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    Subject[17/68] CRED: Fix memory and refcount leaks upon security_prepare_creds() failure
    2.6.32-longterm review patch.  If anyone has any objections, please let us know.

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

    From: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>

    commit fb2b2a1d37f80cc818fd4487b510f4e11816e5e1 upstream.

    In prepare_kernel_cred() since 2.6.29, put_cred(new) is called without
    assigning new->usage when security_prepare_creds() returned an error. As a
    result, memory for new and refcount for new->{user,group_info,tgcred} are
    leaked because put_cred(new) won't call __put_cred() unless old->usage == 1.

    Fix these leaks by assigning new->usage (and new->subscribers which was added
    in 2.6.32) before calling security_prepare_creds().

    Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
    Signed-off-by: David Howells <dhowells@redhat.com>
    Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
    Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

    ---
    kernel/cred.c | 4 ++--
    1 file changed, 2 insertions(+), 2 deletions(-)

    --- a/kernel/cred.c
    +++ b/kernel/cred.c
    @@ -718,6 +718,8 @@ struct cred *prepare_kernel_cred(struct
    validate_creds(old);

    *new = *old;
    + atomic_set(&new->usage, 1);
    + set_cred_subscribers(new, 0);
    get_uid(new->user);
    get_group_info(new->group_info);

    @@ -735,8 +737,6 @@ struct cred *prepare_kernel_cred(struct
    if (security_prepare_creds(new, old, GFP_KERNEL) < 0)
    goto error;

    - atomic_set(&new->usage, 1);
    - set_cred_subscribers(new, 0);
    put_cred(old);
    validate_creds(new);
    return new;



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