Currently it is possible for netlink kernel user to pass custom
filter function to broadcast send function netlink_broadcast_filtered().
However, this is not exposed to multicast send and to generic
netlink users.
Extend the api and introduce a netlink helper nlmsg_multicast_filtered()
and a generic netlink helper genlmsg_multicast_netns_filtered()
to allow generic netlink families to specify filter function
while sending multicast messages.
Signed-off-by: Jiri Pirko <jiri@nvidia.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
The return value from nla_len() is never expected to be negative, and can
never be more than struct nlattr::nla_len (a u16). Adjust the prototype
on the function. This will let GCC's value range optimization passes
know that the return can never be negative, and can never be larger than
u16. As recently discussed[1], this silences the following warning in
GCC 12+:
net/wireless/nl80211.c: In function 'nl80211_set_cqm_rssi.isra':
net/wireless/nl80211.c:12892:17: warning: 'memcpy' specified bound 18446744073709551615 exceeds maximum object size 9223372036854775807 [-Wstringop-overflow=]
12892 | memcpy(cqm_config->rssi_thresholds, thresholds,
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
12893 | flex_array_size(cqm_config, rssi_thresholds,
| ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
12894 | n_thresholds));
| ~~~~~~~~~~~~~~
A future change would be to clamp the subtraction to make sure it never
wraps around if nla_len is somehow less than NLA_HDRLEN, which would
have the additional benefit of being defensive in the face of nlattr
corruption or logic errors.
Reported-by: kernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/oe-kbuild-all/202311090752.hWcJWAHL-lkp@intel.com/ [1]
Cc: Johannes Berg <johannes@sipsolutions.net>
Cc: Jeff Johnson <quic_jjohnson@quicinc.com>
Cc: Michael Walle <mwalle@kernel.org>
Cc: Max Schulze <max.schulze@online.de>
Link: https://lore.kernel.org/r/20231202202539.it.704-kees@kernel.org
Signed-off-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20231206205904.make.018-kees@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
if a PF has 256 or more VFs, ip link command will allocate an order 3
memory or more, and maybe trigger OOM due to memory fragment,
the VFs needed memory size is computed in rtnl_vfinfo_size.
so introduce nlmsg_new_large which calls netlink_alloc_large_skb in
which vmalloc is used for large memory, to avoid the failure of
allocating memory
ip invoked oom-killer: gfp_mask=0xc2cc0(GFP_KERNEL|__GFP_NOWARN|\
__GFP_COMP|__GFP_NOMEMALLOC), order=3, oom_score_adj=0
CPU: 74 PID: 204414 Comm: ip Kdump: loaded Tainted: P OE
Call Trace:
dump_stack+0x57/0x6a
dump_header+0x4a/0x210
oom_kill_process+0xe4/0x140
out_of_memory+0x3e8/0x790
__alloc_pages_slowpath.constprop.116+0x953/0xc50
__alloc_pages_nodemask+0x2af/0x310
kmalloc_large_node+0x38/0xf0
__kmalloc_node_track_caller+0x417/0x4d0
__kmalloc_reserve.isra.61+0x2e/0x80
__alloc_skb+0x82/0x1c0
rtnl_getlink+0x24f/0x370
rtnetlink_rcv_msg+0x12c/0x350
netlink_rcv_skb+0x50/0x100
netlink_unicast+0x1b2/0x280
netlink_sendmsg+0x355/0x4a0
sock_sendmsg+0x5b/0x60
____sys_sendmsg+0x1ea/0x250
___sys_sendmsg+0x88/0xd0
__sys_sendmsg+0x5e/0xa0
do_syscall_64+0x33/0x40
entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x7f95a65a5b70
Cc: Yunsheng Lin <linyunsheng@huawei.com>
Signed-off-by: Li RongQing <lirongqing@baidu.com>
Link: https://lore.kernel.org/r/20231115120108.3711-1-lirongqing@baidu.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
struct nla_policy is usually constant itself, but unless
we make the ranges inside constant we won't be able to
make range structs const. The ranges are not modified
by the core.
Reviewed-by: Johannes Berg <johannes@sipsolutions.net>
Reviewed-by: David Ahern <dsahern@kernel.org>
Reviewed-by: Nikolay Aleksandrov <razor@blackwall.org>
Reviewed-by: Jiri Pirko <jiri@nvidia.com>
Link: https://lore.kernel.org/r/20231025162204.132528-1-kuba@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
We currently push everyone to use padding to align 64b values
in netlink. Un-padded nla_put_u64() doesn't even exist any more.
The story behind this possibly start with this thread:
https://lore.kernel.org/netdev/20121204.130914.1457976839967676240.davem@davemloft.net/
where DaveM was concerned about the alignment of a structure
containing 64b stats. If user space tries to access such struct
directly:
struct some_stats *stats = nla_data(attr);
printf("A: %llu", stats->a);
lack of alignment may become problematic for some architectures.
These days we most often put every single member in a separate
attribute, meaning that the code above would use a helper like
nla_get_u64(), which can deal with alignment internally.
Even for arches which don't have good unaligned access - access
aligned to 4B should be pretty efficient.
Kernel and well known libraries deal with unaligned input already.
Padded 64b is quite space-inefficient (64b + pad means at worst 16B
per attr vs 32b which takes 8B). It is also more typing:
if (nla_put_u64_pad(rsp, NETDEV_A_SOMETHING_SOMETHING,
value, NETDEV_A_SOMETHING_PAD))
Create a new attribute type which will use 32 bits at netlink
level if value is small enough (probably most of the time?),
and (4B-aligned) 64 bits otherwise. Kernel API is just:
if (nla_put_uint(rsp, NETDEV_A_SOMETHING_SOMETHING, value))
Calling this new type "just" sint / uint with no specific size
will hopefully also make people more comfortable with using it.
Currently telling people "don't use u8, you may need the bits,
and netlink will round up to 4B, anyway" is the #1 comment
we give to newcomers.
In terms of netlink layout it looks like this:
0 4 8 12 16
32b: [nlattr][ u32 ]
64b: [ pad ][nlattr][ u64 ]
uint(32) [nlattr][ u32 ]
uint(64) [nlattr][ u64 ]
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Acked-by: Nicolas Dichtel <nicolas.dichtel@6wind.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
__NLA_IS_BEINT_TYPE(tp) isn't useful. NLA_BE16/32 are identical to
NLA_U16/32, the only difference is that it tells the netlink validation
functions that byteorder conversion might be needed before comparing
the value to the policy min/max ones.
After this change all policy macros that can be used with UINT types,
such as NLA_POLICY_MASK() can also be used with NLA_BE16/32.
This will be used to validate nf_tables flag attributes which
are in bigendian byte order.
Signed-off-by: Florian Westphal <fw@strlen.de>
For large ranges (outside of s16) the documentation currently
recommends open-coding the validation, but it's better to use
the NLA_POLICY_FULL_RANGE() or NLA_POLICY_FULL_RANGE_SIGNED()
policy validation instead; recommend that.
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Reviewed-by: Ido Schimmel <idosch@nvidia.com>
Link: https://lore.kernel.org/r/20230127084506.09f280619d64.I5dece85f06efa8ab0f474ca77df9e26d3553d4ab@changeid
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Jakub reported that the addition of the "network_byte_order"
member in struct nla_policy increases size of 32bit platforms.
Instead of scraping the bit from elsewhere Johannes suggested
to add explicit NLA_BE types instead, so do this here.
NLA_POLICY_MAX_BE() macro is removed again, there is no need
for it: NLA_POLICY_MAX(NLA_BE.., ..) will do the right thing.
NLA_BE64 can be added later.
Fixes: 08724ef699 ("netlink: introduce NLA_POLICY_MAX_BE")
Reported-by: Jakub Kicinski <kuba@kernel.org>
Suggested-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: Florian Westphal <fw@strlen.de>
Link: https://lore.kernel.org/r/20221031123407.9158-1-fw@strlen.de
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
This patch pass netlink message header and portid to rtnl_configure_link()
All the functions in this call chain need to add the parameters so we can
use them in the last call rtnl_notify(), and notify the userspace about
the new link info if NLM_F_ECHO flag is set.
- rtnl_configure_link()
- __dev_notify_flags()
- rtmsg_ifinfo()
- rtmsg_ifinfo_event()
- rtmsg_ifinfo_build_skb()
- rtmsg_ifinfo_send()
- rtnl_notify()
Also move __dev_notify_flags() declaration to net/core/dev.h, as Jakub
suggested.
Signed-off-by: Hangbin Liu <liuhangbin@gmail.com>
Reviewed-by: Guillaume Nault <gnault@redhat.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Clean up the use of unsafe_memcpy() by adding a flexible array
at the end of netlink message header and splitting up the header
and data copies.
Reviewed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Mark the validation fields as private, users shouldn't set
them directly and they are too complicated to explain in
a more succinct way (there's already a long explanation
in the comment above).
The strict_start_type field is set directly and has a dedicated
comment so move that above the "private" section.
Link: https://lore.kernel.org/r/20221027212107.2639255-1-kuba@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
netlink allows to specify allowed ranges for integer types.
Unfortunately, nfnetlink passes integers in big endian, so the existing
NLA_POLICY_MAX() cannot be used.
At the moment, nfnetlink users, such as nf_tables, need to resort to
programmatic checking via helpers such as nft_parse_u32_check().
This is both cumbersome and error prone. This adds NLA_POLICY_MAX_BE
which adds range check support for BE16, BE32 and BE64 integers.
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: David S. Miller <davem@davemloft.net>
Add the case when nlh is NULL in nlmsg_report(),
so that the caller doesn't need to deal with this case.
Signed-off-by: Yajun Deng <yajun.deng@linux.dev>
Signed-off-by: David S. Miller <davem@davemloft.net>
Calls to nla_strlcpy are now replaced by calls to nla_strscpy which is the new
name of this function.
Signed-off-by: Francis Laniel <laniel_francis@privacyrequired.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
nla_strlcpy now returns -E2BIG if src was truncated when written to dst.
It also returns this error value if dstsize is 0 or higher than INT_MAX.
For example, if src is "foo\0" and dst is 3 bytes long, the result will be:
1. "foG" after memcpy (G means garbage).
2. "fo\0" after memset.
3. -E2BIG is returned because src was not completely written into dst.
The callers of nla_strlcpy were modified to take into account this modification.
Signed-off-by: Francis Laniel <laniel_francis@privacyrequired.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Add a new attribute NLMSGERR_ATTR_POLICY to the extended ACK
to advertise the policy, e.g. if an attribute was out of range,
you'll know the range that's permissible.
Add new NL_SET_ERR_MSG_ATTR_POL() and NL_SET_ERR_MSG_ATTR_POL()
macros to set this, since realistically it's only useful to do
this when the bad attribute (offset) is also returned.
Use it in lib/nlattr.c which practically does all the policy
validation.
v2:
- add and use netlink_policy_dump_attr_size_estimate()
v3:
- remove redundant break
v4:
- really remove redundant break ... sorry
Reviewed-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
We don't have good validation policy for existing unsigned int attrs
which serve as flags (for new ones we could use NLA_BITFIELD32).
With increased use of policy dumping having the validation be
expressed as part of the policy is important. Add validation
policy in form of a mask of supported/valid bits.
Support u64 in the uAPI to be future-proof, but really for now
the embedded mask member can only hold 32 bits, so anything with
bit 32+ set will always fail validation.
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
There's a number of policies which check if type is a uint or sint.
Factor the checking against the list of value sizes to a helper
for easier reuse.
v2: - new patch
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Rework the policy dump code a bit to support adding multiple
policies to a single dump, in order to e.g. support per-op
policies in generic netlink.
v2:
- move kernel-doc to implementation [Jakub]
- squash the first patch to not flip-flop on the prototype
[Jakub]
- merge netlink_policy_dump_get_policy_idx() with the old
get_policy_idx() we already had
- rebase without Jakub's patch to have per-op dump
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Whenever netlink dump uses more than 2 cb->args[] entries
code gets hard to read. We're about to add more state to
ctrl_dumppolicy() so create a structure.
Since the structure is typed and clearly named we can remove
the local fam_id variable and use ctx->fam_id directly.
v3:
- rebase onto explicit free fix
v1:
- s/nl_policy_dump/netlink_policy_dump_state/
- forward declare struct netlink_policy_dump_state,
and move from passing unsigned long to actual pointer type
- add build bug on
- u16 fam_id
- s/args/ctx/
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Reviewed-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
[ Upstream commit a95bc734e6 ]
If userspace doesn't complete the policy dump, we leak the
allocated state. Fix this.
Fixes: d07dcf9aad ("netlink: add infrastructure to expose policies to userspace")
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Reviewed-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Two minor conflicts:
1) net/ipv4/route.c, adding a new local variable while
moving another local variable and removing it's
initial assignment.
2) drivers/net/dsa/microchip/ksz9477.c, overlapping changes.
One pretty prints the port mode differently, whilst another
changes the driver to try and obtain the port mode from
the port node rather than the switch node.
Signed-off-by: David S. Miller <davem@davemloft.net>
There is no @validate argument.
CC: Johannes Berg <johannes.berg@intel.com>
Fixes: 3de6440354 ("netlink: re-add parse/validate functions in strict mode")
Signed-off-by: Nicolas Dichtel <nicolas.dichtel@6wind.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Add range validation for NLA_BINARY, allowing validation of any
combination of combination minimum or maximum lengths, using the
existing NLA_POLICY_RANGE()/NLA_POLICY_FULL_RANGE() macros, just
like for integers where the value is checked.
Also make NLA_POLICY_EXACT_LEN(), NLA_POLICY_EXACT_LEN_WARN()
and NLA_POLICY_MIN_LEN() special cases of this, removing the old
types NLA_EXACT_LEN and NLA_MIN_LEN.
This allows us to save some code where both minimum and maximum
lengths are requires, currently the policy only allows maximum
(NLA_BINARY), minimum (NLA_MIN_LEN) or exact (NLA_EXACT_LEN), so
a range of lengths cannot be accepted and must be checked by the
code that consumes the attributes later.
Also, this allows advertising the correct ranges in the policy
export to userspace. Here, NLA_MIN_LEN and NLA_EXACT_LEN already
were special cases of NLA_BINARY with min and min/max length
respectively.
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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>
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>
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>
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>
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>
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>
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>
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>
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>
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>
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>
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>
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>
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>
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>
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>
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>
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>
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>
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>
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>
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>
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>
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>
