ag/cpython-source-deps
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

Import OpenSSL 1.1.0f

Browse Source
This commit is contained in:
Steve Dower
2017-09-07 16:27:43 -07:00
committed by Steve Dower
parent ccd3ab4aff
commit f4b81cb7c9
3340 changed files with 325158 additions and 557542 deletions
Download Patch File Download Diff File Expand all files Collapse all files

77
doc/ssl/SSL_CTX_set_generate_session_id.pod
View File

@@ -2,7 +2,9 @@
=head1 NAME
SSL_CTX_set_generate_session_id, SSL_set_generate_session_id, SSL_has_matching_session_id - manipulate generation of SSL session IDs (server only)
SSL_CTX_set_generate_session_id, SSL_set_generate_session_id,
SSL_has_matching_session_id, GEN_SESSION_CB
- manipulate generation of SSL session IDs (server only)
=head1 SYNOPSIS
@@ -14,7 +16,7 @@ SSL_CTX_set_generate_session_id, SSL_set_generate_session_id, SSL_has_matching_s
int SSL_CTX_set_generate_session_id(SSL_CTX *ctx, GEN_SESSION_CB cb);
int SSL_set_generate_session_id(SSL *ssl, GEN_SESSION_CB, cb);
int SSL_has_matching_session_id(const SSL *ssl, const unsigned char *id,
unsigned int id_len);
unsigned int id_len);
=head1 DESCRIPTION
@@ -32,9 +34,8 @@ of the parent context of B<ssl>.
When a new session is established between client and server, the server
generates a session id. The session id is an arbitrary sequence of bytes.
The length of the session id is 16 bytes for SSLv2 sessions and between
1 and 32 bytes for SSLv3/TLSv1. The session id is not security critical
but must be unique for the server. Additionally, the session id is
The length of the session id is between 1 and 32 bytes. The session id is not
security critical but must be unique for the server. Additionally, the session id is
transmitted in the clear when reusing the session so it must not contain
sensitive information.
@@ -51,21 +52,14 @@ The callback is only allowed to generate a shorter id and reduce B<id_len>;
the callback B<must never> increase B<id_len> or write to the location
B<id> exceeding the given limit.
If a SSLv2 session id is generated and B<id_len> is reduced, it will be
restored after the callback has finished and the session id will be padded
with 0x00. It is not recommended to change the B<id_len> for SSLv2 sessions.
The callback can use the L<SSL_get_version(3)|SSL_get_version(3)> function
to check, whether the session is of type SSLv2.
The location B<id> is filled with 0x00 before the callback is called, so the
callback may only fill part of the possible length and leave B<id_len>
untouched while maintaining reproducibility.
Since the sessions must be distinguished, session ids must be unique.
Without the callback a random number is used, so that the probability
of generating the same session id is extremely small (2^128 possible ids
for an SSLv2 session, 2^256 for SSLv3/TLSv1). In order to assure the
uniqueness of the generated session id, the callback must call
of generating the same session id is extremely small (2^256 for SSLv3/TLSv1).
In order to assure the uniqueness of the generated session id, the callback must call
SSL_has_matching_session_id() and generate another id if a conflict occurs.
If an id conflict is not resolved, the handshake will fail.
If the application codes e.g. a unique host id, a unique process number, and
@@ -85,10 +79,6 @@ Collisions can also occur when using an external session cache, since
the external cache is not tested with SSL_has_matching_session_id()
and the same race condition applies.
When calling SSL_has_matching_session_id() for an SSLv2 session with
reduced B<id_len>, the match operation will be performed using the
fixed length required and with a 0x00 padded id.
The callback must return 0 if it cannot generate a session id for whatever
reason and return 1 on success.
@@ -102,31 +92,27 @@ server id given, and will fill the rest with pseudo random bytes:
#define MAX_SESSION_ID_ATTEMPTS 10
static int generate_session_id(const SSL *ssl, unsigned char *id,
unsigned int *id_len)
{
{
unsigned int count = 0;
const char *version;
version = SSL_get_version(ssl);
if (!strcmp(version, "SSLv2"))
/* we must not change id_len */;
do {
RAND_pseudo_bytes(id, *id_len);
/* Prefix the session_id with the required prefix. NB: If our
* prefix is too long, clip it - but there will be worse effects
* anyway, eg. the server could only possibly create 1 session
* ID (ie. the prefix!) so all future session negotiations will
* fail due to conflicts. */
memcpy(id, session_id_prefix,
(strlen(session_id_prefix) < *id_len) ?
strlen(session_id_prefix) : *id_len);
}
while(SSL_has_matching_session_id(ssl, id, *id_len) &&
do {
RAND_pseudo_bytes(id, *id_len);
/*
* Prefix the session_id with the required prefix. NB: If our
* prefix is too long, clip it - but there will be worse effects
* anyway, eg. the server could only possibly create 1 session
* ID (ie. the prefix!) so all future session negotiations will
* fail due to conflicts.
*/
memcpy(id, session_id_prefix,
(strlen(session_id_prefix) < *id_len) ?
strlen(session_id_prefix) : *id_len);
}
while (SSL_has_matching_session_id(ssl, id, *id_len) &&
(++count < MAX_SESSION_ID_ATTEMPTS));
if(count >= MAX_SESSION_ID_ATTEMPTS)
if (count >= MAX_SESSION_ID_ATTEMPTS)
return 0;
return 1;
}
}
=head1 RETURN VALUES
@@ -139,12 +125,15 @@ same id is already in the cache.
=head1 SEE ALSO
L<ssl(3)|ssl(3)>, L<SSL_get_version(3)|SSL_get_version(3)>
L<ssl(7)>, L<SSL_get_version(3)>
=head1 HISTORY
=head1 COPYRIGHT
SSL_CTX_set_generate_session_id(), SSL_set_generate_session_id()
and SSL_has_matching_session_id() have been introduced in
OpenSSL 0.9.7.
Copyright 2001-2016 The OpenSSL Project Authors. All Rights Reserved.
Licensed under the OpenSSL license (the "License"). You may not use
this file except in compliance with the License. You can obtain a copy
in the file LICENSE in the source distribution or at
L<https://www.openssl.org/source/license.html>.
=cut