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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 /security/keys/proc.c
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 'security/keys/proc.c')
-rw-r--r--security/keys/proc.c22
1 files changed, 13 insertions, 9 deletions
diff --git a/security/keys/proc.c b/security/keys/proc.c
index 415f3f1c2da0..b394ad1e874b 100644
--- a/security/keys/proc.c
+++ b/security/keys/proc.c
@@ -110,11 +110,13 @@ static struct key *find_ge_key(struct seq_file *p, key_serial_t id)
}
static void *proc_keys_start(struct seq_file *p, loff_t *_pos)
+ __acquires(rcu)
__acquires(key_serial_lock)
{
key_serial_t pos = *_pos;
struct key *key;
+ rcu_read_lock();
spin_lock(&key_serial_lock);
if (*_pos > INT_MAX)
@@ -144,12 +146,15 @@ static void *proc_keys_next(struct seq_file *p, void *v, loff_t *_pos)
static void proc_keys_stop(struct seq_file *p, void *v)
__releases(key_serial_lock)
+ __releases(rcu)
{
spin_unlock(&key_serial_lock);
+ rcu_read_unlock();
}
static int proc_keys_show(struct seq_file *m, void *v)
{
+ const struct key_acl *acl;
struct rb_node *_p = v;
struct key *key = rb_entry(_p, struct key, serial_node);
unsigned long flags;
@@ -157,6 +162,7 @@ static int proc_keys_show(struct seq_file *m, void *v)
time64_t now, expiry;
char xbuf[16];
short state;
+ bool check_pos;
u64 timo;
int rc;
@@ -170,15 +176,15 @@ static int proc_keys_show(struct seq_file *m, void *v)
KEYRING_SEARCH_RECURSE),
};
- key_ref = make_key_ref(key, 0);
+ acl = rcu_dereference(key->acl);
+ check_pos = acl->possessor_viewable;
/* determine if the key is possessed by this process (a test we can
* skip if the key does not indicate the possessor can view it
*/
- if (key->perm & KEY_POS_VIEW) {
- rcu_read_lock();
+ key_ref = make_key_ref(key, 0);
+ if (check_pos) {
skey_ref = search_cred_keyrings_rcu(&ctx);
- rcu_read_unlock();
if (!IS_ERR(skey_ref)) {
key_ref_put(skey_ref);
key_ref = make_key_ref(key, 1);
@@ -188,12 +194,10 @@ static int proc_keys_show(struct seq_file *m, void *v)
/* check whether the current task is allowed to view the key */
rc = key_task_permission(key_ref, ctx.cred, KEY_NEED_VIEW);
if (rc < 0)
- return 0;
+ goto out;
now = ktime_get_real_seconds();
- rcu_read_lock();
-
/* come up with a suitable timeout value */
expiry = READ_ONCE(key->expiry);
if (expiry == 0) {
@@ -232,7 +236,7 @@ static int proc_keys_show(struct seq_file *m, void *v)
showflag(flags, 'i', KEY_FLAG_INVALIDATED),
refcount_read(&key->usage),
xbuf,
- key->perm,
+ key_acl_to_perm(acl),
from_kuid_munged(seq_user_ns(m), key->uid),
from_kgid_munged(seq_user_ns(m), key->gid),
key->type->name);
@@ -243,7 +247,7 @@ static int proc_keys_show(struct seq_file *m, void *v)
key->type->describe(key, m);
seq_putc(m, '\n');
- rcu_read_unlock();
+out:
return 0;
}