lkml.org 
[lkml]   [2020]   [Apr]   [16]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    Patch in this message
    /
    From
    Subject[PATCH 5.6 109/254] KEYS: reaching the keys quotas correctly
    Date
    From: Yang Xu <xuyang2018.jy@cn.fujitsu.com>

    commit 2e356101e72ab1361821b3af024d64877d9a798d upstream.

    Currently, when we add a new user key, the calltrace as below:

    add_key()
    key_create_or_update()
    key_alloc()
    __key_instantiate_and_link
    generic_key_instantiate
    key_payload_reserve
    ......

    Since commit a08bf91ce28e ("KEYS: allow reaching the keys quotas exactly"),
    we can reach max bytes/keys in key_alloc, but we forget to remove this
    limit when we reserver space for payload in key_payload_reserve. So we
    can only reach max keys but not max bytes when having delta between plen
    and type->def_datalen. Remove this limit when instantiating the key, so we
    can keep consistent with key_alloc.

    Also, fix the similar problem in keyctl_chown_key().

    Fixes: 0b77f5bfb45c ("keys: make the keyring quotas controllable through /proc/sys")
    Fixes: a08bf91ce28e ("KEYS: allow reaching the keys quotas exactly")
    Cc: stable@vger.kernel.org # 5.0.x
    Cc: Eric Biggers <ebiggers@google.com>
    Signed-off-by: Yang Xu <xuyang2018.jy@cn.fujitsu.com>
    Reviewed-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
    Reviewed-by: Eric Biggers <ebiggers@google.com>
    Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
    Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

    ---
    security/keys/key.c | 2 +-
    security/keys/keyctl.c | 4 ++--
    2 files changed, 3 insertions(+), 3 deletions(-)

    --- a/security/keys/key.c
    +++ b/security/keys/key.c
    @@ -382,7 +382,7 @@ int key_payload_reserve(struct key *key,
    spin_lock(&key->user->lock);

    if (delta > 0 &&
    - (key->user->qnbytes + delta >= maxbytes ||
    + (key->user->qnbytes + delta > maxbytes ||
    key->user->qnbytes + delta < key->user->qnbytes)) {
    ret = -EDQUOT;
    }
    --- a/security/keys/keyctl.c
    +++ b/security/keys/keyctl.c
    @@ -937,8 +937,8 @@ long keyctl_chown_key(key_serial_t id, u
    key_quota_root_maxbytes : key_quota_maxbytes;

    spin_lock(&newowner->lock);
    - if (newowner->qnkeys + 1 >= maxkeys ||
    - newowner->qnbytes + key->quotalen >= maxbytes ||
    + if (newowner->qnkeys + 1 > maxkeys ||
    + newowner->qnbytes + key->quotalen > maxbytes ||
    newowner->qnbytes + key->quotalen <
    newowner->qnbytes)
    goto quota_overrun;

    \
     
     \ /
      Last update: 2020-04-16 16:24    [W:4.087 / U:0.104 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site