hardening updates for v6.19-rc1

- string: Add missing kernel-doc return descriptions (Kriish Sharma)
 
 - Update some mis-typed allocations
 
 - Enable GCC diagnostic context for value-tracking warnings
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Merge tag 'hardening-v6.19-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux

Pull hardening updates from Kees Cook:

 - string: Add missing kernel-doc return descriptions (Kriish Sharma)

 - Update some mis-typed allocations

   These correct some accidentally wrong types used in allocations (that
   didn't affect the resulting size) that never got picked up from the
   batch I sent a few months ago.

 - Enable GCC diagnostic context for value-tracking warnings

   This results in better GCC diagnostics for the value range tracking,
   so we can get better visibility into where those values are coming
   from when we get out-of-bounds warnings at compile time.

* tag 'hardening-v6.19-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux:
  kbuild: Enable GCC diagnostic context for value-tracking warnings
  string: Add missing kernel-doc return descriptions
  media: iris: Cast iris_hfi_gen2_get_instance() allocation type
  drm/plane: Remove const qualifier from plane->modifiers allocation type
  comedi: Adjust range_table_list allocation type

Makefile

@@ -940,6 +940,9 @@ KBUILD_CFLAGS += $(call cc-option,-fzero-init-padding-bits=all)
 # for the randomize_kstack_offset feature. Disable it for all compilers.
 KBUILD_CFLAGS	+= $(call cc-option, -fno-stack-clash-protection)
 
+# Get details on warnings generated due to GCC value tracking.
+KBUILD_CFLAGS	+= $(call cc-option, -fdiagnostics-show-context=2)
+
 # Clear used registers at func exit (to reduce data lifetime and ROP gadgets).
 ifdef CONFIG_ZERO_CALL_USED_REGS
 KBUILD_CFLAGS	+= -fzero-call-used-regs=used-gpr

drivers/comedi/drivers/ni_670x.c

@@ -199,7 +199,7 @@ static int ni_670x_auto_attach(struct comedi_device *dev,
 		const struct comedi_lrange **range_table_list;
 
 		range_table_list = kmalloc_array(32,
-						 sizeof(struct comedi_lrange *),
+						 sizeof(*range_table_list),
 						 GFP_KERNEL);
 		if (!range_table_list)
 			return -ENOMEM;

drivers/gpu/drm/drm_plane.c

@@ -425,7 +425,7 @@ static int __drm_universal_plane_init(struct drm_device *dev,
 
 	plane->modifier_count = format_modifier_count;
 	plane->modifiers = kmalloc_array(format_modifier_count,
-					 sizeof(format_modifiers[0]),
+					 sizeof(*plane->modifiers),
 					 GFP_KERNEL);
 
 	if (format_modifier_count && !plane->modifiers) {

drivers/media/platform/qcom/iris/iris_hfi_gen2_command.c

@@ -1212,5 +1212,5 @@ void iris_hfi_gen2_command_ops_init(struct iris_core *core)
 
 struct iris_inst *iris_hfi_gen2_get_instance(void)
 {
-	return kzalloc(sizeof(struct iris_inst_hfi_gen2), GFP_KERNEL);
+	return (struct iris_inst *)kzalloc(sizeof(struct iris_inst_hfi_gen2), GFP_KERNEL);
 }

include/linux/string.h

@@ -371,6 +371,10 @@ static inline void memzero_explicit(void *s, size_t count)
  * kbasename - return the last part of a pathname.
  *
  * @path: path to extract the filename from.
+ *
+ * Returns:
+ * Pointer to the filename portion inside @path. If no '/' exists,
+ * returns @path unchanged.
  */
 static inline const char *kbasename(const char *path)
 {
@@ -556,6 +560,9 @@ static __always_inline size_t str_has_prefix(const char *str, const char *prefix
  * strstarts - does @str start with @prefix?
  * @str: string to examine
  * @prefix: prefix to look for.
+ *
+ * Returns:
+ * True if @str begins with @prefix. False in all other cases.
  */
 static inline bool strstarts(const char *str, const char *prefix)
 {