linux/net/xfrm
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
..
Kconfig xfrm: prefer secpath_set over secpath_dup 2018-12-19 11:21:38 -08:00
Makefile xfrm: Add virtual xfrm interfaces 2018-06-23 16:07:25 +02:00
xfrm_algo.c
xfrm_device.c net: dev: rename queue selection helpers. 2019-03-20 11:18:54 -07:00
xfrm_hash.c mm: remove include/linux/bootmem.h 2018-10-31 08:54:16 -07:00
xfrm_hash.h xfrm: use complete IPv6 addresses for hash 2018-10-15 10:09:18 +02:00
xfrm_input.c Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2018-12-20 11:53:36 -08:00
xfrm_interface.c xfrm: Fix inbound traffic via XFRM interfaces across network namespaces 2019-02-18 10:58:54 +01:00
xfrm_ipcomp.c net: xfrm: use preempt-safe this_cpu_read() in ipcomp_alloc_tfms() 2018-03-13 07:46:37 +01:00
xfrm_output.c Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2018-12-20 11:53:36 -08:00
xfrm_policy.c xfrm: Fix inbound traffic via XFRM interfaces across network namespaces 2019-02-18 10:58:54 +01:00
xfrm_proc.c proc: introduce proc_create_net_single 2018-05-16 07:24:30 +02:00
xfrm_replay.c xfrm: Fix ESN sequence number handling for IPsec GSO packets. 2018-03-01 08:14:50 +01:00
xfrm_state.c xfrm: destroy xfrm_state synchronously on net exit path 2019-02-05 06:29:20 +01:00
xfrm_sysctl.c
xfrm_user.c netlink: make validation more configurable for future strictness 2019-04-27 17:07:21 -04:00