linux-stable/net/ipv6/calipso.c
Paul Moore ad5d07f4a9 cipso,calipso: resolve a number of problems with the DOI refcounts
The current CIPSO and CALIPSO refcounting scheme for the DOI
definitions is a bit flawed in that we:

1. Don't correctly match gets/puts in netlbl_cipsov4_list().
2. Decrement the refcount on each attempt to remove the DOI from the
   DOI list, only removing it from the list once the refcount drops
   to zero.

This patch fixes these problems by adding the missing "puts" to
netlbl_cipsov4_list() and introduces a more conventional, i.e.
not-buggy, refcounting mechanism to the DOI definitions.  Upon the
addition of a DOI to the DOI list, it is initialized with a refcount
of one, removing a DOI from the list removes it from the list and
drops the refcount by one; "gets" and "puts" behave as expected with
respect to refcounts, increasing and decreasing the DOI's refcount by
one.

Fixes: b1edeb1023 ("netlabel: Replace protocol/NetLabel linking with refrerence counts")
Fixes: d7cce01504 ("netlabel: Add support for removing a CALIPSO DOI.")
Reported-by: syzbot+9ec037722d2603a9f52e@syzkaller.appspotmail.com
Signed-off-by: Paul Moore <paul@paul-moore.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2021-03-04 15:26:57 -08:00

1459 lines
38 KiB
C

// SPDX-License-Identifier: GPL-2.0-or-later
/*
* CALIPSO - Common Architecture Label IPv6 Security Option
*
* This is an implementation of the CALIPSO protocol as specified in
* RFC 5570.
*
* Authors: Paul Moore <paul.moore@hp.com>
* Huw Davies <huw@codeweavers.com>
*/
/* (c) Copyright Hewlett-Packard Development Company, L.P., 2006, 2008
* (c) Copyright Huw Davies <huw@codeweavers.com>, 2015
*/
#include <linux/init.h>
#include <linux/types.h>
#include <linux/rcupdate.h>
#include <linux/list.h>
#include <linux/spinlock.h>
#include <linux/string.h>
#include <linux/jhash.h>
#include <linux/audit.h>
#include <linux/slab.h>
#include <net/ip.h>
#include <net/icmp.h>
#include <net/tcp.h>
#include <net/netlabel.h>
#include <net/calipso.h>
#include <linux/atomic.h>
#include <linux/bug.h>
#include <asm/unaligned.h>
#include <linux/crc-ccitt.h>
/* 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)
/* Maximium size of u32 aligned buffer required to hold calipso
* option. Max of 3 initial pad bytes starting from buffer + 3.
* i.e. the worst case is when the previous tlv finishes on 4n + 3.
*/
#define CALIPSO_MAX_BUFFER (6 + CALIPSO_OPT_LEN_MAX)
/* List of available DOI definitions */
static DEFINE_SPINLOCK(calipso_doi_list_lock);
static LIST_HEAD(calipso_doi_list);
/* Label mapping cache */
int calipso_cache_enabled = 1;
int calipso_cache_bucketsize = 10;
#define CALIPSO_CACHE_BUCKETBITS 7
#define CALIPSO_CACHE_BUCKETS BIT(CALIPSO_CACHE_BUCKETBITS)
#define CALIPSO_CACHE_REORDERLIMIT 10
struct calipso_map_cache_bkt {
spinlock_t lock;
u32 size;
struct list_head list;
};
struct calipso_map_cache_entry {
u32 hash;
unsigned char *key;
size_t key_len;
struct netlbl_lsm_cache *lsm_data;
u32 activity;
struct list_head list;
};
static struct calipso_map_cache_bkt *calipso_cache;
static void calipso_cache_invalidate(void);
static void calipso_doi_putdef(struct calipso_doi *doi_def);
/* Label Mapping Cache Functions
*/
/**
* calipso_cache_entry_free - Frees a cache entry
* @entry: the entry to free
*
* Description:
* This function frees the memory associated with a cache entry including the
* LSM cache data if there are no longer any users, i.e. reference count == 0.
*
*/
static void calipso_cache_entry_free(struct calipso_map_cache_entry *entry)
{
if (entry->lsm_data)
netlbl_secattr_cache_free(entry->lsm_data);
kfree(entry->key);
kfree(entry);
}
/**
* calipso_map_cache_hash - Hashing function for the CALIPSO cache
* @key: the hash key
* @key_len: the length of the key in bytes
*
* Description:
* The CALIPSO tag hashing function. Returns a 32-bit hash value.
*
*/
static u32 calipso_map_cache_hash(const unsigned char *key, u32 key_len)
{
return jhash(key, key_len, 0);
}
/**
* calipso_cache_init - Initialize the CALIPSO cache
*
* Description:
* Initializes the CALIPSO label mapping cache, this function should be called
* before any of the other functions defined in this file. Returns zero on
* success, negative values on error.
*
*/
static int __init calipso_cache_init(void)
{
u32 iter;
calipso_cache = kcalloc(CALIPSO_CACHE_BUCKETS,
sizeof(struct calipso_map_cache_bkt),
GFP_KERNEL);
if (!calipso_cache)
return -ENOMEM;
for (iter = 0; iter < CALIPSO_CACHE_BUCKETS; iter++) {
spin_lock_init(&calipso_cache[iter].lock);
calipso_cache[iter].size = 0;
INIT_LIST_HEAD(&calipso_cache[iter].list);
}
return 0;
}
/**
* calipso_cache_invalidate - Invalidates the current CALIPSO cache
*
* Description:
* Invalidates and frees any entries in the CALIPSO cache. Returns zero on
* success and negative values on failure.
*
*/
static void calipso_cache_invalidate(void)
{
struct calipso_map_cache_entry *entry, *tmp_entry;
u32 iter;
for (iter = 0; iter < CALIPSO_CACHE_BUCKETS; iter++) {
spin_lock_bh(&calipso_cache[iter].lock);
list_for_each_entry_safe(entry,
tmp_entry,
&calipso_cache[iter].list, list) {
list_del(&entry->list);
calipso_cache_entry_free(entry);
}
calipso_cache[iter].size = 0;
spin_unlock_bh(&calipso_cache[iter].lock);
}
}
/**
* calipso_cache_check - Check the CALIPSO cache for a label mapping
* @key: the buffer to check
* @key_len: buffer length in bytes
* @secattr: the security attribute struct to use
*
* Description:
* This function checks the cache to see if a label mapping already exists for
* the given key. If there is a match then the cache is adjusted and the
* @secattr struct is populated with the correct LSM security attributes. The
* cache is adjusted in the following manner if the entry is not already the
* first in the cache bucket:
*
* 1. The cache entry's activity counter is incremented
* 2. The previous (higher ranking) entry's activity counter is decremented
* 3. If the difference between the two activity counters is geater than
* CALIPSO_CACHE_REORDERLIMIT the two entries are swapped
*
* Returns zero on success, -ENOENT for a cache miss, and other negative values
* on error.
*
*/
static int calipso_cache_check(const unsigned char *key,
u32 key_len,
struct netlbl_lsm_secattr *secattr)
{
u32 bkt;
struct calipso_map_cache_entry *entry;
struct calipso_map_cache_entry *prev_entry = NULL;
u32 hash;
if (!calipso_cache_enabled)
return -ENOENT;
hash = calipso_map_cache_hash(key, key_len);
bkt = hash & (CALIPSO_CACHE_BUCKETS - 1);
spin_lock_bh(&calipso_cache[bkt].lock);
list_for_each_entry(entry, &calipso_cache[bkt].list, list) {
if (entry->hash == hash &&
entry->key_len == key_len &&
memcmp(entry->key, key, key_len) == 0) {
entry->activity += 1;
refcount_inc(&entry->lsm_data->refcount);
secattr->cache = entry->lsm_data;
secattr->flags |= NETLBL_SECATTR_CACHE;
secattr->type = NETLBL_NLTYPE_CALIPSO;
if (!prev_entry) {
spin_unlock_bh(&calipso_cache[bkt].lock);
return 0;
}
if (prev_entry->activity > 0)
prev_entry->activity -= 1;
if (entry->activity > prev_entry->activity &&
entry->activity - prev_entry->activity >
CALIPSO_CACHE_REORDERLIMIT) {
__list_del(entry->list.prev, entry->list.next);
__list_add(&entry->list,
prev_entry->list.prev,
&prev_entry->list);
}
spin_unlock_bh(&calipso_cache[bkt].lock);
return 0;
}
prev_entry = entry;
}
spin_unlock_bh(&calipso_cache[bkt].lock);
return -ENOENT;
}
/**
* calipso_cache_add - Add an entry to the CALIPSO cache
* @calipso_ptr: the CALIPSO option
* @secattr: the packet's security attributes
*
* Description:
* Add a new entry into the CALIPSO label mapping cache. Add the new entry to
* head of the cache bucket's list, if the cache bucket is out of room remove
* the last entry in the list first. It is important to note that there is
* currently no checking for duplicate keys. Returns zero on success,
* negative values on failure. The key stored starts at calipso_ptr + 2,
* i.e. the type and length bytes are not stored, this corresponds to
* calipso_ptr[1] bytes of data.
*
*/
static int calipso_cache_add(const unsigned char *calipso_ptr,
const struct netlbl_lsm_secattr *secattr)
{
int ret_val = -EPERM;
u32 bkt;
struct calipso_map_cache_entry *entry = NULL;
struct calipso_map_cache_entry *old_entry = NULL;
u32 calipso_ptr_len;
if (!calipso_cache_enabled || calipso_cache_bucketsize <= 0)
return 0;
calipso_ptr_len = calipso_ptr[1];
entry = kzalloc(sizeof(*entry), GFP_ATOMIC);
if (!entry)
return -ENOMEM;
entry->key = kmemdup(calipso_ptr + 2, calipso_ptr_len, GFP_ATOMIC);
if (!entry->key) {
ret_val = -ENOMEM;
goto cache_add_failure;
}
entry->key_len = calipso_ptr_len;
entry->hash = calipso_map_cache_hash(calipso_ptr, calipso_ptr_len);
refcount_inc(&secattr->cache->refcount);
entry->lsm_data = secattr->cache;
bkt = entry->hash & (CALIPSO_CACHE_BUCKETS - 1);
spin_lock_bh(&calipso_cache[bkt].lock);
if (calipso_cache[bkt].size < calipso_cache_bucketsize) {
list_add(&entry->list, &calipso_cache[bkt].list);
calipso_cache[bkt].size += 1;
} else {
old_entry = list_entry(calipso_cache[bkt].list.prev,
struct calipso_map_cache_entry, list);
list_del(&old_entry->list);
list_add(&entry->list, &calipso_cache[bkt].list);
calipso_cache_entry_free(old_entry);
}
spin_unlock_bh(&calipso_cache[bkt].lock);
return 0;
cache_add_failure:
if (entry)
calipso_cache_entry_free(entry);
return ret_val;
}
/* 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 && refcount_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;
refcount_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_info: NetLabel audit information
*
* 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;
}
list_del_rcu(&doi_def->list);
spin_unlock(&calipso_doi_list_lock);
calipso_doi_putdef(doi_def);
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 (!refcount_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 (!refcount_dec_and_test(&doi_def->refcount))
return;
calipso_cache_invalidate();
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 (refcount_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_validate - Validate a CALIPSO option
* @skb: the packet
* @option: the start of the option
*
* Description:
* This routine is called to validate a CALIPSO option.
* If the option is valid then %true is returned, otherwise
* %false is returned.
*
* The caller should have already checked that the length of the
* option (including the TLV header) is >= 10 and that the catmap
* length is consistent with the option length.
*
* We leave checks on the level and categories to the socket layer.
*/
bool calipso_validate(const struct sk_buff *skb, const unsigned char *option)
{
struct calipso_doi *doi_def;
bool ret_val;
u16 crc, len = option[1] + 2;
static const u8 zero[2];
/* The original CRC runs over the option including the TLV header
* with the CRC-16 field (at offset 8) zeroed out. */
crc = crc_ccitt(0xffff, option, 8);
crc = crc_ccitt(crc, zero, sizeof(zero));
if (len > 10)
crc = crc_ccitt(crc, option + 10, len - 10);
crc = ~crc;
if (option[8] != (crc & 0xff) || option[9] != ((crc >> 8) & 0xff))
return false;
rcu_read_lock();
doi_def = calipso_doi_search(get_unaligned_be32(option + 2));
ret_val = !!doi_def;
rcu_read_unlock();
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(sk, old, IPV6_HOPOPTS, hop);
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) {
kfree(new);
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;
if (calipso_cache_check(calipso + 2, calipso[1], secattr) == 0)
return 0;
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;
}
if (secattr->attr.mls.cat)
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);
}
/* request sock functions.
*/
/**
* calipso_req_setattr - Add a CALIPSO option to a connection request socket
* @req: the connection request 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. Returns zero on success and
* negative values on failure.
*
*/
static int calipso_req_setattr(struct request_sock *req,
const struct calipso_doi *doi_def,
const struct netlbl_lsm_secattr *secattr)
{
struct ipv6_txoptions *txopts;
struct inet_request_sock *req_inet = inet_rsk(req);
struct ipv6_opt_hdr *old, *new;
struct sock *sk = sk_to_full_sk(req_to_sk(req));
if (req_inet->ipv6_opt && req_inet->ipv6_opt->hopopt)
old = req_inet->ipv6_opt->hopopt;
else
old = NULL;
new = calipso_opt_insert(old, doi_def, secattr);
if (IS_ERR(new))
return PTR_ERR(new);
txopts = ipv6_renew_options(sk, req_inet->ipv6_opt, IPV6_HOPOPTS, new);
kfree(new);
if (IS_ERR(txopts))
return PTR_ERR(txopts);
txopts = xchg(&req_inet->ipv6_opt, txopts);
if (txopts) {
atomic_sub(txopts->tot_len, &sk->sk_omem_alloc);
txopt_put(txopts);
}
return 0;
}
/**
* calipso_req_delattr - Delete the CALIPSO option from a request socket
* @req: the request socket
*
* Description:
* Removes the CALIPSO option from a request socket, if present.
*
*/
static void calipso_req_delattr(struct request_sock *req)
{
struct inet_request_sock *req_inet = inet_rsk(req);
struct ipv6_opt_hdr *new;
struct ipv6_txoptions *txopts;
struct sock *sk = sk_to_full_sk(req_to_sk(req));
if (!req_inet->ipv6_opt || !req_inet->ipv6_opt->hopopt)
return;
if (calipso_opt_del(req_inet->ipv6_opt->hopopt, &new))
return; /* Nothing to do */
txopts = ipv6_renew_options(sk, req_inet->ipv6_opt, IPV6_HOPOPTS, new);
if (!IS_ERR(txopts)) {
txopts = xchg(&req_inet->ipv6_opt, txopts);
if (txopts) {
atomic_sub(txopts->tot_len, &sk->sk_omem_alloc);
txopt_put(txopts);
}
}
kfree(new);
}
/* skbuff functions.
*/
/**
* calipso_skbuff_optptr - Find the CALIPSO option in the packet
* @skb: the packet
*
* Description:
* Parse the packet's IP header looking for a CALIPSO option. Returns a pointer
* to the start of the CALIPSO option on success, NULL if one if not found.
*
*/
static unsigned char *calipso_skbuff_optptr(const struct sk_buff *skb)
{
const struct ipv6hdr *ip6_hdr = ipv6_hdr(skb);
int offset;
if (ip6_hdr->nexthdr != NEXTHDR_HOP)
return NULL;
offset = ipv6_find_tlv(skb, sizeof(*ip6_hdr), IPV6_TLV_CALIPSO);
if (offset >= 0)
return (unsigned char *)ip6_hdr + offset;
return NULL;
}
/**
* calipso_skbuff_setattr - Set the CALIPSO option on a packet
* @skb: the packet
* @doi_def: the CALIPSO DOI to use
* @secattr: the security attributes
*
* Description:
* Set the CALIPSO option on the given packet based on the security attributes.
* Returns a pointer to the IP header on success and NULL on failure.
*
*/
static int calipso_skbuff_setattr(struct sk_buff *skb,
const struct calipso_doi *doi_def,
const struct netlbl_lsm_secattr *secattr)
{
int ret_val;
struct ipv6hdr *ip6_hdr;
struct ipv6_opt_hdr *hop;
unsigned char buf[CALIPSO_MAX_BUFFER];
int len_delta, new_end, pad, payload;
unsigned int start, end;
ip6_hdr = ipv6_hdr(skb);
if (ip6_hdr->nexthdr == NEXTHDR_HOP) {
hop = (struct ipv6_opt_hdr *)(ip6_hdr + 1);
ret_val = calipso_opt_find(hop, &start, &end);
if (ret_val && ret_val != -ENOENT)
return ret_val;
} else {
start = 0;
end = 0;
}
memset(buf, 0, sizeof(buf));
ret_val = calipso_genopt(buf, start & 3, sizeof(buf), doi_def, secattr);
if (ret_val < 0)
return ret_val;
new_end = start + ret_val;
/* At this point new_end aligns to 4n, so (new_end & 4) pads to 8n */
pad = ((new_end & 4) + (end & 7)) & 7;
len_delta = new_end - (int)end + pad;
ret_val = skb_cow(skb, skb_headroom(skb) + len_delta);
if (ret_val < 0)
return ret_val;
ip6_hdr = ipv6_hdr(skb); /* Reset as skb_cow() may have moved it */
if (len_delta) {
if (len_delta > 0)
skb_push(skb, len_delta);
else
skb_pull(skb, -len_delta);
memmove((char *)ip6_hdr - len_delta, ip6_hdr,
sizeof(*ip6_hdr) + start);
skb_reset_network_header(skb);
ip6_hdr = ipv6_hdr(skb);
payload = ntohs(ip6_hdr->payload_len);
ip6_hdr->payload_len = htons(payload + len_delta);
}
hop = (struct ipv6_opt_hdr *)(ip6_hdr + 1);
if (start == 0) {
struct ipv6_opt_hdr *new_hop = (struct ipv6_opt_hdr *)buf;
new_hop->nexthdr = ip6_hdr->nexthdr;
new_hop->hdrlen = len_delta / 8 - 1;
ip6_hdr->nexthdr = NEXTHDR_HOP;
} else {
hop->hdrlen += len_delta / 8;
}
memcpy((char *)hop + start, buf + (start & 3), new_end - start);
calipso_pad_write((unsigned char *)hop, new_end, pad);
return 0;
}
/**
* calipso_skbuff_delattr - Delete any CALIPSO options from a packet
* @skb: the packet
*
* Description:
* Removes any and all CALIPSO options from the given packet. Returns zero on
* success, negative values on failure.
*
*/
static int calipso_skbuff_delattr(struct sk_buff *skb)
{
int ret_val;
struct ipv6hdr *ip6_hdr;
struct ipv6_opt_hdr *old_hop;
u32 old_hop_len, start = 0, end = 0, delta, size, pad;
if (!calipso_skbuff_optptr(skb))
return 0;
/* since we are changing the packet we should make a copy */
ret_val = skb_cow(skb, skb_headroom(skb));
if (ret_val < 0)
return ret_val;
ip6_hdr = ipv6_hdr(skb);
old_hop = (struct ipv6_opt_hdr *)(ip6_hdr + 1);
old_hop_len = ipv6_optlen(old_hop);
ret_val = calipso_opt_find(old_hop, &start, &end);
if (ret_val)
return ret_val;
if (start == sizeof(*old_hop) && end == old_hop_len) {
/* There's no other option in the header so we delete
* the whole thing. */
delta = old_hop_len;
size = sizeof(*ip6_hdr);
ip6_hdr->nexthdr = old_hop->nexthdr;
} else {
delta = (end - start) & ~7;
if (delta)
old_hop->hdrlen -= delta / 8;
pad = (end - start) & 7;
size = sizeof(*ip6_hdr) + start + pad;
calipso_pad_write((unsigned char *)old_hop, start, pad);
}
if (delta) {
skb_pull(skb, delta);
memmove((char *)ip6_hdr + delta, ip6_hdr, size);
skb_reset_network_header(skb);
}
return 0;
}
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,
.req_setattr = calipso_req_setattr,
.req_delattr = calipso_req_delattr,
.opt_getattr = calipso_opt_getattr,
.skbuff_optptr = calipso_skbuff_optptr,
.skbuff_setattr = calipso_skbuff_setattr,
.skbuff_delattr = calipso_skbuff_delattr,
.cache_invalidate = calipso_cache_invalidate,
.cache_add = calipso_cache_add
};
/**
* 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)
{
int ret_val;
ret_val = calipso_cache_init();
if (!ret_val)
netlbl_calipso_ops_register(&ops);
return ret_val;
}
void calipso_exit(void)
{
netlbl_calipso_ops_register(NULL);
calipso_cache_invalidate();
kfree(calipso_cache);
}