• Michael S. Tsirkin's avatar
    tcm_vhost: Fix vhost_scsi_target structure alignment · 6de7145c
    Michael S. Tsirkin authored
    Here TRANSPORT_IQN_LEN is 224, which is a multiple of 4.
    Since vhost_tpgt is 2 bytes and abi_version is 4, the total size would
    be 230.  But gcc needs struct size be aligned to first field size, which
    is 4 bytes, so it pads the structure by extra 2 bytes to the total of
    232.
    
    This padding is very undesirable in an ABI:
    - it can not be initialized easily
    - it can not be checked easily
    - it can leak information between kernel and userspace
    
    Simplest solution is probably just to make the padding
    explicit.
    
    (v2: Add check for zero'ed backend->reserved field for VHOST_SCSI_SET_ENDPOINT
         and VHOST_SCSI_CLEAR_ENDPOINT ops as requested by MST)
    Reported-by: default avatarMichael S. Tsirkin <mst@redhat.com>
    Signed-off-by: default avatarMichael S. Tsirkin <mst@redhat.com>
    Signed-off-by: default avatarNicholas Bellinger <nab@linux-iscsi.org>
    6de7145c
tcm_vhost.h 3.39 KB