linux/security/keys
Eric Biggers ede0fa98a9 KEYS: always initialize keyring_index_key::desc_len
syzbot hit the 'BUG_ON(index_key->desc_len == 0);' in __key_link_begin()
called from construct_alloc_key() during sys_request_key(), because the
length of the key description was never calculated.

The problem is that we rely on ->desc_len being initialized by
search_process_keyrings(), specifically by search_nested_keyrings().
But, if the process isn't subscribed to any keyrings that never happens.

Fix it by always initializing keyring_index_key::desc_len as soon as the
description is set, like we already do in some places.

The following program reproduces the BUG_ON() when it's run as root and
no session keyring has been installed.  If it doesn't work, try removing
pam_keyinit.so from /etc/pam.d/login and rebooting.

    #include <stdlib.h>
    #include <unistd.h>
    #include <keyutils.h>

    int main(void)
    {
            int id = add_key("keyring", "syz", NULL, 0, KEY_SPEC_USER_KEYRING);

            keyctl_setperm(id, KEY_OTH_WRITE);
            setreuid(5000, 5000);
            request_key("user", "desc", "", id);
    }

Reported-by: syzbot+ec24e95ea483de0a24da@syzkaller.appspotmail.com
Fixes: b2a4df200d ("KEYS: Expand the capacity of a keyring")
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: David Howells <dhowells@redhat.com>
Cc: stable@vger.kernel.org
Signed-off-by: James Morris <james.morris@microsoft.com>
2019-02-22 10:11:34 -08:00
..
encrypted-keys libnvdimm for 4.21 2018-12-28 15:05:13 -08:00
big_key.c big key: get rid of stack array allocation 2018-05-11 13:07:45 -07:00
compat_dh.c KEYS: DH: validate __spare field 2017-07-14 11:01:38 +10:00
compat.c KEYS: Provide keyctls to drive the new key type ops for asymmetric keys [ver #2] 2018-10-26 09:30:46 +01:00
dh.c Revert "uapi/linux/keyctl.h: don't use C++ reserved keyword as a struct member name" 2018-09-25 13:28:58 +02:00
gc.c security: audit and remove any unnecessary uses of module.h 2018-12-12 14:58:51 -08:00
internal.h keys: Fix dependency loop between construction record and auth key 2019-02-15 14:12:09 -08:00
Kconfig security/keys: BIG_KEY requires CONFIG_CRYPTO 2017-10-18 09:12:40 +01:00
key.c keys: Timestamp new keys 2019-02-15 14:12:09 -08:00
keyctl_pkey.c KEYS: fix parsing invalid pkey info string 2019-01-01 13:13:19 -08:00
keyctl.c keys: Fix dependency loop between construction record and auth key 2019-02-15 14:12:09 -08:00
keyring.c KEYS: always initialize keyring_index_key::desc_len 2019-02-22 10:11:34 -08:00
Makefile KEYS: Provide keyctls to drive the new key type ops for asymmetric keys [ver #2] 2018-10-26 09:30:46 +01:00
permission.c security: audit and remove any unnecessary uses of module.h 2018-12-12 14:58:51 -08:00
persistent.c sched/headers: Prepare to remove <linux/cred.h> inclusion from <linux/sched.h> 2017-03-02 08:42:31 +01:00
proc.c KEYS: always initialize keyring_index_key::desc_len 2019-02-22 10:11:34 -08:00
process_keys.c keys: Fix dependency loop between construction record and auth key 2019-02-15 14:12:09 -08:00
request_key_auth.c KEYS: always initialize keyring_index_key::desc_len 2019-02-22 10:11:34 -08:00
request_key.c KEYS: always initialize keyring_index_key::desc_len 2019-02-22 10:11:34 -08:00
sysctl.c security: Convert use of typedef ctl_table to struct ctl_table 2014-04-15 13:39:58 +10:00
trusted.c Merge branch 'linus' of git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6 2018-12-27 13:53:32 -08:00
user_defined.c security: audit and remove any unnecessary uses of module.h 2018-12-12 14:58:51 -08:00