/* * CALIPSO - Common Architecture Label IPv6 Security Option * * This is an implementation of the CALIPSO protocol as specified in * RFC 5570. * * Authors: Paul Moore * Huw Davies * */ /* (c) Copyright Hewlett-Packard Development Company, L.P., 2006, 2008 * (c) Copyright Huw Davies , 2015 * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation; either version 2 of the License, or * (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See * the GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program; if not, see . * */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include /* Maximium size of the calipso option including * the two-byte TLV header. */ #define CALIPSO_OPT_LEN_MAX (2 + 252) /* Size of the minimum calipso option including * the two-byte TLV header. */ #define CALIPSO_HDR_LEN (2 + 8) /* Maximium size of the calipso option including * the two-byte TLV header and upto 3 bytes of * leading pad and 7 bytes of trailing pad. */ #define CALIPSO_OPT_LEN_MAX_WITH_PAD (3 + CALIPSO_OPT_LEN_MAX + 7) /* List of available DOI definitions */ static DEFINE_SPINLOCK(calipso_doi_list_lock); static LIST_HEAD(calipso_doi_list); /* DOI List Functions */ /** * calipso_doi_search - Searches for a DOI definition * @doi: the DOI to search for * * Description: * Search the DOI definition list for a DOI definition with a DOI value that * matches @doi. The caller is responsible for calling rcu_read_[un]lock(). * Returns a pointer to the DOI definition on success and NULL on failure. */ static struct calipso_doi *calipso_doi_search(u32 doi) { struct calipso_doi *iter; list_for_each_entry_rcu(iter, &calipso_doi_list, list) if (iter->doi == doi && atomic_read(&iter->refcount)) return iter; return NULL; } /** * calipso_doi_add - Add a new DOI to the CALIPSO protocol engine * @doi_def: the DOI structure * @audit_info: NetLabel audit information * * Description: * The caller defines a new DOI for use by the CALIPSO engine and calls this * function to add it to the list of acceptable domains. The caller must * ensure that the mapping table specified in @doi_def->map meets all of the * requirements of the mapping type (see calipso.h for details). Returns * zero on success and non-zero on failure. * */ static int calipso_doi_add(struct calipso_doi *doi_def, struct netlbl_audit *audit_info) { int ret_val = -EINVAL; u32 doi; u32 doi_type; struct audit_buffer *audit_buf; doi = doi_def->doi; doi_type = doi_def->type; if (doi_def->doi == CALIPSO_DOI_UNKNOWN) goto doi_add_return; atomic_set(&doi_def->refcount, 1); spin_lock(&calipso_doi_list_lock); if (calipso_doi_search(doi_def->doi)) { spin_unlock(&calipso_doi_list_lock); ret_val = -EEXIST; goto doi_add_return; } list_add_tail_rcu(&doi_def->list, &calipso_doi_list); spin_unlock(&calipso_doi_list_lock); ret_val = 0; doi_add_return: audit_buf = netlbl_audit_start(AUDIT_MAC_CALIPSO_ADD, audit_info); if (audit_buf) { const char *type_str; switch (doi_type) { case CALIPSO_MAP_PASS: type_str = "pass"; break; default: type_str = "(unknown)"; } audit_log_format(audit_buf, " calipso_doi=%u calipso_type=%s res=%u", doi, type_str, ret_val == 0 ? 1 : 0); audit_log_end(audit_buf); } return ret_val; } /** * calipso_doi_free - Frees a DOI definition * @doi_def: the DOI definition * * Description: * This function frees all of the memory associated with a DOI definition. * */ static void calipso_doi_free(struct calipso_doi *doi_def) { kfree(doi_def); } /** * calipso_doi_free_rcu - Frees a DOI definition via the RCU pointer * @entry: the entry's RCU field * * Description: * This function is designed to be used as a callback to the call_rcu() * function so that the memory allocated to the DOI definition can be released * safely. * */ static void calipso_doi_free_rcu(struct rcu_head *entry) { struct calipso_doi *doi_def; doi_def = container_of(entry, struct calipso_doi, rcu); calipso_doi_free(doi_def); } /** * calipso_doi_remove - Remove an existing DOI from the CALIPSO protocol engine * @doi: the DOI value * @audit_secid: the LSM secid to use in the audit message * * Description: * Removes a DOI definition from the CALIPSO engine. The NetLabel routines will * be called to release their own LSM domain mappings as well as our own * domain list. Returns zero on success and negative values on failure. * */ static int calipso_doi_remove(u32 doi, struct netlbl_audit *audit_info) { int ret_val; struct calipso_doi *doi_def; struct audit_buffer *audit_buf; spin_lock(&calipso_doi_list_lock); doi_def = calipso_doi_search(doi); if (!doi_def) { spin_unlock(&calipso_doi_list_lock); ret_val = -ENOENT; goto doi_remove_return; } if (!atomic_dec_and_test(&doi_def->refcount)) { spin_unlock(&calipso_doi_list_lock); ret_val = -EBUSY; goto doi_remove_return; } list_del_rcu(&doi_def->list); spin_unlock(&calipso_doi_list_lock); call_rcu(&doi_def->rcu, calipso_doi_free_rcu); ret_val = 0; doi_remove_return: audit_buf = netlbl_audit_start(AUDIT_MAC_CALIPSO_DEL, audit_info); if (audit_buf) { audit_log_format(audit_buf, " calipso_doi=%u res=%u", doi, ret_val == 0 ? 1 : 0); audit_log_end(audit_buf); } return ret_val; } /** * calipso_doi_getdef - Returns a reference to a valid DOI definition * @doi: the DOI value * * Description: * Searches for a valid DOI definition and if one is found it is returned to * the caller. Otherwise NULL is returned. The caller must ensure that * calipso_doi_putdef() is called when the caller is done. * */ static struct calipso_doi *calipso_doi_getdef(u32 doi) { struct calipso_doi *doi_def; rcu_read_lock(); doi_def = calipso_doi_search(doi); if (!doi_def) goto doi_getdef_return; if (!atomic_inc_not_zero(&doi_def->refcount)) doi_def = NULL; doi_getdef_return: rcu_read_unlock(); return doi_def; } /** * calipso_doi_putdef - Releases a reference for the given DOI definition * @doi_def: the DOI definition * * Description: * Releases a DOI definition reference obtained from calipso_doi_getdef(). * */ static void calipso_doi_putdef(struct calipso_doi *doi_def) { if (!doi_def) return; if (!atomic_dec_and_test(&doi_def->refcount)) return; spin_lock(&calipso_doi_list_lock); list_del_rcu(&doi_def->list); spin_unlock(&calipso_doi_list_lock); call_rcu(&doi_def->rcu, calipso_doi_free_rcu); } /** * calipso_doi_walk - Iterate through the DOI definitions * @skip_cnt: skip past this number of DOI definitions, updated * @callback: callback for each DOI definition * @cb_arg: argument for the callback function * * Description: * Iterate over the DOI definition list, skipping the first @skip_cnt entries. * For each entry call @callback, if @callback returns a negative value stop * 'walking' through the list and return. Updates the value in @skip_cnt upon * return. Returns zero on success, negative values on failure. * */ static int calipso_doi_walk(u32 *skip_cnt, int (*callback)(struct calipso_doi *doi_def, void *arg), void *cb_arg) { int ret_val = -ENOENT; u32 doi_cnt = 0; struct calipso_doi *iter_doi; rcu_read_lock(); list_for_each_entry_rcu(iter_doi, &calipso_doi_list, list) if (atomic_read(&iter_doi->refcount) > 0) { if (doi_cnt++ < *skip_cnt) continue; ret_val = callback(iter_doi, cb_arg); if (ret_val < 0) { doi_cnt--; goto doi_walk_return; } } doi_walk_return: rcu_read_unlock(); *skip_cnt = doi_cnt; return ret_val; } /** * calipso_map_cat_hton - Perform a category mapping from host to network * @doi_def: the DOI definition * @secattr: the security attributes * @net_cat: the zero'd out category bitmap in network/CALIPSO format * @net_cat_len: the length of the CALIPSO bitmap in bytes * * Description: * Perform a label mapping to translate a local MLS category bitmap to the * correct CALIPSO bitmap using the given DOI definition. Returns the minimum * size in bytes of the network bitmap on success, negative values otherwise. * */ static int calipso_map_cat_hton(const struct calipso_doi *doi_def, const struct netlbl_lsm_secattr *secattr, unsigned char *net_cat, u32 net_cat_len) { int spot = -1; u32 net_spot_max = 0; u32 net_clen_bits = net_cat_len * 8; for (;;) { spot = netlbl_catmap_walk(secattr->attr.mls.cat, spot + 1); if (spot < 0) break; if (spot >= net_clen_bits) return -ENOSPC; netlbl_bitmap_setbit(net_cat, spot, 1); if (spot > net_spot_max) net_spot_max = spot; } return (net_spot_max / 32 + 1) * 4; } /** * calipso_map_cat_ntoh - Perform a category mapping from network to host * @doi_def: the DOI definition * @net_cat: the category bitmap in network/CALIPSO format * @net_cat_len: the length of the CALIPSO bitmap in bytes * @secattr: the security attributes * * Description: * Perform a label mapping to translate a CALIPSO bitmap to the correct local * MLS category bitmap using the given DOI definition. Returns zero on * success, negative values on failure. * */ static int calipso_map_cat_ntoh(const struct calipso_doi *doi_def, const unsigned char *net_cat, u32 net_cat_len, struct netlbl_lsm_secattr *secattr) { int ret_val; int spot = -1; u32 net_clen_bits = net_cat_len * 8; for (;;) { spot = netlbl_bitmap_walk(net_cat, net_clen_bits, spot + 1, 1); if (spot < 0) { if (spot == -2) return -EFAULT; return 0; } ret_val = netlbl_catmap_setbit(&secattr->attr.mls.cat, spot, GFP_ATOMIC); if (ret_val != 0) return ret_val; } return -EINVAL; } /** * calipso_pad_write - Writes pad bytes in TLV format * @buf: the buffer * @offset: offset from start of buffer to write padding * @count: number of pad bytes to write * * Description: * Write @count bytes of TLV padding into @buffer starting at offset @offset. * @count should be less than 8 - see RFC 4942. * */ static int calipso_pad_write(unsigned char *buf, unsigned int offset, unsigned int count) { if (WARN_ON_ONCE(count >= 8)) return -EINVAL; switch (count) { case 0: break; case 1: buf[offset] = IPV6_TLV_PAD1; break; default: buf[offset] = IPV6_TLV_PADN; buf[offset + 1] = count - 2; if (count > 2) memset(buf + offset + 2, 0, count - 2); break; } return 0; } /** * calipso_genopt - Generate a CALIPSO option * @buf: the option buffer * @start: offset from which to write * @buf_len: the size of opt_buf * @doi_def: the CALIPSO DOI to use * @secattr: the security attributes * * Description: * Generate a CALIPSO option using the DOI definition and security attributes * passed to the function. This also generates upto three bytes of leading * padding that ensures that the option is 4n + 2 aligned. It returns the * number of bytes written (including any initial padding). */ static int calipso_genopt(unsigned char *buf, u32 start, u32 buf_len, const struct calipso_doi *doi_def, const struct netlbl_lsm_secattr *secattr) { int ret_val; u32 len, pad; u16 crc; static const unsigned char padding[4] = {2, 1, 0, 3}; unsigned char *calipso; /* CALIPSO has 4n + 2 alignment */ pad = padding[start & 3]; if (buf_len <= start + pad + CALIPSO_HDR_LEN) return -ENOSPC; if ((secattr->flags & NETLBL_SECATTR_MLS_LVL) == 0) return -EPERM; len = CALIPSO_HDR_LEN; if (secattr->flags & NETLBL_SECATTR_MLS_CAT) { ret_val = calipso_map_cat_hton(doi_def, secattr, buf + start + pad + len, buf_len - start - pad - len); if (ret_val < 0) return ret_val; len += ret_val; } calipso_pad_write(buf, start, pad); calipso = buf + start + pad; calipso[0] = IPV6_TLV_CALIPSO; calipso[1] = len - 2; *(__be32 *)(calipso + 2) = htonl(doi_def->doi); calipso[6] = (len - CALIPSO_HDR_LEN) / 4; calipso[7] = secattr->attr.mls.lvl, crc = ~crc_ccitt(0xffff, calipso, len); calipso[8] = crc & 0xff; calipso[9] = (crc >> 8) & 0xff; return pad + len; } /* Hop-by-hop hdr helper functions */ /** * calipso_opt_update - Replaces socket's hop options with a new set * @sk: the socket * @hop: new hop options * * Description: * Replaces @sk's hop options with @hop. @hop may be NULL to leave * the socket with no hop options. * */ static int calipso_opt_update(struct sock *sk, struct ipv6_opt_hdr *hop) { struct ipv6_txoptions *old = txopt_get(inet6_sk(sk)), *txopts; txopts = ipv6_renew_options_kern(sk, old, IPV6_HOPOPTS, hop, hop ? ipv6_optlen(hop) : 0); txopt_put(old); if (IS_ERR(txopts)) return PTR_ERR(txopts); txopts = ipv6_update_options(sk, txopts); if (txopts) { atomic_sub(txopts->tot_len, &sk->sk_omem_alloc); txopt_put(txopts); } return 0; } /** * calipso_tlv_len - Returns the length of the TLV * @opt: the option header * @offset: offset of the TLV within the header * * Description: * Returns the length of the TLV option at offset @offset within * the option header @opt. Checks that the entire TLV fits inside * the option header, returns a negative value if this is not the case. */ static int calipso_tlv_len(struct ipv6_opt_hdr *opt, unsigned int offset) { unsigned char *tlv = (unsigned char *)opt; unsigned int opt_len = ipv6_optlen(opt), tlv_len; if (offset < sizeof(*opt) || offset >= opt_len) return -EINVAL; if (tlv[offset] == IPV6_TLV_PAD1) return 1; if (offset + 1 >= opt_len) return -EINVAL; tlv_len = tlv[offset + 1] + 2; if (offset + tlv_len > opt_len) return -EINVAL; return tlv_len; } /** * calipso_opt_find - Finds the CALIPSO option in an IPv6 hop options header * @hop: the hop options header * @start: on return holds the offset of any leading padding * @end: on return holds the offset of the first non-pad TLV after CALIPSO * * Description: * Finds the space occupied by a CALIPSO option (including any leading and * trailing padding). * * If a CALIPSO option exists set @start and @end to the * offsets within @hop of the start of padding before the first * CALIPSO option and the end of padding after the first CALIPSO * option. In this case the function returns 0. * * In the absence of a CALIPSO option, @start and @end will be * set to the start and end of any trailing padding in the header. * This is useful when appending a new option, as the caller may want * to overwrite some of this padding. In this case the function will * return -ENOENT. */ static int calipso_opt_find(struct ipv6_opt_hdr *hop, unsigned int *start, unsigned int *end) { int ret_val = -ENOENT, tlv_len; unsigned int opt_len, offset, offset_s = 0, offset_e = 0; unsigned char *opt = (unsigned char *)hop; opt_len = ipv6_optlen(hop); offset = sizeof(*hop); while (offset < opt_len) { tlv_len = calipso_tlv_len(hop, offset); if (tlv_len < 0) return tlv_len; switch (opt[offset]) { case IPV6_TLV_PAD1: case IPV6_TLV_PADN: if (offset_e) offset_e = offset; break; case IPV6_TLV_CALIPSO: ret_val = 0; offset_e = offset; break; default: if (offset_e == 0) offset_s = offset; else goto out; } offset += tlv_len; } out: if (offset_s) *start = offset_s + calipso_tlv_len(hop, offset_s); else *start = sizeof(*hop); if (offset_e) *end = offset_e + calipso_tlv_len(hop, offset_e); else *end = opt_len; return ret_val; } /** * calipso_opt_insert - Inserts a CALIPSO option into an IPv6 hop opt hdr * @hop: the original hop options header * @doi_def: the CALIPSO DOI to use * @secattr: the specific security attributes of the socket * * Description: * Creates a new hop options header based on @hop with a * CALIPSO option added to it. If @hop already contains a CALIPSO * option this is overwritten, otherwise the new option is appended * after any existing options. If @hop is NULL then the new header * will contain just the CALIPSO option and any needed padding. * */ static struct ipv6_opt_hdr * calipso_opt_insert(struct ipv6_opt_hdr *hop, const struct calipso_doi *doi_def, const struct netlbl_lsm_secattr *secattr) { unsigned int start, end, buf_len, pad, hop_len; struct ipv6_opt_hdr *new; int ret_val; if (hop) { hop_len = ipv6_optlen(hop); ret_val = calipso_opt_find(hop, &start, &end); if (ret_val && ret_val != -ENOENT) return ERR_PTR(ret_val); } else { hop_len = 0; start = sizeof(*hop); end = 0; } buf_len = hop_len + start - end + CALIPSO_OPT_LEN_MAX_WITH_PAD; new = kzalloc(buf_len, GFP_ATOMIC); if (!new) return ERR_PTR(-ENOMEM); if (start > sizeof(*hop)) memcpy(new, hop, start); ret_val = calipso_genopt((unsigned char *)new, start, buf_len, doi_def, secattr); if (ret_val < 0) return ERR_PTR(ret_val); buf_len = start + ret_val; /* At this point buf_len aligns to 4n, so (buf_len & 4) pads to 8n */ pad = ((buf_len & 4) + (end & 7)) & 7; calipso_pad_write((unsigned char *)new, buf_len, pad); buf_len += pad; if (end != hop_len) { memcpy((char *)new + buf_len, (char *)hop + end, hop_len - end); buf_len += hop_len - end; } new->nexthdr = 0; new->hdrlen = buf_len / 8 - 1; return new; } /** * calipso_opt_del - Removes the CALIPSO option from an option header * @hop: the original header * @new: the new header * * Description: * Creates a new header based on @hop without any CALIPSO option. If @hop * doesn't contain a CALIPSO option it returns -ENOENT. If @hop contains * no other non-padding options, it returns zero with @new set to NULL. * Otherwise it returns zero, creates a new header without the CALIPSO * option (and removing as much padding as possible) and returns with * @new set to that header. * */ static int calipso_opt_del(struct ipv6_opt_hdr *hop, struct ipv6_opt_hdr **new) { int ret_val; unsigned int start, end, delta, pad, hop_len; ret_val = calipso_opt_find(hop, &start, &end); if (ret_val) return ret_val; hop_len = ipv6_optlen(hop); if (start == sizeof(*hop) && end == hop_len) { /* There's no other option in the header so return NULL */ *new = NULL; return 0; } delta = (end - start) & ~7; *new = kzalloc(hop_len - delta, GFP_ATOMIC); if (!*new) return -ENOMEM; memcpy(*new, hop, start); (*new)->hdrlen -= delta / 8; pad = (end - start) & 7; calipso_pad_write((unsigned char *)*new, start, pad); if (end != hop_len) memcpy((char *)*new + start + pad, (char *)hop + end, hop_len - end); return 0; } /** * calipso_opt_getattr - Get the security attributes from a memory block * @calipso: the CALIPSO option * @secattr: the security attributes * * Description: * Inspect @calipso and return the security attributes in @secattr. * Returns zero on success and negative values on failure. * */ static int calipso_opt_getattr(const unsigned char *calipso, struct netlbl_lsm_secattr *secattr) { int ret_val = -ENOMSG; u32 doi, len = calipso[1], cat_len = calipso[6] * 4; struct calipso_doi *doi_def; if (cat_len + 8 > len) return -EINVAL; doi = get_unaligned_be32(calipso + 2); rcu_read_lock(); doi_def = calipso_doi_search(doi); if (!doi_def) goto getattr_return; secattr->attr.mls.lvl = calipso[7]; secattr->flags |= NETLBL_SECATTR_MLS_LVL; if (cat_len) { ret_val = calipso_map_cat_ntoh(doi_def, calipso + 10, cat_len, secattr); if (ret_val != 0) { netlbl_catmap_free(secattr->attr.mls.cat); goto getattr_return; } secattr->flags |= NETLBL_SECATTR_MLS_CAT; } secattr->type = NETLBL_NLTYPE_CALIPSO; getattr_return: rcu_read_unlock(); return ret_val; } /* sock functions. */ /** * calipso_sock_getattr - Get the security attributes from a sock * @sk: the sock * @secattr: the security attributes * * Description: * Query @sk to see if there is a CALIPSO option attached to the sock and if * there is return the CALIPSO security attributes in @secattr. This function * requires that @sk be locked, or privately held, but it does not do any * locking itself. Returns zero on success and negative values on failure. * */ static int calipso_sock_getattr(struct sock *sk, struct netlbl_lsm_secattr *secattr) { struct ipv6_opt_hdr *hop; int opt_len, len, ret_val = -ENOMSG, offset; unsigned char *opt; struct ipv6_txoptions *txopts = txopt_get(inet6_sk(sk)); if (!txopts || !txopts->hopopt) goto done; hop = txopts->hopopt; opt = (unsigned char *)hop; opt_len = ipv6_optlen(hop); offset = sizeof(*hop); while (offset < opt_len) { len = calipso_tlv_len(hop, offset); if (len < 0) { ret_val = len; goto done; } switch (opt[offset]) { case IPV6_TLV_CALIPSO: if (len < CALIPSO_HDR_LEN) ret_val = -EINVAL; else ret_val = calipso_opt_getattr(&opt[offset], secattr); goto done; default: offset += len; break; } } done: txopt_put(txopts); return ret_val; } /** * calipso_sock_setattr - Add a CALIPSO option to a socket * @sk: the socket * @doi_def: the CALIPSO DOI to use * @secattr: the specific security attributes of the socket * * Description: * Set the CALIPSO option on the given socket using the DOI definition and * security attributes passed to the function. This function requires * exclusive access to @sk, which means it either needs to be in the * process of being created or locked. Returns zero on success and negative * values on failure. * */ static int calipso_sock_setattr(struct sock *sk, const struct calipso_doi *doi_def, const struct netlbl_lsm_secattr *secattr) { int ret_val; struct ipv6_opt_hdr *old, *new; struct ipv6_txoptions *txopts = txopt_get(inet6_sk(sk)); old = NULL; if (txopts) old = txopts->hopopt; new = calipso_opt_insert(old, doi_def, secattr); txopt_put(txopts); if (IS_ERR(new)) return PTR_ERR(new); ret_val = calipso_opt_update(sk, new); kfree(new); return ret_val; } /** * calipso_sock_delattr - Delete the CALIPSO option from a socket * @sk: the socket * * Description: * Removes the CALIPSO option from a socket, if present. * */ static void calipso_sock_delattr(struct sock *sk) { struct ipv6_opt_hdr *new_hop; struct ipv6_txoptions *txopts = txopt_get(inet6_sk(sk)); if (!txopts || !txopts->hopopt) goto done; if (calipso_opt_del(txopts->hopopt, &new_hop)) goto done; calipso_opt_update(sk, new_hop); kfree(new_hop); done: txopt_put(txopts); } static const struct netlbl_calipso_ops ops = { .doi_add = calipso_doi_add, .doi_free = calipso_doi_free, .doi_remove = calipso_doi_remove, .doi_getdef = calipso_doi_getdef, .doi_putdef = calipso_doi_putdef, .doi_walk = calipso_doi_walk, .sock_getattr = calipso_sock_getattr, .sock_setattr = calipso_sock_setattr, .sock_delattr = calipso_sock_delattr, }; /** * calipso_init - Initialize the CALIPSO module * * Description: * Initialize the CALIPSO module and prepare it for use. Returns zero on * success and negative values on failure. * */ int __init calipso_init(void) { netlbl_calipso_ops_register(&ops); return 0; } void calipso_exit(void) { netlbl_calipso_ops_register(NULL); }