diff options
| -rw-r--r-- | include/net/netlink.h | 67 | ||||
| -rw-r--r-- | lib/nlattr.c | 72 |
2 files changed, 136 insertions, 3 deletions
diff --git a/include/net/netlink.h b/include/net/netlink.h index 3698ca8ff92c..d34ceeba82a8 100644 --- a/include/net/netlink.h +++ b/include/net/netlink.h @@ -188,9 +188,19 @@ enum { #define NLA_TYPE_MAX (__NLA_TYPE_MAX - 1) +enum nla_policy_validation { + NLA_VALIDATE_NONE, + NLA_VALIDATE_RANGE, + NLA_VALIDATE_MIN, + NLA_VALIDATE_MAX, +}; + /** * 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 + * &enum nla_policy_validation * @len: Type specific length of payload * * Policies are defined as arrays of this struct, the array must be @@ -238,7 +248,26 @@ enum { * nested attributes directly inside, while an array has * the nested attributes at another level down and the * attributes directly in the nesting don't matter. - * All other Unused + * All other Unused - but note that it's a union + * + * Meaning of `min' and `max' fields, use via NLA_POLICY_MIN, NLA_POLICY_MAX + * and NLA_POLICY_RANGE: + * NLA_U8, + * NLA_U16, + * NLA_U32, + * NLA_U64, + * NLA_S8, + * NLA_S16, + * NLA_S32, + * NLA_S64 These are used depending on the validation_type + * field, if that is min/max/range then the minimum, + * maximum and both are used (respectively) to check + * the value of the integer attribute. + * Note that in the interest of code simplicity and + * struct size both limits are s16, so you cannot + * enforce a range that doesn't fall within the range + * of s16 - do that as usual in the code instead. + * All other Unused - but note that it's a union * * Example: * static const struct nla_policy my_policy[ATTR_MAX+1] = { @@ -249,9 +278,15 @@ enum { * }; */ struct nla_policy { - u16 type; + u8 type; + u8 validation_type; u16 len; - const void *validation_data; + union { + const void *validation_data; + struct { + s16 min, max; + }; + }; }; #define NLA_POLICY_EXACT_LEN(_len) { .type = NLA_EXACT_LEN, .len = _len } @@ -266,6 +301,32 @@ struct nla_policy { #define NLA_POLICY_NESTED_ARRAY(maxattr, policy) \ { .type = NLA_NESTED_ARRAY, .validation_data = policy, .len = maxattr } +#define __NLA_ENSURE(condition) (sizeof(char[1 - 2*!(condition)]) - 1) +#define NLA_ENSURE_INT_TYPE(tp) \ + (__NLA_ENSURE(tp == NLA_S8 || tp == NLA_U8 || \ + tp == NLA_S16 || tp == NLA_U16 || \ + tp == NLA_S32 || tp == NLA_U32 || \ + tp == NLA_S64 || tp == NLA_U64) + tp) + +#define NLA_POLICY_RANGE(tp, _min, _max) { \ + .type = NLA_ENSURE_INT_TYPE(tp), \ + .validation_type = NLA_VALIDATE_RANGE, \ + .min = _min, \ + .max = _max \ +} + +#define NLA_POLICY_MIN(tp, _min) { \ + .type = NLA_ENSURE_INT_TYPE(tp), \ + .validation_type = NLA_VALIDATE_MIN, \ + .min = _min, \ +} + +#define NLA_POLICY_MAX(tp, _max) { \ + .type = NLA_ENSURE_INT_TYPE(tp), \ + .validation_type = NLA_VALIDATE_MAX, \ + .max = _max, \ +} + /** * struct nl_info - netlink source information * @nlh: Netlink message header of original request diff --git a/lib/nlattr.c b/lib/nlattr.c index 2f8feff669a7..5670e4b7dfef 100644 --- a/lib/nlattr.c +++ b/lib/nlattr.c @@ -95,6 +95,64 @@ static int nla_validate_array(const struct nlattr *head, int len, int maxtype, return 0; } +static int nla_validate_int_range(const struct nla_policy *pt, + const struct nlattr *nla, + struct netlink_ext_ack *extack) +{ + bool validate_min, validate_max; + s64 value; + + validate_min = pt->validation_type == NLA_VALIDATE_RANGE || + pt->validation_type == NLA_VALIDATE_MIN; + validate_max = pt->validation_type == NLA_VALIDATE_RANGE || + pt->validation_type == NLA_VALIDATE_MAX; + + switch (pt->type) { + case NLA_U8: + value = nla_get_u8(nla); + break; + case NLA_U16: + value = nla_get_u16(nla); + break; + case NLA_U32: + value = nla_get_u32(nla); + break; + case NLA_S8: + value = nla_get_s8(nla); + break; + case NLA_S16: + value = nla_get_s16(nla); + break; + case NLA_S32: + value = nla_get_s32(nla); + break; + case NLA_S64: + value = nla_get_s64(nla); + break; + case NLA_U64: + /* treat this one specially, since it may not fit into s64 */ + if ((validate_min && nla_get_u64(nla) < pt->min) || + (validate_max && nla_get_u64(nla) > pt->max)) { + NL_SET_ERR_MSG_ATTR(extack, nla, + "integer out of range"); + return -ERANGE; + } + return 0; + default: + WARN_ON(1); + return -EINVAL; + } + + if ((validate_min && value < pt->min) || + (validate_max && value > pt->max)) { + NL_SET_ERR_MSG_ATTR(extack, nla, + "integer out of range"); + return -ERANGE; + } + + return 0; +} + static int validate_nla(const struct nlattr *nla, int maxtype, const struct nla_policy *policy, struct netlink_ext_ack *extack) @@ -230,6 +288,20 @@ static int validate_nla(const struct nlattr *nla, int maxtype, goto out_err; } + /* further validation */ + switch (pt->validation_type) { + case NLA_VALIDATE_NONE: + /* nothing to do */ + break; + case NLA_VALIDATE_RANGE: + case NLA_VALIDATE_MIN: + case NLA_VALIDATE_MAX: + err = nla_validate_int_range(pt, nla, extack); + if (err) + return err; + break; + } + return 0; out_err: NL_SET_ERR_MSG_ATTR(extack, nla, "Attribute failed policy validation"); |