diff options
| author | David Ahern <dsahern@gmail.com> | 2018-10-07 20:16:27 -0700 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2018-10-08 10:39:04 -0700 |
| commit | 89d35528d17d25819a755a2b52931e911baebc66 (patch) | |
| tree | ce226b66cdbd68f27df7f1fe8df95e49f9fa507a /net/netlink/af_netlink.h | |
| parent | 6ba1e6e856ab0531c5e0a5ecefc9fff8490d9a04 (diff) | |
netlink: Add new socket option to enable strict checking on dumps
Add a new socket option, NETLINK_DUMP_STRICT_CHK, that userspace
can use via setsockopt to request strict checking of headers and
attributes on dump requests.
To get dump features such as kernel side filtering based on data in
the header or attributes appended to the dump request, userspace
must call setsockopt() for NETLINK_DUMP_STRICT_CHK and a non-zero
value. Since the netlink sock and its flags are private to the
af_netlink code, the strict checking flag is passed to dump handlers
via a flag in the netlink_callback struct.
For old userspace on new kernel there is no impact as all of the data
checks in later patches are wrapped in a check on the new strict flag.
For new userspace on old kernel, the setsockopt will fail and even if
new userspace sets data in the headers and appended attributes the
kernel will silently ignore it. Moving forward when the setsockopt
succeeds, the new userspace on old kernel means the dump request can
pass an attribute the kernel does not understand. The dump will then
fail as the older kernel does not understand it.
New userspace on new kernel setting the socket option gets the benefit
of the improved data dump.
Kernel side the NETLINK_DUMP_STRICT_CHK uapi is converted to a generic
NETLINK_F_STRICT_CHK flag which can potentially be leveraged for tighter
checking on the NEW, DEL, and SET commands.
Signed-off-by: David Ahern <dsahern@gmail.com>
Acked-by: Christian Brauner <christian@brauner.io>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/netlink/af_netlink.h')
| -rw-r--r-- | net/netlink/af_netlink.h | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/net/netlink/af_netlink.h b/net/netlink/af_netlink.h index 962de7b3c023..5f454c8de6a4 100644 --- a/net/netlink/af_netlink.h +++ b/net/netlink/af_netlink.h @@ -15,6 +15,7 @@ #define NETLINK_F_LISTEN_ALL_NSID 0x10 #define NETLINK_F_CAP_ACK 0x20 #define NETLINK_F_EXT_ACK 0x40 +#define NETLINK_F_STRICT_CHK 0x80 #define NLGRPSZ(x) (ALIGN(x, sizeof(unsigned long) * 8) / 8) #define NLGRPLONGS(x) (NLGRPSZ(x)/sizeof(unsigned long)) |