Merge tag 'hardening-v6.5-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux

Pull hardening updates from Kees Cook:
"There are three areas of note:

A bunch of strlcpy()->strscpy() conversions ended up living in my tree
since they were either Acked by maintainers for me to carry, or got
ignored for multiple weeks (and were trivial changes).

The compiler option '-fstrict-flex-arrays=3' has been enabled
globally, and has been in -next for the entire devel cycle. This
changes compiler diagnostics (though mainly just -Warray-bounds which
is disabled) and potential UBSAN_BOUNDS and FORTIFY _warning_
coverage. In other words, there are no new restrictions, just
potentially new warnings. Any new FORTIFY warnings we've seen have
been fixed (usually in their respective subsystem trees). For more
details, see commit df8fc4e934c12b.

The under-development compiler attribute __counted_by has been added
so that we can start annotating flexible array members with their
associated structure member that tracks the count of flexible array
elements at run-time. It is possible (likely?) that the exact syntax
of the attribute will change before it is finalized, but GCC and Clang
are working together to sort it out. Any changes can be made to the
macro while we continue to add annotations.

As an example of that last case, I have a treewide commit waiting with
such annotations found via Coccinelle:

https://git.kernel.org/linus/adc5b3cb48a049563dc673f348eab7b6beba8a9b

Also see commit dd06e72e68bcb4 for more details.

Summary:

- Fix KMSAN vs FORTIFY in strlcpy/strlcat (Alexander Potapenko)

- Convert strreplace() to return string start (Andy Shevchenko)

- Flexible array conversions (Arnd Bergmann, Wyes Karny, Kees Cook)

- Add missing function prototypes seen with W=1 (Arnd Bergmann)

- Fix strscpy() kerndoc typo (Arne Welzel)

- Replace strlcpy() with strscpy() across many subsystems which were
either Acked by respective maintainers or were trivial changes that
went ignored for multiple weeks (Azeem Shaikh)

- Remove unneeded cc-option test for UBSAN_TRAP (Nick Desaulniers)

- Add KUnit tests for strcat()-family

- Enable KUnit tests of FORTIFY wrappers under UML

- Add more complete FORTIFY protections for strlcat()

- Add missed disabling of FORTIFY for all arch purgatories.

- Enable -fstrict-flex-arrays=3 globally

- Tightening UBSAN_BOUNDS when using GCC

- Improve checkpatch to check for strcpy, strncpy, and fake flex
arrays

- Improve use of const variables in FORTIFY

- Add requested struct_size_t() helper for types not pointers

- Add __counted_by macro for annotating flexible array size members"

* tag 'hardening-v6.5-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux: (54 commits)
netfilter: ipset: Replace strlcpy with strscpy
uml: Replace strlcpy with strscpy
um: Use HOST_DIR for mrproper
kallsyms: Replace all non-returning strlcpy with strscpy
sh: Replace all non-returning strlcpy with strscpy
of/flattree: Replace all non-returning strlcpy with strscpy
sparc64: Replace all non-returning strlcpy with strscpy
Hexagon: Replace all non-returning strlcpy with strscpy
kobject: Use return value of strreplace()
lib/string_helpers: Change returned value of the strreplace()
jbd2: Avoid printing outside the boundary of the buffer
checkpatch: Check for 0-length and 1-element arrays
riscv/purgatory: Do not use fortified string functions
s390/purgatory: Do not use fortified string functions
x86/purgatory: Do not use fortified string functions
acpi: Replace struct acpi_table_slit 1-element array with flex-array
clocksource: Replace all non-returning strlcpy with strscpy
string: use __builtin_memcpy() in strlcpy/strlcat
staging: most: Replace all non-returning strlcpy with strscpy
drm/i2c: tda998x: Replace all non-returning strlcpy with strscpy
...

Documentation/filesystems/autofs-mount-control.rst

···
 		    struct args_ismountpoint	ismountpoint;
 	    };
 
-	    char path[0];
+	    char path[];
     };
 
 The ioctlfd field is a mount point file descriptor of an autofs mount

Documentation/filesystems/autofs.rst

···
 			struct args_ismountpoint	ismountpoint;
 		};
 
-                char path[0];
+                char path[];
         };
 
 For the **OPEN_MOUNT** and **IS_MOUNTPOINT** commands, the target

MAINTAINERS

···
 F:	include/linux/fortify-string.h
 F:	lib/fortify_kunit.c
 F:	lib/memcpy_kunit.c
+F:	lib/strcat_kunit.c
 F:	lib/strscpy_kunit.c
 F:	lib/test_fortify/*
 F:	scripts/test_fortify.sh

Makefile

···
 # globally built with -Wcast-function-type.
 KBUILD_CFLAGS += $(call cc-option, -Wcast-function-type)
 
+# To gain proper coverage for CONFIG_UBSAN_BOUNDS and CONFIG_FORTIFY_SOURCE,
+# the kernel uses only C99 flexible arrays for dynamically sized trailing
+# arrays. Enforce this for everything that may examine structure sizes and
+# perform bounds checking.
+KBUILD_CFLAGS += $(call cc-option, -fstrict-flex-arrays=3)
+
 # disable stringop warnings in gcc 8+
 KBUILD_CFLAGS += $(call cc-disable-warning, stringop-truncation)
 

arch/hexagon/kernel/setup.c

···
 		on_simulator = 0;
 
 	if (p[0] != '\0')
-		strlcpy(boot_command_line, p, COMMAND_LINE_SIZE);
+		strscpy(boot_command_line, p, COMMAND_LINE_SIZE);
 	else
-		strlcpy(boot_command_line, default_command_line,
+		strscpy(boot_command_line, default_command_line,
 			COMMAND_LINE_SIZE);
 
 	/*
···
 	 * are both picked up by the init code. If no reason to
 	 * make them different, pass the same pointer back.
 	 */
-	strlcpy(cmd_line, boot_command_line, COMMAND_LINE_SIZE);
+	strscpy(cmd_line, boot_command_line, COMMAND_LINE_SIZE);
 	*cmdline_p = cmd_line;
 
 	parse_early_param();

arch/microblaze/kernel/prom.c

···
 
 	early_init_dt_scan(params);
 	if (!strlen(boot_command_line))
-		strlcpy(boot_command_line, cmd_line, COMMAND_LINE_SIZE);
+		strscpy(boot_command_line, cmd_line, COMMAND_LINE_SIZE);
 
 	memblock_allow_resize();
 

arch/riscv/purgatory/Makefile

···
 $(obj)/sha256.o: $(srctree)/lib/crypto/sha256.c FORCE
 	$(call if_changed_rule,cc_o_c)
 
-CFLAGS_sha256.o := -D__DISABLE_EXPORTS
+CFLAGS_sha256.o := -D__DISABLE_EXPORTS -D__NO_FORTIFY
 CFLAGS_string.o := -D__DISABLE_EXPORTS
 CFLAGS_ctype.o := -D__DISABLE_EXPORTS
 

arch/s390/purgatory/Makefile

···
 $(obj)/sha256.o: $(srctree)/lib/crypto/sha256.c FORCE
 	$(call if_changed_rule,cc_o_c)
 
-CFLAGS_sha256.o := -D__DISABLE_EXPORTS
+CFLAGS_sha256.o := -D__DISABLE_EXPORTS -D__NO_FORTIFY
 
 $(obj)/mem.o: $(srctree)/arch/s390/lib/mem.S FORCE
 	$(call if_changed_rule,as_o_S)

arch/sh/drivers/dma/dma-api.c

···
 	if (atomic_xchg(&channel->busy, 1))
 		return -EBUSY;
 
-	strlcpy(channel->dev_id, dev_id, sizeof(channel->dev_id));
+	strscpy(channel->dev_id, dev_id, sizeof(channel->dev_id));
 
 	if (info->ops->request) {
 		result = info->ops->request(channel);

arch/sh/kernel/setup.c

···
 	bss_resource.end = virt_to_phys(__bss_stop)-1;
 
 #ifdef CONFIG_CMDLINE_OVERWRITE
-	strlcpy(command_line, CONFIG_CMDLINE, sizeof(command_line));
+	strscpy(command_line, CONFIG_CMDLINE, sizeof(command_line));
 #else
-	strlcpy(command_line, COMMAND_LINE, sizeof(command_line));
+	strscpy(command_line, COMMAND_LINE, sizeof(command_line));
 #ifdef CONFIG_CMDLINE_EXTEND
 	strlcat(command_line, " ", sizeof(command_line));
 	strlcat(command_line, CONFIG_CMDLINE, sizeof(command_line));

arch/sparc/kernel/ioport.c

···
 		tack += sizeof (struct resource);
 	}
 
-	strlcpy(tack, name, XNMLN+1);
+	strscpy(tack, name, XNMLN+1);
 	res->name = tack;
 
 	va = _sparc_ioremap(res, busno, phys, size);

arch/sparc/kernel/setup_32.c

···
 
 	/* Initialize PROM console and command line. */
 	*cmdline_p = prom_getbootargs();
-	strlcpy(boot_command_line, *cmdline_p, COMMAND_LINE_SIZE);
+	strscpy(boot_command_line, *cmdline_p, COMMAND_LINE_SIZE);
 	parse_early_param();
 
 	boot_flags_init(*cmdline_p);

arch/sparc/kernel/setup_64.c

···
 {
 	/* Initialize PROM console and command line. */
 	*cmdline_p = prom_getbootargs();
-	strlcpy(boot_command_line, *cmdline_p, COMMAND_LINE_SIZE);
+	strscpy(boot_command_line, *cmdline_p, COMMAND_LINE_SIZE);
 	parse_early_param();
 
 	boot_flags_init(*cmdline_p);

arch/sparc/prom/bootstr_32.c

···
 		 * V3 PROM cannot supply as with more than 128 bytes
 		 * of an argument. But a smart bootstrap loader can.
 		 */
-		strlcpy(barg_buf, *romvec->pv_v2bootargs.bootargs, sizeof(barg_buf));
+		strscpy(barg_buf, *romvec->pv_v2bootargs.bootargs, sizeof(barg_buf));
 		break;
 	default:
 		break;

arch/um/Makefile

···
 # When cleaning we don't include .config, so we don't include
 # TT or skas makefiles and don't clean skas_ptregs.h.
 CLEAN_FILES += linux x.i gmon.out
-MRPROPER_FILES += arch/$(SUBARCH)/include/generated
+MRPROPER_FILES += $(HOST_DIR)/include/generated
 
 archclean:
 	@find . \( -name '*.bb' -o -name '*.bbg' -o -name '*.da' \

arch/um/include/shared/user.h

···
 extern int in_aton(char *str);
 extern size_t strlcpy(char *, const char *, size_t);
 extern size_t strlcat(char *, const char *, size_t);
+extern size_t strscpy(char *, const char *, size_t);
 
 /* Copied from linux/compiler-gcc.h since we can't include it directly */
 #define barrier() __asm__ __volatile__("": : :"memory")

arch/um/os-Linux/drivers/tuntap_user.c

···
 		}
 		memset(&ifr, 0, sizeof(ifr));
 		ifr.ifr_flags = IFF_TAP | IFF_NO_PI;
-		strlcpy(ifr.ifr_name, pri->dev_name, sizeof(ifr.ifr_name));
+		strscpy(ifr.ifr_name, pri->dev_name, sizeof(ifr.ifr_name));
 		if (ioctl(pri->fd, TUNSETIFF, &ifr) < 0) {
 			err = -errno;
 			printk(UM_KERN_ERR "TUNSETIFF failed, errno = %d\n",

arch/x86/purgatory/Makefile

···
 $(obj)/sha256.o: $(srctree)/lib/crypto/sha256.c FORCE
 	$(call if_changed_rule,cc_o_c)
 
-CFLAGS_sha256.o := -D__DISABLE_EXPORTS
+CFLAGS_sha256.o := -D__DISABLE_EXPORTS -D__NO_FORTIFY
 
 # When profile-guided optimization is enabled, llvm emits two different
 # overlapping text sections, which is not supported by kexec. Remove profile

drivers/gpu/drm/amd/amdgpu/atom.c

···
 	str = CSTR(idx);
 	if (*str != '\0') {
 		pr_info("ATOM BIOS: %s\n", str);
-		strlcpy(ctx->vbios_version, str, sizeof(ctx->vbios_version));
+		strscpy(ctx->vbios_version, str, sizeof(ctx->vbios_version));
 	}
 
 	atom_rom_header = (struct _ATOM_ROM_HEADER *)CSTR(base);

drivers/gpu/drm/amd/pm/legacy-dpm/legacy_dpm.c

···
 				struct i2c_board_info info = { };
 				const char *name = pp_lib_thermal_controller_names[controller->ucType];
 				info.addr = controller->ucI2cAddress >> 1;
-				strlcpy(info.type, name, sizeof(info.type));
+				strscpy(info.type, name, sizeof(info.type));
 				i2c_new_client_device(&adev->pm.i2c_bus->adapter, &info);
 			}
 		} else {

drivers/gpu/drm/display/drm_dp_helper.c

···
 	aux->ddc.owner = THIS_MODULE;
 	aux->ddc.dev.parent = aux->dev;
 
-	strlcpy(aux->ddc.name, aux->name ? aux->name : dev_name(aux->dev),
+	strscpy(aux->ddc.name, aux->name ? aux->name : dev_name(aux->dev),
 		sizeof(aux->ddc.name));
 
 	ret = drm_dp_aux_register_devnode(aux);

drivers/gpu/drm/display/drm_dp_mst_topology.c

···
 	aux->ddc.dev.parent = parent_dev;
 	aux->ddc.dev.of_node = parent_dev->of_node;
 
-	strlcpy(aux->ddc.name, aux->name ? aux->name : dev_name(parent_dev),
+	strscpy(aux->ddc.name, aux->name ? aux->name : dev_name(parent_dev),
 		sizeof(aux->ddc.name));
 
 	return i2c_add_adapter(&aux->ddc);

drivers/gpu/drm/drm_mipi_dsi.c

···
 
 	device_set_node(&dsi->dev, of_fwnode_handle(info->node));
 	dsi->channel = info->channel;
-	strlcpy(dsi->name, info->type, sizeof(dsi->name));
+	strscpy(dsi->name, info->type, sizeof(dsi->name));
 
 	ret = mipi_dsi_device_add(dsi);
 	if (ret) {

drivers/gpu/drm/i2c/tda998x_drv.c

···
 	 * offset.
 	 */
 	memset(&cec_info, 0, sizeof(cec_info));
-	strlcpy(cec_info.type, "tda9950", sizeof(cec_info.type));
+	strscpy(cec_info.type, "tda9950", sizeof(cec_info.type));
 	cec_info.addr = priv->cec_addr;
 	cec_info.platform_data = &priv->cec_glue;
 	cec_info.irq = client->irq;

drivers/gpu/drm/mediatek/mtk_hdmi_ddc.c

···
 		return ret;
 	}
 
-	strlcpy(ddc->adap.name, "mediatek-hdmi-ddc", sizeof(ddc->adap.name));
+	strscpy(ddc->adap.name, "mediatek-hdmi-ddc", sizeof(ddc->adap.name));
 	ddc->adap.owner = THIS_MODULE;
 	ddc->adap.class = I2C_CLASS_DDC;
 	ddc->adap.algo = &mtk_hdmi_ddc_algorithm;

drivers/gpu/drm/radeon/radeon_atombios.c

···
 			const char *name = thermal_controller_names[power_info->info.
 								    ucOverdriveThermalController];
 			info.addr = power_info->info.ucOverdriveControllerAddress >> 1;
-			strlcpy(info.type, name, sizeof(info.type));
+			strscpy(info.type, name, sizeof(info.type));
 			i2c_new_client_device(&rdev->pm.i2c_bus->adapter, &info);
 		}
 	}
···
 				struct i2c_board_info info = { };
 				const char *name = pp_lib_thermal_controller_names[controller->ucType];
 				info.addr = controller->ucI2cAddress >> 1;
-				strlcpy(info.type, name, sizeof(info.type));
+				strscpy(info.type, name, sizeof(info.type));
 				i2c_new_client_device(&rdev->pm.i2c_bus->adapter, &info);
 			}
 		} else {

drivers/gpu/drm/radeon/radeon_combios.c

···
 				struct i2c_board_info info = { };
 				const char *name = thermal_controller_names[thermal_controller];
 				info.addr = i2c_addr >> 1;
-				strlcpy(info.type, name, sizeof(info.type));
+				strscpy(info.type, name, sizeof(info.type));
 				i2c_new_client_device(&rdev->pm.i2c_bus->adapter, &info);
 			}
 		}
···
 				struct i2c_board_info info = { };
 				const char *name = "f75375";
 				info.addr = 0x28;
-				strlcpy(info.type, name, sizeof(info.type));
+				strscpy(info.type, name, sizeof(info.type));
 				i2c_new_client_device(&rdev->pm.i2c_bus->adapter, &info);
 				DRM_INFO("Possible %s thermal controller at 0x%02x\n",
 					 name, info.addr);

drivers/gpu/drm/rockchip/inno_hdmi.c

···
 	adap->dev.parent = hdmi->dev;
 	adap->dev.of_node = hdmi->dev->of_node;
 	adap->algo = &inno_hdmi_algorithm;
-	strlcpy(adap->name, "Inno HDMI", sizeof(adap->name));
+	strscpy(adap->name, "Inno HDMI", sizeof(adap->name));
 	i2c_set_adapdata(adap, hdmi);
 
 	ret = i2c_add_adapter(adap);

drivers/gpu/drm/rockchip/rk3066_hdmi.c

···
 	adap->dev.parent = hdmi->dev;
 	adap->dev.of_node = hdmi->dev->of_node;
 	adap->algo = &rk3066_hdmi_algorithm;
-	strlcpy(adap->name, "RK3066 HDMI", sizeof(adap->name));
+	strscpy(adap->name, "RK3066 HDMI", sizeof(adap->name));
 	i2c_set_adapdata(adap, hdmi);
 
 	ret = i2c_add_adapter(adap);

drivers/gpu/drm/sun4i/sun4i_hdmi_i2c.c

···
 	adap->owner = THIS_MODULE;
 	adap->class = I2C_CLASS_DDC;
 	adap->algo = &sun4i_hdmi_i2c_algorithm;
-	strlcpy(adap->name, "sun4i_hdmi_i2c adapter", sizeof(adap->name));
+	strscpy(adap->name, "sun4i_hdmi_i2c adapter", sizeof(adap->name));
 	i2c_set_adapdata(adap, hdmi);
 
 	ret = i2c_add_adapter(adap);

drivers/md/raid5.c

···
 
 	conf->active_name = 0;
 	sc = kmem_cache_create(conf->cache_name[conf->active_name],
-			       sizeof(struct stripe_head)+(devs-1)*sizeof(struct r5dev),
+			       struct_size_t(struct stripe_head, dev, devs),
 			       0, 0, NULL);
 	if (!sc)
 		return 1;
···
 
 	/* Step 1 */
 	sc = kmem_cache_create(conf->cache_name[1-conf->active_name],
-			       sizeof(struct stripe_head)+(newsize-1)*sizeof(struct r5dev),
+			       struct_size_t(struct stripe_head, dev, newsize),
 			       0, 0, NULL);
 	if (!sc)
 		return -ENOMEM;

drivers/md/raid5.h

···
 		unsigned long	flags;
 		u32		log_checksum;
 		unsigned short	write_hint;
-	} dev[1]; /* allocated with extra space depending of RAID geometry */
+	} dev[]; /* allocated depending of RAID geometry ("disks" member) */
 };
 
 /* stripe_head_state - collects and tracks the dynamic state of a stripe_head

drivers/misc/lkdtm/bugs.c

···
 struct array_bounds_flex_array {
 	int one;
 	int two;
-	char data[1];
+	char data[];
 };
 
 struct array_bounds {
···
 	 * For the uninstrumented flex array member, also touch 1 byte
 	 * beyond to verify it is correctly uninstrumented.
 	 */
-	for (i = 0; i < sizeof(not_checked->data) + 1; i++)
+	for (i = 0; i < 2; i++)
 		not_checked->data[i] = 'A';
 
 	pr_info("Array access beyond bounds ...\n");

drivers/most/configfs.c

···
 {
 	struct mdev_link *mdev_link = to_mdev_link(item);
 
-	strlcpy(mdev_link->device, page, sizeof(mdev_link->device));
+	strscpy(mdev_link->device, page, sizeof(mdev_link->device));
 	strim(mdev_link->device);
 	return count;
 }
···
 {
 	struct mdev_link *mdev_link = to_mdev_link(item);
 
-	strlcpy(mdev_link->channel, page, sizeof(mdev_link->channel));
+	strscpy(mdev_link->channel, page, sizeof(mdev_link->channel));
 	strim(mdev_link->channel);
 	return count;
 }
···
 {
 	struct mdev_link *mdev_link = to_mdev_link(item);
 
-	strlcpy(mdev_link->comp, page, sizeof(mdev_link->comp));
+	strscpy(mdev_link->comp, page, sizeof(mdev_link->comp));
 	strim(mdev_link->comp);
 	return count;
 }
···
 {
 	struct mdev_link *mdev_link = to_mdev_link(item);
 
-	strlcpy(mdev_link->comp_params, page, sizeof(mdev_link->comp_params));
+	strscpy(mdev_link->comp_params, page, sizeof(mdev_link->comp_params));
 	strim(mdev_link->comp_params);
 	return count;
 }

drivers/net/ethernet/intel/ice/ice_ddp.h

···
 
 #define ICE_MAX_ENTRIES_IN_BUF(hd_sz, ent_sz)                                 \
 	((ICE_PKG_BUF_SIZE -                                                  \
-	  struct_size((struct ice_buf_hdr *)0, section_entry, 1) - (hd_sz)) / \
+	  struct_size_t(struct ice_buf_hdr,  section_entry, 1) - (hd_sz)) / \
 	 (ent_sz))
 
 /* ice package section IDs */
···
 };
 
 #define ICE_MAX_LABELS_IN_BUF                                             \
-	ICE_MAX_ENTRIES_IN_BUF(struct_size((struct ice_label_section *)0, \
+	ICE_MAX_ENTRIES_IN_BUF(struct_size_t(struct ice_label_section,  \
 					   label, 1) -                    \
 				       sizeof(struct ice_label),          \
 			       sizeof(struct ice_label))
···
 };
 
 #define ICE_MAX_BST_TCAMS_IN_BUF                                               \
-	ICE_MAX_ENTRIES_IN_BUF(struct_size((struct ice_boost_tcam_section *)0, \
+	ICE_MAX_ENTRIES_IN_BUF(struct_size_t(struct ice_boost_tcam_section,  \
 					   tcam, 1) -                          \
 				       sizeof(struct ice_boost_tcam_entry),    \
 			       sizeof(struct ice_boost_tcam_entry))
···
 };
 
 #define ICE_MAX_MARKER_PTYPE_TCAMS_IN_BUF                                    \
-	ICE_MAX_ENTRIES_IN_BUF(                                              \
-		struct_size((struct ice_marker_ptype_tcam_section *)0, tcam, \
+	ICE_MAX_ENTRIES_IN_BUF(struct_size_t(struct ice_marker_ptype_tcam_section,  tcam, \
 			    1) -                                             \
 			sizeof(struct ice_marker_ptype_tcam_entry),          \
 		sizeof(struct ice_marker_ptype_tcam_entry))

drivers/nvme/host/fc.c

···
 
 	ret = nvme_alloc_io_tag_set(&ctrl->ctrl, &ctrl->tag_set,
 			&nvme_fc_mq_ops, 1,
-			struct_size((struct nvme_fcp_op_w_sgl *)NULL, priv,
-				    ctrl->lport->ops->fcprqst_priv_sz));
+			struct_size_t(struct nvme_fcp_op_w_sgl, priv,
+				      ctrl->lport->ops->fcprqst_priv_sz));
 	if (ret)
 		return ret;
 
···
 
 	ret = nvme_alloc_admin_tag_set(&ctrl->ctrl, &ctrl->admin_tag_set,
 			&nvme_fc_admin_mq_ops,
-			struct_size((struct nvme_fcp_op_w_sgl *)NULL, priv,
-				    ctrl->lport->ops->fcprqst_priv_sz));
+			struct_size_t(struct nvme_fcp_op_w_sgl, priv,
+				      ctrl->lport->ops->fcprqst_priv_sz));
 	if (ret)
 		goto fail_ctrl;
 

drivers/scsi/3w-9xxx.c

···
 	}
 
 	/* Load rest of compatibility struct */
-	strlcpy(tw_dev->tw_compat_info.driver_version, TW_DRIVER_VERSION,
+	strscpy(tw_dev->tw_compat_info.driver_version, TW_DRIVER_VERSION,
 		sizeof(tw_dev->tw_compat_info.driver_version));
 	tw_dev->tw_compat_info.driver_srl_high = TW_CURRENT_DRIVER_SRL;
 	tw_dev->tw_compat_info.driver_branch_high = TW_CURRENT_DRIVER_BRANCH;

drivers/scsi/aacraid/aachba.c

···
 	else
 		qd.unmapped = 0;
 
-	strlcpy(qd.name, fsa_dev_ptr[qd.cnum].devname,
+	strscpy(qd.name, fsa_dev_ptr[qd.cnum].devname,
 	  min(sizeof(qd.name), sizeof(fsa_dev_ptr[qd.cnum].devname) + 1));
 
 	if (copy_to_user(arg, &qd, sizeof (struct aac_query_disk)))

drivers/scsi/bnx2i/bnx2i_init.c

···
 	if (!stats)
 		return -ENOMEM;
 
-	strlcpy(stats->version, DRV_MODULE_VERSION, sizeof(stats->version));
+	strscpy(stats->version, DRV_MODULE_VERSION, sizeof(stats->version));
 	memcpy(stats->mac_add1 + 2, hba->cnic->mac_addr, ETH_ALEN);
 
 	stats->max_frame_size = hba->netdev->mtu;

drivers/scsi/hptiop.c

···
 	host->cmd_per_lun = le32_to_cpu(iop_config.max_requests);
 	host->max_cmd_len = 16;
 
-	req_size = struct_size((struct hpt_iop_request_scsi_command *)0,
-			       sg_list, hba->max_sg_descriptors);
+	req_size = struct_size_t(struct hpt_iop_request_scsi_command,
+				 sg_list, hba->max_sg_descriptors);
 	if ((req_size & 0x1f) != 0)
 		req_size = (req_size + 0x1f) & ~0x1f;
 

drivers/scsi/ibmvscsi/ibmvscsi.c

···
 
 	ppartition_name = of_get_property(of_root, "ibm,partition-name", NULL);
 	if (ppartition_name)
-		strlcpy(partition_name, ppartition_name,
+		strscpy(partition_name, ppartition_name,
 				sizeof(partition_name));
 	p_number_ptr = of_get_property(of_root, "ibm,partition-no", NULL);
 	if (p_number_ptr)
···
 	if (hostdata->client_migrated)
 		hostdata->caps.flags |= cpu_to_be32(CLIENT_MIGRATED);
 
-	strlcpy(hostdata->caps.name, dev_name(&hostdata->host->shost_gendev),
+	strscpy(hostdata->caps.name, dev_name(&hostdata->host->shost_gendev),
 		sizeof(hostdata->caps.name));
 
 	location = of_get_property(of_node, "ibm,loc-code", NULL);
 	location = location ? location : dev_name(hostdata->dev);
-	strlcpy(hostdata->caps.loc, location, sizeof(hostdata->caps.loc));
+	strscpy(hostdata->caps.loc, location, sizeof(hostdata->caps.loc));
 
 	req->common.type = cpu_to_be32(VIOSRP_CAPABILITIES_TYPE);
 	req->buffer = cpu_to_be64(hostdata->caps_addr);

drivers/scsi/megaraid/megaraid_sas_base.c

···
 		fusion->max_map_sz = ventura_map_sz;
 	} else {
 		fusion->old_map_sz =
-			struct_size((struct MR_FW_RAID_MAP *)0, ldSpanMap,
-				    instance->fw_supported_vd_count);
+			struct_size_t(struct MR_FW_RAID_MAP, ldSpanMap,
+				      instance->fw_supported_vd_count);
 		fusion->new_map_sz =  sizeof(struct MR_FW_RAID_MAP_EXT);
 
 		fusion->max_map_sz =
···
 	struct fusion_context *fusion = instance->ctrl_context;
 	size_t pd_seq_map_sz;
 
-	pd_seq_map_sz = struct_size((struct MR_PD_CFG_SEQ_NUM_SYNC *)0, seq,
-				    MAX_PHYSICAL_DEVICES);
+	pd_seq_map_sz = struct_size_t(struct MR_PD_CFG_SEQ_NUM_SYNC, seq,
+				      MAX_PHYSICAL_DEVICES);
 
 	instance->use_seqnum_jbod_fp =
 		instance->support_seqnum_jbod_fp;
···
 	if (instance->adapter_type != MFI_SERIES) {
 		megasas_release_fusion(instance);
 		pd_seq_map_sz =
-			struct_size((struct MR_PD_CFG_SEQ_NUM_SYNC *)0,
-				    seq, MAX_PHYSICAL_DEVICES);
+			struct_size_t(struct MR_PD_CFG_SEQ_NUM_SYNC,
+				      seq, MAX_PHYSICAL_DEVICES);
 		for (i = 0; i < 2 ; i++) {
 			if (fusion->ld_map[i])
 				dma_free_coherent(&instance->pdev->dev,

drivers/scsi/megaraid/megaraid_sas_fp.c

···
 	else if (instance->supportmax256vd)
 		expected_size = sizeof(struct MR_FW_RAID_MAP_EXT);
 	else
-		expected_size = struct_size((struct MR_FW_RAID_MAP *)0,
-					    ldSpanMap,
-					    le16_to_cpu(pDrvRaidMap->ldCount));
+		expected_size = struct_size_t(struct MR_FW_RAID_MAP,
+					      ldSpanMap,
+					      le16_to_cpu(pDrvRaidMap->ldCount));
 
 	if (le32_to_cpu(pDrvRaidMap->totalSize) != expected_size) {
 		dev_dbg(&instance->pdev->dev, "megasas: map info structure size 0x%x",

drivers/scsi/qedi/qedi_main.c

···
 	sp_params.drv_minor = QEDI_DRIVER_MINOR_VER;
 	sp_params.drv_rev = QEDI_DRIVER_REV_VER;
 	sp_params.drv_eng = QEDI_DRIVER_ENG_VER;
-	strlcpy(sp_params.name, "qedi iSCSI", QED_DRV_VER_STR_SIZE);
+	strscpy(sp_params.name, "qedi iSCSI", QED_DRV_VER_STR_SIZE);
 	rc = qedi_ops->common->slowpath_start(qedi->cdev, &sp_params);
 	if (rc) {
 		QEDI_ERR(&qedi->dbg_ctx, "Cannot start slowpath\n");

drivers/scsi/smartpqi/smartpqi_init.c

···
 }
 
 #define PQI_REPORT_EVENT_CONFIG_BUFFER_LENGTH	\
-	struct_size((struct pqi_event_config *)0, descriptors, PQI_MAX_EVENT_DESCRIPTORS)
+	struct_size_t(struct pqi_event_config,  descriptors, PQI_MAX_EVENT_DESCRIPTORS)
 
 static int pqi_configure_events(struct pqi_ctrl_info *ctrl_info,
 	bool enable_events)

fs/befs/btree.c

···
 		goto error_alloc;
 	}
 
-	strlcpy(keybuf, keystart, keylen + 1);
+	strscpy(keybuf, keystart, keylen + 1);
 	*value = fs64_to_cpu(sb, valarray[cur_key]);
 	*keysize = keylen;
 

fs/befs/linuxvfs.c

···
 	if (S_ISLNK(inode->i_mode) && !(befs_ino->i_flags & BEFS_LONG_SYMLINK)){
 		inode->i_size = 0;
 		inode->i_blocks = befs_sb->block_size / VFS_BLOCK_SIZE;
-		strlcpy(befs_ino->i_data.symlink, raw_inode->data.symlink,
+		strscpy(befs_ino->i_data.symlink, raw_inode->data.symlink,
 			BEFS_SYMLINK_LEN);
 	} else {
 		int num_blks;

fs/dlm/config.c

···
 {
 	struct dlm_cluster *cl = config_item_to_cluster(item);
 
-	strlcpy(dlm_config.ci_cluster_name, buf,
+	strscpy(dlm_config.ci_cluster_name, buf,
 				sizeof(dlm_config.ci_cluster_name));
-	strlcpy(cl->cl_cluster_name, buf, sizeof(cl->cl_cluster_name));
+	strscpy(cl->cl_cluster_name, buf, sizeof(cl->cl_cluster_name));
 	return len;
 }
 

fs/jbd2/journal.c

···
 {
 	journal_t *journal;
 	sector_t blocknr;
-	char *p;
 	int err = 0;
 
 	blocknr = 0;
···
 
 	journal->j_inode = inode;
 	snprintf(journal->j_devname, sizeof(journal->j_devname),
-		 "%pg", journal->j_dev);
-	p = strreplace(journal->j_devname, '/', '!');
-	sprintf(p, "-%lu", journal->j_inode->i_ino);
+		 "%pg-%lu", journal->j_dev, journal->j_inode->i_ino);
+	strreplace(journal->j_devname, '/', '!');
 	jbd2_stats_proc_init(journal);
 
 	return journal;

fs/nfs/nfsroot.c

···
 static int __init root_nfs_copy(char *dest, const char *src,
 				     const size_t destlen)
 {
-	if (strlcpy(dest, src, destlen) > destlen)
+	if (strscpy(dest, src, destlen) == -E2BIG)
 		return -1;
 	return 0;
 }

fs/vboxsf/super.c

···
 	}
 	folder_name->size = size;
 	folder_name->length = size - 1;
-	strlcpy(folder_name->string.utf8, fc->source, size);
+	strscpy(folder_name->string.utf8, fc->source, size);
 	err = vboxsf_map_folder(folder_name, &sbi->root);
 	kfree(folder_name);
 	if (err) {

fs/xfs/libxfs/xfs_btree.h

···
 static inline size_t
 xfs_btree_cur_sizeof(unsigned int nlevels)
 {
-	return struct_size((struct xfs_btree_cur *)NULL, bc_levels, nlevels);
+	return struct_size_t(struct xfs_btree_cur, bc_levels, nlevels);
 }
 
 /* cursor flags */

fs/xfs/scrub/btree.h

···
 static inline size_t
 xchk_btree_sizeof(unsigned int nlevels)
 {
-	return struct_size((struct xchk_btree *)NULL, lastkey, nlevels - 1);
+	return struct_size_t(struct xchk_btree, lastkey, nlevels - 1);
 }
 
 int xchk_btree(struct xfs_scrub *sc, struct xfs_btree_cur *cur,

include/acpi/actbl3.h

···
 struct acpi_table_slit {
 	struct acpi_table_header header;	/* Common ACPI table header */
 	u64 locality_count;
-	u8 entry[1];		/* Real size = localities^2 */
+	u8 entry[];				/* Real size = localities^2 */
 };
 
 /*******************************************************************************

include/linux/compiler_attributes.h

···
 #endif
 
 /*
+ * Optional: only supported since gcc >= 14
+ * Optional: only supported since clang >= 17
+ *
+ *   gcc: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=108896
+ * clang: https://reviews.llvm.org/D148381
+ */
+#if __has_attribute(__element_count__)
+# define __counted_by(member)		__attribute__((__element_count__(#member)))
+#else
+# define __counted_by(member)
+#endif
+
+/*
  * Optional: only supported since clang >= 14.0
  *
  *   gcc: https://gcc.gnu.org/onlinedocs/gcc/Common-Function-Attributes.html#index-error-function-attribute

include/linux/fortify-string.h

···
 ({								\
 	char *__p = (char *)(p);				\
 	size_t __ret = SIZE_MAX;				\
-	size_t __p_size = __member_size(p);			\
+	const size_t __p_size = __member_size(p);		\
 	if (__p_size != SIZE_MAX &&				\
 	    __builtin_constant_p(*__p)) {			\
 		size_t __p_len = __p_size - 1;			\
···
 __FORTIFY_INLINE __diagnose_as(__builtin_strncpy, 1, 2, 3)
 char *strncpy(char * const POS p, const char *q, __kernel_size_t size)
 {
-	size_t p_size = __member_size(p);
+	const size_t p_size = __member_size(p);
 
 	if (__compiletime_lessthan(p_size, size))
 		__write_overflow();
 	if (p_size < size)
 		fortify_panic(__func__);
 	return __underlying_strncpy(p, q, size);
-}
-
-/**
- * strcat - Append a string to an existing string
- *
- * @p: pointer to NUL-terminated string to append to
- * @q: pointer to NUL-terminated source string to append from
- *
- * Do not use this function. While FORTIFY_SOURCE tries to avoid
- * read and write overflows, this is only possible when the
- * destination buffer size is known to the compiler. Prefer
- * building the string with formatting, via scnprintf() or similar.
- * At the very least, use strncat().
- *
- * Returns @p.
- *
- */
-__FORTIFY_INLINE __diagnose_as(__builtin_strcat, 1, 2)
-char *strcat(char * const POS p, const char *q)
-{
-	size_t p_size = __member_size(p);
-
-	if (p_size == SIZE_MAX)
-		return __underlying_strcat(p, q);
-	if (strlcat(p, q, p_size) >= p_size)
-		fortify_panic(__func__);
-	return p;
 }
 
 extern __kernel_size_t __real_strnlen(const char *, __kernel_size_t) __RENAME(strnlen);
···
  */
 __FORTIFY_INLINE __kernel_size_t strnlen(const char * const POS p, __kernel_size_t maxlen)
 {
-	size_t p_size = __member_size(p);
-	size_t p_len = __compiletime_strlen(p);
+	const size_t p_size = __member_size(p);
+	const size_t p_len = __compiletime_strlen(p);
 	size_t ret;
 
 	/* We can take compile-time actions when maxlen is const. */
···
 __FORTIFY_INLINE __diagnose_as(__builtin_strlen, 1)
 __kernel_size_t __fortify_strlen(const char * const POS p)
 {
+	const size_t p_size = __member_size(p);
 	__kernel_size_t ret;
-	size_t p_size = __member_size(p);
 
 	/* Give up if we don't know how large p is. */
 	if (p_size == SIZE_MAX)
···
  */
 __FORTIFY_INLINE size_t strlcpy(char * const POS p, const char * const POS q, size_t size)
 {
-	size_t p_size = __member_size(p);
-	size_t q_size = __member_size(q);
+	const size_t p_size = __member_size(p);
+	const size_t q_size = __member_size(q);
 	size_t q_len;	/* Full count of source string length. */
 	size_t len;	/* Count of characters going into destination. */
 
···
  * @q: Where to copy the string from
  * @size: Size of destination buffer
  *
- * Copy the source string @p, or as much of it as fits, into the destination
- * @q buffer. The behavior is undefined if the string buffers overlap. The
+ * Copy the source string @q, or as much of it as fits, into the destination
+ * @p buffer. The behavior is undefined if the string buffers overlap. The
  * destination @p buffer is always NUL terminated, unless it's zero-sized.
  *
  * Preferred to strlcpy() since the API doesn't require reading memory
···
  */
 __FORTIFY_INLINE ssize_t strscpy(char * const POS p, const char * const POS q, size_t size)
 {
-	size_t len;
 	/* Use string size rather than possible enclosing struct size. */
-	size_t p_size = __member_size(p);
-	size_t q_size = __member_size(q);
+	const size_t p_size = __member_size(p);
+	const size_t q_size = __member_size(q);
+	size_t len;
 
 	/* If we cannot get size of p and q default to call strscpy. */
 	if (p_size == SIZE_MAX && q_size == SIZE_MAX)
···
 	return __real_strscpy(p, q, len);
 }
 
+/* Defined after fortified strlen() to reuse it. */
+extern size_t __real_strlcat(char *p, const char *q, size_t avail) __RENAME(strlcat);
+/**
+ * strlcat - Append a string to an existing string
+ *
+ * @p: pointer to %NUL-terminated string to append to
+ * @q: pointer to %NUL-terminated string to append from
+ * @avail: Maximum bytes available in @p
+ *
+ * Appends %NUL-terminated string @q after the %NUL-terminated
+ * string at @p, but will not write beyond @avail bytes total,
+ * potentially truncating the copy from @q. @p will stay
+ * %NUL-terminated only if a %NUL already existed within
+ * the @avail bytes of @p. If so, the resulting number of
+ * bytes copied from @q will be at most "@avail - strlen(@p) - 1".
+ *
+ * Do not use this function. While FORTIFY_SOURCE tries to avoid
+ * read and write overflows, this is only possible when the sizes
+ * of @p and @q are known to the compiler. Prefer building the
+ * string with formatting, via scnprintf(), seq_buf, or similar.
+ *
+ * Returns total bytes that _would_ have been contained by @p
+ * regardless of truncation, similar to snprintf(). If return
+ * value is >= @avail, the string has been truncated.
+ *
+ */
+__FORTIFY_INLINE
+size_t strlcat(char * const POS p, const char * const POS q, size_t avail)
+{
+	const size_t p_size = __member_size(p);
+	const size_t q_size = __member_size(q);
+	size_t p_len, copy_len;
+	size_t actual, wanted;
+
+	/* Give up immediately if both buffer sizes are unknown. */
+	if (p_size == SIZE_MAX && q_size == SIZE_MAX)
+		return __real_strlcat(p, q, avail);
+
+	p_len = strnlen(p, avail);
+	copy_len = strlen(q);
+	wanted = actual = p_len + copy_len;
+
+	/* Cannot append any more: report truncation. */
+	if (avail <= p_len)
+		return wanted;
+
+	/* Give up if string is already overflowed. */
+	if (p_size <= p_len)
+		fortify_panic(__func__);
+
+	if (actual >= avail) {
+		copy_len = avail - p_len - 1;
+		actual = p_len + copy_len;
+	}
+
+	/* Give up if copy will overflow. */
+	if (p_size <= actual)
+		fortify_panic(__func__);
+	__underlying_memcpy(p + p_len, q, copy_len);
+	p[actual] = '\0';
+
+	return wanted;
+}
+
+/* Defined after fortified strlcat() to reuse it. */
+/**
+ * strcat - Append a string to an existing string
+ *
+ * @p: pointer to NUL-terminated string to append to
+ * @q: pointer to NUL-terminated source string to append from
+ *
+ * Do not use this function. While FORTIFY_SOURCE tries to avoid
+ * read and write overflows, this is only possible when the
+ * destination buffer size is known to the compiler. Prefer
+ * building the string with formatting, via scnprintf() or similar.
+ * At the very least, use strncat().
+ *
+ * Returns @p.
+ *
+ */
+__FORTIFY_INLINE __diagnose_as(__builtin_strcat, 1, 2)
+char *strcat(char * const POS p, const char *q)
+{
+	const size_t p_size = __member_size(p);
+
+	if (strlcat(p, q, p_size) >= p_size)
+		fortify_panic(__func__);
+	return p;
+}
+
 /**
  * strncat - Append a string to an existing string
  *
···
 __FORTIFY_INLINE __diagnose_as(__builtin_strncat, 1, 2, 3)
 char *strncat(char * const POS p, const char * const POS q, __kernel_size_t count)
 {
+	const size_t p_size = __member_size(p);
+	const size_t q_size = __member_size(q);
 	size_t p_len, copy_len;
-	size_t p_size = __member_size(p);
-	size_t q_size = __member_size(q);
 
 	if (p_size == SIZE_MAX && q_size == SIZE_MAX)
 		return __underlying_strncat(p, q, count);
···
 extern void *__real_memscan(void *, int, __kernel_size_t) __RENAME(memscan);
 __FORTIFY_INLINE void *memscan(void * const POS0 p, int c, __kernel_size_t size)
 {
-	size_t p_size = __struct_size(p);
+	const size_t p_size = __struct_size(p);
 
 	if (__compiletime_lessthan(p_size, size))
 		__read_overflow();
···
 __FORTIFY_INLINE __diagnose_as(__builtin_memcmp, 1, 2, 3)
 int memcmp(const void * const POS0 p, const void * const POS0 q, __kernel_size_t size)
 {
-	size_t p_size = __struct_size(p);
-	size_t q_size = __struct_size(q);
+	const size_t p_size = __struct_size(p);
+	const size_t q_size = __struct_size(q);
 
 	if (__builtin_constant_p(size)) {
 		if (__compiletime_lessthan(p_size, size))
···
 __FORTIFY_INLINE __diagnose_as(__builtin_memchr, 1, 2, 3)
 void *memchr(const void * const POS0 p, int c, __kernel_size_t size)
 {
-	size_t p_size = __struct_size(p);
+	const size_t p_size = __struct_size(p);
 
 	if (__compiletime_lessthan(p_size, size))
 		__read_overflow();
···
 void *__real_memchr_inv(const void *s, int c, size_t n) __RENAME(memchr_inv);
 __FORTIFY_INLINE void *memchr_inv(const void * const POS0 p, int c, size_t size)
 {
-	size_t p_size = __struct_size(p);
+	const size_t p_size = __struct_size(p);
 
 	if (__compiletime_lessthan(p_size, size))
 		__read_overflow();
···
 								    __realloc_size(2);
 __FORTIFY_INLINE void *kmemdup(const void * const POS0 p, size_t size, gfp_t gfp)
 {
-	size_t p_size = __struct_size(p);
+	const size_t p_size = __struct_size(p);
 
 	if (__compiletime_lessthan(p_size, size))
 		__read_overflow();
···
 __FORTIFY_INLINE __diagnose_as(__builtin_strcpy, 1, 2)
 char *strcpy(char * const POS p, const char * const POS q)
 {
-	size_t p_size = __member_size(p);
-	size_t q_size = __member_size(q);
+	const size_t p_size = __member_size(p);
+	const size_t q_size = __member_size(q);
 	size_t size;
 
 	/* If neither buffer size is known, immediately give up. */

include/linux/overflow.h

···
  * @member: Name of the array member.
  * @count: Number of elements in the array.
  *
- * Calculates size of memory needed for structure @p followed by an
+ * Calculates size of memory needed for structure of @p followed by an
  * array of @count number of @member elements.
  *
  * Return: number of bytes needed or SIZE_MAX on overflow.
···
 	__builtin_choose_expr(__is_constexpr(count),			\
 		sizeof(*(p)) + flex_array_size(p, member, count),	\
 		size_add(sizeof(*(p)), flex_array_size(p, member, count)))
+
+/**
+ * struct_size_t() - Calculate size of structure with trailing flexible array
+ * @type: structure type name.
+ * @member: Name of the array member.
+ * @count: Number of elements in the array.
+ *
+ * Calculates size of memory needed for structure @type followed by an
+ * array of @count number of @member elements. Prefer using struct_size()
+ * when possible instead, to keep calculations associated with a specific
+ * instance variable of type @type.
+ *
+ * Return: number of bytes needed or SIZE_MAX on overflow.
+ */
+#define struct_size_t(type, member, count)					\
+	struct_size((type *)NULL, member, count)
 
 #endif /* __LINUX_OVERFLOW_H */

include/linux/string.h

···
 #endif
 
 void *memchr_inv(const void *s, int c, size_t n);
-char *strreplace(char *s, char old, char new);
+char *strreplace(char *str, char old, char new);
 
 extern void kfree_const(const void *x);
 

include/uapi/linux/auto_dev-ioctl.h

···
 		struct args_ismountpoint	ismountpoint;
 	};
 
-	char path[0];
+	char path[];
 };
 
 static inline void init_autofs_dev_ioctl(struct autofs_dev_ioctl *in)

kernel/kallsyms.c

···
 {
 	int ret;
 
-	strlcpy(iter->module_name, "bpf", MODULE_NAME_LEN);
+	strscpy(iter->module_name, "bpf", MODULE_NAME_LEN);
 	iter->exported = 0;
 	ret = bpf_get_kallsym(iter->pos - iter->pos_ftrace_mod_end,
 			      &iter->value, &iter->type,
···
  */
 static int get_ksymbol_kprobe(struct kallsym_iter *iter)
 {
-	strlcpy(iter->module_name, "__builtin__kprobes", MODULE_NAME_LEN);
+	strscpy(iter->module_name, "__builtin__kprobes", MODULE_NAME_LEN);
 	iter->exported = 0;
 	return kprobe_get_kallsym(iter->pos - iter->pos_bpf_end,
 				  &iter->value, &iter->type,

kernel/params.c

···
 			name_len = 0;
 		} else {
 			name_len = dot - kp->name + 1;
-			strlcpy(modname, kp->name, name_len);
+			strscpy(modname, kp->name, name_len);
 		}
 		kernel_add_sysfs_param(modname, kp, name_len);
 	}

kernel/time/clocksource.c

···
 {
 	mutex_lock(&clocksource_mutex);
 	if (str)
-		strlcpy(override_name, str, sizeof(override_name));
+		strscpy(override_name, str, sizeof(override_name));
 	mutex_unlock(&clocksource_mutex);
 	return 1;
 }

kernel/trace/ftrace.c

···
 static int __init set_ftrace_notrace(char *str)
 {
 	ftrace_filter_param = true;
-	strlcpy(ftrace_notrace_buf, str, FTRACE_FILTER_SIZE);
+	strscpy(ftrace_notrace_buf, str, FTRACE_FILTER_SIZE);
 	return 1;
 }
 __setup("ftrace_notrace=", set_ftrace_notrace);
···
 static int __init set_ftrace_filter(char *str)
 {
 	ftrace_filter_param = true;
-	strlcpy(ftrace_filter_buf, str, FTRACE_FILTER_SIZE);
+	strscpy(ftrace_filter_buf, str, FTRACE_FILTER_SIZE);
 	return 1;
 }
 __setup("ftrace_filter=", set_ftrace_filter);
···
 
 static int __init set_graph_function(char *str)
 {
-	strlcpy(ftrace_graph_buf, str, FTRACE_FILTER_SIZE);
+	strscpy(ftrace_graph_buf, str, FTRACE_FILTER_SIZE);
 	return 1;
 }
 __setup("ftrace_graph_filter=", set_graph_function);
 
 static int __init set_graph_notrace_function(char *str)
 {
-	strlcpy(ftrace_graph_notrace_buf, str, FTRACE_FILTER_SIZE);
+	strscpy(ftrace_graph_notrace_buf, str, FTRACE_FILTER_SIZE);
 	return 1;
 }
 __setup("ftrace_graph_notrace=", set_graph_notrace_function);
···
 			continue;
 		*value = op->trampoline;
 		*type = 't';
-		strlcpy(name, FTRACE_TRAMPOLINE_SYM, KSYM_NAME_LEN);
-		strlcpy(module_name, FTRACE_TRAMPOLINE_MOD, MODULE_NAME_LEN);
+		strscpy(name, FTRACE_TRAMPOLINE_SYM, KSYM_NAME_LEN);
+		strscpy(module_name, FTRACE_TRAMPOLINE_MOD, MODULE_NAME_LEN);
 		*exported = 0;
 		return 0;
 	}
···
 		if (off)
 			*off = addr - found_func->ip;
 		if (sym)
-			strlcpy(sym, found_func->name, KSYM_NAME_LEN);
+			strscpy(sym, found_func->name, KSYM_NAME_LEN);
 
 		return found_func->name;
 	}
···
 
 			*value = mod_func->ip;
 			*type = 'T';
-			strlcpy(name, mod_func->name, KSYM_NAME_LEN);
-			strlcpy(module_name, mod_map->mod->name, MODULE_NAME_LEN);
+			strscpy(name, mod_func->name, KSYM_NAME_LEN);
+			strscpy(module_name, mod_map->mod->name, MODULE_NAME_LEN);
 			*exported = 1;
 			preempt_enable();
 			return 0;

kernel/trace/trace.c

···
 
 static int __init set_cmdline_ftrace(char *str)
 {
-	strlcpy(bootup_tracer_buf, str, MAX_TRACER_SIZE);
+	strscpy(bootup_tracer_buf, str, MAX_TRACER_SIZE);
 	default_bootup_tracer = bootup_tracer_buf;
 	/* We are using ftrace early, expand it */
 	ring_buffer_expanded = true;
···
 
 static int __init set_trace_boot_options(char *str)
 {
-	strlcpy(trace_boot_options_buf, str, MAX_TRACER_SIZE);
+	strscpy(trace_boot_options_buf, str, MAX_TRACER_SIZE);
 	return 1;
 }
 __setup("trace_options=", set_trace_boot_options);
···
 
 static int __init set_trace_boot_clock(char *str)
 {
-	strlcpy(trace_boot_clock_buf, str, MAX_TRACER_SIZE);
+	strscpy(trace_boot_clock_buf, str, MAX_TRACER_SIZE);
 	trace_boot_clock = trace_boot_clock_buf;
 	return 1;
 }
···
 	if (map != NO_CMDLINE_MAP) {
 		tpid = savedcmd->map_cmdline_to_pid[map];
 		if (tpid == pid) {
-			strlcpy(comm, get_saved_cmdlines(map), TASK_COMM_LEN);
+			strscpy(comm, get_saved_cmdlines(map), TASK_COMM_LEN);
 			return;
 		}
 	}

kernel/trace/trace_events.c

···
 	char *buf;
 	int i;
 
-	strlcpy(bootup_trigger_buf, str, COMMAND_LINE_SIZE);
+	strscpy(bootup_trigger_buf, str, COMMAND_LINE_SIZE);
 	ring_buffer_expanded = true;
 	disable_tracing_selftest("running event triggers");
 
···
 
 static __init int setup_trace_event(char *str)
 {
-	strlcpy(bootup_event_buf, str, COMMAND_LINE_SIZE);
+	strscpy(bootup_event_buf, str, COMMAND_LINE_SIZE);
 	ring_buffer_expanded = true;
 	disable_tracing_selftest("running event tracing");
 

kernel/trace/trace_events_inject.c

···
 			char *addr = (char *)(unsigned long) val;
 
 			if (field->filter_type == FILTER_STATIC_STRING) {
-				strlcpy(entry + field->offset, addr, field->size);
+				strscpy(entry + field->offset, addr, field->size);
 			} else if (field->filter_type == FILTER_DYN_STRING ||
 				   field->filter_type == FILTER_RDYN_STRING) {
 				int str_len = strlen(addr) + 1;
···
 				}
 				entry = *pentry;
 
-				strlcpy(entry + (entry_size - str_len), addr, str_len);
+				strscpy(entry + (entry_size - str_len), addr, str_len);
 				str_item = (u32 *)(entry + field->offset);
 				if (field->filter_type == FILTER_RDYN_STRING)
 					str_loc -= field->offset + field->size;

kernel/trace/trace_kprobe.c

···
 
 static int __init set_kprobe_boot_events(char *str)
 {
-	strlcpy(kprobe_boot_events_buf, str, COMMAND_LINE_SIZE);
+	strscpy(kprobe_boot_events_buf, str, COMMAND_LINE_SIZE);
 	disable_tracing_selftest("running kprobe events");
 
 	return 1;

kernel/trace/trace_probe.c

···
 			trace_probe_log_err(offset, GROUP_TOO_LONG);
 			return -EINVAL;
 		}
-		strlcpy(buf, event, slash - event + 1);
+		strscpy(buf, event, slash - event + 1);
 		if (!is_good_system_name(buf)) {
 			trace_probe_log_err(offset, BAD_GROUP_NAME);
 			return -EINVAL;

lib/Kconfig.debug

···
 
 config FORTIFY_KUNIT_TEST
 	tristate "Test fortified str*() and mem*() function internals at runtime" if !KUNIT_ALL_TESTS
-	depends on KUNIT && FORTIFY_SOURCE
+	depends on KUNIT
 	default KUNIT_ALL_TESTS
 	help
 	  Builds unit tests for checking internals of FORTIFY_SOURCE as used
···
 	  Tests for hw_breakpoint constraints accounting.
 
 	  If unsure, say N.
+
+config STRCAT_KUNIT_TEST
+	tristate "Test strcat() family of functions at runtime" if !KUNIT_ALL_TESTS
+	depends on KUNIT
+	default KUNIT_ALL_TESTS
 
 config STRSCPY_KUNIT_TEST
 	tristate "Test strscpy*() family of functions at runtime" if !KUNIT_ALL_TESTS

lib/Kconfig.ubsan

···
 config UBSAN_TRAP
 	bool "On Sanitizer warnings, abort the running kernel code"
 	depends on !COMPILE_TEST
-	depends on $(cc-option, -fsanitize-undefined-trap-on-error)
 	help
 	  Building kernels with Sanitizer features enabled tends to grow
 	  the kernel size by around 5%, due to adding all the debugging
···
 	  the system. For some system builders this is an acceptable
 	  trade-off.
 
-config CC_HAS_UBSAN_BOUNDS
-	def_bool $(cc-option,-fsanitize=bounds)
+config CC_HAS_UBSAN_BOUNDS_STRICT
+	def_bool $(cc-option,-fsanitize=bounds-strict)
+	help
+	  The -fsanitize=bounds-strict option is only available on GCC,
+	  but uses the more strict handling of arrays that includes knowledge
+	  of flexible arrays, which is comparable to Clang's regular
+	  -fsanitize=bounds.
 
 config CC_HAS_UBSAN_ARRAY_BOUNDS
 	def_bool $(cc-option,-fsanitize=array-bounds)
+	help
+	  Under Clang, the -fsanitize=bounds option is actually composed
+	  of two more specific options, -fsanitize=array-bounds and
+	  -fsanitize=local-bounds. However, -fsanitize=local-bounds can
+	  only be used when trap mode is enabled. (See also the help for
+	  CONFIG_LOCAL_BOUNDS.) Explicitly check for -fsanitize=array-bounds
+	  so that we can build up the options needed for UBSAN_BOUNDS
+	  with or without UBSAN_TRAP.
 
 config UBSAN_BOUNDS
 	bool "Perform array index bounds checking"
 	default UBSAN
-	depends on CC_HAS_UBSAN_ARRAY_BOUNDS || CC_HAS_UBSAN_BOUNDS
+	depends on CC_HAS_UBSAN_ARRAY_BOUNDS || CC_HAS_UBSAN_BOUNDS_STRICT
 	help
 	  This option enables detection of directly indexed out of bounds
 	  array accesses, where the array size is known at compile time.
···
 	  to the {str,mem}*cpy() family of functions (that is addressed
 	  by CONFIG_FORTIFY_SOURCE).
 
-config UBSAN_ONLY_BOUNDS
-	def_bool CC_HAS_UBSAN_BOUNDS && !CC_HAS_UBSAN_ARRAY_BOUNDS
-	depends on UBSAN_BOUNDS
+config UBSAN_BOUNDS_STRICT
+	def_bool UBSAN_BOUNDS && CC_HAS_UBSAN_BOUNDS_STRICT
 	help
-	  This is a weird case: Clang's -fsanitize=bounds includes
-	  -fsanitize=local-bounds, but it's trapping-only, so for
-	  Clang, we must use -fsanitize=array-bounds when we want
-	  traditional array bounds checking enabled. For GCC, we
-	  want -fsanitize=bounds.
+	  GCC's bounds sanitizer. This option is used to select the
+	  correct options in Makefile.ubsan.
 
 config UBSAN_ARRAY_BOUNDS
-	def_bool CC_HAS_UBSAN_ARRAY_BOUNDS
-	depends on UBSAN_BOUNDS
+	def_bool UBSAN_BOUNDS && CC_HAS_UBSAN_ARRAY_BOUNDS
+	help
+	  Clang's array bounds sanitizer. This option is used to select
+	  the correct options in Makefile.ubsan.
 
 config UBSAN_LOCAL_BOUNDS
-	bool "Perform array local bounds checking"
-	depends on UBSAN_TRAP
-	depends on $(cc-option,-fsanitize=local-bounds)
+	def_bool UBSAN_ARRAY_BOUNDS && UBSAN_TRAP
 	help
-	  This option enables -fsanitize=local-bounds which traps when an
-	  exception/error is detected. Therefore, it may only be enabled
-	  with CONFIG_UBSAN_TRAP.
-
-	  Enabling this option detects errors due to accesses through a
-	  pointer that is derived from an object of a statically-known size,
-	  where an added offset (which may not be known statically) is
-	  out-of-bounds.
+	  This option enables Clang's -fsanitize=local-bounds which traps
+	  when an access through a pointer that is derived from an object
+	  of a statically-known size, where an added offset (which may not
+	  be known statically) is out-of-bounds. Since this option is
+	  trap-only, it depends on CONFIG_UBSAN_TRAP.
 
 config UBSAN_SHIFT
 	bool "Perform checking for bit-shift overflows"

lib/Makefile

···
 CFLAGS_fortify_kunit.o += $(call cc-disable-warning, unsequenced)
 CFLAGS_fortify_kunit.o += $(DISABLE_STRUCTLEAK_PLUGIN)
 obj-$(CONFIG_FORTIFY_KUNIT_TEST) += fortify_kunit.o
+obj-$(CONFIG_STRCAT_KUNIT_TEST) += strcat_kunit.o
 obj-$(CONFIG_STRSCPY_KUNIT_TEST) += strscpy_kunit.o
 obj-$(CONFIG_SIPHASH_KUNIT_TEST) += siphash_kunit.o
 

lib/fortify_kunit.c

···
 static const char *ptr_of_11 = "this is 11!";
 static char array_unknown[] = "compiler thinks I might change";
 
+/* Handle being built without CONFIG_FORTIFY_SOURCE */
+#ifndef __compiletime_strlen
+# define __compiletime_strlen __builtin_strlen
+#endif
+
 static void known_sizes_test(struct kunit *test)
 {
 	KUNIT_EXPECT_EQ(test, __compiletime_strlen("88888888"), 8);
···
 } while (0)
 DEFINE_ALLOC_SIZE_TEST_PAIR(devm_kmalloc)
 
+static int fortify_test_init(struct kunit *test)
+{
+	if (!IS_ENABLED(CONFIG_FORTIFY_SOURCE))
+		kunit_skip(test, "Not built with CONFIG_FORTIFY_SOURCE=y");
+
+	return 0;
+}
+
 static struct kunit_case fortify_test_cases[] = {
 	KUNIT_CASE(known_sizes_test),
 	KUNIT_CASE(control_flow_split_test),
···
 
 static struct kunit_suite fortify_test_suite = {
 	.name = "fortify",
+	.init = fortify_test_init,
 	.test_cases = fortify_test_cases,
 };
 

lib/kobject.c

···
 		kfree_const(s);
 		if (!t)
 			return -ENOMEM;
-		strreplace(t, '/', '!');
-		s = t;
+		s = strreplace(t, '/', '!');
 	}
 	kfree_const(kobj->name);
 	kobj->name = s;

lib/overflow_kunit.c

···
 static void overflow_size_helpers_test(struct kunit *test)
 {
 	/* Make sure struct_size() can be used in a constant expression. */
-	u8 ce_array[struct_size((struct __test_flex_array *)0, data, 55)];
+	u8 ce_array[struct_size_t(struct __test_flex_array, data, 55)];
 	struct __test_flex_array *obj;
 	int count = 0;
 	int var;

lib/strcat_kunit.c

···
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Kernel module for testing 'strcat' family of functions.
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <kunit/test.h>
+#include <linux/string.h>
+
+static volatile int unconst;
+
+static void strcat_test(struct kunit *test)
+{
+	char dest[8];
+
+	/* Destination is terminated. */
+	memset(dest, 0, sizeof(dest));
+	KUNIT_EXPECT_EQ(test, strlen(dest), 0);
+	/* Empty copy does nothing. */
+	KUNIT_EXPECT_TRUE(test, strcat(dest, "") == dest);
+	KUNIT_EXPECT_STREQ(test, dest, "");
+	/* 4 characters copied in, stops at %NUL. */
+	KUNIT_EXPECT_TRUE(test, strcat(dest, "four\000123") == dest);
+	KUNIT_EXPECT_STREQ(test, dest, "four");
+	KUNIT_EXPECT_EQ(test, dest[5], '\0');
+	/* 2 more characters copied in okay. */
+	KUNIT_EXPECT_TRUE(test, strcat(dest, "AB") == dest);
+	KUNIT_EXPECT_STREQ(test, dest, "fourAB");
+}
+
+static void strncat_test(struct kunit *test)
+{
+	char dest[8];
+
+	/* Destination is terminated. */
+	memset(dest, 0, sizeof(dest));
+	KUNIT_EXPECT_EQ(test, strlen(dest), 0);
+	/* Empty copy of size 0 does nothing. */
+	KUNIT_EXPECT_TRUE(test, strncat(dest, "", 0 + unconst) == dest);
+	KUNIT_EXPECT_STREQ(test, dest, "");
+	/* Empty copy of size 1 does nothing too. */
+	KUNIT_EXPECT_TRUE(test, strncat(dest, "", 1 + unconst) == dest);
+	KUNIT_EXPECT_STREQ(test, dest, "");
+	/* Copy of max 0 characters should do nothing. */
+	KUNIT_EXPECT_TRUE(test, strncat(dest, "asdf", 0 + unconst) == dest);
+	KUNIT_EXPECT_STREQ(test, dest, "");
+
+	/* 4 characters copied in, even if max is 8. */
+	KUNIT_EXPECT_TRUE(test, strncat(dest, "four\000123", 8 + unconst) == dest);
+	KUNIT_EXPECT_STREQ(test, dest, "four");
+	KUNIT_EXPECT_EQ(test, dest[5], '\0');
+	KUNIT_EXPECT_EQ(test, dest[6], '\0');
+	/* 2 characters copied in okay, 2 ignored. */
+	KUNIT_EXPECT_TRUE(test, strncat(dest, "ABCD", 2 + unconst) == dest);
+	KUNIT_EXPECT_STREQ(test, dest, "fourAB");
+}
+
+static void strlcat_test(struct kunit *test)
+{
+	char dest[8] = "";
+	int len = sizeof(dest) + unconst;
+
+	/* Destination is terminated. */
+	KUNIT_EXPECT_EQ(test, strlen(dest), 0);
+	/* Empty copy is size 0. */
+	KUNIT_EXPECT_EQ(test, strlcat(dest, "", len), 0);
+	KUNIT_EXPECT_STREQ(test, dest, "");
+	/* Size 1 should keep buffer terminated, report size of source only. */
+	KUNIT_EXPECT_EQ(test, strlcat(dest, "four", 1 + unconst), 4);
+	KUNIT_EXPECT_STREQ(test, dest, "");
+
+	/* 4 characters copied in. */
+	KUNIT_EXPECT_EQ(test, strlcat(dest, "four", len), 4);
+	KUNIT_EXPECT_STREQ(test, dest, "four");
+	/* 2 characters copied in okay, gets to 6 total. */
+	KUNIT_EXPECT_EQ(test, strlcat(dest, "AB", len), 6);
+	KUNIT_EXPECT_STREQ(test, dest, "fourAB");
+	/* 2 characters ignored if max size (7) reached. */
+	KUNIT_EXPECT_EQ(test, strlcat(dest, "CD", 7 + unconst), 8);
+	KUNIT_EXPECT_STREQ(test, dest, "fourAB");
+	/* 1 of 2 characters skipped, now at true max size. */
+	KUNIT_EXPECT_EQ(test, strlcat(dest, "EFG", len), 9);
+	KUNIT_EXPECT_STREQ(test, dest, "fourABE");
+	/* Everything else ignored, now at full size. */
+	KUNIT_EXPECT_EQ(test, strlcat(dest, "1234", len), 11);
+	KUNIT_EXPECT_STREQ(test, dest, "fourABE");
+}
+
+static struct kunit_case strcat_test_cases[] = {
+	KUNIT_CASE(strcat_test),
+	KUNIT_CASE(strncat_test),
+	KUNIT_CASE(strlcat_test),
+	{}
+};
+
+static struct kunit_suite strcat_test_suite = {
+	.name = "strcat",
+	.test_cases = strcat_test_cases,
+};
+
+kunit_test_suite(strcat_test_suite);
+
+MODULE_LICENSE("GPL");

lib/string.c

···
 
 	if (size) {
 		size_t len = (ret >= size) ? size - 1 : ret;
-		memcpy(dest, src, len);
+		__builtin_memcpy(dest, src, len);
 		dest[len] = '\0';
 	}
 	return ret;
···
 	count -= dsize;
 	if (len >= count)
 		len = count-1;
-	memcpy(dest, src, len);
+	__builtin_memcpy(dest, src, len);
 	dest[len] = 0;
 	return res;
 }

lib/string_helpers.c

···
 
 /**
  * strreplace - Replace all occurrences of character in string.
- * @s: The string to operate on.
+ * @str: The string to operate on.
  * @old: The character being replaced.
  * @new: The character @old is replaced with.
  *
- * Returns pointer to the nul byte at the end of @s.
+ * Replaces the each @old character with a @new one in the given string @str.
+ *
+ * Return: pointer to the string @str itself.
  */
-char *strreplace(char *s, char old, char new)
+char *strreplace(char *str, char old, char new)
 {
+	char *s = str;
+
 	for (; *s; ++s)
 		if (*s == old)
 			*s = new;
-	return s;
+	return str;
 }
 EXPORT_SYMBOL(strreplace);
 

lib/ubsan.c

···
 
 void __ubsan_handle_alignment_assumption(void *_data, unsigned long ptr,
 					 unsigned long align,
-					 unsigned long offset);
-void __ubsan_handle_alignment_assumption(void *_data, unsigned long ptr,
-					 unsigned long align,
 					 unsigned long offset)
 {
 	struct alignment_assumption_data *data = _data;

lib/ubsan.h

···
 typedef u64 u_max;
 #endif
 
+void __ubsan_handle_divrem_overflow(void *_data, void *lhs, void *rhs);
+void __ubsan_handle_type_mismatch(struct type_mismatch_data *data, void *ptr);
+void __ubsan_handle_type_mismatch_v1(void *_data, void *ptr);
+void __ubsan_handle_out_of_bounds(void *_data, void *index);
+void __ubsan_handle_shift_out_of_bounds(void *_data, void *lhs, void *rhs);
+void __ubsan_handle_builtin_unreachable(void *_data);
+void __ubsan_handle_load_invalid_value(void *_data, void *val);
+void __ubsan_handle_alignment_assumption(void *_data, unsigned long ptr,
+					 unsigned long align,
+					 unsigned long offset);
+
 #endif

net/netfilter/ipset/ip_set_hash_netiface.c

···
 #define IP_SET_HASH_WITH_MULTI
 #define IP_SET_HASH_WITH_NET0
 
-#define STRLCPY(a, b)	strlcpy(a, b, IFNAMSIZ)
+#define STRSCPY(a, b)	strscpy(a, b, IFNAMSIZ)
 
 /* IPv4 variant */
 
···
 
 		if (!eiface)
 			return -EINVAL;
-		STRLCPY(e.iface, eiface);
+		STRSCPY(e.iface, eiface);
 		e.physdev = 1;
 #endif
 	} else {
-		STRLCPY(e.iface, SRCDIR ? IFACE(in) : IFACE(out));
+		STRSCPY(e.iface, SRCDIR ? IFACE(in) : IFACE(out));
 	}
 
 	if (strlen(e.iface) == 0)
···
 
 		if (!eiface)
 			return -EINVAL;
-		STRLCPY(e.iface, eiface);
+		STRSCPY(e.iface, eiface);
 		e.physdev = 1;
 #endif
 	} else {
-		STRLCPY(e.iface, SRCDIR ? IFACE(in) : IFACE(out));
+		STRSCPY(e.iface, SRCDIR ? IFACE(in) : IFACE(out));
 	}
 
 	if (strlen(e.iface) == 0)

scripts/Makefile.ubsan

···
 
 # Enable available and selected UBSAN features.
 ubsan-cflags-$(CONFIG_UBSAN_ALIGNMENT)		+= -fsanitize=alignment
-ubsan-cflags-$(CONFIG_UBSAN_ONLY_BOUNDS)	+= -fsanitize=bounds
+ubsan-cflags-$(CONFIG_UBSAN_BOUNDS_STRICT)	+= -fsanitize=bounds-strict
 ubsan-cflags-$(CONFIG_UBSAN_ARRAY_BOUNDS)	+= -fsanitize=array-bounds
 ubsan-cflags-$(CONFIG_UBSAN_LOCAL_BOUNDS)	+= -fsanitize=local-bounds
 ubsan-cflags-$(CONFIG_UBSAN_SHIFT)		+= -fsanitize=shift

scripts/checkpatch.pl

···
 #			}
 #		}
 
+# strcpy uses that should likely be strscpy
+		if ($line =~ /\bstrcpy\s*\(/) {
+			WARN("STRCPY",
+			     "Prefer strscpy over strcpy - see: https://github.com/KSPP/linux/issues/88\n" . $herecurr);
+		}
+
 # strlcpy uses that should likely be strscpy
 		if ($line =~ /\bstrlcpy\s*\(/) {
 			WARN("STRLCPY",
-			     "Prefer strscpy over strlcpy - see: https://lore.kernel.org/r/CAHk-=wgfRnXz0W3D37d01q3JFkr_i_uTL=V6A6G1oUZcprmknw\@mail.gmail.com/\n" . $herecurr);
+			     "Prefer strscpy over strlcpy - see: https://github.com/KSPP/linux/issues/89\n" . $herecurr);
+		}
+
+# strncpy uses that should likely be strscpy or strscpy_pad
+		if ($line =~ /\bstrncpy\s*\(/) {
+			WARN("STRNCPY",
+			     "Prefer strscpy, strscpy_pad, or __nonstring over strncpy - see: https://github.com/KSPP/linux/issues/90\n" . $herecurr);
 		}
 
 # typecasts on min/max could be min_t/max_t
···
 				 "return sysfs_emit(...) formats should include a terminating newline\n" . $herecurr) &&
 			    $fix) {
 				substr($fixed[$fixlinenr], $offset, 0) = '\\n';
+			}
+		}
+
+# check for array definition/declarations that should use flexible arrays instead
+		if ($sline =~ /^[\+ ]\s*\}(?:\s*__packed)?\s*;\s*$/ &&
+		    $prevline =~ /^\+\s*(?:\}(?:\s*__packed\s*)?|$Type)\s*$Ident\s*\[\s*(0|1)\s*\]\s*;\s*$/) {
+			if (ERROR("FLEXIBLE_ARRAY",
+				  "Use C99 flexible arrays - see https://docs.kernel.org/process/deprecated.html#zero-length-and-one-element-arrays\n" . $hereprev) &&
+			    $1 == '0' && $fix) {
+				$fixed[$fixlinenr - 1] =~ s/\[\s*0\s*\]/[]/;
 			}
 		}
 

tools/testing/kunit/configs/all_tests.config

···
 CONFIG_KUNIT_EXAMPLE_TEST=y
 CONFIG_KUNIT_ALL_TESTS=y
 
+CONFIG_FORTIFY_SOURCE=y
+
 CONFIG_IIO=y
 
 CONFIG_EXT4_FS=y

tools/testing/kunit/configs/arch_uml.config

···
 # Enable virtio/pci, as a lot of tests require it.
 CONFIG_VIRTIO_UML=y
 CONFIG_UML_PCI_OVER_VIRTIO=y
+
+# Enable FORTIFY_SOURCE for wider checking.
+CONFIG_FORTIFY_SOURCE=y