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authorLinus Torvalds <torvalds@linux-foundation.org>2019-07-09 05:56:57 +0300
committerLinus Torvalds <torvalds@linux-foundation.org>2019-07-09 05:56:57 +0300
commit0f75ef6a9cff49ff612f7ce0578bced9d0b38325 (patch)
treebdd2a6b7f35695b1d7ab1209efbb40187501fe7d /net/dns_resolver
parentc84ca912b07901be528e5184fd254fca1dddf2ac (diff)
parent7a1ade847596dadc94b37e49f8c03f167fd71748 (diff)
downloadlinux-0f75ef6a9cff49ff612f7ce0578bced9d0b38325.tar.xz
Merge tag 'keys-acl-20190703' of git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs
Pull keyring ACL support from David Howells: "This changes the permissions model used by keys and keyrings to be based on an internal ACL by the following means: - Replace the permissions mask internally with an ACL that contains a list of ACEs, each with a specific subject with a permissions mask. Potted default ACLs are available for new keys and keyrings. ACE subjects can be macroised to indicate the UID and GID specified on the key (which remain). Future commits will be able to add additional subject types, such as specific UIDs or domain tags/namespaces. Also split a number of permissions to give finer control. Examples include splitting the revocation permit from the change-attributes permit, thereby allowing someone to be granted permission to revoke a key without allowing them to change the owner; also the ability to join a keyring is split from the ability to link to it, thereby stopping a process accessing a keyring by joining it and thus acquiring use of possessor permits. - Provide a keyctl to allow the granting or denial of one or more permits to a specific subject. Direct access to the ACL is not granted, and the ACL cannot be viewed" * tag 'keys-acl-20190703' of git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs: keys: Provide KEYCTL_GRANT_PERMISSION keys: Replace uid/gid/perm permissions checking with an ACL
Diffstat (limited to 'net/dns_resolver')
-rw-r--r--net/dns_resolver/dns_key.c12
-rw-r--r--net/dns_resolver/dns_query.c15
2 files changed, 22 insertions, 5 deletions
diff --git a/net/dns_resolver/dns_key.c b/net/dns_resolver/dns_key.c
index 3e1a90669006..6b201531b165 100644
--- a/net/dns_resolver/dns_key.c
+++ b/net/dns_resolver/dns_key.c
@@ -46,6 +46,15 @@ const struct cred *dns_resolver_cache;
#define DNS_ERRORNO_OPTION "dnserror"
+static struct key_acl dns_keyring_acl = {
+ .usage = REFCOUNT_INIT(1),
+ .nr_ace = 2,
+ .aces = {
+ KEY_POSSESSOR_ACE(KEY_ACE_SEARCH | KEY_ACE_WRITE),
+ KEY_OWNER_ACE(KEY_ACE_VIEW | KEY_ACE_READ | KEY_ACE_CLEAR),
+ }
+};
+
/*
* Preparse instantiation data for a dns_resolver key.
*
@@ -343,8 +352,7 @@ static int __init init_dns_resolver(void)
keyring = keyring_alloc(".dns_resolver",
GLOBAL_ROOT_UID, GLOBAL_ROOT_GID, cred,
- (KEY_POS_ALL & ~KEY_POS_SETATTR) |
- KEY_USR_VIEW | KEY_USR_READ,
+ &dns_keyring_acl,
KEY_ALLOC_NOT_IN_QUOTA, NULL, NULL);
if (IS_ERR(keyring)) {
ret = PTR_ERR(keyring);
diff --git a/net/dns_resolver/dns_query.c b/net/dns_resolver/dns_query.c
index cab4e0df924f..236baf2bfa4c 100644
--- a/net/dns_resolver/dns_query.c
+++ b/net/dns_resolver/dns_query.c
@@ -47,6 +47,16 @@
#include "internal.h"
+static struct key_acl dns_key_acl = {
+ .usage = REFCOUNT_INIT(1),
+ .nr_ace = 2,
+ .possessor_viewable = true,
+ .aces = {
+ KEY_POSSESSOR_ACE(KEY_ACE_VIEW | KEY_ACE_SEARCH | KEY_ACE_READ),
+ KEY_OWNER_ACE(KEY_ACE_VIEW | KEY_ACE_INVAL),
+ }
+};
+
/**
* dns_query - Query the DNS
* @net: The network namespace to operate in.
@@ -125,7 +135,8 @@ int dns_query(struct net *net,
* add_key() to preinstall malicious redirections
*/
saved_cred = override_creds(dns_resolver_cache);
- rkey = request_key_net(&key_type_dns_resolver, desc, net, options);
+ rkey = request_key_net(&key_type_dns_resolver, desc, net, options,
+ &dns_key_acl);
revert_creds(saved_cred);
kfree(desc);
if (IS_ERR(rkey)) {
@@ -135,8 +146,6 @@ int dns_query(struct net *net,
down_read(&rkey->sem);
set_bit(KEY_FLAG_ROOT_CAN_INVAL, &rkey->flags);
- rkey->perm |= KEY_USR_VIEW;
-
ret = key_validate(rkey);
if (ret < 0)
goto put;