lkml.org 
[lkml]   [2020]   [Mar]   [18]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    /
    From
    Subject[PATCH v5 0/2] KEYS: Read keys to internal buffer & then copy to userspace
    Date
    v5:
    - Merge v4 patches 2 and 3 into 1 to avoid sparse warning. Merge some of
    commit logs into patch 1 as well. There is no further change.

    v4:
    - Remove the __user annotation from big_key_read() and user_read() in
    patch 1.
    - Add a new patch 2 to remove __user annotation from rxrpc_read().
    - Add a new patch 3 to remove __user annotation from dns_resolver_read().
    - Merge the original patches 2 and 3 into a single patch 4 and refactor
    it as suggested by Jarkko and Eric.

    v3:
    - Reorganize the keyctl_read_key() code to make it more readable as
    suggested by Jarkko Sakkinen.
    - Add patch 3 to use kvmalloc() for safer large buffer allocation as
    suggested by David Howells.

    v2:
    - Handle NULL buffer and buflen properly in patch 1.
    - Fix a bug in big_key.c.
    - Add patch 2 to handle arbitrary large user-supplied buflen.

    The current security key read methods are called with the key semaphore
    held. The methods then copy out the key data to userspace which is
    subjected to page fault and may acquire the mmap semaphore. That can
    result in circular lock dependency and hence a chance to get into
    deadlock.

    To avoid such a deadlock, an internal buffer is now allocated for getting
    out the necessary data first. After releasing the key semaphore, the
    key data are then copied out to userspace sidestepping the circular
    lock dependency.

    The keyutils test suite was run and the test passed with these patchset
    applied without any falure.

    Waiman Long (2):
    KEYS: Don't write out to userspace while holding key semaphore
    KEYS: Avoid false positive ENOMEM error on key read

    include/keys/big_key-type.h | 2 +-
    include/keys/user-type.h | 3 +-
    include/linux/key-type.h | 2 +-
    net/dns_resolver/dns_key.c | 2 +-
    net/rxrpc/key.c | 27 +++----
    security/keys/big_key.c | 11 ++-
    security/keys/encrypted-keys/encrypted.c | 7 +-
    security/keys/internal.h | 12 ++++
    security/keys/keyctl.c | 86 ++++++++++++++++++++---
    security/keys/keyring.c | 6 +-
    security/keys/request_key_auth.c | 7 +-
    security/keys/trusted-keys/trusted_tpm1.c | 14 +---
    security/keys/user_defined.c | 5 +-
    13 files changed, 116 insertions(+), 68 deletions(-)

    --
    2.18.1

    \
     
     \ /
      Last update: 2020-03-18 23:16    [W:2.599 / U:0.144 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site