From c1d8b5d1f7c3ae991e9dd5cff7857b1d133e73e8 Mon Sep 17 00:00:00 2001
From: guenther <guenther@openbsd.org>
Date: Fri, 2 Aug 2024 01:53:21 +0000
Subject: [PATCH] getentropy(2) is in POSIX-2024, so adjust the #include
 visibility, change the "too much" error to EINVAL, add GETENTROPY_MAX to
 <limits.h> (via sys/syslimits.h), and update the manpage.

ok deraadt@
---
 include/unistd.h          |  7 +++++--
 lib/libc/sys/getentropy.2 | 17 ++++++++++++-----
 sys/dev/rnd.c             |  7 ++++---
 sys/sys/syslimits.h       |  6 +++++-
 4 files changed, 26 insertions(+), 11 deletions(-)

diff --git a/include/unistd.h b/include/unistd.h
index 1fda33a9cda..04972072f96 100644
--- a/include/unistd.h
+++ b/include/unistd.h
@@ -1,4 +1,4 @@
-/*	$OpenBSD: unistd.h,v 1.109 2024/05/18 05:20:22 guenther Exp $ */
+/*	$OpenBSD: unistd.h,v 1.110 2024/08/02 01:53:21 guenther Exp $ */
 /*	$NetBSD: unistd.h,v 1.26.4.1 1996/05/28 02:31:51 mrg Exp $	*/
 
 /*-
@@ -471,6 +471,10 @@ int	symlinkat(const char *, int, const char *);
 int	unlinkat(int, const char *, int);
 #endif
 
+#if __POSIX_VISIBLE >= 202405 || __BSD_VISIBLE
+int	getentropy(void *, size_t);
+#endif
+
 #if __BSD_VISIBLE
 int	dup3(int, int, int);
 int	pipe2(int [2], int);
@@ -525,7 +529,6 @@ int	 setthrname(pid_t, const char *);
 void	 setusershell(void);
 int	 strtofflags(char **, u_int32_t *, u_int32_t *);
 int	 swapctl(int cmd, const void *arg, int misc);
-int	 getentropy(void *, size_t);
 int	 pledge(const char *, const char *);
 int	 unveil(const char *, const char *);
 pid_t	 __tfork_thread(const struct __tfork *, size_t, void (*)(void *),
diff --git a/lib/libc/sys/getentropy.2 b/lib/libc/sys/getentropy.2
index 3f4fb058a48..54320698e58 100644
--- a/lib/libc/sys/getentropy.2
+++ b/lib/libc/sys/getentropy.2
@@ -1,4 +1,4 @@
-.\"	$OpenBSD: getentropy.2,v 1.10 2022/02/06 00:29:02 jsg Exp $
+.\"	$OpenBSD: getentropy.2,v 1.11 2024/08/02 01:53:21 guenther Exp $
 .\"
 .\" Copyright (c) 2014 Theo de Raadt
 .\"
@@ -14,7 +14,7 @@
 .\" ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 .\" OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 .\"
-.Dd $Mdocdate: February 6 2022 $
+.Dd $Mdocdate: August 2 2024 $
 .Dt GETENTROPY 2
 .Os
 .Sh NAME
@@ -30,7 +30,9 @@ fills a buffer with high-quality entropy, which can be used
 as input for process-context pseudorandom generators like
 .Xr arc4random 3 .
 .Pp
-The maximum buffer size permitted is 256 bytes.
+The maximum buffer size permitted is
+.Dv GETENTROPY_MAX
+(256) bytes.
 .Pp
 .Fn getentropy
 is not intended for regular code; use the
@@ -51,11 +53,16 @@ The
 .Fa buf
 parameter points to an
 invalid address.
-.It Bq Er EIO
-Too many bytes requested, or some other fatal error occurred.
+.It Bq Er EINVAL
+Too many bytes requested.
 .El
 .Sh SEE ALSO
 .Xr arc4random 3
+.Sh STANDARDS
+The
+.Fn getentropy
+function conforms to
+.St -p1003.1-2024 .
 .Sh HISTORY
 The
 .Fn getentropy
diff --git a/sys/dev/rnd.c b/sys/dev/rnd.c
index 4ad4a73a0fc..259721d90c0 100644
--- a/sys/dev/rnd.c
+++ b/sys/dev/rnd.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: rnd.c,v 1.228 2024/06/14 10:17:05 claudio Exp $	*/
+/*	$OpenBSD: rnd.c,v 1.229 2024/08/02 01:53:21 guenther Exp $	*/
 
 /*
  * Copyright (c) 2011,2020 Theo de Raadt.
@@ -75,6 +75,7 @@
 #include <sys/msgbuf.h>
 #include <sys/mount.h>
 #include <sys/syscallargs.h>
+#include <sys/syslimits.h>
 
 #include <crypto/sha2.h>
 
@@ -814,11 +815,11 @@ sys_getentropy(struct proc *p, void *v, register_t *retval)
 		syscallarg(void *) buf;
 		syscallarg(size_t) nbyte;
 	} */ *uap = v;
-	char buf[256];
+	char buf[GETENTROPY_MAX];
 	int error;
 
 	if (SCARG(uap, nbyte) > sizeof(buf))
-		return (EIO);
+		return (EINVAL);
 	arc4random_buf(buf, SCARG(uap, nbyte));
 	if ((error = copyout(buf, SCARG(uap, buf), SCARG(uap, nbyte))) != 0)
 		return (error);
diff --git a/sys/sys/syslimits.h b/sys/sys/syslimits.h
index 4ebc656224b..d8c98a9ea59 100644
--- a/sys/sys/syslimits.h
+++ b/sys/sys/syslimits.h
@@ -1,4 +1,4 @@
-/*	$OpenBSD: syslimits.h,v 1.15 2022/02/22 16:58:08 deraadt Exp $	*/
+/*	$OpenBSD: syslimits.h,v 1.16 2024/08/02 01:53:21 guenther Exp $	*/
 /*	$NetBSD: syslimits.h,v 1.12 1995/10/05 05:26:19 thorpej Exp $	*/
 
 /*
@@ -76,4 +76,8 @@
 #define HOST_NAME_MAX		255	/* max hostname length w/o NUL */
 #endif
 
+#if __POSIX_VISIBLE >= 202405
+#define	GETENTROPY_MAX		  256	/* max bytes from getentropy(2) */
+#endif
+
 #define _MAXCOMLEN		24	/* includes NUL */
-- 
2.20.1