Attachment 730759 Details for Bug 1025084

[patch] Proposal for pure getentropy() patch (without fallbacks to getrandom() / dev/urandom)

diff (text/plain), 1.82 KB, created by Stefan Dirsch on 2017-06-29 14:49:54 UTC

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Creator: Stefan Dirsch

Created: 2017-06-29 14:49:54 UTC

Size: 1.82 KB

patch

obsolete

>--- xorg-server-1.19.3.old/configure.ac	2017-06-29 14:26:49.799533369 +0000
>+++ xorg-server-1.19.3/configure.ac	2017-06-29 14:27:38.884491476 +0000
>@@ -226,7 +226,7 @@
> AM_CONDITIONAL(POLL, [test "x$ac_cv_func_poll" = "xyes"])
> 
> AC_CHECK_LIB([bsd], [arc4random_buf])
>-AC_CHECK_FUNCS([arc4random_buf])
>+AC_CHECK_FUNCS([arc4random_buf getentropy])
> 
> AC_CHECK_DECLS([program_invocation_short_name], [], [], [[#include <errno.h>]])
> 
>--- xorg-server-1.19.3.old/include/dix-config.h.in	2017-06-29 14:26:49.859534541 +0000
>+++ xorg-server-1.19.3/include/dix-config.h.in	2017-06-29 14:27:38.884491476 +0000
>@@ -167,6 +167,9 @@
> /* Define to 1 if you have the `arc4random_buf' function. */
> #undef HAVE_ARC4RANDOM_BUF
> 
>+/* Define to 1 if you have the `getentropy' function. */
>+#undef HAVE_GETENTROPY
>+
> /* Define to use libc SHA1 functions */
> #undef HAVE_SHA1_IN_LIBC
> 
>--- xorg-server-1.19.3.old/os/auth.c	2017-06-29 14:26:49.935536025 +0000
>+++ xorg-server-1.19.3/os/auth.c	2017-06-29 14:27:38.884491476 +0000
>@@ -302,18 +302,44 @@
>     return -1;
> }
> 
>-void
>-GenerateRandomData(int len, char *buf)
>+#ifndef HAVE_ARC4RANDOM_BUF
>+
>+static void
>+emulate_getrandom_buf (
>+	char *auth,
>+	int len
>+)
> {
>-#ifdef HAVE_ARC4RANDOM_BUF
>-    arc4random_buf(buf, len);
>-#else
>     int fd;
> 
>     fd = open("/dev/urandom", O_RDONLY);
>     read(fd, buf, len);
>     close(fd);
>-#endif
>+}
>+
>+static void
>+arc4random_buf (
>+	char *auth,
>+	int len
>+)
>+{
>+    int            ret;
>+
>+#if HAVE_GETENTROPY
>+    /* weak emulation of arc4random through the entropy libc */
>+    ret = getentropy (auth, len);
>+    if (ret == 0)
>+	return;
>+#endif /* HAVE_GETENTROPY */
>+
>+    emulate_getrandom_buf (auth, len);
>+}
>+#endif /* !defined(HAVE_ARC4RANDOM_BUF) */
>+
>+void
>+GenerateRandomData(int len, char *buf)
>+{
>+    arc4random_buf(buf, len);
> }
> 
> #endif                          /* XCSECURITY */

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Attachments on bug 1025084: 730759 | 730907 | 731000 | 732617