| 1 | =pod
|
|---|
| 2 |
|
|---|
| 3 | =head1 NAME
|
|---|
| 4 |
|
|---|
| 5 | RAND_load_file, RAND_write_file, RAND_file_name - PRNG seed file
|
|---|
| 6 |
|
|---|
| 7 | =head1 SYNOPSIS
|
|---|
| 8 |
|
|---|
| 9 | #include <openssl/rand.h>
|
|---|
| 10 |
|
|---|
| 11 | int RAND_load_file(const char *filename, long max_bytes);
|
|---|
| 12 |
|
|---|
| 13 | int RAND_write_file(const char *filename);
|
|---|
| 14 |
|
|---|
| 15 | const char *RAND_file_name(char *buf, size_t num);
|
|---|
| 16 |
|
|---|
| 17 | =head1 DESCRIPTION
|
|---|
| 18 |
|
|---|
| 19 | RAND_load_file() reads a number of bytes from file B<filename> and
|
|---|
| 20 | adds them to the PRNG. If B<max_bytes> is non-negative,
|
|---|
| 21 | up to B<max_bytes> are read;
|
|---|
| 22 | if B<max_bytes> is -1, the complete file is read.
|
|---|
| 23 | Do not load the same file multiple times unless its contents have
|
|---|
| 24 | been updated by RAND_write_file() between reads.
|
|---|
| 25 | Also, note that B<filename> should be adequately protected so that an
|
|---|
| 26 | attacker cannot replace or examine the contents.
|
|---|
| 27 | If B<filename> is not a regular file, then user is considered to be
|
|---|
| 28 | responsible for any side effects, e.g. non-anticipated blocking or
|
|---|
| 29 | capture of controlling terminal.
|
|---|
| 30 |
|
|---|
| 31 | RAND_write_file() writes a number of random bytes (currently 128) to
|
|---|
| 32 | file B<filename> which can be used to initialize the PRNG by calling
|
|---|
| 33 | RAND_load_file() in a later session.
|
|---|
| 34 |
|
|---|
| 35 | RAND_file_name() generates a default path for the random seed
|
|---|
| 36 | file. B<buf> points to a buffer of size B<num> in which to store the
|
|---|
| 37 | filename.
|
|---|
| 38 |
|
|---|
| 39 | On all systems, if the environment variable B<RANDFILE> is set, its
|
|---|
| 40 | value will be used as the seed file name.
|
|---|
| 41 | Otherwise, the file is called C<.rnd>, found in platform dependent locations:
|
|---|
| 42 |
|
|---|
| 43 | =over 4
|
|---|
| 44 |
|
|---|
| 45 | =item On Windows (in order of preference)
|
|---|
| 46 |
|
|---|
| 47 | %HOME%, %USERPROFILE%, %SYSTEMROOT%, C:\
|
|---|
| 48 |
|
|---|
| 49 | =item On VMS
|
|---|
| 50 |
|
|---|
| 51 | SYS$LOGIN:
|
|---|
| 52 |
|
|---|
| 53 | =item On all other systems
|
|---|
| 54 |
|
|---|
| 55 | $HOME
|
|---|
| 56 |
|
|---|
| 57 | =back
|
|---|
| 58 |
|
|---|
| 59 | If C<$HOME> (on non-Windows and non-VMS system) is not set either, or
|
|---|
| 60 | B<num> is too small for the path name, an error occurs.
|
|---|
| 61 |
|
|---|
| 62 | =head1 RETURN VALUES
|
|---|
| 63 |
|
|---|
| 64 | RAND_load_file() returns the number of bytes read or -1 on error.
|
|---|
| 65 |
|
|---|
| 66 | RAND_write_file() returns the number of bytes written, or -1 if the
|
|---|
| 67 | bytes written were generated without appropriate seeding.
|
|---|
| 68 |
|
|---|
| 69 | RAND_file_name() returns a pointer to B<buf> on success, and NULL on
|
|---|
| 70 | error.
|
|---|
| 71 |
|
|---|
| 72 | =head1 SEE ALSO
|
|---|
| 73 |
|
|---|
| 74 | L<RAND_add(3)>,
|
|---|
| 75 | L<RAND_bytes(3)>,
|
|---|
| 76 | L<RAND(7)>
|
|---|
| 77 |
|
|---|
| 78 | =head1 COPYRIGHT
|
|---|
| 79 |
|
|---|
| 80 | Copyright 2000-2018 The OpenSSL Project Authors. All Rights Reserved.
|
|---|
| 81 |
|
|---|
| 82 | Licensed under the OpenSSL license (the "License"). You may not use
|
|---|
| 83 | this file except in compliance with the License. You can obtain a copy
|
|---|
| 84 | in the file LICENSE in the source distribution or at
|
|---|
| 85 | L<https://www.openssl.org/source/license.html>.
|
|---|
| 86 |
|
|---|
| 87 | =cut
|
|---|
