Submitted By: Robert Connolly <robert at linuxfromscratch dot org> (ashes)
Date: 2005-10-02
Initial Package Version: 0.9.28
Upstream Status: Submitted, declined
Origin: http://www.openbsd.org/cgi-bin/cvsweb/src/lib/libc/crypt/arc4random.c
Description: This patch adds the arc4random() and arc4randomII() functions
to uClibc, and hooks so mktemp(3) and SSP can use arc4randomII().

Also see:
http://www.linuxfromscratch.org/hlfs/
http://www.linuxfromscratch.org/hints/downloads/files/entropy.txt

diff -Naur uClibc-0.9.28.orig/extra/Configs/Config.in uClibc-0.9.28/extra/Configs/Config.in
--- uClibc-0.9.28.orig/extra/Configs/Config.in	2005-08-17 22:49:41.000000000 +0000
+++ uClibc-0.9.28/extra/Configs/Config.in	2005-09-12 04:04:55.000000000 +0000
@@ -1138,6 +1138,49 @@
 		libraries have to be built with -fPIC or -fpic, and all assembler
 		functions must be written as position independent code (PIC).
 
+config UCLIBC_HAS_ARC4RANDOM
+	bool "Add the arc4random() function to the library"
+	depends on UCLIBC_SECURITY
+	default n
+	help
+	  Answer Y to add the OpenBSD-like arc4random() function. arc4random()
+	  generates a pseudo-random number using the ARC4 key stream cipher.
+	  The arc4random() function is seeded automatically from /dev/urandom
+	  and can be in about (2**1700) states. gettimeofday(2) is always
+	  included when initializing the state, making it impossible to
+	  generate the same random sequence twice. arc4randomII() is identical
+	  to arc4random() except that erandom is used as the seed source.
+	  arc4random() is safe for an entropy source for cryptography, while
+	  arc4randomII() is suited for mktemp, and other functions with a short
+	  lifespan. This library is very small (approx. 2KB) and very fast.
+	  If you answer Y here, mktemp(3), and propolice stack protection, can
+	  use arc4randomII() for their entropy source.
+	  OpenSSL and OpenNTPD also support this function.
+	  Erandom requires a modified kernel. More informataion is on:
+	  http://frandom.sourceforge.net/
+	  and
+	  http://www.linuxfromscratch.org/hlfs/
+	  Most people will answer N.
+
+config MKTEMP_USE_ARC4RANDOM
+	bool "Use arc4randomII() in mktemp(3)"
+	depends on UCLIBC_HAS_ARC4RANDOM
+	default n
+	help
+	  Answer Y to use arc4randomII() as mktemp's (tempname.c) entropy source.
+	  This will save kernel entropy while making tempfiles unpredictable.
+	  Most people will answer N.
+
+config ARC4RANDOM_USE_SYSCTL
+	bool "Make arc4random() use sysctl if /dev is not accessible"
+	depends on UCLIBC_HAS_ARC4RANDOM
+	default n
+	help
+	  Answer Y to use sysctl only if /dev/*random fails (chroot).
+	  This requires a modified kernel.
+	  For more info see: http://www.linuxfromscratch.org/hlfs/
+	  Most people will answer N.
+
 config UCLIBC_HAS_SSP
 	bool "Support for propolice smashing stack protector"
 	depends on UCLIBC_SECURITY
@@ -1152,26 +1195,14 @@
 	  <http://www.research.ibm.com/trl/projects/security/ssp/>
 	  Most people will answer N.
 
-config SSP_QUICK_CANARY
-	bool "Use simple guard values without accessing /dev/urandom"
-	depends on UCLIBC_HAS_SSP
-	default n
-	help
-	  Use gettimeofday(2) to define the __guard without accessing
-	  /dev/urandom.
-	  WARNING: This makes smashing stack protector vulnerable to timing
-	  	attacks.
-	  Most people will answer N.
-
-config SSP_USE_ERANDOM
-	bool "Use erandom for setting guard value if /dev/urandom fails"
-	depends on UCLIBC_HAS_SSP && !SSP_QUICK_CANARY
+config SSP_USE_ARC4RANDOM
+	bool "Make propolice use arc4randomII()"
+	depends on UCLIBC_HAS_ARC4RANDOM
 	default n
 	help
-	  Use /dev/erandom to define the guard if /dev/urandom fails (chroot).
-	  This requires a modified kernel.
-	  More information at:
-	  <http://frandom.sourceforge.net/>
+	  Answer Y to use arc4randomII() as propolice's __guard entropy
+	  source. This will save kernel entropy while making __guard's value
+	  unpredictable.
 	  Most people will answer N.
 
 choice
diff -Naur uClibc-0.9.28.orig/include/stdlib.h uClibc-0.9.28/include/stdlib.h
--- uClibc-0.9.28.orig/include/stdlib.h	2005-08-17 22:49:41.000000000 +0000
+++ uClibc-0.9.28/include/stdlib.h	2005-09-12 04:04:55.000000000 +0000
@@ -449,7 +449,18 @@
 
 extern int lcong48_r (unsigned short int __param[7],
 		      struct drand48_data *__buffer) __THROW;
-# endif	/* Use misc.  */
+
+#if defined(__UCLIBC_HAS_ARC4RANDOM__)
+#define HAVE_ARC4RANDOM
+u_int32_t arc4random(void);
+void arc4random_stir(void);
+void arc4random_addrandom(unsigned char *, int);
+u_int32_t arc4randomII(void);
+void arc4random_stirII(void);
+void arc4random_addrandomII(unsigned char *, int);
+#endif
+
+# endif /* Use misc.  */
 #endif	/* Use SVID or X/Open.  */
 
 #endif /* don't just need malloc and calloc */
diff -Naur uClibc-0.9.28.orig/libc/misc/internals/tempname.c uClibc-0.9.28/libc/misc/internals/tempname.c
--- uClibc-0.9.28.orig/libc/misc/internals/tempname.c	2005-08-17 22:49:48.000000000 +0000
+++ uClibc-0.9.28/libc/misc/internals/tempname.c	2005-09-12 04:04:55.000000000 +0000
@@ -122,6 +122,7 @@
 static const char letters[] =
 "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789";
 
+#if !defined(__MKTEMP_USE_ARC4RANDOM__)
 static unsigned int fillrand(unsigned char *buf, unsigned int len)
 {
     int fd;
@@ -136,6 +137,7 @@
     }
     return result;
 }
+#endif
 
 static void brain_damaged_fillrand(unsigned char *buf, unsigned int len)
 {
@@ -193,10 +195,16 @@
     XXXXXX = &tmpl[len - 6];
 
     /* Get some random data.  */
+    #if defined(__MKTEMP_USE_ARC4RANDOM__)
+	for (i = 0 ; i < sizeof(randomness) ; i++) {
+	randomness[i] = (arc4randomII() % 62);
+	}
+    #else
 	if (fillrand(randomness, sizeof(randomness)) != sizeof(randomness)) {
 		/* if random device nodes failed us, lets use the braindamaged ver */
 		brain_damaged_fillrand(randomness, sizeof(randomness));
     }
+    #endif
     for (i = 0 ; i < sizeof(randomness) ; i++) {
 	k = ((randomness[i]) % 62);
 	XXXXXX[i] = letters[k];
diff -Naur uClibc-0.9.28.orig/libc/stdlib/Makefile uClibc-0.9.28/libc/stdlib/Makefile
--- uClibc-0.9.28.orig/libc/stdlib/Makefile	2005-08-17 22:49:41.000000000 +0000
+++ uClibc-0.9.28/libc/stdlib/Makefile	2005-09-12 04:04:55.000000000 +0000
@@ -90,6 +90,10 @@
 ifeq ($(UCLIBC_HAS_FLOATS),y)
 	CSRC += drand48.c drand48_r.c erand48.c erand48_r.c
 endif
+ifeq ($(UCLIBC_HAS_ARC4RANDOM),y)
+	CSRC += arc4random.c arc4randomII.c
+endif
+
 COBJS=$(patsubst %.c,%.o, $(CSRC))
 
 OBJS=$(MOBJ) $(MOBJx) $(MOBJ1) $(MOBJ1x) $(MOBJ2) $(COBJS)
diff -Naur uClibc-0.9.28.orig/libc/stdlib/arc4random.c uClibc-0.9.28/libc/stdlib/arc4random.c
--- uClibc-0.9.28.orig/libc/stdlib/arc4random.c	1970-01-01 00:00:00.000000000 +0000
+++ uClibc-0.9.28/libc/stdlib/arc4random.c	2005-09-12 04:04:55.000000000 +0000
@@ -0,0 +1,217 @@
+/*
+ * Arc4 random number generator for OpenBSD.
+ * Copyright 1996 David Mazieres <dm@lcs.mit.edu>.
+ *
+ * Modification and redistribution in source and binary forms is
+ * permitted provided that due credit is given to the author and the
+ * OpenBSD project by leaving this copyright notice intact.
+ */
+
+/*
+ * This code is derived from section 17.1 of Applied Cryptography,
+ * second edition, which describes a stream cipher allegedly
+ * compatible with RSA Labs "RC4" cipher (the actual description of
+ * which is a trade secret).  The same algorithm is used as a stream
+ * cipher called "arcfour" in Tatu Ylonen's ssh package.
+ *
+ * Here the stream cipher has been modified always to include the time
+ * when initializing the state.  That makes it impossible to
+ * regenerate the same random sequence twice, so this can't be used
+ * for encryption, but will generate good random numbers.
+ *
+ * RC4 is a registered trademark of RSA Laboratories.
+ */
+
+/*
+ * Modified by Robert Connolly from OpenBSD lib/libc/crypt/arc4random.c v1.11.
+ * This is arc4random(3) using urandom.
+ */
+
+#include <fcntl.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <sys/types.h>
+#include <sys/param.h>
+#include <sys/time.h>
+#if defined(__ARC4RANDOM_USE_SYSCTL__)
+#include <sys/sysctl.h>
+#endif
+
+#ifdef __GNUC__
+#define inline __inline
+#else				/* !__GNUC__ */
+#define inline
+#endif				/* !__GNUC__ */
+
+#ifdef __UCLIBC__
+extern int __libc_open(__const char *file, int flags, ...);
+extern ssize_t __libc_read(int fd, void *buf, size_t count);
+extern int __libc_close(int fd);
+#else
+# define __libc_open(file, flags) __open(file, flags)
+# define __libc_read(fd, buf, count) __read(fd, buf, count)
+# define __libc_close(fd) __close(fd)
+#endif
+
+struct arc4_stream {
+	u_int8_t i;
+	u_int8_t j;
+	u_int8_t s[256];
+};
+
+static int rs_initialized;
+static struct arc4_stream rs;
+static pid_t arc4_stir_pid;
+
+static inline u_int8_t arc4_getbyte(struct arc4_stream *);
+
+static inline void
+arc4_init(struct arc4_stream *as)
+{
+	int     n;
+
+	for (n = 0; n < 256; n++)
+		as->s[n] = n;
+	as->i = 0;
+	as->j = 0;
+}
+
+static inline void
+arc4_addrandom(struct arc4_stream *as, u_char *dat, int datlen)
+{
+	int     n;
+	u_int8_t si;
+
+	as->i--;
+	for (n = 0; n < 256; n++) {
+		as->i = (as->i + 1);
+		si = as->s[as->i];
+		as->j = (as->j + si + dat[n % datlen]);
+		as->s[as->i] = as->s[as->j];
+		as->s[as->j] = si;
+	}
+	as->j = as->i;
+}
+
+static void
+arc4_stir(struct arc4_stream *as)
+{
+	int     n, fd;
+	struct {
+		struct timeval tv;
+		u_int rnd[(128 - sizeof(struct timeval)) / sizeof(u_int)];
+	}       rdat;
+
+	gettimeofday(&rdat.tv, NULL);
+
+	/* /dev/urandom is a multithread interface, sysctl is not. */
+	/* Try to use /dev/urandom before sysctl. */
+	fd = __libc_open("/dev/urandom", O_RDONLY);
+	if (fd != -1) {
+		__libc_read(fd, rdat.rnd, sizeof(rdat.rnd));
+		__libc_close(fd);
+	}
+
+#if defined(__ARC4RANDOM_USE_SYSCTL__)
+	else {
+		/* /dev/urandom failed? Maybe we're in a chroot. */
+		int mib[]={CTL_KERN, KERN_RANDOM, RANDOM_URANDOM};
+		u_int i;
+		size_t len;
+
+		for (i = 0; i < sizeof(rdat.rnd) / sizeof(u_int); i ++) {
+			len = sizeof(u_int);
+			if (sysctl(mib, 3, &rdat.rnd[i], &len, NULL, 0) == -1)
+				break;
+		}
+	  if (i < sizeof(rdat.rnd) / 4) {
+	  /* Sysctl urandom failed? Maybe we're running a vanilla kernel. */
+		mib[2] = RANDOM_UUID;
+		for (i = 0; i < sizeof(rdat.rnd) / sizeof(u_int); i ++) {
+			len = sizeof(u_int);
+			if (sysctl(mib, 3, &rdat.rnd[i], &len, NULL, 0) == -1)
+				break;
+		}
+	  }
+	}
+#endif
+
+	arc4_stir_pid = getpid();
+	/*
+	 * Time to give up. If no entropy could be found then we will just
+	 * use gettimeofday.
+	 */
+	arc4_addrandom(as, (void *)&rdat, sizeof(rdat));
+
+	/*
+	 * Discard early keystream, as per recommendations in:
+	 * http://www.wisdom.weizmann.ac.il/~itsik/RC4/Papers/Rc4_ksa.ps
+	 * We discard 256 words. A long word is 4 bytes.
+	 */
+	for (n = 0; n < 256 * 4; n ++)
+		arc4_getbyte(as);
+}
+
+static inline u_int8_t
+arc4_getbyte(struct arc4_stream *as)
+{
+	u_int8_t si, sj;
+
+	as->i = (as->i + 1);
+	si = as->s[as->i];
+	as->j = (as->j + si);
+	sj = as->s[as->j];
+	as->s[as->i] = sj;
+	as->s[as->j] = si;
+	return (as->s[(si + sj) & 0xff]);
+}
+
+static inline u_int32_t
+arc4_getword(struct arc4_stream *as)
+{
+	u_int32_t val;
+	val = arc4_getbyte(as) << 24;
+	val |= arc4_getbyte(as) << 16;
+	val |= arc4_getbyte(as) << 8;
+	val |= arc4_getbyte(as);
+	return val;
+}
+
+void
+arc4random_stir(void)
+{
+	if (!rs_initialized) {
+		arc4_init(&rs);
+		rs_initialized = 1;
+	}
+	arc4_stir(&rs);
+}
+
+void
+arc4random_addrandom(u_char *dat, int datlen)
+{
+	if (!rs_initialized)
+		arc4random_stir();
+	arc4_addrandom(&rs, dat, datlen);
+}
+
+u_int32_t
+arc4random(void)
+{
+	if (!rs_initialized || arc4_stir_pid != getpid())
+		arc4random_stir();
+	return arc4_getword(&rs);
+}
+
+#if 0
+/*-------- Test code --------*/
+#include <stdlib.h>
+#include <stdio.h>
+
+int main(void) {
+	int random_number;
+	random_number = arc4random() % 65536;
+	printf("A random number between 0 and 65536 is %d\n", random_number);
+	return 0;
+}
+#endif
diff -Naur uClibc-0.9.28.orig/libc/stdlib/arc4randomII.c uClibc-0.9.28/libc/stdlib/arc4randomII.c
--- uClibc-0.9.28.orig/libc/stdlib/arc4randomII.c	1970-01-01 00:00:00.000000000 +0000
+++ uClibc-0.9.28/libc/stdlib/arc4randomII.c	2005-09-12 04:04:55.000000000 +0000
@@ -0,0 +1,208 @@
+/*
+ * Arc4 random number generator for OpenBSD.
+ * Copyright 1996 David Mazieres <dm@lcs.mit.edu>.
+ *
+ * Modification and redistribution in source and binary forms is
+ * permitted provided that due credit is given to the author and the
+ * OpenBSD project by leaving this copyright notice intact.
+ */
+
+/*
+ * This code is derived from section 17.1 of Applied Cryptography,
+ * second edition, which describes a stream cipher allegedly
+ * compatible with RSA Labs "RC4" cipher (the actual description of
+ * which is a trade secret).  The same algorithm is used as a stream
+ * cipher called "arcfour" in Tatu Ylonen's ssh package.
+ *
+ * Here the stream cipher has been modified always to include the time
+ * when initializing the state.  That makes it impossible to
+ * regenerate the same random sequence twice, so this can't be used
+ * for encryption, but will generate good random numbers.
+ *
+ * RC4 is a registered trademark of RSA Laboratories.
+ */
+
+/*
+ * Modified by Robert Connolly from OpenBSD lib/libc/crypt/arc4random.c v1.11.
+ * This is arc4randomII(3) using erandom.
+ */
+
+#include <fcntl.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <sys/types.h>
+#include <sys/param.h>
+#include <sys/time.h>
+#if defined(__ARC4RANDOM_USE_SYSCTL__)
+#include <sys/sysctl.h>
+#endif
+
+#ifdef __GNUC__
+#define inline __inline
+#else				/* !__GNUC__ */
+#define inline
+#endif				/* !__GNUC__ */
+
+#ifdef __UCLIBC__
+extern int __libc_open(__const char *file, int flags, ...);
+extern ssize_t __libc_read(int fd, void *buf, size_t count);
+extern int __libc_close(int fd);
+#else
+# define __libc_open(file, flags) __open(file, flags)
+# define __libc_read(fd, buf, count) __read(fd, buf, count)
+# define __libc_close(fd) __close(fd)
+#endif
+
+struct arc4_streamII {
+	u_int8_t i;
+	u_int8_t j;
+	u_int8_t s[256];
+};
+
+static int rs_initializedII;
+static struct arc4_streamII rs;
+static pid_t arc4_stir_pidII;
+
+static inline u_int8_t arc4_getbyteII(struct arc4_streamII *);
+
+static inline void
+arc4_initII(struct arc4_streamII *as)
+{
+	int     n;
+
+	for (n = 0; n < 256; n++)
+		as->s[n] = n;
+	as->i = 0;
+	as->j = 0;
+}
+
+static inline void
+arc4_addrandomII(struct arc4_streamII *as, u_char *dat, int datlen)
+{
+	int     n;
+	u_int8_t si;
+
+	as->i--;
+	for (n = 0; n < 256; n++) {
+		as->i = (as->i + 1);
+		si = as->s[as->i];
+		as->j = (as->j + si + dat[n % datlen]);
+		as->s[as->i] = as->s[as->j];
+		as->s[as->j] = si;
+	}
+	as->j = as->i;
+}
+
+static void
+arc4_stirII(struct arc4_streamII *as)
+{
+	int     n, fd;
+	struct {
+		struct timeval tv;
+		u_int rnd[(128 - sizeof(struct timeval)) / sizeof(u_int)];
+	}       rdat;
+
+	gettimeofday(&rdat.tv, NULL);
+
+	/* /dev/urandom is a multithread interface, sysctl is not. */
+	/* Try to use /dev/urandom before sysctl. */
+	fd = __libc_open("/dev/erandom", O_RDONLY);
+	if (fd != -1) {
+		__libc_read(fd, rdat.rnd, sizeof(rdat.rnd));
+		__libc_close(fd);
+	}
+
+#if defined(__ARC4RANDOM_USE_SYSCTL__)
+	else {
+		/* /dev/urandom failed? Maybe we're in a chroot. */
+		int mib[]={CTL_KERN, KERN_RANDOM, RANDOM_ERANDOM};
+		u_int i;
+		size_t len;
+
+		for (i = 0; i < sizeof(rdat.rnd) / sizeof(u_int); i++) {
+			len = sizeof(u_int);
+			if (sysctl(mib, 3, &rdat.rnd[i], &len, NULL, 0) == -1)
+				break;
+		}
+	}
+#endif
+
+	arc4_stir_pidII = getpid();
+	/*
+	 * Time to give up. If no entropy could be found then we will just
+	 * use gettimeofday.
+	 */
+	arc4_addrandomII(as, (void *)&rdat, sizeof(rdat));
+
+	/*
+	 * Discard early keystream, as per recommendations in:
+	 * http://www.wisdom.weizmann.ac.il/~itsik/RC4/Papers/Rc4_ksa.ps
+	 * We discard 256 words. A long word is 4 bytes.
+	 */
+	for (n = 0; n < 256 * 4; n ++)
+		arc4_getbyteII(as);
+}
+
+static inline u_int8_t
+arc4_getbyteII(struct arc4_streamII *as)
+{
+	u_int8_t si, sj;
+
+	as->i = (as->i + 1);
+	si = as->s[as->i];
+	as->j = (as->j + si);
+	sj = as->s[as->j];
+	as->s[as->i] = sj;
+	as->s[as->j] = si;
+	return (as->s[(si + sj) & 0xff]);
+}
+
+static inline u_int32_t
+arc4_getwordII(struct arc4_streamII *as)
+{
+	u_int32_t val;
+	val = arc4_getbyteII(as) << 24;
+	val |= arc4_getbyteII(as) << 16;
+	val |= arc4_getbyteII(as) << 8;
+	val |= arc4_getbyteII(as);
+	return val;
+}
+
+void
+arc4random_stirII(void)
+{
+	if (!rs_initializedII) {
+		arc4_initII(&rs);
+		rs_initializedII = 1;
+	}
+	arc4_stirII(&rs);
+}
+
+void
+arc4random_addrandomII(u_char *dat, int datlen)
+{
+	if (!rs_initializedII)
+		arc4random_stirII();
+	arc4_addrandomII(&rs, dat, datlen);
+}
+
+u_int32_t
+arc4randomII(void)
+{
+	if (!rs_initializedII || arc4_stir_pidII != getpid())
+		arc4random_stirII();
+	return arc4_getwordII(&rs);
+}
+
+#if 0
+/*-------- Test code --------*/
+#include <stdlib.h>
+#include <stdio.h>
+
+int main(void) {
+	int random_number;
+	random_number = arc4randomII() % 65536;
+	printf("A random number between 0 and 65536 is %d\n", random_number);
+	return 0;
+}
+#endif
diff -Naur uClibc-0.9.28.orig/libc/stdlib/man/arc4random.3 uClibc-0.9.28/libc/stdlib/man/arc4random.3
--- uClibc-0.9.28.orig/libc/stdlib/man/arc4random.3	1970-01-01 00:00:00.000000000 +0000
+++ uClibc-0.9.28/libc/stdlib/man/arc4random.3	2005-09-12 04:04:55.000000000 +0000
@@ -0,0 +1,74 @@
+.TH ARC4RANDOM 3 "February 11, 2005"
+.SH NAME
+arc4random - arc4 random number generator
+.SH SYNOPSIS 
+.nf
+.B #include <stdlib.h>
+.sp
+.I u_int32_t
+.B arc4random(void);
+.sp
+.I u_int32_t
+.B arc4randomII(void);
+.fi
+.SH DESCRIPTION 
+The \fBarc4random()\fP function generates a pseudo-random number using the
+ARC4 cipher key stream generator. ARCFOUR uses 8*8 8 bit S-Boxes, and can
+be in about (2**1700) states.
+
+The \fBarc4random()\fP function is seeded automatically from /dev/urandom,
+or from sysctl \fBurandom\fP if /dev/urandom is not accessible (chroot), or from
+sysctl random.uuid if sysctl \fBurandom\fP is not accessible. \fBgettimeofday(2)\fP
+is always included when initializing the state of \fBarc4random()\fP, this makes
+it impossible to generate the same random sequence twice. \fBarc4random()\fP
+is intended to be safe to use with encryption software to provide entropy.
+
+The \fBarc4randomII()\fP function is identical to \fBarc4random()\fP except
+that \fBarc4randomII()\fP is seeded automatically from /dev/erandom, and
+sysctl erandom. \fBarc4randomII()\fP is NOT intended for cryptography, but is
+ideal for \fBmktemp(3)\fP, and other functions with a short lifespan.
+\fBarc4randomII()\fP and erandom do not consume any kernel entropy.
+
+Sysctl urandom, and erandom require a modified kernel. See:
+http://www.linuxfromscratch.org/hlfs/
+
+.SH EXAMPLES
+.TP 
+Return a random number between 0 and 100.
+.sp
+arc4random() % 100;
+.TP
+Return any random number.
+.sp
+arc4random();
+.TP
+.nf
+Sample program; this will display a number between 0 and 65536.
+
+#include <stdlib.h>
+#include <stdio.h>
+
+int main(void) {
+    int random_number;
+    random_number = arc4random() % 65536;
+    printf("%d\n", random_number);
+    return 0;
+}
+.fi
+.SH "SEE ALSO"
+.BR random (3),
+.BR gettimeofday (2),
+.BR mktemp (3)
+
+.SH HISTORY
+An algorithm called RC4 was designed by RSA Data Security, Inc.  It was
+considered a trade secret, but not trademarked.  Because it was a trade
+secret, it obviously could not be patented.  A clone of this was posted
+anonymously to USENET and confirmed to be equivalent by several sources
+who had access to the original cipher.  Because of the trade secret situation,
+RSA Data Security, Inc. can do nothing about the release of the
+ARC4 algorithm.  Since RC4 used to be a trade secret, the cipher is now
+referred to as ARC4 (Another RC4).
+
+These functions first appeared in OpenBSD 2.1.
+
diff -Naur uClibc-0.9.28.orig/libc/sysdeps/linux/common/ssp.c uClibc-0.9.28/libc/sysdeps/linux/common/ssp.c
--- uClibc-0.9.28.orig/libc/sysdeps/linux/common/ssp.c	2005-08-17 22:49:42.000000000 +0000
+++ uClibc-0.9.28/libc/sysdeps/linux/common/ssp.c	2005-09-12 04:06:31.000000000 +0000
@@ -16,16 +16,15 @@
  *
  */
 
-#ifdef HAVE_CONFIG_H
-# include <config.h>
-#endif
-
 #ifdef __SSP__
 # error ssp.c has to be built w/ -fno-stack-protector
 #endif
 
 #include <stdio.h>
 #include <string.h>
+#if defined(__SSP_USE_ARC4RANDOM__)
+#include <stdlib.h> /* For arc4random() */
+#endif
 #include <fcntl.h>
 #include <unistd.h>
 #include <signal.h>
@@ -33,9 +32,6 @@
 #include <sys/un.h>
 #include <sys/syslog.h>
 #include <sys/time.h>
-#ifdef __SSP_USE_ERANDOM__
-# include <sys/sysctl.h>
-#endif
 
 #ifdef __PROPOLICE_BLOCK_SEGV__
 # define SSP_SIGTYPE SIGSEGV
@@ -65,7 +61,9 @@
 void __guard_setup(void) __attribute__ ((constructor));
 void __guard_setup(void)
 {
-	size_t size;
+	int     i=0;
+	size_t  size;
+	struct  timeval tv;
 
 	if (__guard != 0UL)
 		return;
@@ -73,48 +71,26 @@
 	/* Start with the "terminator canary". */
 	__guard = 0xFF0A0D00UL;
 
-#ifndef __SSP_QUICK_CANARY__
-# ifdef __SSP_USE_ERANDOM__
-	{
-		int mib[3];
-		/* Random is another depth in Linux, hence an array of 3. */
-		mib[0] = CTL_KERN;
-		mib[1] = KERN_RANDOM;
-		mib[2] = RANDOM_ERANDOM;
+	/* Then with the time. */
+	gettimeofday(&tv, NULL);
+	__guard ^= tv.tv_usec ^ tv.tv_sec;
 
+#if defined(__SSP_USE_ARC4RANDOM__)
+	for (i = 0; i < sizeof(__guard) / 4; i ++) {
 		size = sizeof(unsigned long);
-		if (__sysctl(mib, 3, &__guard, &size, NULL, 0) != (-1))
-			if (__guard != 0UL)
-				return;
+		if ((__guard = (int)(arc4randomII())) == (-1))
+			break;
 	}
-# endif /* ifdef __SSP_USE_ERANDOM__ */
-	/* 
-	 * Attempt to open kernel pseudo random device if one exists before 
-	 * opening urandom to avoid system entropy depletion.
-	 */
-	{
-		int fd;
-
-# ifdef __SSP_USE_ERANDOM__
-		if ((fd = __libc_open("/dev/erandom", O_RDONLY)) == (-1))
-# endif
-			fd = __libc_open("/dev/urandom", O_RDONLY);
+#else
+	int	fd=0;
+	if (i < sizeof(__guard) / 4) {
+		fd = __libc_open("/dev/urandom", O_RDONLY);
 		if (fd != (-1)) {
 			size = __libc_read(fd, (char *) &__guard, sizeof(__guard));
-			__libc_close(fd);
-			if (size == sizeof(__guard))
-				return;
-		}
-	}
-#endif /* ifndef __SSP_QUICK_CANARY__ */
-
-	/* Everything failed? Or we are using a weakened model of the 
-	 * terminator canary */
-	{
-		struct timeval tv;
-		gettimeofday(&tv, NULL);
-		__guard ^= tv.tv_usec ^ tv.tv_sec;
-	}
+				__libc_close(fd);
+		if (size == sizeof(__guard))
+			return;
+#endif
 }
 
 void __stack_smash_handler(char func[], int damaged __attribute__ ((unused)));
