1=pod 2 3=head1 NAME 4 5SSL_CTX_set_default_passwd_cb, SSL_CTX_set_default_passwd_cb_userdata, 6SSL_CTX_get_default_passwd_cb, SSL_CTX_get_default_passwd_cb_userdata, 7SSL_set_default_passwd_cb, SSL_set_default_passwd_cb_userdata, 8SSL_get_default_passwd_cb, SSL_get_default_passwd_cb_userdata - set or 9get passwd callback for encrypted PEM file handling 10 11=head1 SYNOPSIS 12 13 #include <openssl/ssl.h> 14 15 void SSL_CTX_set_default_passwd_cb(SSL_CTX *ctx, pem_password_cb *cb); 16 void SSL_CTX_set_default_passwd_cb_userdata(SSL_CTX *ctx, void *u); 17 pem_password_cb *SSL_CTX_get_default_passwd_cb(SSL_CTX *ctx); 18 void *SSL_CTX_get_default_passwd_cb_userdata(SSL_CTX *ctx); 19 20 void SSL_set_default_passwd_cb(SSL *s, pem_password_cb *cb); 21 void SSL_set_default_passwd_cb_userdata(SSL *s, void *u); 22 pem_password_cb *SSL_get_default_passwd_cb(SSL *s); 23 void *SSL_get_default_passwd_cb_userdata(SSL *s); 24 25=head1 DESCRIPTION 26 27SSL_CTX_set_default_passwd_cb() sets the default password callback called 28when loading/storing a PEM certificate with encryption. 29 30SSL_CTX_set_default_passwd_cb_userdata() sets a pointer to userdata, B<u>, 31which will be provided to the password callback on invocation. 32 33SSL_CTX_get_default_passwd_cb() returns a function pointer to the password 34callback currently set in B<ctx>. If no callback was explicitly set, the 35NULL pointer is returned. 36 37SSL_CTX_get_default_passwd_cb_userdata() returns a pointer to the userdata 38currently set in B<ctx>. If no userdata was explicitly set, the NULL pointer 39is returned. 40 41SSL_set_default_passwd_cb(), SSL_set_default_passwd_cb_userdata(), 42SSL_get_default_passwd_cb() and SSL_get_default_passwd_cb_userdata() perform 43the same function as their SSL_CTX counterparts, but using an SSL object. 44 45The password callback, which must be provided by the application, hands back the 46password to be used during decryption. 47On invocation a pointer to userdata 48is provided. The function must store the password into the provided buffer 49B<buf> which is of size B<size>. The actual length of the password must 50be returned to the calling function. B<rwflag> indicates whether the 51callback is used for reading/decryption (rwflag=0) or writing/encryption 52(rwflag=1). 53For more details, see L<pem_password_cb(3)>. 54 55=head1 NOTES 56 57When loading or storing private keys, a password might be supplied to 58protect the private key. The way this password can be supplied may depend 59on the application. If only one private key is handled, it can be practical 60to have the callback handle the password dialog interactively. If several 61keys have to be handled, it can be practical to ask for the password once, 62then keep it in memory and use it several times. In the last case, the 63password could be stored into the userdata storage and the 64callback only returns the password already stored. 65 66When asking for the password interactively, the callback can use 67B<rwflag> to check, whether an item shall be encrypted (rwflag=1). 68In this case the password dialog may ask for the same password twice 69for comparison in order to catch typos, that would make decryption 70impossible. 71 72Other items in PEM formatting (certificates) can also be encrypted, it is 73however not usual, as certificate information is considered public. 74 75=head1 RETURN VALUES 76 77These functions do not provide diagnostic information. 78 79=head1 EXAMPLES 80 81The following example returns the password provided as userdata to the 82calling function. The password is considered to be a '\0' terminated 83string. If the password does not fit into the buffer, the password is 84truncated. 85 86 int my_cb(char *buf, int size, int rwflag, void *u) 87 { 88 strncpy(buf, (char *)u, size); 89 buf[size - 1] = '\0'; 90 return strlen(buf); 91 } 92 93=head1 SEE ALSO 94 95L<ssl(7)>, 96L<SSL_CTX_use_certificate(3)> 97 98=head1 HISTORY 99 100SSL_CTX_get_default_passwd_cb(), SSL_CTX_get_default_passwd_cb_userdata(), 101SSL_set_default_passwd_cb() and SSL_set_default_passwd_cb_userdata() were 102added in OpenSSL 1.1.0. 103 104=head1 COPYRIGHT 105 106Copyright 2000-2019 The OpenSSL Project Authors. All Rights Reserved. 107 108Licensed under the OpenSSL license (the "License"). You may not use 109this file except in compliance with the License. You can obtain a copy 110in the file LICENSE in the source distribution or at 111L<https://www.openssl.org/source/license.html>. 112 113=cut 114