linux/fs/afs/addr_list.c
Linus Torvalds c84ca912b0 Keyrings namespacing
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Merge tag 'keys-namespace-20190627' of git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs

Pull keyring namespacing from David Howells:
 "These patches help make keys and keyrings more namespace aware.

  Firstly some miscellaneous patches to make the process easier:

   - Simplify key index_key handling so that the word-sized chunks
     assoc_array requires don't have to be shifted about, making it
     easier to add more bits into the key.

   - Cache the hash value in the key so that we don't have to calculate
     on every key we examine during a search (it involves a bunch of
     multiplications).

   - Allow keying_search() to search non-recursively.

  Then the main patches:

   - Make it so that keyring names are per-user_namespace from the point
     of view of KEYCTL_JOIN_SESSION_KEYRING so that they're not
     accessible cross-user_namespace.

     keyctl_capabilities() shows KEYCTL_CAPS1_NS_KEYRING_NAME for this.

   - Move the user and user-session keyrings to the user_namespace
     rather than the user_struct. This prevents them propagating
     directly across user_namespaces boundaries (ie. the KEY_SPEC_*
     flags will only pick from the current user_namespace).

   - Make it possible to include the target namespace in which the key
     shall operate in the index_key. This will allow the possibility of
     multiple keys with the same description, but different target
     domains to be held in the same keyring.

     keyctl_capabilities() shows KEYCTL_CAPS1_NS_KEY_TAG for this.

   - Make it so that keys are implicitly invalidated by removal of a
     domain tag, causing them to be garbage collected.

   - Institute a network namespace domain tag that allows keys to be
     differentiated by the network namespace in which they operate. New
     keys that are of a type marked 'KEY_TYPE_NET_DOMAIN' are assigned
     the network domain in force when they are created.

   - Make it so that the desired network namespace can be handed down
     into the request_key() mechanism. This allows AFS, NFS, etc. to
     request keys specific to the network namespace of the superblock.

     This also means that the keys in the DNS record cache are
     thenceforth namespaced, provided network filesystems pass the
     appropriate network namespace down into dns_query().

     For DNS, AFS and NFS are good, whilst CIFS and Ceph are not. Other
     cache keyrings, such as idmapper keyrings, also need to set the
     domain tag - for which they need access to the network namespace of
     the superblock"

* tag 'keys-namespace-20190627' of git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs:
  keys: Pass the network namespace into request_key mechanism
  keys: Network namespace domain tag
  keys: Garbage collect keys for which the domain has been removed
  keys: Include target namespace in match criteria
  keys: Move the user and user-session keyrings to the user_namespace
  keys: Namespace keyring names
  keys: Add a 'recurse' flag for keyring searches
  keys: Cache the hash value to avoid lots of recalculation
  keys: Simplify key description management
2019-07-08 19:36:47 -07:00

405 lines
8.6 KiB
C

// SPDX-License-Identifier: GPL-2.0-or-later
/* Server address list management
*
* Copyright (C) 2017 Red Hat, Inc. All Rights Reserved.
* Written by David Howells (dhowells@redhat.com)
*/
#include <linux/slab.h>
#include <linux/ctype.h>
#include <linux/dns_resolver.h>
#include <linux/inet.h>
#include <keys/rxrpc-type.h>
#include "internal.h"
#include "afs_fs.h"
/*
* Release an address list.
*/
void afs_put_addrlist(struct afs_addr_list *alist)
{
if (alist && refcount_dec_and_test(&alist->usage))
call_rcu(&alist->rcu, (rcu_callback_t)kfree);
}
/*
* Allocate an address list.
*/
struct afs_addr_list *afs_alloc_addrlist(unsigned int nr,
unsigned short service,
unsigned short port)
{
struct afs_addr_list *alist;
unsigned int i;
_enter("%u,%u,%u", nr, service, port);
if (nr > AFS_MAX_ADDRESSES)
nr = AFS_MAX_ADDRESSES;
alist = kzalloc(struct_size(alist, addrs, nr), GFP_KERNEL);
if (!alist)
return NULL;
refcount_set(&alist->usage, 1);
alist->max_addrs = nr;
for (i = 0; i < nr; i++) {
struct sockaddr_rxrpc *srx = &alist->addrs[i];
srx->srx_family = AF_RXRPC;
srx->srx_service = service;
srx->transport_type = SOCK_DGRAM;
srx->transport_len = sizeof(srx->transport.sin6);
srx->transport.sin6.sin6_family = AF_INET6;
srx->transport.sin6.sin6_port = htons(port);
}
return alist;
}
/*
* Parse a text string consisting of delimited addresses.
*/
struct afs_vlserver_list *afs_parse_text_addrs(struct afs_net *net,
const char *text, size_t len,
char delim,
unsigned short service,
unsigned short port)
{
struct afs_vlserver_list *vllist;
struct afs_addr_list *alist;
const char *p, *end = text + len;
const char *problem;
unsigned int nr = 0;
int ret = -ENOMEM;
_enter("%*.*s,%c", (int)len, (int)len, text, delim);
if (!len) {
_leave(" = -EDESTADDRREQ [empty]");
return ERR_PTR(-EDESTADDRREQ);
}
if (delim == ':' && (memchr(text, ',', len) || !memchr(text, '.', len)))
delim = ',';
/* Count the addresses */
p = text;
do {
if (!*p) {
problem = "nul";
goto inval;
}
if (*p == delim)
continue;
nr++;
if (*p == '[') {
p++;
if (p == end) {
problem = "brace1";
goto inval;
}
p = memchr(p, ']', end - p);
if (!p) {
problem = "brace2";
goto inval;
}
p++;
if (p >= end)
break;
}
p = memchr(p, delim, end - p);
if (!p)
break;
p++;
} while (p < end);
_debug("%u/%u addresses", nr, AFS_MAX_ADDRESSES);
vllist = afs_alloc_vlserver_list(1);
if (!vllist)
return ERR_PTR(-ENOMEM);
vllist->nr_servers = 1;
vllist->servers[0].server = afs_alloc_vlserver("<dummy>", 7, AFS_VL_PORT);
if (!vllist->servers[0].server)
goto error_vl;
alist = afs_alloc_addrlist(nr, service, AFS_VL_PORT);
if (!alist)
goto error;
/* Extract the addresses */
p = text;
do {
const char *q, *stop;
unsigned int xport = port;
__be32 x[4];
int family;
if (*p == delim) {
p++;
continue;
}
if (*p == '[') {
p++;
q = memchr(p, ']', end - p);
} else {
for (q = p; q < end; q++)
if (*q == '+' || *q == delim)
break;
}
if (in4_pton(p, q - p, (u8 *)&x[0], -1, &stop)) {
family = AF_INET;
} else if (in6_pton(p, q - p, (u8 *)x, -1, &stop)) {
family = AF_INET6;
} else {
problem = "family";
goto bad_address;
}
p = q;
if (stop != p) {
problem = "nostop";
goto bad_address;
}
if (q < end && *q == ']')
p++;
if (p < end) {
if (*p == '+') {
/* Port number specification "+1234" */
xport = 0;
p++;
if (p >= end || !isdigit(*p)) {
problem = "port";
goto bad_address;
}
do {
xport *= 10;
xport += *p - '0';
if (xport > 65535) {
problem = "pval";
goto bad_address;
}
p++;
} while (p < end && isdigit(*p));
} else if (*p == delim) {
p++;
} else {
problem = "weird";
goto bad_address;
}
}
if (family == AF_INET)
afs_merge_fs_addr4(alist, x[0], xport);
else
afs_merge_fs_addr6(alist, x, xport);
} while (p < end);
rcu_assign_pointer(vllist->servers[0].server->addresses, alist);
_leave(" = [nr %u]", alist->nr_addrs);
return vllist;
inval:
_leave(" = -EINVAL [%s %zu %*.*s]",
problem, p - text, (int)len, (int)len, text);
return ERR_PTR(-EINVAL);
bad_address:
_leave(" = -EINVAL [%s %zu %*.*s]",
problem, p - text, (int)len, (int)len, text);
ret = -EINVAL;
error:
afs_put_addrlist(alist);
error_vl:
afs_put_vlserverlist(net, vllist);
return ERR_PTR(ret);
}
/*
* Compare old and new address lists to see if there's been any change.
* - How to do this in better than O(Nlog(N)) time?
* - We don't really want to sort the address list, but would rather take the
* list as we got it so as not to undo record rotation by the DNS server.
*/
#if 0
static int afs_cmp_addr_list(const struct afs_addr_list *a1,
const struct afs_addr_list *a2)
{
}
#endif
/*
* Perform a DNS query for VL servers and build a up an address list.
*/
struct afs_vlserver_list *afs_dns_query(struct afs_cell *cell, time64_t *_expiry)
{
struct afs_vlserver_list *vllist;
char *result = NULL;
int ret;
_enter("%s", cell->name);
ret = dns_query(cell->net->net, "afsdb", cell->name, cell->name_len,
"srv=1", &result, _expiry, true);
if (ret < 0) {
_leave(" = %d [dns]", ret);
return ERR_PTR(ret);
}
if (*_expiry == 0)
*_expiry = ktime_get_real_seconds() + 60;
if (ret > 1 && result[0] == 0)
vllist = afs_extract_vlserver_list(cell, result, ret);
else
vllist = afs_parse_text_addrs(cell->net, result, ret, ',',
VL_SERVICE, AFS_VL_PORT);
kfree(result);
if (IS_ERR(vllist) && vllist != ERR_PTR(-ENOMEM))
pr_err("Failed to parse DNS data %ld\n", PTR_ERR(vllist));
return vllist;
}
/*
* Merge an IPv4 entry into a fileserver address list.
*/
void afs_merge_fs_addr4(struct afs_addr_list *alist, __be32 xdr, u16 port)
{
struct sockaddr_rxrpc *srx;
u32 addr = ntohl(xdr);
int i;
if (alist->nr_addrs >= alist->max_addrs)
return;
for (i = 0; i < alist->nr_ipv4; i++) {
struct sockaddr_in *a = &alist->addrs[i].transport.sin;
u32 a_addr = ntohl(a->sin_addr.s_addr);
u16 a_port = ntohs(a->sin_port);
if (addr == a_addr && port == a_port)
return;
if (addr == a_addr && port < a_port)
break;
if (addr < a_addr)
break;
}
if (i < alist->nr_addrs)
memmove(alist->addrs + i + 1,
alist->addrs + i,
sizeof(alist->addrs[0]) * (alist->nr_addrs - i));
srx = &alist->addrs[i];
srx->srx_family = AF_RXRPC;
srx->transport_type = SOCK_DGRAM;
srx->transport_len = sizeof(srx->transport.sin);
srx->transport.sin.sin_family = AF_INET;
srx->transport.sin.sin_port = htons(port);
srx->transport.sin.sin_addr.s_addr = xdr;
alist->nr_ipv4++;
alist->nr_addrs++;
}
/*
* Merge an IPv6 entry into a fileserver address list.
*/
void afs_merge_fs_addr6(struct afs_addr_list *alist, __be32 *xdr, u16 port)
{
struct sockaddr_rxrpc *srx;
int i, diff;
if (alist->nr_addrs >= alist->max_addrs)
return;
for (i = alist->nr_ipv4; i < alist->nr_addrs; i++) {
struct sockaddr_in6 *a = &alist->addrs[i].transport.sin6;
u16 a_port = ntohs(a->sin6_port);
diff = memcmp(xdr, &a->sin6_addr, 16);
if (diff == 0 && port == a_port)
return;
if (diff == 0 && port < a_port)
break;
if (diff < 0)
break;
}
if (i < alist->nr_addrs)
memmove(alist->addrs + i + 1,
alist->addrs + i,
sizeof(alist->addrs[0]) * (alist->nr_addrs - i));
srx = &alist->addrs[i];
srx->srx_family = AF_RXRPC;
srx->transport_type = SOCK_DGRAM;
srx->transport_len = sizeof(srx->transport.sin6);
srx->transport.sin6.sin6_family = AF_INET6;
srx->transport.sin6.sin6_port = htons(port);
memcpy(&srx->transport.sin6.sin6_addr, xdr, 16);
alist->nr_addrs++;
}
/*
* Get an address to try.
*/
bool afs_iterate_addresses(struct afs_addr_cursor *ac)
{
unsigned long set, failed;
int index;
if (!ac->alist)
return false;
set = ac->alist->responded;
failed = ac->alist->failed;
_enter("%lx-%lx-%lx,%d", set, failed, ac->tried, ac->index);
ac->nr_iterations++;
set &= ~(failed | ac->tried);
if (!set)
return false;
index = READ_ONCE(ac->alist->preferred);
if (test_bit(index, &set))
goto selected;
index = __ffs(set);
selected:
ac->index = index;
set_bit(index, &ac->tried);
ac->responded = false;
return true;
}
/*
* Release an address list cursor.
*/
int afs_end_cursor(struct afs_addr_cursor *ac)
{
struct afs_addr_list *alist;
alist = ac->alist;
if (alist) {
if (ac->responded &&
ac->index != alist->preferred &&
test_bit(ac->alist->preferred, &ac->tried))
WRITE_ONCE(alist->preferred, ac->index);
afs_put_addrlist(alist);
ac->alist = NULL;
}
return ac->error;
}