From d9f3a2c6639e694c8d6fc4ad00d6a37d6e1f9bf6 Mon Sep 17 00:00:00 2001
From: Cheyenne Wills <cwills@sinenomine.net>
Date: Mon, 11 Mar 2024 09:05:33 -0600
Subject: [PATCH] Linux 6.8: Use roken's strlcpy() in kernel module

The Linux 6.8 commit 'string: Remove strlcpy()' (d26270061a) removed the
the strlcpy function from the Linux kernel.  The replacement function,
strscpy(), cannot be used as a drop-in replacement as its currently a
Linux kernel specific function and there are differences in the returned
value.

We can use roken's strlcpy() (provided in roken/strlcpy.c).

Create a configure test to that defines its own strlcpy() to test
if the kernel doesn't provide one itself. Note, we need to use a
different function signature for strlcpy() from what the kernel might
have otherwise the test build succeeds when the kernel does provide a
strlcpy().

Update the OpenAFS kernel specific roken.h to define the prototype for
strlcpy when it's not present in the Linux kernel.  We need to match the
defines used in the 'real' roken.h so the roken/strlcpy.c can build
properly. Add defines for ROKEN_LIB_FUNCTION, ROKEN_LIB_CALL and
ROKEN_LIB_VARIABLE to the kernel roken.h

Update Linux's osi_machdep.h to include roken.h so the strlcpy protoype
is available.

Update the Linux MakefileProto to include the strcpy-kernel object
when building the kernel module.

Reviewed-on: https://gerrit.openafs.org/15646
Tested-by: BuildBot <buildbot@rampaginggeek.com>
Reviewed-by: Benjamin Kaduk <kaduk@mit.edu>
(cherry picked from commit 30b18c165752e6d0ce7b6daa6a90453f5e5e6d17)

Change-Id: I8013623e8f735d15bb7d4ac84ed0867f12b77783
---

diff --git a/src/afs/LINUX/osi_machdep.h b/src/afs/LINUX/osi_machdep.h
index 916a1df..263c863 100644
--- a/src/afs/LINUX/osi_machdep.h
+++ b/src/afs/LINUX/osi_machdep.h
@@ -77,6 +77,7 @@
 #endif
 
 #include "afs/sysincludes.h"
+#include "roken.h"
 
 #if !defined(HAVE_LINUX_TIME_T)
 typedef time64_t time_t;
diff --git a/src/cf/linux-kernel-func.m4 b/src/cf/linux-kernel-func.m4
index 7f3000f..6f9d350 100644
--- a/src/cf/linux-kernel-func.m4
+++ b/src/cf/linux-kernel-func.m4
@@ -252,6 +252,17 @@
 		    [inode_set_atime(NULL, 0, 0);
 		     inode_set_mtime(NULL, 0, 0);])
 
+dnl Linux 6.8 removed the strlcpy() function.  We test to see if we can redefine
+dnl a strlcpy() function.  We use a totally different function signature to
+dnl to ensure that this fails when the kernel does provide strlcpy().
+AC_CHECK_LINUX_FUNC([no_strlcpy],
+		    [[#include <linux/string.h>
+		     size_t strlcpy(char *d);
+		     size_t strlcpy(char *d) { return strlen(d); }]],
+		    [[static char buff[10];
+		     size_t s;
+		     s = strlcpy(buff);]])
+
 dnl Consequences - things which get set as a result of the
 dnl                above tests
 AS_IF([test "x$ac_cv_linux_func_d_alloc_anon" = "xno"],
diff --git a/src/crypto/hcrypto/kernel/roken.h b/src/crypto/hcrypto/kernel/roken.h
index f8c2334..6cb0601 100644
--- a/src/crypto/hcrypto/kernel/roken.h
+++ b/src/crypto/hcrypto/kernel/roken.h
@@ -11,6 +11,35 @@
 # error "This header is for kernel code only"
 #endif
 
+/*
+ * The following function annotations are not needed when building for kernel
+ * space
+ */
+#define ROKEN_LIB_FUNCTION
+#define ROKEN_LIB_CALL
+#define ROKEN_LIB_VARIABLE
+
+/*
+ * Our HAVE_STRLCPY from autoconf refers to whether strlcpy() is available in
+ * userspace. Whether it's available in the kernel is another question, so
+ * override HAVE_STRLCPY here. Usually it is available (only a few cases lack
+ * it), so turn it on by default, and turn it off for a few cases below.
+ */
+#undef HAVE_STRLCPY
+#define HAVE_STRLCPY 1
+
+#ifdef AFS_AIX_ENV
+# undef HAVE_STRLCPY
+#elif defined(AFS_LINUX_ENV) && defined(HAVE_LINUX_NO_STRLCPY)
+# undef HAVE_STRLCPY
+#endif
+
+/* strlcpy.c */
+#if defined (AFS_LINUX_ENV) && !defined(HAVE_STRLCPY)
+# define strlcpy rk_strlcpy
+ROKEN_LIB_FUNCTION size_t ROKEN_LIB_CALL strlcpy (char *, const char *, size_t);
+#endif
+
 /* ct.c */
 int ct_memcmp(const void *p1, const void *p2, size_t len);
 
diff --git a/src/external/libafsdep b/src/external/libafsdep
index fb365df..9d36a30 100644
--- a/src/external/libafsdep
+++ b/src/external/libafsdep
@@ -24,3 +24,4 @@
 heimdal/krb5/keyblock.c
 heimdal/krb5/store-int.c
 heimdal/roken/ct.c
+heimdal/roken/strlcpy.c
\ No newline at end of file
diff --git a/src/libafs/MakefileProto.LINUX.in b/src/libafs/MakefileProto.LINUX.in
index 8744ab8..6e62c8c 100644
--- a/src/libafs/MakefileProto.LINUX.in
+++ b/src/libafs/MakefileProto.LINUX.in
@@ -42,7 +42,8 @@
 	osi_ioctl.o \
 	osi_proc.o \
 	osi_vnodeops.o \
-	osi_pagecopy.o
+	osi_pagecopy.o \
+	strlcpy-kernel.o
 
 AFS_OS_PAGOBJS = \
 	osi_alloc.o \
@@ -59,7 +60,8 @@
 	osi_flush.o \
 <all>
 	osi_ioctl.o \
-	osi_pag_module.o 
+	osi_pag_module.o \
+	strlcpy-kernel.o
 
 AFS_OS_NFSOBJS =