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[people/ms/ipfire-3.x.git] / glibc / patches / glibc-2.10.1-arc4random.patch

Submitted By: Robert Connolly <robert at linuxfromscratch dot org> (ashes)
Date: 2006-01-01
Initial Package Version: 2.3.6
Upstream Status: Not submitted
Origin: http://www.openbsd.org/cgi-bin/cvsweb/src/lib/libc/crypt/arc4random.c
Description: This patch adds the arc4random() and arc4randomII() functions
to Glibc, and hooks so mktemp(3) can use arc4randomII().

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

diff -Naur glibc-2.3.6.orig/manual/arc4random.3 glibc-2.3.6/manual/arc4random.3
--- glibc-2.3.6.orig/manual/arc4random.3	1970-01-01 00:00:00.000000000 +0000
+++ glibc-2.3.6/manual/arc4random.3	2006-01-01 07:48:48.000000000 +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 glibc-2.3.6.orig/stdlib/Makefile glibc-2.3.6/stdlib/Makefile
--- glibc-2.3.6.orig/stdlib/Makefile	2005-02-16 11:23:58.000000000 +0000
+++ glibc-2.3.6/stdlib/Makefile	2006-01-01 07:48:48.000000000 +0000
@@ -27,7 +27,7 @@
 
 routines	:=							      \
 	atof atoi atol atoll						      \
-	abort								      \
+	abort arc4random arc4randomII					      \
 	bsearch qsort msort						      \
 	getenv putenv setenv secure-getenv				      \
 	exit on_exit atexit cxa_atexit cxa_finalize old_atexit		      \
diff -Naur glibc-2.3.6.orig/stdlib/Versions glibc-2.3.6/stdlib/Versions
--- glibc-2.3.6.orig/stdlib/Versions	2004-05-03 21:25:53.000000000 +0000
+++ glibc-2.3.6/stdlib/Versions	2006-01-01 07:50:28.000000000 +0000
@@ -11,6 +11,8 @@
 
     # a*
     a64l; abort; abs; atexit; atof; atoi; atol; atoll;
+    arc4random_stir; arc4random_addrandom; arc4random;
+    arc4random_stirII; arc4random_addrandomII; arc4randomII;
 
     # b*
     bsearch;
diff -Naur glibc-2.3.6.orig/stdlib/arc4random.c glibc-2.3.6/stdlib/arc4random.c
--- glibc-2.3.6.orig/stdlib/arc4random.c	1970-01-01 00:00:00.000000000 +0000
+++ glibc-2.3.6/stdlib/arc4random.c	2006-01-01 07:48:48.000000000 +0000
@@ -0,0 +1,205 @@
+/*
+ * 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>
+#include <sys/sysctl.h>
+
+#ifdef __GNUC__
+#define inline __inline
+#else				/* !__GNUC__ */
+#define inline
+#endif				/* !__GNUC__ */
+
+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 = open("/dev/urandom", O_RDONLY);
+	if (fd != -1) {
+		read(fd, rdat.rnd, sizeof(rdat.rnd));
+		close(fd);
+	}
+
+#if defined(SYSCTL_URANDOM)
+	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 glibc-2.3.6.orig/stdlib/arc4randomII.c glibc-2.3.6/stdlib/arc4randomII.c
--- glibc-2.3.6.orig/stdlib/arc4randomII.c	1970-01-01 00:00:00.000000000 +0000
+++ glibc-2.3.6/stdlib/arc4randomII.c	2006-01-01 07:48:48.000000000 +0000
@@ -0,0 +1,196 @@
+/*
+ * 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>
+#include <sys/sysctl.h>
+
+#ifdef __GNUC__
+#define inline __inline
+#else				/* !__GNUC__ */
+#define inline
+#endif				/* !__GNUC__ */
+
+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 = open("/dev/erandom", O_RDONLY);
+	if (fd != -1) {
+		read(fd, rdat.rnd, sizeof(rdat.rnd));
+		close(fd);
+	}
+
+#if defined(SYSCTL_ERANDOM)
+	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 glibc-2.3.6.orig/stdlib/stdlib.h glibc-2.3.6/stdlib/stdlib.h
--- glibc-2.3.6.orig/stdlib/stdlib.h	2005-07-18 01:15:30.000000000 +0000
+++ glibc-2.3.6/stdlib/stdlib.h	2006-01-01 07:48:48.000000000 +0000
@@ -572,6 +572,15 @@
 extern int lcong48_r (unsigned short int __param[7],
 		      struct drand48_data *__buffer)
      __THROW __nonnull ((1, 2));
+
+#define LIBC_HAS_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	/* Use misc.  */
 #endif	/* Use SVID or X/Open.  */