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SSL_CTX_set_default_passwd_cb(3)
NAME
  SSL_CTX_set_default_passwd_cb, SSL_CTX_set_default_passwd_cb_userdata - Set
  password callback for encrypted PEM file handling

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 );

DESCRIPTION
  The SSL_CTX_set_default_passwd_cb() function sets the default password
  callback called when loading or storing a PEM certificate with encryption.

  The SSL_CTX_set_default_passwd_cb_userdata() function sets a pointer to
  userdata which will be provided to the password callback on invocation.

  The pem_passwd_cb() function, which must be provided by the application,
  hands back the password to be used during decryption.	 On invocation a
  pointer to userdata is provided. The pem_passwd_cb() must write the
  password into the provided buffer buf which is of size size. The actual
  length of the password must be returned to the calling function. The
  <literal role="strong">rwflag indicates whether the callback is used for
  reading/decryption (rwflag=0) or writing/encryption (rwflag=1).

NOTES
  When loading or storing private keys, a password might be supplied to
  protect the private key. The way this password can be supplied might 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 userdata storage and the
  pem_passwd_cb() only returns the password already stored.

  When asking for the password interactively, pem_passwd_cb() can use rwflag
  to check whether an item shall be encrypted (rwflag=3D1).  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
  not usual, as certificate information is considered public.

RETURN VALUES
  The SSL_CTX_set_default_passwd_cb() and
  SSL_CTX_set_default_passwd_cb_userdata() functions do not provide
  diagnostic information.

EXAMPLES
  The following example returns the password provided as 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));
	}

SEE ALSO
  Functions: ssl(3), SSL_CTX_use_certificate(3)

Index for Section 3

Alphabetical listing for S

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