plucky (3) nbd_set_pread_initialize.3.gz

Provided by: libnbd-dev_1.22.0-1_amd64 bug

NAME
       nbd_set_pread_initialize - control whether libnbd pre-initializes read buffers


SYNOPSIS
        #include <libnbd.h>

        int nbd_set_pread_initialize (
              struct nbd_handle *h, bool request
            );


DESCRIPTION
       By default, libnbd will pre-initialize the contents of a buffer passed to calls such as nbd_pread(3) to
       all zeroes prior to checking for any other errors, so that even if a client application passed in an
       uninitialized buffer but fails to check for errors, it will not result in a potential security risk
       caused by an accidental leak of prior heap contents (see CVE-2022-0485 in libnbd-security(3) for an
       example of a security hole in an application built against an earlier version of libnbd that lacked
       consistent pre-initialization).  However, for a client application that has audited that an uninitialized
       buffer is never dereferenced, or which performs its own pre-initialization, libnbd's sanitization efforts
       merely pessimize performance (although the time spent in pre-initialization may pale in comparison to
       time spent waiting on network packets).

       Calling this function with "request" set to false tells libnbd to skip the buffer initialization step in
       read commands.


RETURN VALUE
       If the call is successful the function returns 0.


ERRORS
       On error -1 is returned.

       Refer to "ERROR HANDLING" in libnbd(3) for how to get further details of the error.

       The following parameters must not be NULL: "h".  For more information see "Non-NULL parameters" in
       libnbd(3).


VERSION
       This function first appeared in libnbd 1.12.

       If you need to test if this function is available at compile time check if the following macro is
       defined:

        #define LIBNBD_HAVE_NBD_SET_PREAD_INITIALIZE 1


SEE ALSO
       nbd_aio_pread(3), nbd_aio_pread_structured(3), nbd_create(3), nbd_get_pread_initialize(3), nbd_pread(3),
       nbd_pread_structured(3), nbd_set_strict_mode(3), libnbd(3).


AUTHORS
       Eric Blake

       Richard W.M. Jones


       Copyright Red Hat


LICENSE
       This library is free software; you can redistribute it and/or modify it under the terms of the GNU Lesser
       General Public License as published by the Free Software Foundation; either version 2 of the License, or
       (at your option) any later version.

       This library is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even
       the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Lesser General
       Public License for more details.

       You should have received a copy of the GNU Lesser General Public License along with this library; if not,
       write to the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA