---
name: "gnutls_srp_set_server_credentials_function"
section: "3"
platform: "linux"
package: "gnutls"
version: "3.8.13-3"
release: "Arch Linux 2026-11-01"
platforms: ["linux"]
url: "https://new.carta.tech/gnutls_srp_set_server_credentials_function"
---

# gnutls\_srp\_set\_server\_credentials\_function(3)

API function

## NAME

gnutls\_srp\_set\_server\_credentials\_function - API function

## SYNOPSIS

**#include \<gnutls/gnutls.h\>**

**void gnutls\_srp\_set\_server\_credentials\_function(gnutls\_srp\_server\_credentials\_t** *cred***, gnutls\_srp\_server\_credentials\_function \*** *func***);**

## ARGUMENTS

- gnutls\_srp\_server\_credentials\_t cred

  is a **gnutls\_srp\_server\_credentials\_t** type.

- gnutls\_srp\_server\_credentials\_function \* func

  is the callback function

## DESCRIPTION

This function can be used to set a callback to retrieve the user's SRP credentials.  The callback's function form is:

int (\*callback)(gnutls\_session\_t, const char\* username, gnutls\_datum\_t \*salt, gnutls\_datum\_t \*verifier, gnutls\_datum\_t \*generator, gnutls\_datum\_t \*prime);

 *username* contains the actual username. The  *salt* ,  *verifier* ,  *generator* and  *prime* must be filled in using the **gnutls\_malloc()**. For convenience  *prime* and  *generator* may also be one of the static parameters defined in gnutls.h.

Initially, the data field is NULL in every **gnutls\_datum\_t** structure that the callback has to fill in. When the callback is done GnuTLS deallocates all of those buffers which are non-NULL, regardless of the return value.

In order to prevent attackers from guessing valid usernames, if a user does not exist, g and n values should be filled in using a random user's parameters. In that case the callback must return the special value (1). See **gnutls\_srp\_set\_server\_fake\_salt\_seed** too. If this is not required for your application, return a negative number from the callback to abort the handshake.

The callback function will only be called once per handshake. The callback function should return 0 on success, while -1 indicates an error.

## REPORTING BUGS

Report bugs to \<bugs@gnutls.org\>.\
 Home page: https://www.gnutls.org

## COPYRIGHT

Copyright © 2001-2023 Free Software Foundation, Inc., and others.\
 Copying and distribution of this file, with or without modification, are permitted in any medium without royalty provided the copyright notice and this notice are preserved.

## SEE ALSO

The full documentation for **gnutls** is maintained as a Texinfo manual. If the /usr/share/doc/gnutls/ directory does not contain the HTML form visit

- https://www.gnutls.org/manual/