diff options
author | Johannes Berg <johannes.berg@intel.com> | 2018-09-27 11:28:36 +0200 |
---|---|---|
committer | David S. Miller <davem@davemloft.net> | 2018-10-01 23:05:31 -0700 |
commit | 33188bd6430ef06d206ae4fda2cc92f14f16fd20 (patch) | |
tree | bd3980a02a9896a5a1d60936b451ce40efc44349 | |
parent | 3e48be05f3c7eb6f6126939e9d957903c5cfeee5 (diff) | |
download | linux-33188bd6430ef06d206ae4fda2cc92f14f16fd20.tar.bz2 |
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>
-rw-r--r-- | include/net/netlink.h | 24 | ||||
-rw-r--r-- | lib/nlattr.c | 7 |
2 files changed, 30 insertions, 1 deletions
diff --git a/include/net/netlink.h b/include/net/netlink.h index d34ceeba82a8..6a106ef5ca56 100644 --- a/include/net/netlink.h +++ b/include/net/netlink.h @@ -193,13 +193,14 @@ enum nla_policy_validation { NLA_VALIDATE_RANGE, NLA_VALIDATE_MIN, NLA_VALIDATE_MAX, + NLA_VALIDATE_FUNCTION, }; /** * struct nla_policy - attribute validation policy * @type: Type of attribute or NLA_UNSPEC * @validation_type: type of attribute validation done in addition to - * type-specific validation (e.g. range), see + * type-specific validation (e.g. range, function call), see * &enum nla_policy_validation * @len: Type specific length of payload * @@ -269,6 +270,13 @@ enum nla_policy_validation { * of s16 - do that as usual in the code instead. * All other Unused - but note that it's a union * + * Meaning of `validate' field, use via NLA_POLICY_VALIDATE_FN: + * NLA_BINARY Validation function called for the attribute, + * not compatible with use of the validation_data + * as in NLA_BITFIELD32, NLA_REJECT, NLA_NESTED and + * NLA_NESTED_ARRAY. + * All other Unused - but note that it's a union + * * Example: * static const struct nla_policy my_policy[ATTR_MAX+1] = { * [ATTR_FOO] = { .type = NLA_U16 }, @@ -286,6 +294,8 @@ struct nla_policy { struct { s16 min, max; }; + int (*validate)(const struct nlattr *attr, + struct netlink_ext_ack *extack); }; }; @@ -307,6 +317,11 @@ struct nla_policy { tp == NLA_S16 || tp == NLA_U16 || \ tp == NLA_S32 || tp == NLA_U32 || \ tp == NLA_S64 || tp == NLA_U64) + tp) +#define NLA_ENSURE_NO_VALIDATION_PTR(tp) \ + (__NLA_ENSURE(tp != NLA_BITFIELD32 && \ + tp != NLA_REJECT && \ + tp != NLA_NESTED && \ + tp != NLA_NESTED_ARRAY) + tp) #define NLA_POLICY_RANGE(tp, _min, _max) { \ .type = NLA_ENSURE_INT_TYPE(tp), \ @@ -327,6 +342,13 @@ struct nla_policy { .max = _max, \ } +#define NLA_POLICY_VALIDATE_FN(tp, fn, ...) { \ + .type = NLA_ENSURE_NO_VALIDATION_PTR(tp), \ + .validation_type = NLA_VALIDATE_FUNCTION, \ + .validate = fn, \ + .len = __VA_ARGS__ + 0, \ +} + /** * struct nl_info - netlink source information * @nlh: Netlink message header of original request diff --git a/lib/nlattr.c b/lib/nlattr.c index 5670e4b7dfef..1e900bb414ef 100644 --- a/lib/nlattr.c +++ b/lib/nlattr.c @@ -300,6 +300,13 @@ static int validate_nla(const struct nlattr *nla, int maxtype, if (err) return err; break; + case NLA_VALIDATE_FUNCTION: + if (pt->validate) { + err = pt->validate(nla, extack); + if (err) + return err; + } + break; } return 0; |