("Exact length" isn't true, the
policy checks are for "minimum length") and a bit
misleading. Make it more complete and explain what
really happens.

Cc: Thomas Graf <tgraf@suug.ch>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2011-11-04 17:48:23 -04:00
Johannes Berg 670dc2833d netlink: advertise incomplete dumps
Consider the following situation:
 * a dump that would show 8 entries, four in the first
   round, and four in the second
 * between the first and second rounds, 6 entries are
   removed
 * now the second round will not show any entry, and
   even if there is a sequence/generation counter the
   application will not know

To solve this problem, add a new flag NLM_F_DUMP_INTR
to the netlink header that indicates the dump wasn't
consistent, this flag can also be set on the MSG_DONE
message that terminates the dump, and as such above
situation can be detected.

To achieve this, add a sequence counter to the netlink
callback struct. Of course, netlink code still needs
to use this new functionality. The correct way to do
that is to always set cb->seq when a dumpit callback
is invoked and call nl_dump_check_consistent() for
each new message. The core code will also call this
function for the final MSG_DONE message.

To make it usable with generic netlink, a new function
genlmsg_nlhdr() is needed to obtain the netlink header
from the genetlink user header.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Acked-by: David S. Miller <davem@davemloft.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
2011-06-22 16:09:45 -04:00
Justin P. Mattock 70f23fd66b treewide: fix a few typos in comments
- kenrel -> kernel
- whetehr -> whether
- ttt -> tt
- sss -> ss

Signed-off-by: Justin P. Mattock <justinmattock@gmail.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
2011-05-10 10:16:21 +02:00
Jozsef Kadlecsik f703651ef8 netfilter: NFNL_SUBSYS_IPSET id and NLA_PUT_NET* macros
The patch adds the NFNL_SUBSYS_IPSET id and NLA_PUT_NET* macros to the
vanilla kernel.

Signed-off-by: Jozsef Kadlecsik <kadlec@blackhole.kfki.hu>
Signed-off-by: Patrick McHardy <kaber@trash.net>
2011-02-01 15:20:14 +01:00
Jan Engelhardt 3654654f7a netlink: let nlmsg and nla functions take pointer-to-const args
The changed functions do not modify the NL messages and/or attributes
at all. They should use const (similar to strchr), so that callers
which have a const nlmsg/nlattr around can make use of them without
casting.

While at it, constify a data array.

Signed-off-by: Jan Engelhardt <jengelh@medozas.de>
Signed-off-by: David S. Miller <davem@davemloft.net>
2010-11-16 09:52:32 -08:00
Nelson Elhage 6b8c92ba07 netlink: Make nlmsg_find_attr take a const nlmsghdr*.
This will let us use it on a nlmsghdr stored inside a netlink_callback.

Signed-off-by: Nelson Elhage <nelhage@ksplice.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2010-11-04 12:26:34 -07:00
Justin P. Mattock 1dc8d8c06d net: Fix a typo in netlink.h
Fix a typo in include/net/netlink.h
should be finalize instead of finanlize

Signed-off-by: Justin P. Mattock <justinmattock@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2010-06-23 12:58:40 -07:00
Pablo Neira Ayuso f5d410f2ea netlink: fix unaligned access in nla_get_be64()
This patch fixes a unaligned access in nla_get_be64() that was
introduced by myself in a17c859849.

Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
2010-03-19 22:47:23 -07:00
Alexey Dobriyan b54452b07a const: struct nla_policy
Make remaining netlink policies as const.
Fixup coding style where needed.

Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2010-02-18 14:30:18 -08:00
Patrick McHardy 3a6c2b419b netlink: constify nlmsghdr arguments
Consitfy nlmsghdr arguments to a couple of functions as preparation
for the next patch, which will constify the netlink message data in
all nfnetlink users.

Signed-off-by: Patrick McHardy <kaber@trash.net>
2009-08-25 16:07:40 +02:00
Pablo Neira Ayuso a17c859849 netfilter: conntrack: add support for DCCP handshake sequence to ctnetlink
This patch adds CTA_PROTOINFO_DCCP_HANDSHAKE_SEQ that exposes
the u64 handshake sequence number to user-space.

Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Patrick McHardy <kaber@trash.net>
2009-05-27 17:50:35 +02:00
Holger Eitzenberger e487eb99cf netlink: add nla_policy_len()
It calculates the max. length of a Netlink policy, which is usefull
for allocating Netlink buffers roughly the size of the actual
message.

Signed-off-by: Holger Eitzenberger <holger@eitzenberger.org>
Signed-off-by: Patrick McHardy <kaber@trash.net>
2009-03-25 18:26:30 +01:00
Vegard Nossum 619e803d3c netlink: fix (theoretical) overrun in message iteration
See commit 1045b03e07 ("netlink: fix
overrun in attribute iteration") for a detailed explanation of why
this patch is necessary.

In short, nlmsg_next() can make "remaining" go negative, and the
remaining >= sizeof(...) comparison will promote "remaining" to an
unsigned type, which means that the expression will evaluate to
true for negative numbers, even though it was not intended.

I put "theoretical" in the title because I have no evidence that
this can actually happen, but I suspect that a crafted netlink
packet can trigger some badness.

Note that the last test, which seemingly has the exact same
problem (also true for nla_ok()), is perfectly OK, since we
already know that remaining is positive.

Signed-off-by: Vegard Nossum <vegard.nossum@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2008-12-25 17:21:17 -08:00
Patrick McHardy b057efd4d2 netlink: constify struct nlattr * arg to parsing functions
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
2008-10-28 11:59:11 -07:00
David S. Miller b262e60309 Merge branch 'master' of master.kernel.org:/pub/scm/linux/kernel/git/davem/net-2.6
Conflicts:

	drivers/net/wireless/ath9k/core.c
	drivers/net/wireless/ath9k/main.c
	net/core/dev.c
2008-10-01 06:12:56 -07:00
Vegard Nossum 1045b03e07 netlink: fix overrun in attribute iteration
kmemcheck reported this:

  kmemcheck: Caught 16-bit read from uninitialized memory (f6c1ba30)
  0500110001508abf050010000500000002017300140000006f72672e66726565
   i i i i i i i i i i i i i u u u u u u u u u u u u u u u u u u u
                                   ^

  Pid: 3462, comm: wpa_supplicant Not tainted (2.6.27-rc3-00054-g6397ab9-dirty #13)
  EIP: 0060:[<c05de64a>] EFLAGS: 00010296 CPU: 0
  EIP is at nla_parse+0x5a/0xf0
  EAX: 00000008 EBX: fffffffd ECX: c06f16c0 EDX: 00000005
  ESI: 00000010 EDI: f6c1ba30 EBP: f6367c6c ESP: c0a11e88
   DS: 007b ES: 007b FS: 00d8 GS: 0033 SS: 0068
  CR0: 8005003b CR2: f781cc84 CR3: 3632f000 CR4: 000006d0
  DR0: c0ead9bc DR1: 00000000 DR2: 00000000 DR3: 00000000
  DR6: ffff4ff0 DR7: 00000400
   [<c05d4b23>] rtnl_setlink+0x63/0x130
   [<c05d5f75>] rtnetlink_rcv_msg+0x165/0x200
   [<c05ddf66>] netlink_rcv_skb+0x76/0xa0
   [<c05d5dfe>] rtnetlink_rcv+0x1e/0x30
   [<c05dda21>] netlink_unicast+0x281/0x290
   [<c05ddbe9>] netlink_sendmsg+0x1b9/0x2b0
   [<c05beef2>] sock_sendmsg+0xd2/0x100
   [<c05bf945>] sys_sendto+0xa5/0xd0
   [<c05bf9a6>] sys_send+0x36/0x40
   [<c05c03d6>] sys_socketcall+0x1e6/0x2c0
   [<c020353b>] sysenter_do_call+0x12/0x3f
   [<ffffffff>] 0xffffffff

This is the line in nla_ok():

  /**
   * nla_ok - check if the netlink attribute fits into the remaining bytes
   * @nla: netlink attribute
   * @remaining: number of bytes remaining in attribute stream
   */
  static inline int nla_ok(const struct nlattr *nla, int remaining)
  {
          return remaining >= sizeof(*nla) &&
                 nla->nla_len >= sizeof(*nla) &&
                 nla->nla_len <= remaining;
  }

It turns out that remaining can become negative due to alignment in
nla_next(). But GCC promotes "remaining" to unsigned in the test
against sizeof(*nla) above. Therefore the test succeeds, and the
nla_for_each_attr() may access memory outside the received buffer.

A short example illustrating this point is here:

  #include <stdio.h>

  main(void)
  {
          printf("%d\n", -1 >= sizeof(int));
  }

...which prints "1".

This patch adds a cast in front of the sizeof so that GCC will make
a signed comparison and fix the illegal memory dereference. With the
patch applied, there is no kmemcheck report.

Signed-off-by: Vegard Nossum <vegard.nossum@gmail.com>
Acked-by: Thomas Graf <tgraf@suug.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>
2008-09-11 19:05:29 -07:00