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Date: Tue, 04 Aug 2009 21:39:23 +0100
From: David Howells <dhowells@...hat.com>
To: torvalds@...l.org, akpm@...ux-foundation.org, jmorris@...ei.org
Cc: serue@...ibm.com, linux-kernel@...r.kernel.org,
linux-security-module@...r.kernel.org,
David Howells <dhowells@...hat.com>,
Serge Hallyn <serue@...ibm.com>
Subject: [PATCH 1/6] KEYS: Deal with dead-type keys appropriately [ver #2]
Allow keys for which the key type has been removed to be unlinked. Currently
dead-type keys can only be disposed of by completely clearing the keyrings
that point to them.
Signed-off-by: David Howells <dhowells@...hat.com>
Acked-by: Serge Hallyn <serue@...ibm.com>
---
security/keys/internal.h | 5 +++-
security/keys/key.c | 6 ++---
security/keys/keyctl.c | 50 ++++++++++++++++++++++++------------------
security/keys/process_keys.c | 18 +++++++++++----
4 files changed, 48 insertions(+), 31 deletions(-)
diff --git a/security/keys/internal.h b/security/keys/internal.h
index 9fb679c..a7252e7 100644
--- a/security/keys/internal.h
+++ b/security/keys/internal.h
@@ -124,8 +124,11 @@ extern struct key *request_key_and_link(struct key_type *type,
struct key *dest_keyring,
unsigned long flags);
-extern key_ref_t lookup_user_key(key_serial_t id, int create, int partial,
+extern key_ref_t lookup_user_key(key_serial_t id, unsigned long flags,
key_perm_t perm);
+#define KEY_LOOKUP_CREATE 0x01
+#define KEY_LOOKUP_PARTIAL 0x02
+#define KEY_LOOKUP_FOR_UNLINK 0x04
extern long join_session_keyring(const char *name);
diff --git a/security/keys/key.c b/security/keys/key.c
index 4a1297d..3762d5b 100644
--- a/security/keys/key.c
+++ b/security/keys/key.c
@@ -642,10 +642,8 @@ struct key *key_lookup(key_serial_t id)
goto error;
found:
- /* pretend it doesn't exist if it's dead */
- if (atomic_read(&key->usage) == 0 ||
- test_bit(KEY_FLAG_DEAD, &key->flags) ||
- key->type == &key_type_dead)
+ /* pretend it doesn't exist if it is awaiting deletion */
+ if (atomic_read(&key->usage) == 0)
goto not_found;
/* this races with key_put(), but that doesn't matter since key_put()
diff --git a/security/keys/keyctl.c b/security/keys/keyctl.c
index 7f09fb8..b85ace2 100644
--- a/security/keys/keyctl.c
+++ b/security/keys/keyctl.c
@@ -103,7 +103,7 @@ SYSCALL_DEFINE5(add_key, const char __user *, _type,
}
/* find the target keyring (which must be writable) */
- keyring_ref = lookup_user_key(ringid, 1, 0, KEY_WRITE);
+ keyring_ref = lookup_user_key(ringid, KEY_LOOKUP_CREATE, KEY_WRITE);
if (IS_ERR(keyring_ref)) {
ret = PTR_ERR(keyring_ref);
goto error3;
@@ -185,7 +185,8 @@ SYSCALL_DEFINE4(request_key, const char __user *, _type,
/* get the destination keyring if specified */
dest_ref = NULL;
if (destringid) {
- dest_ref = lookup_user_key(destringid, 1, 0, KEY_WRITE);
+ dest_ref = lookup_user_key(destringid, KEY_LOOKUP_CREATE,
+ KEY_WRITE);
if (IS_ERR(dest_ref)) {
ret = PTR_ERR(dest_ref);
goto error3;
@@ -233,9 +234,11 @@ SYSCALL_DEFINE4(request_key, const char __user *, _type,
long keyctl_get_keyring_ID(key_serial_t id, int create)
{
key_ref_t key_ref;
+ unsigned long lflags;
long ret;
- key_ref = lookup_user_key(id, create, 0, KEY_SEARCH);
+ lflags = create ? KEY_LOOKUP_CREATE : 0;
+ key_ref = lookup_user_key(id, lflags, KEY_SEARCH);
if (IS_ERR(key_ref)) {
ret = PTR_ERR(key_ref);
goto error;
@@ -309,7 +312,7 @@ long keyctl_update_key(key_serial_t id,
}
/* find the target key (which must be writable) */
- key_ref = lookup_user_key(id, 0, 0, KEY_WRITE);
+ key_ref = lookup_user_key(id, 0, KEY_WRITE);
if (IS_ERR(key_ref)) {
ret = PTR_ERR(key_ref);
goto error2;
@@ -337,7 +340,7 @@ long keyctl_revoke_key(key_serial_t id)
key_ref_t key_ref;
long ret;
- key_ref = lookup_user_key(id, 0, 0, KEY_WRITE);
+ key_ref = lookup_user_key(id, 0, KEY_WRITE);
if (IS_ERR(key_ref)) {
ret = PTR_ERR(key_ref);
goto error;
@@ -363,7 +366,7 @@ long keyctl_keyring_clear(key_serial_t ringid)
key_ref_t keyring_ref;
long ret;
- keyring_ref = lookup_user_key(ringid, 1, 0, KEY_WRITE);
+ keyring_ref = lookup_user_key(ringid, KEY_LOOKUP_CREATE, KEY_WRITE);
if (IS_ERR(keyring_ref)) {
ret = PTR_ERR(keyring_ref);
goto error;
@@ -389,13 +392,13 @@ long keyctl_keyring_link(key_serial_t id, key_serial_t ringid)
key_ref_t keyring_ref, key_ref;
long ret;
- keyring_ref = lookup_user_key(ringid, 1, 0, KEY_WRITE);
+ keyring_ref = lookup_user_key(ringid, KEY_LOOKUP_CREATE, KEY_WRITE);
if (IS_ERR(keyring_ref)) {
ret = PTR_ERR(keyring_ref);
goto error;
}
- key_ref = lookup_user_key(id, 1, 0, KEY_LINK);
+ key_ref = lookup_user_key(id, KEY_LOOKUP_CREATE, KEY_LINK);
if (IS_ERR(key_ref)) {
ret = PTR_ERR(key_ref);
goto error2;
@@ -423,13 +426,13 @@ long keyctl_keyring_unlink(key_serial_t id, key_serial_t ringid)
key_ref_t keyring_ref, key_ref;
long ret;
- keyring_ref = lookup_user_key(ringid, 0, 0, KEY_WRITE);
+ keyring_ref = lookup_user_key(ringid, 0, KEY_WRITE);
if (IS_ERR(keyring_ref)) {
ret = PTR_ERR(keyring_ref);
goto error;
}
- key_ref = lookup_user_key(id, 0, 0, 0);
+ key_ref = lookup_user_key(id, KEY_LOOKUP_FOR_UNLINK, 0);
if (IS_ERR(key_ref)) {
ret = PTR_ERR(key_ref);
goto error2;
@@ -465,7 +468,7 @@ long keyctl_describe_key(key_serial_t keyid,
char *tmpbuf;
long ret;
- key_ref = lookup_user_key(keyid, 0, 1, KEY_VIEW);
+ key_ref = lookup_user_key(keyid, KEY_LOOKUP_PARTIAL, KEY_VIEW);
if (IS_ERR(key_ref)) {
/* viewing a key under construction is permitted if we have the
* authorisation token handy */
@@ -474,7 +477,8 @@ long keyctl_describe_key(key_serial_t keyid,
if (!IS_ERR(instkey)) {
key_put(instkey);
key_ref = lookup_user_key(keyid,
- 0, 1, 0);
+ KEY_LOOKUP_PARTIAL,
+ 0);
if (!IS_ERR(key_ref))
goto okay;
}
@@ -558,7 +562,7 @@ long keyctl_keyring_search(key_serial_t ringid,
}
/* get the keyring at which to begin the search */
- keyring_ref = lookup_user_key(ringid, 0, 0, KEY_SEARCH);
+ keyring_ref = lookup_user_key(ringid, 0, KEY_SEARCH);
if (IS_ERR(keyring_ref)) {
ret = PTR_ERR(keyring_ref);
goto error2;
@@ -567,7 +571,8 @@ long keyctl_keyring_search(key_serial_t ringid,
/* get the destination keyring if specified */
dest_ref = NULL;
if (destringid) {
- dest_ref = lookup_user_key(destringid, 1, 0, KEY_WRITE);
+ dest_ref = lookup_user_key(destringid, KEY_LOOKUP_CREATE,
+ KEY_WRITE);
if (IS_ERR(dest_ref)) {
ret = PTR_ERR(dest_ref);
goto error3;
@@ -637,7 +642,7 @@ long keyctl_read_key(key_serial_t keyid, char __user *buffer, size_t buflen)
long ret;
/* find the key first */
- key_ref = lookup_user_key(keyid, 0, 0, 0);
+ key_ref = lookup_user_key(keyid, 0, 0);
if (IS_ERR(key_ref)) {
ret = -ENOKEY;
goto error;
@@ -700,7 +705,8 @@ long keyctl_chown_key(key_serial_t id, uid_t uid, gid_t gid)
if (uid == (uid_t) -1 && gid == (gid_t) -1)
goto error;
- key_ref = lookup_user_key(id, 1, 1, KEY_SETATTR);
+ key_ref = lookup_user_key(id, KEY_LOOKUP_CREATE | KEY_LOOKUP_PARTIAL,
+ KEY_SETATTR);
if (IS_ERR(key_ref)) {
ret = PTR_ERR(key_ref);
goto error;
@@ -805,7 +811,8 @@ long keyctl_setperm_key(key_serial_t id, key_perm_t perm)
if (perm & ~(KEY_POS_ALL | KEY_USR_ALL | KEY_GRP_ALL | KEY_OTH_ALL))
goto error;
- key_ref = lookup_user_key(id, 1, 1, KEY_SETATTR);
+ key_ref = lookup_user_key(id, KEY_LOOKUP_CREATE | KEY_LOOKUP_PARTIAL,
+ KEY_SETATTR);
if (IS_ERR(key_ref)) {
ret = PTR_ERR(key_ref);
goto error;
@@ -847,7 +854,7 @@ static long get_instantiation_keyring(key_serial_t ringid,
/* if a specific keyring is nominated by ID, then use that */
if (ringid > 0) {
- dkref = lookup_user_key(ringid, 1, 0, KEY_WRITE);
+ dkref = lookup_user_key(ringid, KEY_LOOKUP_CREATE, KEY_WRITE);
if (IS_ERR(dkref))
return PTR_ERR(dkref);
*_dest_keyring = key_ref_to_ptr(dkref);
@@ -1083,7 +1090,8 @@ long keyctl_set_timeout(key_serial_t id, unsigned timeout)
time_t expiry;
long ret;
- key_ref = lookup_user_key(id, 1, 1, KEY_SETATTR);
+ key_ref = lookup_user_key(id, KEY_LOOKUP_CREATE | KEY_LOOKUP_PARTIAL,
+ KEY_SETATTR);
if (IS_ERR(key_ref)) {
ret = PTR_ERR(key_ref);
goto error;
@@ -1170,7 +1178,7 @@ long keyctl_get_security(key_serial_t keyid,
char *context;
long ret;
- key_ref = lookup_user_key(keyid, 0, 1, KEY_VIEW);
+ key_ref = lookup_user_key(keyid, KEY_LOOKUP_PARTIAL, KEY_VIEW);
if (IS_ERR(key_ref)) {
if (PTR_ERR(key_ref) != -EACCES)
return PTR_ERR(key_ref);
@@ -1182,7 +1190,7 @@ long keyctl_get_security(key_serial_t keyid,
return PTR_ERR(key_ref);
key_put(instkey);
- key_ref = lookup_user_key(keyid, 0, 1, 0);
+ key_ref = lookup_user_key(keyid, KEY_LOOKUP_PARTIAL, 0);
if (IS_ERR(key_ref))
return PTR_ERR(key_ref);
}
diff --git a/security/keys/process_keys.c b/security/keys/process_keys.c
index 276d278..349c315 100644
--- a/security/keys/process_keys.c
+++ b/security/keys/process_keys.c
@@ -487,7 +487,7 @@ static int lookup_user_key_possessed(const struct key *key, const void *target)
* - don't create special keyrings unless so requested
* - partially constructed keys aren't found unless requested
*/
-key_ref_t lookup_user_key(key_serial_t id, int create, int partial,
+key_ref_t lookup_user_key(key_serial_t id, unsigned long lflags,
key_perm_t perm)
{
struct request_key_auth *rka;
@@ -503,7 +503,7 @@ try_again:
switch (id) {
case KEY_SPEC_THREAD_KEYRING:
if (!cred->thread_keyring) {
- if (!create)
+ if (!(lflags & KEY_LOOKUP_CREATE))
goto error;
ret = install_thread_keyring();
@@ -521,7 +521,7 @@ try_again:
case KEY_SPEC_PROCESS_KEYRING:
if (!cred->tgcred->process_keyring) {
- if (!create)
+ if (!(lflags & KEY_LOOKUP_CREATE))
goto error;
ret = install_process_keyring();
@@ -642,7 +642,14 @@ try_again:
break;
}
- if (!partial) {
+ /* unlink does not use the nominated key in any way, so can skip all
+ * the permission checks as it is only concerned with the keyring */
+ if (lflags & KEY_LOOKUP_FOR_UNLINK) {
+ ret = 0;
+ goto error;
+ }
+
+ if (!(lflags & KEY_LOOKUP_PARTIAL)) {
ret = wait_for_key_construction(key, true);
switch (ret) {
case -ERESTARTSYS:
@@ -660,7 +667,8 @@ try_again:
}
ret = -EIO;
- if (!partial && !test_bit(KEY_FLAG_INSTANTIATED, &key->flags))
+ if (!(lflags & KEY_LOOKUP_PARTIAL) &&
+ !test_bit(KEY_FLAG_INSTANTIATED, &key->flags))
goto invalid_key;
/* check the permissions */
--
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