Commit cf0891b8 authored by Kurt Roeckx's avatar Kurt Roeckx
Browse files

Look up availability of getentropy() at runtime. 



This will actually support most OSs, and at least adds support for
Solaris and OSX

Fixes: #6403
Reviewed-by: default avatarAndy Polyakov <appro@openssl.org>
GH: #6405
parent 8f576627

crypto/rand/rand_unix.c

+24 −5
Original line number Diff line number Diff line
@@ -15,6 +15,7 @@ 
#include "rand_lcl.h"

#include "internal/rand_int.h"

#include <stdio.h>

#include "internal/dso.h"

#if defined(__linux)

# include <sys/syscall.h>

#endif
@@ -242,10 +243,33 @@ static size_t sysctl_random(char *buf, size_t buflen) 
 */

int syscall_random(void *buf, size_t buflen)

{

    union {

        void *p;

        int (*f)(void *buffer, size_t length);

    } p_getentropy;



    /*

     * Do runtime detection to find getentropy().

     *

     * We could cache the result of the lookup, but we normally don't

     * call this function often.

     *

     * Known OSs that should support this:

     * - Darwin since 16 (OSX 10.12, IOS 10.0).

     * - Solaris since 11.3

     * - OpenBSD since 5.6

     * - Linux since 3.17 with glibc 2.25

     * - FreeBSD since 12.0 (1200061)

     */

    p_getentropy.p = DSO_global_lookup("getentropy");

    if (p_getentropy.p != NULL)

        return p_getentropy.f(buf, buflen);



#  if defined(OPENSSL_HAVE_GETRANDOM)

    return (int)getrandom(buf, buflen, 0);

#  endif



    /* Linux supports this since version 3.17 */

#  if defined(__linux) && defined(SYS_getrandom)

    return (int)syscall(SYS_getrandom, buf, buflen, 0);

#  endif
@@ -254,11 +278,6 @@ int syscall_random(void *buf, size_t buflen) 
    return (int)sysctl_random(buf, buflen);

#  endif



   /* Supported since OpenBSD 5.6 */

#  if defined(__OpenBSD__) && OpenBSD >= 201411

    return getentropy(buf, buflen);

#  endif



    return -1;

}