Attachment 730002 Details for Bug 1025068

[patch] Merge getrandom() and /dev/urandom usage in one function

U_Use-getentropy-if-arc4random_buf-is-not-available.patch.addon.new (text/plain), 2.18 KB, created by Stefan Dirsch on 2017-06-23 09:05:43 UTC

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Creator: Stefan Dirsch

Created: 2017-06-23 09:05:43 UTC

Size: 2.18 KB

patch

obsolete

>--- libICE-1.0.9.old/src/iceauth.c	2017-06-23 08:39:26.401109435 +0000
>+++ libICE-1.0.9/src/iceauth.c	2017-06-23 08:58:57.387743473 +0000
>@@ -40,6 +40,15 @@ Author: Ralph Mor, X Consortium
> #include <bsd/stdlib.h>	/* for arc4random_buf() */
> #endif
> 
>+#ifndef HAVE_GETENTROPY
>+#include <sys/types.h>
>+#include <sys/stat.h>
>+#include <fcntl.h>
>+#include <errno.h>
>+#include <linux/random.h>
>+#include <sys/syscall.h>
>+#endif
>+
> static int was_called_state;
> 
> #ifndef HAVE_ARC4RANDOM_BUF
>@@ -78,20 +87,85 @@ emulate_getrandom_buf (
>     }
> }
> 
>+#ifndef HAVE_GETENTROPY
>+static int 
>+emulate_getentropy
>+(
>+	void *buffer, 
>+	size_t length
>+)
>+{
>+    int random_fd = -1;
>+    int res;
>+    size_t filled = 0;
>+    int use_getrandom = 1;
>+
>+    if( length > 256 ) {
>+	errno = EIO;
>+	return -1;
>+    }
>+
>+    /* try getrandom() first */
>+    res = syscall(SYS_getrandom, (char*)buffer, length, 0);
>+
>+    if( (res == -1) && (errno == ENOSYS)) {
>+	/* fallback to /dev/urandrom */    
>+	random_fd = open("/dev/urandom", O_RDONLY | O_CLOEXEC);
>+
>+	if( random_fd == -1 ) {
>+	    return -1;
>+	}
>+
>+	/* use /dev/urandom further on */
>+	use_getrandom = 0;
>+    }
>+
>+    while( filled < length ) {
>+	if (use_getrandom) {
>+	    /*
>+	     * glibc does not contain a syscall wrapper for this in older
>+	     * versions
>+	    */
>+	    res = syscall(SYS_getrandom, (char*)buffer + filled, length - filled, 0);
>+	} else {
>+	    res = read(random_fd, (char*)buffer + filled, length - filled);
>+	}
>+
>+	if( res == -1 ) {
>+	    if( errno == EINTR )
>+		continue;
>+
>+	    return -1;
>+	} else if ( res == 0 ) {
>+	    // no more bytes available? should not happen
>+	    errno = EIO;
>+	    return -1;
>+	}
>+
>+	filled += res;
>+    }
>+
>+    return 0;
>+}
>+#endif
>+
> static void
> arc4random_buf (
> 	char *auth,
> 	int len
> )
> {
>-    int	    ret;
>+    int	    ret = -1;
> 
> #if HAVE_GETENTROPY
>     /* weak emulation of arc4random through the entropy libc */
>     ret = getentropy (auth, len);
>+#else 
>+    /* drop-in replacement for getentropy() using getrandom() or /dev/urandom directly */
>+    ret = emulate_getentropy(auth, len); 
>+#endif /* HAVE_GETENTROPY */
>     if (ret == 0)
> 	return;
>-#endif /* HAVE_GETENTROPY */
> 
>     emulate_getrandom_buf (auth, len);
> }

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Attachments on bug 1025068: 715740 | 715748 | 729646 | 729648 | 729649 | 729681 | 729683 | 730002 | 730193 | 730205 | 730212 | 730213 | 730361 | 730982 | 731944