Commit Graph

8 Commits

Author SHA1 Message Date
Johannes Berg 8cb081746c netlink: make validation more configurable for future strictness
We currently have two levels of strict validation:

 1) liberal (default)
     - undefined (type >= max) & NLA_UNSPEC attributes accepted
     - attribute length >= expected accepted
     - garbage at end of message accepted
 2) strict (opt-in)
     - NLA_UNSPEC attributes accepted
     - attribute length >= expected accepted

Split out parsing strictness into four different options:
 * TRAILING     - check that there's no trailing data after parsing
                  attributes (in message or nested)
 * MAXTYPE      - reject attrs > max known type
 * UNSPEC       - reject attributes with NLA_UNSPEC policy entries
 * STRICT_ATTRS - strictly validate attribute size

The default for future things should be *everything*.
The current *_strict() is a combination of TRAILING and MAXTYPE,
and is renamed to _deprecated_strict().
The current regular parsing has none of this, and is renamed to
*_parse_deprecated().

Additionally it allows us to selectively set one of the new flags
even on old policies. Notably, the UNSPEC flag could be useful in
this case, since it can be arranged (by filling in the policy) to
not be an incompatible userspace ABI change, but would then going
forward prevent forgetting attribute entries. Similar can apply
to the POLICY flag.

We end up with the following renames:
 * nla_parse           -> nla_parse_deprecated
 * nla_parse_strict    -> nla_parse_deprecated_strict
 * nlmsg_parse         -> nlmsg_parse_deprecated
 * nlmsg_parse_strict  -> nlmsg_parse_deprecated_strict
 * nla_parse_nested    -> nla_parse_nested_deprecated
 * nla_validate_nested -> nla_validate_nested_deprecated

Using spatch, of course:
    @@
    expression TB, MAX, HEAD, LEN, POL, EXT;
    @@
    -nla_parse(TB, MAX, HEAD, LEN, POL, EXT)
    +nla_parse_deprecated(TB, MAX, HEAD, LEN, POL, EXT)

    @@
    expression NLH, HDRLEN, TB, MAX, POL, EXT;
    @@
    -nlmsg_parse(NLH, HDRLEN, TB, MAX, POL, EXT)
    +nlmsg_parse_deprecated(NLH, HDRLEN, TB, MAX, POL, EXT)

    @@
    expression NLH, HDRLEN, TB, MAX, POL, EXT;
    @@
    -nlmsg_parse_strict(NLH, HDRLEN, TB, MAX, POL, EXT)
    +nlmsg_parse_deprecated_strict(NLH, HDRLEN, TB, MAX, POL, EXT)

    @@
    expression TB, MAX, NLA, POL, EXT;
    @@
    -nla_parse_nested(TB, MAX, NLA, POL, EXT)
    +nla_parse_nested_deprecated(TB, MAX, NLA, POL, EXT)

    @@
    expression START, MAX, POL, EXT;
    @@
    -nla_validate_nested(START, MAX, POL, EXT)
    +nla_validate_nested_deprecated(START, MAX, POL, EXT)

    @@
    expression NLH, HDRLEN, MAX, POL, EXT;
    @@
    -nlmsg_validate(NLH, HDRLEN, MAX, POL, EXT)
    +nlmsg_validate_deprecated(NLH, HDRLEN, MAX, POL, EXT)

For this patch, don't actually add the strict, non-renamed versions
yet so that it breaks compile if I get it wrong.

Also, while at it, make nla_validate and nla_parse go down to a
common __nla_validate_parse() function to avoid code duplication.

Ultimately, this allows us to have very strict validation for every
new caller of nla_parse()/nlmsg_parse() etc as re-introduced in the
next patch, while existing things will continue to work as is.

In effect then, this adds fully strict validation for any new command.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2019-04-27 17:07:21 -04:00
Michal Kubecek ae0be8de9a netlink: make nla_nest_start() add NLA_F_NESTED flag
Even if the NLA_F_NESTED flag was introduced more than 11 years ago, most
netlink based interfaces (including recently added ones) are still not
setting it in kernel generated messages. Without the flag, message parsers
not aware of attribute semantics (e.g. wireshark dissector or libmnl's
mnl_nlmsg_fprintf()) cannot recognize nested attributes and won't display
the structure of their contents.

Unfortunately we cannot just add the flag everywhere as there may be
userspace applications which check nlattr::nla_type directly rather than
through a helper masking out the flags. Therefore the patch renames
nla_nest_start() to nla_nest_start_noflag() and introduces nla_nest_start()
as a wrapper adding NLA_F_NESTED. The calls which add NLA_F_NESTED manually
are rewritten to use nla_nest_start().

Except for changes in include/net/netlink.h, the patch was generated using
this semantic patch:

@@ expression E1, E2; @@
-nla_nest_start(E1, E2)
+nla_nest_start_noflag(E1, E2)

@@ expression E1, E2; @@
-nla_nest_start_noflag(E1, E2 | NLA_F_NESTED)
+nla_nest_start(E1, E2)

Signed-off-by: Michal Kubecek <mkubecek@suse.cz>
Acked-by: Jiri Pirko <jiri@mellanox.com>
Acked-by: David Ahern <dsahern@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2019-04-27 17:03:44 -04:00
Johannes Berg b7b14ec1eb Merge remote-tracking branch 'net-next/master' into mac80211-next
Merge net-next to resolve a conflict and to get the mac80211
rhashtable fixes so further patches can be applied on top.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
2019-02-22 13:48:13 +01:00
Mao Wenan 767637416e cfg80211: pmsr: use eth_broadcast_addr() to assign broadcast address
This patch is to use eth_broadcast_addr() to assign broadcast address
insetad of memset().

Signed-off-by: Mao Wenan <maowenan@huawei.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
2019-02-22 13:34:30 +01:00
Johannes Berg ff1bab1ba1 cfg80211: pmsr: record netlink port ID
Without recording the netlink port ID, we cannot return the
results or complete messages to userspace, nor will we be
able to abort if the socket is closed, so clearly we need
to fill the value.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
2019-02-11 15:50:56 +01:00
Johannes Berg 73350424be cfg80211: pmsr: fix abort locking
When we destroy the interface we already hold the wdev->mtx
while calling cfg80211_pmsr_wdev_down(), which assumes this
isn't true and flushes the worker that takes the lock, thus
leading to a deadlock.

Fix this by refactoring the worker and calling its code in
cfg80211_pmsr_wdev_down() directly.

We still need to flush the work later to make sure it's not
still running and will crash, but it will not do anything.

Fixes: 9bb7e0f24e ("cfg80211: add peer measurement with FTM initiator API")
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
2019-02-06 10:38:00 +01:00
Johannes Berg 0acd99282b cfg80211: pmsr: fix MAC address setting
When we *don't* have a MAC address attribute, we shouldn't
try to use this - this was intended to copy the local MAC
address instead, so fix it.

Fixes: 9bb7e0f24e ("cfg80211: add peer measurement with FTM initiator API")
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
2019-02-06 10:37:42 +01:00
Johannes Berg 9bb7e0f24e cfg80211: add peer measurement with FTM initiator API
Add a new "peer measurement" API, that can be used to measure
certain things related to a peer. Right now, only implement
FTM (flight time measurement) over it, but the idea is that
it'll be extensible to also support measuring the necessary
things to calculate e.g. angle-of-arrival for WiGig.

The API is structured to have a generic list of peers and
channels to measure with/on, and then for each of those a
set of measurements (again, only FTM right now) to perform.

Results are sent to the requesting socket, including a final
complete message.

Closing the controlling netlink socket will abort a running
measurement.

v3:
 - add a bit to report "final" for partial results
 - remove list keeping etc. and just unicast out the results
   to the requester (big code reduction ...)
 - also send complete message unicast, and as a result
   remove the multicast group
 - separate out struct cfg80211_pmsr_ftm_request_peer
   from struct cfg80211_pmsr_request_peer
 - document timeout == 0 if no timeout
 - disallow setting timeout nl80211 attribute to 0,
   must not include attribute for no timeout
 - make MAC address randomization optional
 - change num bursts exponent default to 0 (1 burst, rather
   rather than the old default of 15==don't care)

v4:
 - clarify NL80211_ATTR_TIMEOUT documentation

v5:
 - remove unnecessary nl80211 multicast/family changes
 - remove partial results bit/flag, final is sufficient
 - add max_bursts_exponent, max_ftms_per_burst to capability
 - rename "frames per burst" -> "FTMs per burst"

v6:
 - rename cfg80211_pmsr_free_wdev() to cfg80211_pmsr_wdev_down()
   and call it in leave, so the device can't go down with any
   pending measurements

v7:
 - wording fixes (Lior)
 - fix ftm.max_bursts_exponent to allow having the limit of 0 (Lior)

v8:
 - copyright statements
 - minor coding style fixes
 - fix error path leak

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
2018-11-09 11:20:13 +01:00