diff options
Diffstat (limited to 'lib/nlattr.c')
| -rw-r--r-- | lib/nlattr.c | 396 |
1 files changed, 313 insertions, 83 deletions
diff --git a/lib/nlattr.c b/lib/nlattr.c index cace9b307781..b67a53e29b8f 100644 --- a/lib/nlattr.c +++ b/lib/nlattr.c @@ -44,8 +44,22 @@ static const u8 nla_attr_minlen[NLA_TYPE_MAX+1] = { [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 u32 valid_flags_mask) { const struct nla_bitfield32 *bf = nla_data(nla); @@ -53,11 +67,11 @@ static int validate_nla_bitfield32(const struct nlattr *nla, return -EINVAL; /*disallow invalid bit selector */ - if (bf->selector & ~*valid_flags_mask) + if (bf->selector & ~valid_flags_mask) return -EINVAL; /*disallow invalid bit values */ - if (bf->value & ~*valid_flags_mask) + if (bf->value & ~valid_flags_mask) return -EINVAL; /*disallow valid bit values that are not selected*/ @@ -70,7 +84,7 @@ static int validate_nla_bitfield32(const struct nlattr *nla, 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 validate, unsigned int depth) { const struct nlattr *entry; int rem; @@ -82,13 +96,14 @@ static int nla_validate_array(const struct nlattr *head, int len, int maxtype, continue; if (nla_len(entry) < NLA_HDRLEN) { - NL_SET_ERR_MSG_ATTR(extack, entry, - "Array element too short"); + NL_SET_ERR_MSG_ATTR_POL(extack, entry, policy, + "Array element too short"); return -ERANGE; } - ret = __nla_validate(nla_data(entry), nla_len(entry), - maxtype, policy, validate, extack); + ret = __nla_validate_parse(nla_data(entry), nla_len(entry), + maxtype, policy, validate, extack, + NULL, depth + 1); if (ret < 0) return ret; } @@ -96,17 +111,63 @@ 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) +void nla_get_range_unsigned(const struct nla_policy *pt, + struct netlink_range_validation *range) { - bool validate_min, validate_max; - s64 value; + WARN_ON_ONCE(pt->validation_type != NLA_VALIDATE_RANGE_PTR && + (pt->min < 0 || pt->max < 0)); - 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; + 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: @@ -118,6 +179,109 @@ static int nla_validate_int_range(const struct nla_policy *pt, 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; @@ -130,25 +294,73 @@ static int nla_validate_int_range(const struct nla_policy *pt, 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: - /* 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; + 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; } +} - if ((validate_min && value < pt->min) || - (validate_max && value > pt->max)) { - NL_SET_ERR_MSG_ATTR(extack, nla, - "integer out of range"); - return -ERANGE; +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; + default: + return -EINVAL; + } + + if (value & ~(u64)pt->mask) { + NL_SET_ERR_MSG_ATTR(extack, nla, "reserved bit set"); + return -EINVAL; } return 0; @@ -156,7 +368,7 @@ static int nla_validate_int_range(const struct nla_policy *pt, static int validate_nla(const struct nlattr *nla, int maxtype, const struct nla_policy *policy, unsigned int validate, - struct netlink_ext_ack *extack) + struct netlink_ext_ack *extack, unsigned int depth) { u16 strict_start_type = policy[0].strict_start_type; const struct nla_policy *pt; @@ -173,13 +385,12 @@ static int validate_nla(const struct nlattr *nla, int maxtype, 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)) { + 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(extack, nla, - "invalid attribute length"); + NL_SET_ERR_MSG_ATTR_POL(extack, nla, pt, + "invalid attribute length"); return -EINVAL; } } @@ -187,28 +398,23 @@ static int validate_nla(const struct nlattr *nla, int maxtype, 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"); + 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(extack, nla, - "NLA_F_NESTED not expected"); + NL_SET_ERR_MSG_ATTR_POL(extack, nla, pt, + "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) { + if (extack && pt->reject_message) { NL_SET_BAD_ATTR(extack, nla); - extack->_msg = pt->validation_data; + extack->_msg = pt->reject_message; return -EINVAL; } err = -EINVAL; @@ -223,7 +429,7 @@ static int validate_nla(const struct nlattr *nla, int maxtype, if (attrlen != sizeof(struct nla_bitfield32)) goto out_err; - err = validate_nla_bitfield32(nla, pt->validation_data); + err = validate_nla_bitfield32(nla, pt->bitfield32_valid); if (err) goto out_err; break; @@ -238,7 +444,7 @@ static int validate_nla(const struct nlattr *nla, int maxtype, err = -EINVAL; goto out_err; } - /* fall through */ + fallthrough; case NLA_STRING: if (attrlen < 1) @@ -268,10 +474,11 @@ static int validate_nla(const struct nlattr *nla, int maxtype, 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 (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 @@ -289,12 +496,12 @@ static int validate_nla(const struct nlattr *nla, int maxtype, break; if (attrlen < NLA_HDRLEN) goto out_err; - if (pt->validation_data) { + if (pt->nested_policy) { int err; err = nla_validate_array(nla_data(nla), nla_len(nla), - pt->len, pt->validation_data, - extack, validate); + pt->len, pt->nested_policy, + extack, validate, depth); if (err < 0) { /* * return directly to preserve the inner @@ -311,8 +518,6 @@ static int validate_nla(const struct nlattr *nla, int maxtype, "Unsupported attribute"); return -EINVAL; } - /* fall through */ - case NLA_MIN_LEN: if (attrlen < pt->len) goto out_err; break; @@ -332,10 +537,17 @@ static int validate_nla(const struct nlattr *nla, int maxtype, 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); + 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; @@ -350,7 +562,8 @@ static int validate_nla(const struct nlattr *nla, int maxtype, return 0; out_err: - NL_SET_ERR_MSG_ATTR(extack, nla, "Attribute failed policy validation"); + NL_SET_ERR_MSG_ATTR_POL(extack, nla, pt, + "Attribute failed policy validation"); return err; } @@ -358,11 +571,17 @@ 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) + 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)); @@ -379,7 +598,7 @@ static int __nla_validate_parse(const struct nlattr *head, int len, int maxtype, } if (policy) { int err = validate_nla(nla, maxtype, policy, - validate, extack); + validate, extack, depth); if (err < 0) return err; @@ -412,7 +631,7 @@ static int __nla_validate_parse(const struct nlattr *head, int len, int maxtype, * 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. + * See documentation of struct nla_policy for more details. * * Returns 0 on success or a negative error code. */ @@ -421,12 +640,12 @@ int __nla_validate(const struct nlattr *head, int len, int maxtype, struct netlink_ext_ack *extack) { return __nla_validate_parse(head, len, maxtype, policy, validate, - extack, NULL); + extack, NULL, 0); } EXPORT_SYMBOL(__nla_validate); /** - * nla_policy_len - Determin the max. length of a policy + * nla_policy_len - Determine the max. length of a policy * @policy: policy to use * @n: number of policies * @@ -476,7 +695,7 @@ int __nla_parse(struct nlattr **tb, int maxtype, struct netlink_ext_ack *extack) { return __nla_validate_parse(head, len, maxtype, policy, validate, - extack, tb); + extack, tb, 0); } EXPORT_SYMBOL(__nla_parse); @@ -502,35 +721,47 @@ struct nlattr *nla_find(const struct nlattr *head, int len, int attrtype) EXPORT_SYMBOL(nla_find); /** - * nla_strlcpy - 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 + * 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. - * The result is always a valid NUL-terminated string. Unlike - * strlcpy the destination buffer is always padded out. + * Unlike strlcpy the destination buffer is always padded out. * - * Returns the length of the source buffer. + * 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. */ -size_t nla_strlcpy(char *dst, const struct nlattr *nla, size_t 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 (dstsize > 0) { - size_t len = (srclen >= dstsize) ? dstsize - 1 : srclen; - - memset(dst, 0, dstsize); - memcpy(dst, src, len); + if (srclen >= dstsize) { + len = dstsize - 1; + ret = -E2BIG; + } else { + len = srclen; + ret = len; } - return srclen; + memcpy(dst, src, len); + /* Zero pad end of dst. */ + memset(dst + len, 0, dstsize - len); + + return ret; } -EXPORT_SYMBOL(nla_strlcpy); +EXPORT_SYMBOL(nla_strscpy); /** * nla_strdup - Copy string attribute payload into a newly allocated buffer @@ -609,7 +840,7 @@ int nla_strcmp(const struct nlattr *nla, const char *str) int attrlen = nla_len(nla); int d; - if (attrlen > 0 && buf[attrlen - 1] == '\0') + while (attrlen > 0 && buf[attrlen - 1] == '\0') attrlen--; d = attrlen - len; @@ -664,8 +895,7 @@ EXPORT_SYMBOL(__nla_reserve); struct nlattr *__nla_reserve_64bit(struct sk_buff *skb, int attrtype, int attrlen, int padattr) { - if (nla_need_padding_for_64bit(skb)) - nla_align_64bit(skb, padattr); + nla_align_64bit(skb, padattr); return __nla_reserve(skb, attrtype, attrlen); } |