Merge tag 'hardening-v6.2-rc1-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux

Pull kernel hardening fixes from Kees Cook:

 - Fix CFI failure with KASAN (Sami Tolvanen)

 - Fix LKDTM + CFI under GCC 7 and 8 (Kristina Martsenko)

 - Limit CONFIG_ZERO_CALL_USED_REGS to Clang > 15.0.6 (Nathan
   Chancellor)

 - Ignore "contents" argument in LoadPin's LSM hook handling

 - Fix paste-o in /sys/kernel/warn_count API docs

 - Use READ_ONCE() consistently for oops/warn limit reading

* tag 'hardening-v6.2-rc1-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux:
  cfi: Fix CFI failure with KASAN
  exit: Use READ_ONCE() for all oops/warn limit reads
  security: Restrict CONFIG_ZERO_CALL_USED_REGS to gcc or clang > 15.0.6
  lkdtm: cfi: Make PAC test work with GCC 7 and 8
  docs: Fix path paste-o for /sys/kernel/warn_count
  LoadPin: Ignore the "contents" argument of the LSM hooks

2 files changed, 21 insertions, 12 deletions

diff --git a/security/Kconfig.hardening b/security/Kconfig.hardening
index d766b7d0ffd1..53baa95cb644 100644
--- a/security/Kconfig.hardening
+++ b/security/Kconfig.hardening
@@ -257,6 +257,9 @@ config INIT_ON_FREE_DEFAULT_ON
 
 config CC_HAS_ZERO_CALL_USED_REGS
 	def_bool $(cc-option,-fzero-call-used-regs=used-gpr)
+	# https://github.com/ClangBuiltLinux/linux/issues/1766
+	# https://github.com/llvm/llvm-project/issues/59242
+	depends on !CC_IS_CLANG || CLANG_VERSION > 150006
 
 config ZERO_CALL_USED_REGS
 	bool "Enable register zeroing on function exit"
diff --git a/security/loadpin/loadpin.c b/security/loadpin/loadpin.c
index de41621f4998..110a5ab2b46b 100644
--- a/security/loadpin/loadpin.c
+++ b/security/loadpin/loadpin.c
@@ -122,21 +122,11 @@ static void loadpin_sb_free_security(struct super_block *mnt_sb)
 	}
 }
 
-static int loadpin_read_file(struct file *file, enum kernel_read_file_id id,
-			     bool contents)
+static int loadpin_check(struct file *file, enum kernel_read_file_id id)
 {
 	struct super_block *load_root;
 	const char *origin = kernel_read_file_id_str(id);
 
-	/*
-	 * If we will not know that we'll be seeing the full contents
-	 * then we cannot trust a load will be complete and unchanged
-	 * off disk. Treat all contents=false hooks as if there were
-	 * no associated file struct.
-	 */
-	if (!contents)
-		file = NULL;
-
 	/* If the file id is excluded, ignore the pinning. */
 	if ((unsigned int)id < ARRAY_SIZE(ignore_read_file_id) &&
 	    ignore_read_file_id[id]) {
@@ -192,9 +182,25 @@ static int loadpin_read_file(struct file *file, enum kernel_read_file_id id,
 	return 0;
 }
 
+static int loadpin_read_file(struct file *file, enum kernel_read_file_id id,
+			     bool contents)
+{
+	/*
+	 * LoadPin only cares about the _origin_ of a file, not its
+	 * contents, so we can ignore the "are full contents available"
+	 * argument here.
+	 */
+	return loadpin_check(file, id);
+}
+
 static int loadpin_load_data(enum kernel_load_data_id id, bool contents)
 {
-	return loadpin_read_file(NULL, (enum kernel_read_file_id) id, contents);
+	/*
+	 * LoadPin only cares about the _origin_ of a file, not its
+	 * contents, so a NULL file is passed, and we can ignore the
+	 * state of "contents".
+	 */
+	return loadpin_check(NULL, (enum kernel_read_file_id) id);
 }
 
 static struct security_hook_list loadpin_hooks[] __lsm_ro_after_init = {