net/samba416: Patch to prevent abnormal smbd abort

Update a call to memcpy() because readdir() only guarantees memory up to
result+result->d_reclen is readable.  Under certain conditions,
result+sizeof(struct dirent) landed in unmapped memory.

Most of the legwork to pinpoint the problem, as well as a solution
similar to the one applied here, was submitted by uratan@miomio.jp.
Martin Simmons <martin@lispworks.com> contributed to understanding the
problem and wrote a useful test case.

PR:		275597
Approved by:	maintainer timeout
Sponsored by:	The FreeBSD Foundation
Differential Revision:	https://reviews.freebsd.org/D43171

net/samba416/Makefile

@@ -1,6 +1,6 @@
 PORTNAME=			${SAMBA4_BASENAME}416
 PORTVERSION=			${SAMBA4_VERSION}
-PORTREVISION=			3
+PORTREVISION=			4
 CATEGORIES?=			net
 MASTER_SITES=			SAMBA/samba/stable SAMBA/samba/rc
 DISTNAME=			${SAMBA4_DISTNAME}

net/samba416/files/patch-source3_modules_vfs__cap.c

@@ -0,0 +1,14 @@
+--- source3/modules/vfs_cap.c.orig	2022-01-24 10:26:59 UTC
++++ source3/modules/vfs_cap.c
+@@ -112,7 +112,10 @@ static struct dirent *cap_readdir(vfs_handle_struct *h
+ 		return NULL;
+ 	}
+ 	talloc_set_name_const(newdirent, "struct dirent");
+-	memcpy(newdirent, result, sizeof(struct dirent));
++	/* See FreeBSD bug #275597 for an explanation of this patch. */
++	/* memcpy(newdirent, result, sizeof(struct dirent)); */
++	memcpy(newdirent, result, result->d_reclen);
++	/*******************************************************************/
+ 	memcpy(&newdirent->d_name, newname, newnamelen);
+ 	return newdirent;
+ }