[packages/kernel] Fix for internal compiler error while building landlock

[arekm]

commit fa18f01114472e1f2745efffb7cc4bb8722b9d88
Author: Arkadiusz Miśkiewicz <arekm at maven.pl>
Date:   Mon May 26 11:38:43 2025 +0200

    Fix for internal compiler error while building landlock

 kernel-small_fixes.patch | 114 +++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 114 insertions(+)
---
diff --git a/kernel-small_fixes.patch b/kernel-small_fixes.patch
index dc2c31ff..d06c6649 100644
--- a/kernel-small_fixes.patch
+++ b/kernel-small_fixes.patch
@@ -107,3 +107,117 @@ diff -ur linux-5.3/drivers/scsi/aacraid.org/linit.c linux-5.3/drivers/scsi/aacra
  
  	if (dev->msi_enabled)
 
+From e136a4062174a9a8d1c1447ca040ea81accfa6a8 Mon Sep 17 00:00:00 2001
+From: Kees Cook <kees at kernel.org>
+Date: Sat, 26 Apr 2025 00:37:52 -0700
+Subject: randstruct: gcc-plugin: Remove bogus void member
+MIME-Version: 1.0
+Content-Type: text/plain; charset=UTF-8
+Content-Transfer-Encoding: 8bit
+
+When building the randomized replacement tree of struct members, the
+randstruct GCC plugin would insert, as the first member, a 0-sized void
+member. This appears as though it was done to catch non-designated
+("unnamed") static initializers, which wouldn't be stable since they
+depend on the original struct layout order.
+
+This was accomplished by having the side-effect of the "void member"
+tripping an assert in GCC internals (count_type_elements) if the member
+list ever needed to be counted (e.g. for figuring out the order of members
+during a non-designated initialization), which would catch impossible type
+(void) in the struct:
+
+security/landlock/fs.c: In function ‘hook_file_ioctl_common’:
+security/landlock/fs.c:1745:61: internal compiler error: in count_type_elements, at expr.cc:7075
+ 1745 |                         .u.op = &(struct lsm_ioctlop_audit) {
+      |                                                             ^
+
+static HOST_WIDE_INT
+count_type_elements (const_tree type, bool for_ctor_p)
+{
+  switch (TREE_CODE (type))
+...
+    case VOID_TYPE:
+    default:
+      gcc_unreachable ();
+    }
+}
+
+However this is a redundant safety measure since randstruct uses the
+__designated_initializer attribute both internally and within the
+__randomized_layout attribute macro so that this would be enforced
+by the compiler directly even when randstruct was not enabled (via
+-Wdesignated-init).
+
+A recent change in Landlock ended up tripping the same member counting
+routine when using a full-struct copy initializer as part of an anonymous
+initializer. This, however, is a false positive as the initializer is
+copying between identical structs (and hence identical layouts). The
+"path" member is "struct path", a randomized struct, and is being copied
+to from another "struct path", the "f_path" member:
+
+        landlock_log_denial(landlock_cred(file->f_cred), &(struct landlock_request) {
+                .type = LANDLOCK_REQUEST_FS_ACCESS,
+                .audit = {
+                        .type = LSM_AUDIT_DATA_IOCTL_OP,
+                        .u.op = &(struct lsm_ioctlop_audit) {
+                                .path = file->f_path,
+                                .cmd = cmd,
+                        },
+                },
+	...
+
+As can be seen with the coming randstruct KUnit test, there appears to
+be no behavioral problems with this kind of initialization when the void
+member is removed from the randstruct GCC plugin, so remove it.
+
+Reported-by: "Dr. David Alan Gilbert" <linux at treblig.org>
+Closes: https://lore.kernel.org/lkml/Z_PRaKx7q70MKgCA@gallifrey/
+Reported-by: Mark Brown <broonie at kernel.org>
+Closes: https://lore.kernel.org/lkml/20250407-kbuild-disable-gcc-plugins-v1-1-5d46ae583f5e@kernel.org/
+Reported-by: WangYuli <wangyuli at uniontech.com>
+Closes: https://lore.kernel.org/lkml/337D5D4887277B27+3c677db3-a8b9-47f0-93a4-7809355f1381@uniontech.com/
+Fixes: 313dd1b62921 ("gcc-plugins: Add the randstruct plugin")
+Signed-off-by: Kees Cook <kees at kernel.org>
+---
+ scripts/gcc-plugins/randomize_layout_plugin.c | 18 +-----------------
+ 1 file changed, 1 insertion(+), 17 deletions(-)
+
+diff --git a/scripts/gcc-plugins/randomize_layout_plugin.c b/scripts/gcc-plugins/randomize_layout_plugin.c
+index 5694df3da2e95b..971a1908a8cc40 100644
+--- a/scripts/gcc-plugins/randomize_layout_plugin.c
++++ b/scripts/gcc-plugins/randomize_layout_plugin.c
+@@ -344,29 +344,13 @@ static int relayout_struct(tree type)
+ 
+ 	shuffle(type, (tree *)newtree, shuffle_length);
+ 
+-	/*
+-	 * set up a bogus anonymous struct field designed to error out on unnamed struct initializers
+-	 * as gcc provides no other way to detect such code
+-	 */
+-	list = make_node(FIELD_DECL);
+-	TREE_CHAIN(list) = newtree[0];
+-	TREE_TYPE(list) = void_type_node;
+-	DECL_SIZE(list) = bitsize_zero_node;
+-	DECL_NONADDRESSABLE_P(list) = 1;
+-	DECL_FIELD_BIT_OFFSET(list) = bitsize_zero_node;
+-	DECL_SIZE_UNIT(list) = size_zero_node;
+-	DECL_FIELD_OFFSET(list) = size_zero_node;
+-	DECL_CONTEXT(list) = type;
+-	// to satisfy the constify plugin
+-	TREE_READONLY(list) = 1;
+-
+ 	for (i = 0; i < num_fields - 1; i++)
+ 		TREE_CHAIN(newtree[i]) = newtree[i+1];
+ 	TREE_CHAIN(newtree[num_fields - 1]) = NULL_TREE;
+ 
+ 	main_variant = TYPE_MAIN_VARIANT(type);
+ 	for (variant = main_variant; variant; variant = TYPE_NEXT_VARIANT(variant)) {
+-		TYPE_FIELDS(variant) = list;
++		TYPE_FIELDS(variant) = newtree[0];
+ 		TYPE_ATTRIBUTES(variant) = copy_list(TYPE_ATTRIBUTES(variant));
+ 		TYPE_ATTRIBUTES(variant) = tree_cons(get_identifier("randomize_performed"), NULL_TREE, TYPE_ATTRIBUTES(variant));
+ 		TYPE_ATTRIBUTES(variant) = tree_cons(get_identifier("designated_init"), NULL_TREE, TYPE_ATTRIBUTES(variant));
+-- 
+cgit 1.2.3-korg
+
================================================================

---- gitweb:

http://git.pld-linux.org/gitweb.cgi/packages/kernel.git/commitdiff/fa18f01114472e1f2745efffb7cc4bb8722b9d88