.\" $OpenBSD: SSL_CTX_set_default_passwd_cb.3,v 1.9 2023/09/19 09:40:35 schwarze Exp $ .\" full merge up to: OpenSSL 9b86974e Aug 17 15:21:33 2015 -0400 .\" selective merge up to: OpenSSL 18bad535 Apr 9 15:13:55 2019 +0100 .\" .\" This file is a derived work. .\" The changes are covered by the following Copyright and license: .\" .\" Copyright (c) 2023 Ingo Schwarze .\" .\" Permission to use, copy, modify, and distribute this software for any .\" purpose with or without fee is hereby granted, provided that the above .\" copyright notice and this permission notice appear in all copies. .\" .\" THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES .\" WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF .\" MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR .\" ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES .\" WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN .\" ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF .\" OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. .\" .\" The original file was written by Lutz Jaenicke .\" and Christian Heimes . .\" Copyright (c) 2000, 2001, 2016 The OpenSSL Project. All rights reserved. .\" .\" Redistribution and use in source and binary forms, with or without .\" modification, are permitted provided that the following conditions .\" are met: .\" .\" 1. Redistributions of source code must retain the above copyright .\" notice, this list of conditions and the following disclaimer. .\" .\" 2. Redistributions in binary form must reproduce the above copyright .\" notice, this list of conditions and the following disclaimer in .\" the documentation and/or other materials provided with the .\" distribution. .\" .\" 3. All advertising materials mentioning features or use of this .\" software must display the following acknowledgment: .\" "This product includes software developed by the OpenSSL Project .\" for use in the OpenSSL Toolkit. (http://www.openssl.org/)" .\" .\" 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to .\" endorse or promote products derived from this software without .\" prior written permission. For written permission, please contact .\" openssl-core@openssl.org. .\" .\" 5. Products derived from this software may not be called "OpenSSL" .\" nor may "OpenSSL" appear in their names without prior written .\" permission of the OpenSSL Project. .\" .\" 6. Redistributions of any form whatsoever must retain the following .\" acknowledgment: .\" "This product includes software developed by the OpenSSL Project .\" for use in the OpenSSL Toolkit (http://www.openssl.org/)" .\" .\" THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY .\" EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE .\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR .\" PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE OpenSSL PROJECT OR .\" ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, .\" SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT .\" NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; .\" LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) .\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, .\" STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) .\" ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED .\" OF THE POSSIBILITY OF SUCH DAMAGE. .\" .Dd $Mdocdate: September 19 2023 $ .Dt SSL_CTX_SET_DEFAULT_PASSWD_CB 3 .Os .Sh NAME .Nm SSL_CTX_set_default_passwd_cb , .Nm SSL_CTX_set_default_passwd_cb_userdata , .Nm SSL_CTX_get_default_passwd_cb , .Nm SSL_CTX_get_default_passwd_cb_userdata .Nd set or get passwd callback for encrypted PEM file handling .Sh SYNOPSIS .In openssl/ssl.h .Ft void .Fn SSL_CTX_set_default_passwd_cb "SSL_CTX *ctx" "pem_password_cb *cb" .Ft void .Fn SSL_CTX_set_default_passwd_cb_userdata "SSL_CTX *ctx" "void *userdata" .Ft pem_password_cb * .Fn SSL_CTX_get_default_passwd_cb "SSL_CTX *ctx" .Ft void * .Fn SSL_CTX_get_default_passwd_cb_userdata "SSL_CTX *ctx" .Sh DESCRIPTION .Fn SSL_CTX_set_default_passwd_cb sets the password callback for loading a certificate or private key from encrypted PEM format. In particular, the callback is used by .Xr SSL_CTX_use_certificate_file 3 , .Xr SSL_use_certificate_file 3 , .Xr SSL_CTX_use_certificate_chain_file 3 , .Xr SSL_use_certificate_chain_file 3 , .Xr SSL_CTX_use_certificate_chain_mem 3 , .Xr SSL_CTX_use_PrivateKey_file 3 , .Xr SSL_use_PrivateKey_file 3 , .Xr SSL_CTX_use_RSAPrivateKey_file 3 , and .Xr SSL_use_RSAPrivateKey_file 3 . .Pp The function pointer type of the .Fa cb argument is documented in the .Xr pem_password_cb 3 manual page. If .Fn SSL_CTX_set_default_passwd_cb is not called on .Fa ctx or if it is called with a .Fa cb argument of .Dv NULL , .Xr PEM_def_callback 3 is used instead. .Pp .Fn SSL_CTX_set_default_passwd_cb_userdata sets a pointer to the .Fa userdata which will be provided to the password callback on invocation. .Pp Since the .Fa cb passed to .Fn SSL_CTX_set_default_passwd_cb will only be used for reading and decryption and not for writing and encryption, the library will only call it with a .Fa verify argument of 0. .Pp If an application program only needs to read and decrypt one single private key, it can be practical to have the callback handle the password dialog interactively. This happens by default if neither .Fn SSL_CTX_set_default_passwd_cb nor .Fn SSL_CTX_set_default_passwd_cb_userdata is called. In that case, the library uses .Xr PEM_def_callback 3 with a .Fa userdata argument of .Dv NULL . .Pp If several keys have to be handled, it can be practical to ask for the password once, for example using .Xr UI_UTIL_read_pw_string 3 , then keep it in memory and use it several times by passing a pointer to it to .Fn SSL_CTX_set_default_passwd_cb_userdata . .Xr PEM_def_callback 3 is able to handle this case, too, so calling .Fn SSL_CTX_set_default_passwd_cb is not needed in this case either. .Pp Other items in PEM formatting (certificates) can also be encrypted; it is however atypical, as certificate information is considered public. .Sh RETURN VALUES .Fn SSL_CTX_get_default_passwd_cb returns a function pointer to the password callback currently set in .Fa ctx , or .Dv NULL if none is set. .Pp .Fn SSL_CTX_get_default_passwd_cb_userdata returns a pointer to the userdata currently set in .Fa ctx , or .Dv NULL if none is set. .Sh EXAMPLES The following example provides a subset of the functionality of .Xr PEM_def_callback 3 , except that .Xr PEM_def_callback 3 does not NUL-terminate and copies up to .Fa size rather than .Fa size No \- 1 bytes. It interprets .Fa userdata as a NUL-terminated string and copies it to the .Fa password buffer, truncating the copy if it does not fit. .Bd -literal int trivial_passwd_cb(char *password, int size, int verify, void *userdata) { strlcpy(password, userdata, size); return strlen(password); } .Ed .Sh SEE ALSO .Xr pem_password_cb 3 , .Xr ssl 3 , .Xr SSL_CTX_use_certificate 3 .Sh HISTORY .Fn SSL_CTX_set_default_passwd_cb first appeared in SSLeay 0.6.2 and has been available since .Ox 2.4 . .Pp .Fn SSL_CTX_set_default_passwd_cb_userdata first appeared in OpenSSL 0.9.4 and has been available since .Ox 2.6 . .Pp .Fn SSL_CTX_get_default_passwd_cb and .Fn SSL_CTX_get_default_passwd_cb_userdata first appeared in OpenSSL 1.1.0 and have been available since .Ox 6.3 .