From 5593122eec26b061cc0b6fbff32118f1aadf4a27 Mon Sep 17 00:00:00 2001 From: David Howells Date: Wed, 2 Sep 2009 09:13:45 +0100 Subject: KEYS: Deal with dead-type keys appropriately [try #6] 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 Acked-by: Serge Hallyn Signed-off-by: James Morris --- 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 9fb679c66b8a..a7252e7b2e05 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 4a1297d1ada4..3762d5b1ce64 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 7f09fb897d2b..b85ace218395 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 ed929af466d3..4739cfbb41b7 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 */ -- cgit v1.2.3-59-g8ed1b