1nbd_set_pread_initialize(3)         LIBNBD         nbd_set_pread_initialize(3)
2
3
4

NAME

6       nbd_set_pread_initialize - control whether libnbd pre-initializes read
7       buffers
8

SYNOPSIS

10        #include <libnbd.h>
11
12        int nbd_set_pread_initialize (
13              struct nbd_handle *h, bool request
14            );
15

DESCRIPTION

17       By default, libnbd will pre-initialize the contents of a buffer passed
18       to calls such as nbd_pread(3) to all zeroes prior to checking for any
19       other errors, so that even if a client application passed in an
20       uninitialized buffer but fails to check for errors, it will not result
21       in a potential security risk caused by an accidental leak of prior heap
22       contents (see CVE-2022-0485 in libnbd-security(3) for an example of a
23       security hole in an application built against an earlier version of
24       libnbd that lacked consistent pre-initialization).  However, for a
25       client application that has audited that an uninitialized buffer is
26       never dereferenced, or which performs its own pre-initialization,
27       libnbd's sanitization efforts merely pessimize performance (although
28       the time spent in pre-initialization may pale in comparison to time
29       spent waiting on network packets).
30
31       Calling this function with "request" set to false tells libnbd to skip
32       the buffer initialization step in read commands.
33

RETURN VALUE

35       If the call is successful the function returns 0.
36

ERRORS

38       On error -1 is returned.
39
40       Refer to "ERROR HANDLING" in libnbd(3) for how to get further details
41       of the error.
42
43       The following parameters must not be NULL: "h".  For more information
44       see "Non-NULL parameters" in libnbd(3).
45

VERSION

47       This function first appeared in libnbd 1.12.
48
49       If you need to test if this function is available at compile time check
50       if the following macro is defined:
51
52        #define LIBNBD_HAVE_NBD_SET_PREAD_INITIALIZE 1
53

SEE ALSO

55       nbd_aio_pread(3), nbd_aio_pread_structured(3), nbd_create(3),
56       nbd_get_pread_initialize(3), nbd_pread(3), nbd_pread_structured(3),
57       nbd_set_strict_mode(3), libnbd(3).
58

AUTHORS

60       Eric Blake
61
62       Richard W.M. Jones
63
65       Copyright Red Hat
66

LICENSE

68       This library is free software; you can redistribute it and/or modify it
69       under the terms of the GNU Lesser General Public License as published
70       by the Free Software Foundation; either version 2 of the License, or
71       (at your option) any later version.
72
73       This library is distributed in the hope that it will be useful, but
74       WITHOUT ANY WARRANTY; without even the implied warranty of
75       MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
76       Lesser General Public License for more details.
77
78       You should have received a copy of the GNU Lesser General Public
79       License along with this library; if not, write to the Free Software
80       Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
81       02110-1301 USA
82
83
84
85libnbd-1.18.1                     2023-10-31       nbd_set_pread_initialize(3)
Impressum