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    Subject[16/98] keys: the request_key() syscall should link an existing key to the dest keyring
    2.6.32-stable review patch.  If anyone has any objections, please let us know.

    ------------------

    From: David Howells <dhowells@redhat.com>

    commit 03449cd9eaa4fa3a7faa4a59474bafe2e90bd143 upstream.

    The request_key() system call and request_key_and_link() should make a
    link from an existing key to the destination keyring (if supplied), not
    just from a new key to the destination keyring.

    This can be tested by:

    ring=`keyctl newring fred @s`
    keyctl request2 user debug:a a
    keyctl request user debug:a $ring
    keyctl list $ring

    If it says:

    keyring is empty

    then it didn't work. If it shows something like:

    1 key in keyring:
    1070462727: --alswrv 0 0 user: debug:a

    then it did.

    request_key() system call is meant to recursively search all your keyrings for
    the key you desire, and, optionally, if it doesn't exist, call out to userspace
    to create one for you.

    If request_key() finds or creates a key, it should, optionally, create a link
    to that key from the destination keyring specified.

    Therefore, if, after a successful call to request_key() with a desination
    keyring specified, you see the destination keyring empty, the code didn't work
    correctly.

    If you see the found key in the keyring, then it did - which is what the patch
    is required for.

    Signed-off-by: David Howells <dhowells@redhat.com>
    Cc: James Morris <jmorris@namei.org>
    Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
    Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
    Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

    ---
    security/keys/request_key.c | 9 ++++++++-
    1 file changed, 8 insertions(+), 1 deletion(-)

    --- a/security/keys/request_key.c
    +++ b/security/keys/request_key.c
    @@ -336,8 +336,10 @@ static int construct_alloc_key(struct ke

    key_already_present:
    mutex_unlock(&key_construction_mutex);
    - if (dest_keyring)
    + if (dest_keyring) {
    + __key_link(dest_keyring, key_ref_to_ptr(key_ref));
    up_write(&dest_keyring->sem);
    + }
    mutex_unlock(&user->cons_lock);
    key_put(key);
    *_key = key = key_ref_to_ptr(key_ref);
    @@ -428,6 +430,11 @@ struct key *request_key_and_link(struct

    if (!IS_ERR(key_ref)) {
    key = key_ref_to_ptr(key_ref);
    + if (dest_keyring) {
    + construct_get_dest_keyring(&dest_keyring);
    + key_link(dest_keyring, key);
    + key_put(dest_keyring);
    + }
    } else if (PTR_ERR(key_ref) != -EAGAIN) {
    key = ERR_CAST(key_ref);
    } else {



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