Commit Graph

121 Commits

Author SHA1 Message Date
Johannes Berg
d07dcf9aad netlink: add infrastructure to expose policies to userspace
Add, and use in generic netlink, helpers to dump out a netlink
policy to userspace, including all the range validation data,
nested policies etc.

This lets userspace discover what the kernel understands.

For families/commands other than generic netlink, the helpers
need to be used directly in an appropriate command, or we can
add some infrastructure (a new netlink family) that those can
register their policies with for introspection. I'm not that
familiar with non-generic netlink, so that's left out for now.

The data exposed to userspace also includes min and max length
for binary/string data, I've done that instead of letting the
userspace tools figure out whether min/max is intended based
on the type so that we can extend this later in the kernel, we
might want to just use the range data for example.

Because of this, I opted to not directly expose the NLA_*
values, even if some of them are already exposed via BPF, as
with min/max length we don't need to have different types here
for NLA_BINARY/NLA_MIN_LEN/NLA_EXACT_LEN, we just make them
all NL_ATTR_TYPE_BINARY with min/max length optionally set.

Similarly, we don't really need NLA_MSECS, and perhaps can
remove it in the future - but not if we encode it into the
userspace API now. It gets mapped to NL_ATTR_TYPE_U64 here.

Note that the exposing here corresponds to the strict policy
interpretation, and NLA_UNSPEC items are omitted entirely.
To get those, change them to NLA_MIN_LEN which behaves in
exactly the same way, but is exposed.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2020-04-30 17:51:42 -07:00
Johannes Berg
2c28ae48f2 netlink: factor out policy range helpers
Add helpers to get the policy's signed/unsigned range
validation data.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2020-04-30 17:51:42 -07:00
Johannes Berg
c7721c05a6 netlink: remove NLA_EXACT_LEN_WARN
Use a validation type instead, so we can later expose
the NLA_* values to userspace for policy descriptions.

Some transformations were done with this spatch:

    @@
    identifier p;
    expression X, L, A;
    @@
    struct nla_policy p[X] = {
    [A] =
    -{ .type = NLA_EXACT_LEN_WARN, .len = L },
    +NLA_POLICY_EXACT_LEN_WARN(L),
    ...
    };

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2020-04-30 17:51:42 -07:00
Johannes Berg
da4063bdfc netlink: allow NLA_MSECS to have range validation
Since NLA_MSECS is really equivalent to NLA_U64, allow
it to have range validation as well.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2020-04-30 17:51:42 -07:00
Johannes Berg
d06a09b94c netlink: extend policy range validation
Using a pointer to a struct indicating the min/max values,
extend the ability to do range validation for arbitrary
values. Small values in the s16 range can be kept in the
policy directly.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2020-04-30 17:51:42 -07:00
Johannes Berg
47a1494b82 netlink: remove type-unsafe validation_data pointer
In the netlink policy, we currently have a void *validation_data
that's pointing to different things:
 * a u32 value for bitfield32,
 * the netlink policy for nested/nested array
 * the string for NLA_REJECT

Remove the pointer and place appropriate type-safe items in the
union instead.

While at it, completely dissolve the pointer for the bitfield32
case and just put the value there directly.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2020-04-30 17:51:41 -07:00
Jiri Pirko
8953b0770f net: introduce nla_put_bitfield32() helper and use it
Introduce a helper to pass value and selector to. The helper packs them
into struct and puts them into netlink message.

Signed-off-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2020-03-30 11:06:49 -07:00
Michal Kubecek
32d5109a9d netlink: rename nl80211_validate_nested() to nla_validate_nested()
Function nl80211_validate_nested() is not specific to nl80211, it's
a counterpart to nla_validate_nested_deprecated() with strict validation.
For consistency with other validation and parse functions, rename it to
nla_validate_nested().

Signed-off-by: Michal Kubecek <mkubecek@suse.cz>
Acked-by: Jiri Pirko <jiri@mellanox.com>
Reviewed-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
2019-12-12 17:07:05 -08:00
David Ahern
d00ee64e1d netlink: Fix nlmsg_parse as a wrapper for strict message parsing
Eric reported a syzbot warning:

BUG: KMSAN: uninit-value in nh_valid_get_del_req+0x6f1/0x8c0 net/ipv4/nexthop.c:1510
CPU: 0 PID: 11812 Comm: syz-executor444 Not tainted 5.3.0-rc3+ #17
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x191/0x1f0 lib/dump_stack.c:113
 kmsan_report+0x162/0x2d0 mm/kmsan/kmsan_report.c:109
 __msan_warning+0x75/0xe0 mm/kmsan/kmsan_instr.c:294
 nh_valid_get_del_req+0x6f1/0x8c0 net/ipv4/nexthop.c:1510
 rtm_del_nexthop+0x1b1/0x610 net/ipv4/nexthop.c:1543
 rtnetlink_rcv_msg+0x115a/0x1580 net/core/rtnetlink.c:5223
 netlink_rcv_skb+0x431/0x620 net/netlink/af_netlink.c:2477
 rtnetlink_rcv+0x50/0x60 net/core/rtnetlink.c:5241
 netlink_unicast_kernel net/netlink/af_netlink.c:1302 [inline]
 netlink_unicast+0xf6c/0x1050 net/netlink/af_netlink.c:1328
 netlink_sendmsg+0x110f/0x1330 net/netlink/af_netlink.c:1917
 sock_sendmsg_nosec net/socket.c:637 [inline]
 sock_sendmsg net/socket.c:657 [inline]
 ___sys_sendmsg+0x14ff/0x1590 net/socket.c:2311
 __sys_sendmmsg+0x53a/0xae0 net/socket.c:2413
 __do_sys_sendmmsg net/socket.c:2442 [inline]
 __se_sys_sendmmsg+0xbd/0xe0 net/socket.c:2439
 __x64_sys_sendmmsg+0x56/0x70 net/socket.c:2439
 do_syscall_64+0xbc/0xf0 arch/x86/entry/common.c:297
 entry_SYSCALL_64_after_hwframe+0x63/0xe7

The root cause is nlmsg_parse calling __nla_parse which means the
header struct size is not checked.

nlmsg_parse should be a wrapper around __nlmsg_parse with
NL_VALIDATE_STRICT for the validate argument very much like
nlmsg_parse_deprecated is for NL_VALIDATE_LIBERAL.

Fixes: 3de6440354 ("netlink: re-add parse/validate functions in strict mode")
Reported-by: Eric Dumazet <edumazet@google.com>
Reported-by: syzbot <syzkaller@googlegroups.com>
Signed-off-by: David Ahern <dsahern@gmail.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
2019-08-13 20:37:16 -07:00
Ido Schimmel
c82481f7ea netlink: Add field to skip in-kernel notifications
The struct includes a 'skip_notify' flag that indicates if netlink
notifications to user space should be suppressed. As explained in commit
3b1137fe74 ("net: ipv6: Change notifications for multipath add to
RTA_MULTIPATH"), this is useful to suppress per-nexthop RTM_NEWROUTE
notifications when an IPv6 multipath route is added / deleted. Instead,
one notification is sent for the entire multipath route.

This concept is also useful for in-kernel notifications. Sending one
in-kernel notification for the addition / deletion of an IPv6 multipath
route - instead of one per-nexthop - provides a significant increase in
the insertion / deletion rate to underlying devices.

Add a 'skip_notify_kernel' flag to suppress in-kernel notifications.

Signed-off-by: Ido Schimmel <idosch@mellanox.com>
Acked-by: Jiri Pirko <jiri@mellanox.com>
Reviewed-by: David Ahern <dsahern@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2019-06-18 09:45:36 -07:00
Ido Schimmel
3de205cde4 netlink: Document all fields of 'struct nl_info'
Some fields were not documented. Add documentation.

Signed-off-by: Ido Schimmel <idosch@mellanox.com>
Acked-by: Jiri Pirko <jiri@mellanox.com>
Reviewed-by: David Ahern <dsahern@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2019-06-18 09:45:36 -07:00
Johannes Berg
901bb98918 nl80211: require and validate vendor command policy
Require that each vendor command give a policy of its sub-attributes
in NL80211_ATTR_VENDOR_DATA, and then (stricly) check the contents,
including the NLA_F_NESTED flag that we couldn't check on the outer
layer because there we don't know yet.

It is possible to use VENDOR_CMD_RAW_DATA for raw data, but then no
nested data can be given (NLA_F_NESTED flag must be clear) and the
data is just passed as is to the command.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
2019-06-14 14:12:01 +02:00
Michal Kubecek
b424e432e7 netlink: add validation of NLA_F_NESTED flag
Add new validation flag NL_VALIDATE_NESTED which adds three consistency
checks of NLA_F_NESTED_FLAG:

  - the flag is set on attributes with NLA_NESTED{,_ARRAY} policy
  - the flag is not set on attributes with other policies except NLA_UNSPEC
  - the flag is set on attribute passed to nla_parse_nested()

Signed-off-by: Michal Kubecek <mkubecek@suse.cz>

v2: change error messages to mention NLA_F_NESTED explicitly
Reviewed-by: Johannes Berg <johannes@sipsolutions.net>
Reviewed-by: David Ahern <dsahern@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2019-05-04 01:27:11 -04:00
Johannes Berg
56738f4608 netlink: add strict parsing for future attributes
Unfortunately, we cannot add strict parsing for all attributes, as
that would break existing userspace. We currently warn about it, but
that's about all we can do.

For new attributes, however, the story is better: nobody is using
them, so we can reject bad sizes.

Also, for new attributes, we need not accept them when the policy
doesn't declare their usage.

David Ahern and I went back and forth on how to best encode this, and
the best way we found was to have a "boundary type", from which point
on new attributes have all possible validation applied, and NLA_UNSPEC
is rejected.

As we didn't want to add another argument to all functions that get a
netlink policy, the workaround is to encode that boundary in the first
entry of the policy array (which is for type 0 and thus probably not
really valid anyway). I put it into the validation union for the rare
possibility that somebody is actually using attribute 0, which would
continue to work fine unless they tried to use the extended validation,
which isn't likely. We also didn't find any in-tree users with type 0.

The reason for setting the "start strict here" attribute is that we
never really need to start strict from 0, which is invalid anyway (or
in legacy families where that isn't true, it cannot be set to strict),
so we can thus reserve the value 0 for "don't do this check" and don't
have to add the tag to all policies right now.

Thus, policies can now opt in to this validation, which we should do
for all existing policies, at least when adding new attributes.

Note that entirely *new* policies won't need to set it, as the use
of that should be using nla_parse()/nlmsg_parse() etc. which anyway
do fully strict validation now, regardless of this.

So in effect, this patch only covers the "existing command with new
attribute" case.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2019-04-27 17:07:22 -04:00
Johannes Berg
3de6440354 netlink: re-add parse/validate functions in strict mode
This re-adds the parse and validate functions like nla_parse()
that are now actually strict after the previous rename and were
just split out to make sure everything is converted (and if not
compilation of the previous patch would fail.)

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2019-04-27 17:07:22 -04:00
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
Johannes Berg
6f455f5f4e netlink: add NLA_MIN_LEN
Rather than using NLA_UNSPEC for this type of thing, use NLA_MIN_LEN
so we can make NLA_UNSPEC be NLA_REJECT under certain conditions for
future attributes.

While at it, also use NLA_EXACT_LEN for the struct example.

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
23323289b1 netlink: reduce NLA_POLICY_NESTED{,_ARRAY} arguments
In typical cases, there's no need to pass both the maxattr
and the policy array pointer, as the maxattr should just be
ARRAY_SIZE(policy) - 1. Therefore, to be less error prone,
just remove the maxattr argument from the default macros
and deduce the size accordingly.

Leave the original macros with a leading underscore to use
here and in case somebody needs to pass a policy pointer
where the policy isn't declared in the same place and thus
ARRAY_SIZE() cannot be used.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
2019-02-01 11:06:55 +01:00
Johannes Berg
5886d932e5 netlink: replace __NLA_ENSURE implementation
We already have BUILD_BUG_ON_ZERO() which I just hadn't found
before, so we should use it here instead of open-coding another
implementation thereof.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2018-10-12 11:00:22 -07:00
David Ahern
a5f6cba291 netlink: Add strict version of nlmsg_parse and nla_parse
nla_parse is currently lenient on message parsing, allowing type to be 0
or greater than max expected and only logging a message

    "netlink: %d bytes leftover after parsing attributes in process `%s'."

if the netlink message has unknown data at the end after parsing. What this
could mean is that the header at the front of the attributes is actually
wrong and the parsing is shifted from what is expected.

Add a new strict version that actually fails with EINVAL if there are any
bytes remaining after the parsing loop completes, if the atttrbitue type
is 0 or greater than max expected.

Signed-off-by: David Ahern <dsahern@gmail.com>
Acked-by: Christian Brauner <christian@brauner.io>
Signed-off-by: David S. Miller <davem@davemloft.net>
2018-10-08 10:39:04 -07:00
David Ahern
3d0d4337d7 netlink: Add extack message to nlmsg_parse for invalid header length
Give a user a reason why EINVAL is returned in nlmsg_parse.

Signed-off-by: David Ahern <dsahern@gmail.com>
Acked-by: Christian Brauner <christian@brauner.io>
Signed-off-by: David S. Miller <davem@davemloft.net>
2018-10-08 10:39:03 -07:00
David S. Miller
6f41617bf2 Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net
Minor conflict in net/core/rtnetlink.c, David Ahern's bug fix in 'net'
overlapped the renaming of a netlink attribute in net-next.

Signed-off-by: David S. Miller <davem@davemloft.net>
2018-10-03 21:00:17 -07:00
Johannes Berg
33188bd643 netlink: add validation function to policy
Add the ability to have an arbitrary validation function attached
to a netlink policy that doesn't already use the validation_data
pointer in another way.

This can be useful to validate for example the content of a binary
attribute, like in nl80211 the "(information) elements", which must
be valid streams of "u8 type, u8 length, u8 value[length]".

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2018-10-01 23:05:31 -07:00
Johannes Berg
3e48be05f3 netlink: add attribute range validation to policy
Without further bloating the policy structs, we can overload
the `validation_data' pointer with a struct of s16 min, max
and use those to validate ranges in NLA_{U,S}{8,16,32,64}
attributes.

It may sound strange to validate NLA_U32 with a s16 max, but
in many cases NLA_U32 is used for enums etc. since there's no
size benefit in using a smaller attribute width anyway, due
to netlink attribute alignment; in cases like that it's still
useful, particularly when the attribute really transports an
enum value.

Doing so lets us remove quite a bit of validation code, if we
can be sure that these attributes aren't used by userspace in
places where they're ignored today.

To achieve all this, split the 'type' field and introduce a
new 'validation_type' field which indicates what further
validation (beyond the validation prescribed by the type of
the attribute) is done. This currently allows for no further
validation (the default), as well as min, max and range checks.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2018-10-01 23:05:31 -07:00
Johannes Berg
43955a45dc netlink: fix typo in nla_parse_nested() comment
Fix a simple typo: attribuets -> attributes

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2018-09-29 11:48:26 -07:00
Johannes Berg
1501d13596 netlink: add nested array policy validation
Sometimes nested netlink attributes are just used as arrays, with
the nla_type() of each not being used; we have this in nl80211 and
e.g. NFTA_SET_ELEM_LIST_ELEMENTS.

Add the ability to validate this type of message directly in the
policy, by adding the type NLA_NESTED_ARRAY which does exactly
this: require a first level of nesting but ignore the attribute
type, and then inside each require a second level of nested and
validate those attributes against a given policy (if present).

Note that some nested array types actually require that all of
the entries have the same index, this is possible to express in
a nested policy already, apart from the validation that only the
one allowed type is used.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2018-09-28 10:24:39 -07:00
Johannes Berg
9a659a35ba netlink: allow NLA_NESTED to specify nested policy to validate
Now that we have a validation_data pointer, and the len field in
the policy is unused for NLA_NESTED, we can allow using them both
to have nested validation. This can be nice in code, although we
still have to use nla_parse_nested() or similar which would also
take a policy; however, it also serves as documentation in the
policy without requiring a look at the code.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2018-09-28 10:24:39 -07:00
Johannes Berg
48fde90a78 netlink: make validation_data const
The validation data is only used within the policy that
should usually already be const, and isn't changed in any
code that uses it. Therefore, make the validation_data
pointer const.

While at it, remove the duplicate variable in the bitfield
validation that I'd otherwise have to change to const.

Reviewed-by: David Ahern <dsahern@gmail.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2018-09-28 10:24:39 -07:00
Johannes Berg
fe3b30ddb9 netlink: remove NLA_NESTED_COMPAT
This isn't used anywhere, so we might as well get rid of it.

Reviewed-by: David Ahern <dsahern@gmail.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2018-09-28 10:24:39 -07:00
Johannes Berg
b60b87fc29 netlink: add ethernet address policy types
Commonly, ethernet addresses are just using a policy of
	{ .len = ETH_ALEN }
which leaves userspace free to send more data than it should,
which may hide bugs.

Introduce NLA_EXACT_LEN which checks for exact size, rejecting
the attribute if it's not exactly that length. Also add
NLA_EXACT_LEN_WARN which requires the minimum length and will
warn on longer attributes, for backward compatibility.

Use these to define NLA_POLICY_ETH_ADDR (new strict policy) and
NLA_POLICY_ETH_ADDR_COMPAT (compatible policy with warning);
these are used like this:

    static const struct nla_policy <name>[...] = {
        [NL_ATTR_NAME] = NLA_POLICY_ETH_ADDR,
        ...
    };

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Reviewed-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2018-09-18 19:51:29 -07:00
Johannes Berg
568b742a9d netlink: add NLA_REJECT policy type
In some situations some netlink attributes may be used for output
only (kernel->userspace) or may be reserved for future use. It's
then helpful to be able to prevent userspace from using them in
messages sent to the kernel, since they'd otherwise be ignored and
any future will become impossible if this happens.

Add NLA_REJECT to the policy which does nothing but reject (with
EINVAL) validation of any messages containing this attribute.
Allow for returning a specific extended ACK error message in the
validation_data pointer.

While at it clear up the documentation a bit - the NLA_BITFIELD32
documentation was added to the list of len field descriptions.

Also, use NL_SET_BAD_ATTR() in one place where it's open-coded.

The specific case I have in mind now is a shared nested attribute
containing request/response data, and it would be pointless and
potentially confusing to have userspace include response data in
the messages that actually contain a request.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Reviewed-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2018-09-18 19:51:29 -07:00
Greg Kroah-Hartman
b24413180f License cleanup: add SPDX GPL-2.0 license identifier to files with no license
Many source files in the tree are missing licensing information, which
makes it harder for compliance tools to determine the correct license.

By default all files without license information are under the default
license of the kernel, which is GPL version 2.

Update the files which contain no license information with the 'GPL-2.0'
SPDX license identifier.  The SPDX identifier is a legally binding
shorthand, which can be used instead of the full boiler plate text.

This patch is based on work done by Thomas Gleixner and Kate Stewart and
Philippe Ombredanne.

How this work was done:

Patches were generated and checked against linux-4.14-rc6 for a subset of
the use cases:
 - file had no licensing information it it.
 - file was a */uapi/* one with no licensing information in it,
 - file was a */uapi/* one with existing licensing information,

Further patches will be generated in subsequent months to fix up cases
where non-standard license headers were used, and references to license
had to be inferred by heuristics based on keywords.

The analysis to determine which SPDX License Identifier to be applied to
a file was done in a spreadsheet of side by side results from of the
output of two independent scanners (ScanCode & Windriver) producing SPDX
tag:value files created by Philippe Ombredanne.  Philippe prepared the
base worksheet, and did an initial spot review of a few 1000 files.

The 4.13 kernel was the starting point of the analysis with 60,537 files
assessed.  Kate Stewart did a file by file comparison of the scanner
results in the spreadsheet to determine which SPDX license identifier(s)
to be applied to the file. She confirmed any determination that was not
immediately clear with lawyers working with the Linux Foundation.

Criteria used to select files for SPDX license identifier tagging was:
 - Files considered eligible had to be source code files.
 - Make and config files were included as candidates if they contained >5
   lines of source
 - File already had some variant of a license header in it (even if <5
   lines).

All documentation files were explicitly excluded.

The following heuristics were used to determine which SPDX license
identifiers to apply.

 - when both scanners couldn't find any license traces, file was
   considered to have no license information in it, and the top level
   COPYING file license applied.

   For non */uapi/* files that summary was:

   SPDX license identifier                            # files
   ---------------------------------------------------|-------
   GPL-2.0                                              11139

   and resulted in the first patch in this series.

   If that file was a */uapi/* path one, it was "GPL-2.0 WITH
   Linux-syscall-note" otherwise it was "GPL-2.0".  Results of that was:

   SPDX license identifier                            # files
   ---------------------------------------------------|-------
   GPL-2.0 WITH Linux-syscall-note                        930

   and resulted in the second patch in this series.

 - if a file had some form of licensing information in it, and was one
   of the */uapi/* ones, it was denoted with the Linux-syscall-note if
   any GPL family license was found in the file or had no licensing in
   it (per prior point).  Results summary:

   SPDX license identifier                            # files
   ---------------------------------------------------|------
   GPL-2.0 WITH Linux-syscall-note                       270
   GPL-2.0+ WITH Linux-syscall-note                      169
   ((GPL-2.0 WITH Linux-syscall-note) OR BSD-2-Clause)    21
   ((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause)    17
   LGPL-2.1+ WITH Linux-syscall-note                      15
   GPL-1.0+ WITH Linux-syscall-note                       14
   ((GPL-2.0+ WITH Linux-syscall-note) OR BSD-3-Clause)    5
   LGPL-2.0+ WITH Linux-syscall-note                       4
   LGPL-2.1 WITH Linux-syscall-note                        3
   ((GPL-2.0 WITH Linux-syscall-note) OR MIT)              3
   ((GPL-2.0 WITH Linux-syscall-note) AND MIT)             1

   and that resulted in the third patch in this series.

 - when the two scanners agreed on the detected license(s), that became
   the concluded license(s).

 - when there was disagreement between the two scanners (one detected a
   license but the other didn't, or they both detected different
   licenses) a manual inspection of the file occurred.

 - In most cases a manual inspection of the information in the file
   resulted in a clear resolution of the license that should apply (and
   which scanner probably needed to revisit its heuristics).

 - When it was not immediately clear, the license identifier was
   confirmed with lawyers working with the Linux Foundation.

 - If there was any question as to the appropriate license identifier,
   the file was flagged for further research and to be revisited later
   in time.

In total, over 70 hours of logged manual review was done on the
spreadsheet to determine the SPDX license identifiers to apply to the
source files by Kate, Philippe, Thomas and, in some cases, confirmation
by lawyers working with the Linux Foundation.

Kate also obtained a third independent scan of the 4.13 code base from
FOSSology, and compared selected files where the other two scanners
disagreed against that SPDX file, to see if there was new insights.  The
Windriver scanner is based on an older version of FOSSology in part, so
they are related.

Thomas did random spot checks in about 500 files from the spreadsheets
for the uapi headers and agreed with SPDX license identifier in the
files he inspected. For the non-uapi files Thomas did random spot checks
in about 15000 files.

In initial set of patches against 4.14-rc6, 3 files were found to have
copy/paste license identifier errors, and have been fixed to reflect the
correct identifier.

Additionally Philippe spent 10 hours this week doing a detailed manual
inspection and review of the 12,461 patched files from the initial patch
version early this week with:
 - a full scancode scan run, collecting the matched texts, detected
   license ids and scores
 - reviewing anything where there was a license detected (about 500+
   files) to ensure that the applied SPDX license was correct
 - reviewing anything where there was no detection but the patch license
   was not GPL-2.0 WITH Linux-syscall-note to ensure that the applied
   SPDX license was correct

This produced a worksheet with 20 files needing minor correction.  This
worksheet was then exported into 3 different .csv files for the
different types of files to be modified.

These .csv files were then reviewed by Greg.  Thomas wrote a script to
parse the csv files and add the proper SPDX tag to the file, in the
format that the file expected.  This script was further refined by Greg
based on the output to detect more types of files automatically and to
distinguish between header and source .c files (which need different
comment types.)  Finally Greg ran the script using the .csv files to
generate the patches.

Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org>
Reviewed-by: Philippe Ombredanne <pombredanne@nexb.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-11-02 11:10:55 +01:00
Arnd Bergmann
b4391db423 netlink: fix nla_put_{u8,u16,u32} for KASAN
When CONFIG_KASAN is enabled, the "--param asan-stack=1" causes rather large
stack frames in some functions. This goes unnoticed normally because
CONFIG_FRAME_WARN is disabled with CONFIG_KASAN by default as of commit
3f181b4d86 ("lib/Kconfig.debug: disable -Wframe-larger-than warnings with
KASAN=y").

The kernelci.org build bot however has the warning enabled and that led
me to investigate it a little further, as every build produces these warnings:

net/wireless/nl80211.c:4389:1: warning: the frame size of 2240 bytes is larger than 2048 bytes [-Wframe-larger-than=]
net/wireless/nl80211.c:1895:1: warning: the frame size of 3776 bytes is larger than 2048 bytes [-Wframe-larger-than=]
net/wireless/nl80211.c:1410:1: warning: the frame size of 2208 bytes is larger than 2048 bytes [-Wframe-larger-than=]
net/bridge/br_netlink.c:1282:1: warning: the frame size of 2544 bytes is larger than 2048 bytes [-Wframe-larger-than=]

Most of this problem is now solved in gcc-8, which can consolidate
the stack slots for the inline function arguments. On older compilers
we can add a workaround by declaring a local variable in each function
to pass the inline function argument.

Cc: stable@vger.kernel.org
Link: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=81715
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: David S. Miller <davem@davemloft.net>
2017-09-25 20:18:27 -07:00
David S. Miller
b63f6044d8 Merge git://git.kernel.org/pub/scm/linux/kernel/git/pablo/nf-next
Pablo Neira Ayuso says:

====================
Netfilter updates for net-next

The following patchset contains Netfilter updates for your net-next
tree. Basically, updates to the conntrack core, enhancements for
nf_tables, conversion of netfilter hooks from linked list to array to
improve memory locality and asorted improvements for the Netfilter
codebase. More specifically, they are:

1) Add expection to hashes after timer initialization to prevent
   access from another CPU that walks on the hashes and calls
   del_timer(), from Florian Westphal.

2) Don't update nf_tables chain counters from hot path, this is only
   used by the x_tables compatibility layer.

3) Get rid of nested rcu_read_lock() calls from netfilter hook path.
   Hooks are always guaranteed to run from rcu read side, so remove
   nested rcu_read_lock() where possible. Patch from Taehee Yoo.

4) nf_tables new ruleset generation notifications include PID and name
   of the process that has updated the ruleset, from Phil Sutter.

5) Use skb_header_pointer() from nft_fib, so we can reuse this code from
   the nf_family netdev family. Patch from Pablo M. Bermudo.

6) Add support for nft_fib in nf_tables netdev family, also from Pablo.

7) Use deferrable workqueue for conntrack garbage collection, to reduce
   power consumption, from Patch from Subash Abhinov Kasiviswanathan.

8) Add nf_ct_expect_iterate_net() helper and use it. From Florian
   Westphal.

9) Call nf_ct_unconfirmed_destroy only from cttimeout, from Florian.

10) Drop references on conntrack removal path when skbuffs has escaped via
    nfqueue, from Florian.

11) Don't queue packets to nfqueue with dying conntrack, from Florian.

12) Constify nf_hook_ops structure, from Florian.

13) Remove neededlessly branch in nf_tables trace code, from Phil Sutter.

14) Add nla_strdup(), from Phil Sutter.

15) Rise nf_tables objects name size up to 255 chars, people want to use
    DNS names, so increase this according to what RFC 1035 specifies.
    Patch series from Phil Sutter.

16) Kill nf_conntrack_default_on, it's broken. Default on conntrack hook
    registration on demand, suggested by Eric Dumazet, patch from Florian.

17) Remove unused variables in compat_copy_entry_from_user both in
    ip_tables and arp_tables code. Patch from Taehee Yoo.

18) Constify struct nf_conntrack_l4proto, from Julia Lawall.

19) Constify nf_loginfo structure, also from Julia.

20) Use a single rb root in connlimit, from Taehee Yoo.

21) Remove unused netfilter_queue_init() prototype, from Taehee Yoo.

22) Use audit_log() instead of open-coding it, from Geliang Tang.

23) Allow to mangle tcp options via nft_exthdr, from Florian.

24) Allow to fetch TCP MSS from nft_rt, from Florian. This includes
    a fix for a miscalculation of the minimal length.

25) Simplify branch logic in h323 helper, from Nick Desaulniers.

26) Calculate netlink attribute size for conntrack tuple at compile
    time, from Florian.

27) Remove protocol name field from nf_conntrack_{l3,l4}proto structure.
    From Florian.

28) Remove holes in nf_conntrack_l4proto structure, so it becomes
    smaller. From Florian.

29) Get rid of print_tuple() indirection for /proc conntrack listing.
    Place all the code in net/netfilter/nf_conntrack_standalone.c.
    Patch from Florian.

30) Do not built in print_conntrack() if CONFIG_NF_CONNTRACK_PROCFS is
    off. From Florian.

31) Constify most nf_conntrack_{l3,l4}proto helper functions, from
    Florian.

32) Fix broken indentation in ebtables extensions, from Colin Ian King.

33) Fix several harmless sparse warning, from Florian.

34) Convert netfilter hook infrastructure to use array for better memory
    locality, joint work done by Florian and Aaron Conole. Moreover, add
    some instrumentation to debug this.

35) Batch nf_unregister_net_hooks() calls, to call synchronize_net once
    per batch, from Florian.

36) Get rid of noisy logging in ICMPv6 conntrack helper, from Florian.

37) Get rid of obsolete NFDEBUG() instrumentation, from Varsha Rao.

38) Remove unused code in the generic protocol tracker, from Davide
    Caratti.

I think I will have material for a second Netfilter batch in my queue if
time allow to make it fit in this merge window.
====================

Signed-off-by: David S. Miller <davem@davemloft.net>
2017-09-03 17:08:42 -07:00
Phil Sutter
2cf0c8b3e6 netlink: Introduce nla_strdup()
This is similar to strdup() for netlink string attributes.

Signed-off-by: Phil Sutter <phil@nwl.cc>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
2017-07-31 20:41:50 +02:00
Jamal Hadi Salim
64c83d8373 net netlink: Add new type NLA_BITFIELD32
Generic bitflags attribute content sent to the kernel by user.
With this netlink attr type the user can either set or unset a
flag in the kernel.

The value is a bitmap that defines the bit values being set
The selector is a bitmask that defines which value bit is to be
considered.

A check is made to ensure the rules that a kernel subsystem always
conforms to bitflags the kernel already knows about. i.e
if the user tries to set a bit flag that is not understood then
the _it will be rejected_.

In the most basic form, the user specifies the attribute policy as:
[ATTR_GOO] = { .type = NLA_BITFIELD32, .validation_data = &myvalidflags },

where myvalidflags is the bit mask of the flags the kernel understands.

If the user _does not_ provide myvalidflags then the attribute will
also be rejected.

Examples:
value = 0x0, and selector = 0x1
implies we are selecting bit 1 and we want to set its value to 0.

value = 0x2, and selector = 0x2
implies we are selecting bit 2 and we want to set its value to 1.

Suggested-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: Jamal Hadi Salim <jhs@mojatatu.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2017-07-30 19:28:08 -07:00
Rolf Eike Beer
2683701201 netlink: correctly document nla_put_u64_64bit()
Signed-off-by: Rolf Eike Beer <eb@emlix.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2017-07-13 09:26:27 -07:00
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