diff options
Diffstat (limited to 'openssl/doc/ssl/SSL_CTX_set_default_passwd_cb.pod')
-rw-r--r-- | openssl/doc/ssl/SSL_CTX_set_default_passwd_cb.pod | 76 |
1 files changed, 76 insertions, 0 deletions
diff --git a/openssl/doc/ssl/SSL_CTX_set_default_passwd_cb.pod b/openssl/doc/ssl/SSL_CTX_set_default_passwd_cb.pod new file mode 100644 index 000000000..2b87f01ca --- /dev/null +++ b/openssl/doc/ssl/SSL_CTX_set_default_passwd_cb.pod @@ -0,0 +1,76 @@ +=pod + +=head1 NAME + +SSL_CTX_set_default_passwd_cb, SSL_CTX_set_default_passwd_cb_userdata - set passwd callback for encrypted PEM file handling + +=head1 SYNOPSIS + + #include <openssl/ssl.h> + + void SSL_CTX_set_default_passwd_cb(SSL_CTX *ctx, pem_password_cb *cb); + void SSL_CTX_set_default_passwd_cb_userdata(SSL_CTX *ctx, void *u); + + int pem_passwd_cb(char *buf, int size, int rwflag, void *userdata); + +=head1 DESCRIPTION + +SSL_CTX_set_default_passwd_cb() sets the default password callback called +when loading/storing a PEM certificate with encryption. + +SSL_CTX_set_default_passwd_cb_userdata() sets a pointer to B<userdata> which +will be provided to the password callback on invocation. + +The pem_passwd_cb(), which must be provided by the application, hands back the +password to be used during decryption. On invocation a pointer to B<userdata> +is provided. The pem_passwd_cb must write the password into the provided buffer +B<buf> which is of size B<size>. The actual length of the password must +be returned to the calling function. B<rwflag> indicates whether the +callback is used for reading/decryption (rwflag=0) or writing/encryption +(rwflag=1). + +=head1 NOTES + +When loading or storing private keys, a password might be supplied to +protect the private key. The way this password can be supplied may depend +on the application. If only one private key is handled, it can be practical +to have pem_passwd_cb() handle the password dialog interactively. If several +keys have to be handled, it can be practical to ask for the password once, +then keep it in memory and use it several times. In the last case, the +password could be stored into the B<userdata> storage and the +pem_passwd_cb() only returns the password already stored. + +When asking for the password interactively, pem_passwd_cb() can use +B<rwflag> to check, whether an item shall be encrypted (rwflag=1). +In this case the password dialog may ask for the same password twice +for comparison in order to catch typos, that would make decryption +impossible. + +Other items in PEM formatting (certificates) can also be encrypted, it is +however not usual, as certificate information is considered public. + +=head1 RETURN VALUES + +SSL_CTX_set_default_passwd_cb() and SSL_CTX_set_default_passwd_cb_userdata() +do not provide diagnostic information. + +=head1 EXAMPLES + +The following example returns the password provided as B<userdata> to the +calling function. The password is considered to be a '\0' terminated +string. If the password does not fit into the buffer, the password is +truncated. + + int pem_passwd_cb(char *buf, int size, int rwflag, void *password) + { + strncpy(buf, (char *)(password), size); + buf[size - 1] = '\0'; + return(strlen(buf)); + } + +=head1 SEE ALSO + +L<ssl(3)|ssl(3)>, +L<SSL_CTX_use_certificate(3)|SSL_CTX_use_certificate(3)> + +=cut |