SSLCTXsetdefaultpasswdcb(3) OpenSSL SSLCTXsetdefaultpasswdcb(3)

NAME
       SSLCTXsetdefaultpasswdcb, SSLCTXsetdefaultpasswdcbuserdata -
       set passwd callback for encrypted PEM file handling

SYNOPSIS
        #include 

        void SSLCTXsetdefaultpasswdcb(SSLCTX *ctx, pempasswordcb *cb);
        void SSLCTXsetdefaultpasswdcbuserdata(SSLCTX *ctx, void *u);

        int pempasswdcb(char *buf, int size, int rwflag, void *userdata);

DESCRIPTION
       SSLCTXsetdefaultpasswdcb() sets the default password callback
       called when loading/storing a PEM certificate with encryption.

       SSLCTXsetdefaultpasswdcbuserdata() sets a pointer to uusseerrddaattaa
       which will be provided to the password callback on invocation.

       The pempasswdcb(), which must be provided by the application, hands
       back the password to be used during decryption. On invocation a pointer
       to uusseerrddaattaa is provided. The pempasswdcb must write the password into
       the provided buffer bbuuff which is of size ssiizzee. The actual length of the
       password must be returned to the calling function. rrwwffllaagg indicates
       whether the callback is used for reading/decryption (rwflag=0) or
       writing/encryption (rwflag=1).

NNOOTTEESS
       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 pempasswdcb() 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 uusseerrddaattaa
       storage and the pempasswdcb() only returns the password already
       stored.

       When asking for the password interactively, pempasswdcb() can use
       rrwwffllaagg 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.

RETURN VALUES
       SSLCTXsetdefaultpasswdcb() and
       SSLCTXsetdefaultpasswdcbuserdata() do not provide diagnostic
       information.

EEXXAAMMPPLLEESS
       The following example returns the password provided as uusseerrddaattaa 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 pempasswdcb(char *buf, int size, int rwflag, void *password)
        {
         strncpy(buf, (char *)(password), size);
         buf[size - 1] = '\0';
         return(strlen(buf));
        }

SEE ALSO
       ssl(3), SSLCTXusecertificate(3)



0.9.7l                            2001-07-11  SSLCTXsetdefaultpasswdcb(3)