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>
diff --git a/net/sched/sch_gred.c b/net/sched/sch_gred.c
index 9bfa15e..dfa657d 100644
--- a/net/sched/sch_gred.c
+++ b/net/sched/sch_gred.c
@@ -538,7 +538,8 @@ static void gred_vq_apply(struct gred_sched *table, const struct nlattr *entry)
struct nlattr *tb[TCA_GRED_VQ_MAX + 1];
u32 dp;
- nla_parse_nested(tb, TCA_GRED_VQ_MAX, entry, gred_vq_policy, NULL);
+ nla_parse_nested_deprecated(tb, TCA_GRED_VQ_MAX, entry,
+ gred_vq_policy, NULL);
dp = nla_get_u32(tb[TCA_GRED_VQ_DP]);
@@ -568,8 +569,8 @@ static int gred_vq_validate(struct gred_sched *table, u32 cdp,
int err;
u32 dp;
- err = nla_parse_nested(tb, TCA_GRED_VQ_MAX, entry, gred_vq_policy,
- extack);
+ err = nla_parse_nested_deprecated(tb, TCA_GRED_VQ_MAX, entry,
+ gred_vq_policy, extack);
if (err < 0)
return err;
@@ -610,8 +611,8 @@ static int gred_vqs_validate(struct gred_sched *table, u32 cdp,
const struct nlattr *attr;
int rem, err;
- err = nla_validate_nested(vqs, TCA_GRED_VQ_ENTRY_MAX,
- gred_vqe_policy, extack);
+ err = nla_validate_nested_deprecated(vqs, TCA_GRED_VQ_ENTRY_MAX,
+ gred_vqe_policy, extack);
if (err < 0)
return err;
@@ -650,7 +651,8 @@ static int gred_change(struct Qdisc *sch, struct nlattr *opt,
if (opt == NULL)
return -EINVAL;
- err = nla_parse_nested(tb, TCA_GRED_MAX, opt, gred_policy, extack);
+ err = nla_parse_nested_deprecated(tb, TCA_GRED_MAX, opt, gred_policy,
+ extack);
if (err < 0)
return err;
@@ -737,7 +739,8 @@ static int gred_init(struct Qdisc *sch, struct nlattr *opt,
if (!opt)
return -EINVAL;
- err = nla_parse_nested(tb, TCA_GRED_MAX, opt, gred_policy, extack);
+ err = nla_parse_nested_deprecated(tb, TCA_GRED_MAX, opt, gred_policy,
+ extack);
if (err < 0)
return err;
