crandom.c File Reference

Cryptographically strong random number generator. More...

#include <gpxe/crypto.h>
#include <stdlib.h>

Go to the source code of this file.

Functions
	FILE_LICENCE (GPL2_OR_LATER)
void	get_random_bytes (void *buf, size_t len)
	Get cryptographically strong random bytes.

---

Detailed Description

Cryptographically strong random number generator.

Currently the cryptographic part is not implemented, and this just uses random().

Definition in file crandom.c.

---

Function Documentation

FILE_LICENCE

(

GPL2_OR_LATER

)

void get_random_bytes	(	void *	buf,
		size_t	len
	)

Get cryptographically strong random bytes.

Parameters:

	buf	Buffer in which to store random bytes
	len	Number of random bytes to generate

WARNING: This function is currently underimplemented, and does not give numbers any stronger than random()!

Definition at line 41 of file crandom.c.

References random(), and u8.

Referenced by forcedeth_probe(), and wpa_handle_1_of_4().

{
        u8 *bufp = buf;

        /*
         * Somewhat arbitrarily, choose the 0x00FF0000-masked byte
         * returned by random() as having good entropy. PRNGs often
         * don't provide good entropy in lower bits, and the top byte
         * might show a pattern because of sign issues.
         */

        while ( len-- ) {
                *bufp++ = ( random() >> 16 ) & 0xFF;
        }
}