diff options
Diffstat (limited to 'compat/backport-5.2.c')
-rw-r--r-- | compat/backport-5.2.c | 481 |
1 files changed, 481 insertions, 0 deletions
diff --git a/compat/backport-5.2.c b/compat/backport-5.2.c new file mode 100644 index 0000000..5624d5f --- /dev/null +++ b/compat/backport-5.2.c @@ -0,0 +1,481 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * NETLINK Netlink attributes + * + * Authors: Thomas Graf <tgraf@suug.ch> + * Alexey Kuznetsov <kuznet@ms2.inr.ac.ru> + */ + +#include <linux/export.h> +#include <linux/kernel.h> +#include <linux/errno.h> +#include <linux/jiffies.h> +#include <linux/skbuff.h> +#include <linux/string.h> +#include <linux/types.h> +#include <net/netlink.h> + +/* For these data types, attribute length should be exactly the given + * size. However, to maintain compatibility with broken commands, if the + * attribute length does not match the expected size a warning is emitted + * to the user that the command is sending invalid data and needs to be fixed. + */ +static const u8 nla_attr_len[NLA_TYPE_MAX+1] = { + [NLA_U8] = sizeof(u8), + [NLA_U16] = sizeof(u16), + [NLA_U32] = sizeof(u32), + [NLA_U64] = sizeof(u64), + [NLA_S8] = sizeof(s8), + [NLA_S16] = sizeof(s16), + [NLA_S32] = sizeof(s32), + [NLA_S64] = sizeof(s64), +}; + +static const u8 nla_attr_minlen[NLA_TYPE_MAX+1] = { + [NLA_U8] = sizeof(u8), + [NLA_U16] = sizeof(u16), + [NLA_U32] = sizeof(u32), + [NLA_U64] = sizeof(u64), + [NLA_MSECS] = sizeof(u64), + [NLA_NESTED] = NLA_HDRLEN, + [NLA_S8] = sizeof(s8), + [NLA_S16] = sizeof(s16), + [NLA_S32] = sizeof(s32), + [NLA_S64] = sizeof(s64), +}; + +static int validate_nla_bitfield32(const struct nlattr *nla, + const u32 *valid_flags_mask) +{ + const struct nla_bitfield32 *bf = nla_data(nla); + + if (!valid_flags_mask) + return -EINVAL; + + /*disallow invalid bit selector */ + if (bf->selector & ~*valid_flags_mask) + return -EINVAL; + + /*disallow invalid bit values */ + if (bf->value & ~*valid_flags_mask) + return -EINVAL; + + /*disallow valid bit values that are not selected*/ + if (bf->value & ~bf->selector) + return -EINVAL; + + return 0; +} + +static int nla_validate_array(const struct nlattr *head, int len, int maxtype, + const struct nla_policy *policy, + struct netlink_ext_ack *extack, + unsigned int validate) +{ + const struct nlattr *entry; + int rem; + + nla_for_each_attr(entry, head, len, rem) { + int ret; + + if (nla_len(entry) == 0) + continue; + + if (nla_len(entry) < NLA_HDRLEN) { + NL_SET_ERR_MSG_ATTR(extack, entry, + "Array element too short"); + return -ERANGE; + } + + ret = __nla_validate(nla_data(entry), nla_len(entry), + maxtype, policy, validate, extack); + if (ret < 0) + return ret; + } + + 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, unsigned int validate, + struct netlink_ext_ack *extack) +{ + u16 strict_start_type = policy[0].strict_start_type; + const struct nla_policy *pt; + int minlen = 0, attrlen = nla_len(nla), type = nla_type(nla); + int err = -ERANGE; + + if (strict_start_type && type >= strict_start_type) + validate |= NL_VALIDATE_STRICT; + + if (type <= 0 || type > maxtype) + return 0; + + pt = &policy[type]; + + BUG_ON(pt->type > NLA_TYPE_MAX); + + if ((nla_attr_len[pt->type] && attrlen != nla_attr_len[pt->type]) || + (pt->type == NLA_EXACT_LEN_WARN && attrlen != pt->len)) { + pr_warn_ratelimited("netlink: '%s': attribute type %d has an invalid length.\n", + current->comm, type); + if (validate & NL_VALIDATE_STRICT_ATTRS) { + NL_SET_ERR_MSG_ATTR(extack, nla, + "invalid attribute length"); + return -EINVAL; + } + } + + if (validate & NL_VALIDATE_NESTED) { + if ((pt->type == NLA_NESTED || pt->type == NLA_NESTED_ARRAY) && + !(nla->nla_type & NLA_F_NESTED)) { + NL_SET_ERR_MSG_ATTR(extack, nla, + "NLA_F_NESTED is missing"); + return -EINVAL; + } + if (pt->type != NLA_NESTED && pt->type != NLA_NESTED_ARRAY && + pt->type != NLA_UNSPEC && (nla->nla_type & NLA_F_NESTED)) { + NL_SET_ERR_MSG_ATTR(extack, nla, + "NLA_F_NESTED not expected"); + return -EINVAL; + } + } + + switch (pt->type) { + case NLA_EXACT_LEN: + if (attrlen != pt->len) + goto out_err; + break; + + case NLA_REJECT: + if (extack && pt->validation_data) { + NL_SET_BAD_ATTR(extack, nla); + extack->_msg = pt->validation_data; + return -EINVAL; + } + err = -EINVAL; + goto out_err; + + case NLA_FLAG: + if (attrlen > 0) + goto out_err; + break; + + case NLA_BITFIELD32: + if (attrlen != sizeof(struct nla_bitfield32)) + goto out_err; + + err = validate_nla_bitfield32(nla, pt->validation_data); + if (err) + goto out_err; + break; + + case NLA_NUL_STRING: + if (pt->len) + minlen = min_t(int, attrlen, pt->len + 1); + else + minlen = attrlen; + + if (!minlen || memchr(nla_data(nla), '\0', minlen) == NULL) { + err = -EINVAL; + goto out_err; + } + /* fall through */ + + case NLA_STRING: + if (attrlen < 1) + goto out_err; + + if (pt->len) { + char *buf = nla_data(nla); + + if (buf[attrlen - 1] == '\0') + attrlen--; + + if (attrlen > pt->len) + goto out_err; + } + break; + + case NLA_BINARY: + if (pt->len && attrlen > pt->len) + goto out_err; + break; + + case NLA_NESTED: + /* a nested attributes is allowed to be empty; if its not, + * it must have a size of at least NLA_HDRLEN. + */ + if (attrlen == 0) + break; + if (attrlen < NLA_HDRLEN) + goto out_err; + if (pt->validation_data) { + err = __nla_validate(nla_data(nla), nla_len(nla), pt->len, + pt->validation_data, validate, + extack); + if (err < 0) { + /* + * return directly to preserve the inner + * error message/attribute pointer + */ + return err; + } + } + break; + case NLA_NESTED_ARRAY: + /* a nested array attribute is allowed to be empty; if its not, + * it must have a size of at least NLA_HDRLEN. + */ + if (attrlen == 0) + break; + if (attrlen < NLA_HDRLEN) + goto out_err; + if (pt->validation_data) { + int err; + + err = nla_validate_array(nla_data(nla), nla_len(nla), + pt->len, pt->validation_data, + extack, validate); + if (err < 0) { + /* + * return directly to preserve the inner + * error message/attribute pointer + */ + return err; + } + } + break; + + case NLA_UNSPEC: + if (validate & NL_VALIDATE_UNSPEC) { + NL_SET_ERR_MSG_ATTR(extack, nla, + "Unsupported attribute"); + return -EINVAL; + } + /* fall through */ + case NLA_MIN_LEN: + if (attrlen < pt->len) + goto out_err; + break; + + default: + if (pt->len) + minlen = pt->len; + else + minlen = nla_attr_minlen[pt->type]; + + if (attrlen < minlen) + 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; + case NLA_VALIDATE_FUNCTION: + if (pt->validate) { + err = pt->validate(nla, extack); + if (err) + return err; + } + break; + } + + return 0; +out_err: + NL_SET_ERR_MSG_ATTR(extack, nla, "Attribute failed policy validation"); + return err; +} + +static int __nla_validate_parse(const struct nlattr *head, int len, int maxtype, + const struct nla_policy *policy, + unsigned int validate, + struct netlink_ext_ack *extack, + struct nlattr **tb) +{ + const struct nlattr *nla; + int rem; + + if (tb) + memset(tb, 0, sizeof(struct nlattr *) * (maxtype + 1)); + + nla_for_each_attr(nla, head, len, rem) { + u16 type = nla_type(nla); + + if (type == 0 || type > maxtype) { + if (validate & NL_VALIDATE_MAXTYPE) { + NL_SET_ERR_MSG_ATTR(extack, nla, + "Unknown attribute type"); + return -EINVAL; + } + continue; + } + if (policy) { + int err = validate_nla(nla, maxtype, policy, + validate, extack); + + if (err < 0) + return err; + } + + if (tb) + tb[type] = (struct nlattr *)nla; + } + + if (unlikely(rem > 0)) { + pr_warn_ratelimited("netlink: %d bytes leftover after parsing attributes in process `%s'.\n", + rem, current->comm); + NL_SET_ERR_MSG(extack, "bytes leftover after parsing attributes"); + if (validate & NL_VALIDATE_TRAILING) + return -EINVAL; + } + + return 0; +} + +/** + * __nla_validate - Validate a stream of attributes + * @head: head of attribute stream + * @len: length of attribute stream + * @maxtype: maximum attribute type to be expected + * @policy: validation policy + * @validate: validation strictness + * @extack: extended ACK report struct + * + * Validates all attributes in the specified attribute stream against the + * specified policy. Validation depends on the validate flags passed, see + * &enum netlink_validation for more details on that. + * See documenation of struct nla_policy for more details. + * + * Returns 0 on success or a negative error code. + */ +int __nla_validate(const struct nlattr *head, int len, int maxtype, + const struct nla_policy *policy, unsigned int validate, + struct netlink_ext_ack *extack) +{ + return __nla_validate_parse(head, len, maxtype, policy, validate, + extack, NULL); +} +EXPORT_SYMBOL(__nla_validate); + +/** + * nla_policy_len - Determin the max. length of a policy + * @policy: policy to use + * @n: number of policies + * + * Determines the max. length of the policy. It is currently used + * to allocated Netlink buffers roughly the size of the actual + * message. + * + * Returns 0 on success or a negative error code. + */ +int +nla_policy_len(const struct nla_policy *p, int n) +{ + int i, len = 0; + + for (i = 0; i < n; i++, p++) { + if (p->len) + len += nla_total_size(p->len); + else if (nla_attr_len[p->type]) + len += nla_total_size(nla_attr_len[p->type]); + else if (nla_attr_minlen[p->type]) + len += nla_total_size(nla_attr_minlen[p->type]); + } + + return len; +} +EXPORT_SYMBOL(nla_policy_len); + +/** + * __nla_parse - Parse a stream of attributes into a tb buffer + * @tb: destination array with maxtype+1 elements + * @maxtype: maximum attribute type to be expected + * @head: head of attribute stream + * @len: length of attribute stream + * @policy: validation policy + * @validate: validation strictness + * @extack: extended ACK pointer + * + * Parses a stream of attributes and stores a pointer to each attribute in + * the tb array accessible via the attribute type. + * Validation is controlled by the @validate parameter. + * + * Returns 0 on success or a negative error code. + */ +int __nla_parse(struct nlattr **tb, int maxtype, + const struct nlattr *head, int len, + const struct nla_policy *policy, unsigned int validate, + struct netlink_ext_ack *extack) +{ + return __nla_validate_parse(head, len, maxtype, policy, validate, + extack, tb); +} +EXPORT_SYMBOL(__nla_parse); |