diff options
Diffstat (limited to 'lib/nlattr.c')
| -rw-r--r-- | lib/nlattr.c | 1143 |
1 files changed, 1143 insertions, 0 deletions
diff --git a/lib/nlattr.c b/lib/nlattr.c new file mode 100644 index 0000000000..7a2b6c38fd --- /dev/null +++ b/lib/nlattr.c @@ -0,0 +1,1143 @@ +// 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/nospec.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), +}; + +/* + * Nested policies might refer back to the original + * policy in some cases, and userspace could try to + * abuse that and recurse by nesting in the right + * ways. Limit recursion to avoid this problem. + */ +#define MAX_POLICY_RECURSION_DEPTH 10 + +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, unsigned int depth); + +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, unsigned int depth) +{ + 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_POL(extack, entry, policy, + "Array element too short"); + return -ERANGE; + } + + ret = __nla_validate_parse(nla_data(entry), nla_len(entry), + maxtype, policy, validate, extack, + NULL, depth + 1); + if (ret < 0) + return ret; + } + + return 0; +} + +void nla_get_range_unsigned(const struct nla_policy *pt, + struct netlink_range_validation *range) +{ + WARN_ON_ONCE(pt->validation_type != NLA_VALIDATE_RANGE_PTR && + (pt->min < 0 || pt->max < 0)); + + range->min = 0; + + switch (pt->type) { + case NLA_U8: + range->max = U8_MAX; + break; + case NLA_U16: + case NLA_BE16: + case NLA_BINARY: + range->max = U16_MAX; + break; + case NLA_U32: + case NLA_BE32: + range->max = U32_MAX; + break; + case NLA_U64: + case NLA_MSECS: + range->max = U64_MAX; + break; + default: + WARN_ON_ONCE(1); + return; + } + + switch (pt->validation_type) { + case NLA_VALIDATE_RANGE: + case NLA_VALIDATE_RANGE_WARN_TOO_LONG: + range->min = pt->min; + range->max = pt->max; + break; + case NLA_VALIDATE_RANGE_PTR: + *range = *pt->range; + break; + case NLA_VALIDATE_MIN: + range->min = pt->min; + break; + case NLA_VALIDATE_MAX: + range->max = pt->max; + break; + default: + break; + } +} + +static int nla_validate_range_unsigned(const struct nla_policy *pt, + const struct nlattr *nla, + struct netlink_ext_ack *extack, + unsigned int validate) +{ + struct netlink_range_validation range; + u64 value; + + 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_U64: + value = nla_get_u64(nla); + break; + case NLA_MSECS: + value = nla_get_u64(nla); + break; + case NLA_BINARY: + value = nla_len(nla); + break; + case NLA_BE16: + value = ntohs(nla_get_be16(nla)); + break; + case NLA_BE32: + value = ntohl(nla_get_be32(nla)); + break; + default: + return -EINVAL; + } + + nla_get_range_unsigned(pt, &range); + + if (pt->validation_type == NLA_VALIDATE_RANGE_WARN_TOO_LONG && + pt->type == NLA_BINARY && value > range.max) { + pr_warn_ratelimited("netlink: '%s': attribute type %d has an invalid length.\n", + current->comm, pt->type); + if (validate & NL_VALIDATE_STRICT_ATTRS) { + NL_SET_ERR_MSG_ATTR_POL(extack, nla, pt, + "invalid attribute length"); + return -EINVAL; + } + + /* this assumes min <= max (don't validate against min) */ + return 0; + } + + if (value < range.min || value > range.max) { + bool binary = pt->type == NLA_BINARY; + + if (binary) + NL_SET_ERR_MSG_ATTR_POL(extack, nla, pt, + "binary attribute size out of range"); + else + NL_SET_ERR_MSG_ATTR_POL(extack, nla, pt, + "integer out of range"); + + return -ERANGE; + } + + return 0; +} + +void nla_get_range_signed(const struct nla_policy *pt, + struct netlink_range_validation_signed *range) +{ + switch (pt->type) { + case NLA_S8: + range->min = S8_MIN; + range->max = S8_MAX; + break; + case NLA_S16: + range->min = S16_MIN; + range->max = S16_MAX; + break; + case NLA_S32: + range->min = S32_MIN; + range->max = S32_MAX; + break; + case NLA_S64: + range->min = S64_MIN; + range->max = S64_MAX; + break; + default: + WARN_ON_ONCE(1); + return; + } + + switch (pt->validation_type) { + case NLA_VALIDATE_RANGE: + range->min = pt->min; + range->max = pt->max; + break; + case NLA_VALIDATE_RANGE_PTR: + *range = *pt->range_signed; + break; + case NLA_VALIDATE_MIN: + range->min = pt->min; + break; + case NLA_VALIDATE_MAX: + range->max = pt->max; + break; + default: + break; + } +} + +static int nla_validate_int_range_signed(const struct nla_policy *pt, + const struct nlattr *nla, + struct netlink_ext_ack *extack) +{ + struct netlink_range_validation_signed range; + s64 value; + + switch (pt->type) { + 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; + default: + return -EINVAL; + } + + nla_get_range_signed(pt, &range); + + if (value < range.min || value > range.max) { + NL_SET_ERR_MSG_ATTR_POL(extack, nla, pt, + "integer out of range"); + return -ERANGE; + } + + return 0; +} + +static int nla_validate_int_range(const struct nla_policy *pt, + const struct nlattr *nla, + struct netlink_ext_ack *extack, + unsigned int validate) +{ + switch (pt->type) { + case NLA_U8: + case NLA_U16: + case NLA_U32: + case NLA_U64: + case NLA_MSECS: + case NLA_BINARY: + case NLA_BE16: + case NLA_BE32: + return nla_validate_range_unsigned(pt, nla, extack, validate); + case NLA_S8: + case NLA_S16: + case NLA_S32: + case NLA_S64: + return nla_validate_int_range_signed(pt, nla, extack); + default: + WARN_ON(1); + return -EINVAL; + } +} + +static int nla_validate_mask(const struct nla_policy *pt, + const struct nlattr *nla, + struct netlink_ext_ack *extack) +{ + u64 value; + + 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_U64: + value = nla_get_u64(nla); + break; + case NLA_BE16: + value = ntohs(nla_get_be16(nla)); + break; + case NLA_BE32: + value = ntohl(nla_get_be32(nla)); + break; + default: + return -EINVAL; + } + + if (value & ~(u64)pt->mask) { + NL_SET_ERR_MSG_ATTR(extack, nla, "reserved bit set"); + return -EINVAL; + } + + 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, unsigned int depth) +{ + 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; + + type = array_index_nospec(type, maxtype + 1); + pt = &policy[type]; + + BUG_ON(pt->type > NLA_TYPE_MAX); + + if (nla_attr_len[pt->type] && attrlen != nla_attr_len[pt->type]) { + 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_POL(extack, nla, pt, + "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_POL(extack, nla, pt, + "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_POL(extack, nla, pt, + "NLA_F_NESTED not expected"); + return -EINVAL; + } + } + + switch (pt->type) { + case NLA_REJECT: + if (extack && pt->reject_message) { + NL_SET_BAD_ATTR(extack, nla); + extack->_msg = pt->reject_message; + 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->bitfield32_valid); + 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; + } + fallthrough; + + 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->nested_policy) { + err = __nla_validate_parse(nla_data(nla), nla_len(nla), + pt->len, pt->nested_policy, + validate, extack, NULL, + depth + 1); + 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->nested_policy) { + int err; + + err = nla_validate_array(nla_data(nla), nla_len(nla), + pt->len, pt->nested_policy, + extack, validate, depth); + 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; + } + 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_PTR: + case NLA_VALIDATE_RANGE: + case NLA_VALIDATE_RANGE_WARN_TOO_LONG: + case NLA_VALIDATE_MIN: + case NLA_VALIDATE_MAX: + err = nla_validate_int_range(pt, nla, extack, validate); + if (err) + return err; + break; + case NLA_VALIDATE_MASK: + err = nla_validate_mask(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_POL(extack, nla, pt, + "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, unsigned int depth) +{ + const struct nlattr *nla; + int rem; + + if (depth >= MAX_POLICY_RECURSION_DEPTH) { + NL_SET_ERR_MSG(extack, + "allowed policy recursion depth exceeded"); + return -EINVAL; + } + + 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; + } + type = array_index_nospec(type, maxtype + 1); + if (policy) { + int err = validate_nla(nla, maxtype, policy, + validate, extack, depth); + + 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 documentation 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, 0); +} +EXPORT_SYMBOL(__nla_validate); + +/** + * nla_policy_len - Determine the max. length of a policy + * @p: 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, 0); +} +EXPORT_SYMBOL(__nla_parse); + +/** + * nla_find - Find a specific attribute in a stream of attributes + * @head: head of attribute stream + * @len: length of attribute stream + * @attrtype: type of attribute to look for + * + * Returns the first attribute in the stream matching the specified type. + */ +struct nlattr *nla_find(const struct nlattr *head, int len, int attrtype) +{ + const struct nlattr *nla; + int rem; + + nla_for_each_attr(nla, head, len, rem) + if (nla_type(nla) == attrtype) + return (struct nlattr *)nla; + + return NULL; +} +EXPORT_SYMBOL(nla_find); + +/** + * nla_strscpy - Copy string attribute payload into a sized buffer + * @dst: Where to copy the string to. + * @nla: Attribute to copy the string from. + * @dstsize: Size of destination buffer. + * + * Copies at most dstsize - 1 bytes into the destination buffer. + * Unlike strlcpy the destination buffer is always padded out. + * + * Return: + * * srclen - Returns @nla length (not including the trailing %NUL). + * * -E2BIG - If @dstsize is 0 or greater than U16_MAX or @nla length greater + * than @dstsize. + */ +ssize_t nla_strscpy(char *dst, const struct nlattr *nla, size_t dstsize) +{ + size_t srclen = nla_len(nla); + char *src = nla_data(nla); + ssize_t ret; + size_t len; + + if (dstsize == 0 || WARN_ON_ONCE(dstsize > U16_MAX)) + return -E2BIG; + + if (srclen > 0 && src[srclen - 1] == '\0') + srclen--; + + if (srclen >= dstsize) { + len = dstsize - 1; + ret = -E2BIG; + } else { + len = srclen; + ret = len; + } + + memcpy(dst, src, len); + /* Zero pad end of dst. */ + memset(dst + len, 0, dstsize - len); + + return ret; +} +EXPORT_SYMBOL(nla_strscpy); + +/** + * nla_strdup - Copy string attribute payload into a newly allocated buffer + * @nla: attribute to copy the string from + * @flags: the type of memory to allocate (see kmalloc). + * + * Returns a pointer to the allocated buffer or NULL on error. + */ +char *nla_strdup(const struct nlattr *nla, gfp_t flags) +{ + size_t srclen = nla_len(nla); + char *src = nla_data(nla), *dst; + + if (srclen > 0 && src[srclen - 1] == '\0') + srclen--; + + dst = kmalloc(srclen + 1, flags); + if (dst != NULL) { + memcpy(dst, src, srclen); + dst[srclen] = '\0'; + } + return dst; +} +EXPORT_SYMBOL(nla_strdup); + +/** + * nla_memcpy - Copy a netlink attribute into another memory area + * @dest: where to copy to memcpy + * @src: netlink attribute to copy from + * @count: size of the destination area + * + * Note: The number of bytes copied is limited by the length of + * attribute's payload. memcpy + * + * Returns the number of bytes copied. + */ +int nla_memcpy(void *dest, const struct nlattr *src, int count) +{ + int minlen = min_t(int, count, nla_len(src)); + + memcpy(dest, nla_data(src), minlen); + if (count > minlen) + memset(dest + minlen, 0, count - minlen); + + return minlen; +} +EXPORT_SYMBOL(nla_memcpy); + +/** + * nla_memcmp - Compare an attribute with sized memory area + * @nla: netlink attribute + * @data: memory area + * @size: size of memory area + */ +int nla_memcmp(const struct nlattr *nla, const void *data, + size_t size) +{ + int d = nla_len(nla) - size; + + if (d == 0) + d = memcmp(nla_data(nla), data, size); + + return d; +} +EXPORT_SYMBOL(nla_memcmp); + +/** + * nla_strcmp - Compare a string attribute against a string + * @nla: netlink string attribute + * @str: another string + */ +int nla_strcmp(const struct nlattr *nla, const char *str) +{ + int len = strlen(str); + char *buf = nla_data(nla); + int attrlen = nla_len(nla); + int d; + + while (attrlen > 0 && buf[attrlen - 1] == '\0') + attrlen--; + + d = attrlen - len; + if (d == 0) + d = memcmp(nla_data(nla), str, len); + + return d; +} +EXPORT_SYMBOL(nla_strcmp); + +#ifdef CONFIG_NET +/** + * __nla_reserve - reserve room for attribute on the skb + * @skb: socket buffer to reserve room on + * @attrtype: attribute type + * @attrlen: length of attribute payload + * + * Adds a netlink attribute header to a socket buffer and reserves + * room for the payload but does not copy it. + * + * The caller is responsible to ensure that the skb provides enough + * tailroom for the attribute header and payload. + */ +struct nlattr *__nla_reserve(struct sk_buff *skb, int attrtype, int attrlen) +{ + struct nlattr *nla; + + nla = skb_put(skb, nla_total_size(attrlen)); + nla->nla_type = attrtype; + nla->nla_len = nla_attr_size(attrlen); + + memset((unsigned char *) nla + nla->nla_len, 0, nla_padlen(attrlen)); + + return nla; +} +EXPORT_SYMBOL(__nla_reserve); + +/** + * __nla_reserve_64bit - reserve room for attribute on the skb and align it + * @skb: socket buffer to reserve room on + * @attrtype: attribute type + * @attrlen: length of attribute payload + * @padattr: attribute type for the padding + * + * Adds a netlink attribute header to a socket buffer and reserves + * room for the payload but does not copy it. It also ensure that this + * attribute will have a 64-bit aligned nla_data() area. + * + * The caller is responsible to ensure that the skb provides enough + * tailroom for the attribute header and payload. + */ +struct nlattr *__nla_reserve_64bit(struct sk_buff *skb, int attrtype, + int attrlen, int padattr) +{ + nla_align_64bit(skb, padattr); + + return __nla_reserve(skb, attrtype, attrlen); +} +EXPORT_SYMBOL(__nla_reserve_64bit); + +/** + * __nla_reserve_nohdr - reserve room for attribute without header + * @skb: socket buffer to reserve room on + * @attrlen: length of attribute payload + * + * Reserves room for attribute payload without a header. + * + * The caller is responsible to ensure that the skb provides enough + * tailroom for the payload. + */ +void *__nla_reserve_nohdr(struct sk_buff *skb, int attrlen) +{ + return skb_put_zero(skb, NLA_ALIGN(attrlen)); +} +EXPORT_SYMBOL(__nla_reserve_nohdr); + +/** + * nla_reserve - reserve room for attribute on the skb + * @skb: socket buffer to reserve room on + * @attrtype: attribute type + * @attrlen: length of attribute payload + * + * Adds a netlink attribute header to a socket buffer and reserves + * room for the payload but does not copy it. + * + * Returns NULL if the tailroom of the skb is insufficient to store + * the attribute header and payload. + */ +struct nlattr *nla_reserve(struct sk_buff *skb, int attrtype, int attrlen) +{ + if (unlikely(skb_tailroom(skb) < nla_total_size(attrlen))) + return NULL; + + return __nla_reserve(skb, attrtype, attrlen); +} +EXPORT_SYMBOL(nla_reserve); + +/** + * nla_reserve_64bit - reserve room for attribute on the skb and align it + * @skb: socket buffer to reserve room on + * @attrtype: attribute type + * @attrlen: length of attribute payload + * @padattr: attribute type for the padding + * + * Adds a netlink attribute header to a socket buffer and reserves + * room for the payload but does not copy it. It also ensure that this + * attribute will have a 64-bit aligned nla_data() area. + * + * Returns NULL if the tailroom of the skb is insufficient to store + * the attribute header and payload. + */ +struct nlattr *nla_reserve_64bit(struct sk_buff *skb, int attrtype, int attrlen, + int padattr) +{ + size_t len; + + if (nla_need_padding_for_64bit(skb)) + len = nla_total_size_64bit(attrlen); + else + len = nla_total_size(attrlen); + if (unlikely(skb_tailroom(skb) < len)) + return NULL; + + return __nla_reserve_64bit(skb, attrtype, attrlen, padattr); +} +EXPORT_SYMBOL(nla_reserve_64bit); + +/** + * nla_reserve_nohdr - reserve room for attribute without header + * @skb: socket buffer to reserve room on + * @attrlen: length of attribute payload + * + * Reserves room for attribute payload without a header. + * + * Returns NULL if the tailroom of the skb is insufficient to store + * the attribute payload. + */ +void *nla_reserve_nohdr(struct sk_buff *skb, int attrlen) +{ + if (unlikely(skb_tailroom(skb) < NLA_ALIGN(attrlen))) + return NULL; + + return __nla_reserve_nohdr(skb, attrlen); +} +EXPORT_SYMBOL(nla_reserve_nohdr); + +/** + * __nla_put - Add a netlink attribute to a socket buffer + * @skb: socket buffer to add attribute to + * @attrtype: attribute type + * @attrlen: length of attribute payload + * @data: head of attribute payload + * + * The caller is responsible to ensure that the skb provides enough + * tailroom for the attribute header and payload. + */ +void __nla_put(struct sk_buff *skb, int attrtype, int attrlen, + const void *data) +{ + struct nlattr *nla; + + nla = __nla_reserve(skb, attrtype, attrlen); + memcpy(nla_data(nla), data, attrlen); +} +EXPORT_SYMBOL(__nla_put); + +/** + * __nla_put_64bit - Add a netlink attribute to a socket buffer and align it + * @skb: socket buffer to add attribute to + * @attrtype: attribute type + * @attrlen: length of attribute payload + * @data: head of attribute payload + * @padattr: attribute type for the padding + * + * The caller is responsible to ensure that the skb provides enough + * tailroom for the attribute header and payload. + */ +void __nla_put_64bit(struct sk_buff *skb, int attrtype, int attrlen, + const void *data, int padattr) +{ + struct nlattr *nla; + + nla = __nla_reserve_64bit(skb, attrtype, attrlen, padattr); + memcpy(nla_data(nla), data, attrlen); +} +EXPORT_SYMBOL(__nla_put_64bit); + +/** + * __nla_put_nohdr - Add a netlink attribute without header + * @skb: socket buffer to add attribute to + * @attrlen: length of attribute payload + * @data: head of attribute payload + * + * The caller is responsible to ensure that the skb provides enough + * tailroom for the attribute payload. + */ +void __nla_put_nohdr(struct sk_buff *skb, int attrlen, const void *data) +{ + void *start; + + start = __nla_reserve_nohdr(skb, attrlen); + memcpy(start, data, attrlen); +} +EXPORT_SYMBOL(__nla_put_nohdr); + +/** + * nla_put - Add a netlink attribute to a socket buffer + * @skb: socket buffer to add attribute to + * @attrtype: attribute type + * @attrlen: length of attribute payload + * @data: head of attribute payload + * + * Returns -EMSGSIZE if the tailroom of the skb is insufficient to store + * the attribute header and payload. + */ +int nla_put(struct sk_buff *skb, int attrtype, int attrlen, const void *data) +{ + if (unlikely(skb_tailroom(skb) < nla_total_size(attrlen))) + return -EMSGSIZE; + + __nla_put(skb, attrtype, attrlen, data); + return 0; +} +EXPORT_SYMBOL(nla_put); + +/** + * nla_put_64bit - Add a netlink attribute to a socket buffer and align it + * @skb: socket buffer to add attribute to + * @attrtype: attribute type + * @attrlen: length of attribute payload + * @data: head of attribute payload + * @padattr: attribute type for the padding + * + * Returns -EMSGSIZE if the tailroom of the skb is insufficient to store + * the attribute header and payload. + */ +int nla_put_64bit(struct sk_buff *skb, int attrtype, int attrlen, + const void *data, int padattr) +{ + size_t len; + + if (nla_need_padding_for_64bit(skb)) + len = nla_total_size_64bit(attrlen); + else + len = nla_total_size(attrlen); + if (unlikely(skb_tailroom(skb) < len)) + return -EMSGSIZE; + + __nla_put_64bit(skb, attrtype, attrlen, data, padattr); + return 0; +} +EXPORT_SYMBOL(nla_put_64bit); + +/** + * nla_put_nohdr - Add a netlink attribute without header + * @skb: socket buffer to add attribute to + * @attrlen: length of attribute payload + * @data: head of attribute payload + * + * Returns -EMSGSIZE if the tailroom of the skb is insufficient to store + * the attribute payload. + */ +int nla_put_nohdr(struct sk_buff *skb, int attrlen, const void *data) +{ + if (unlikely(skb_tailroom(skb) < NLA_ALIGN(attrlen))) + return -EMSGSIZE; + + __nla_put_nohdr(skb, attrlen, data); + return 0; +} +EXPORT_SYMBOL(nla_put_nohdr); + +/** + * nla_append - Add a netlink attribute without header or padding + * @skb: socket buffer to add attribute to + * @attrlen: length of attribute payload + * @data: head of attribute payload + * + * Returns -EMSGSIZE if the tailroom of the skb is insufficient to store + * the attribute payload. + */ +int nla_append(struct sk_buff *skb, int attrlen, const void *data) +{ + if (unlikely(skb_tailroom(skb) < NLA_ALIGN(attrlen))) + return -EMSGSIZE; + + skb_put_data(skb, data, attrlen); + return 0; +} +EXPORT_SYMBOL(nla_append); +#endif |