bpf: mark a NULL kfunc argument precisegrafted

check_kfunc_arg() allows bpf_register_is_null() for nullable arguments
w/o marking the underlying scalar register precise. Hence a checkpoint
created on such a path would prune against arbitrary scalar value.

Fixes: 3bda08b63670 ("bpf: Allow NULL buffers in bpf_dynptr_slice(_rw)")
Signed-off-by: Eduard Zingerman <eddyz87@gmail.com>
Link: https://lore.kernel.org/r/20260904-register-is-null-precise-fixes-v1-5-0f5a360ff15d@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

1 files changed, 92 insertions, 0 deletions

diff --git a/arch/arm/boot/Makefile b/arch/arm/boot/Makefile
new file mode 100644
index 000000000..ba9b9a802
--- /dev/null
+++ b/arch/arm/boot/Makefile
@@ -0,0 +1,92 @@
+#
+# arch/arm/boot/Makefile
+#
+# This file is included by the global makefile so that you can add your own
+# architecture-specific flags and dependencies.
+#
+# This file is subject to the terms and conditions of the GNU General Public
+# License.  See the file "COPYING" in the main directory of this archive
+# for more details.
+#
+# Copyright (C) 1995-2002 Russell King
+#
+OBJCOPYFLAGS	:=-O binary -R .comment -S
+
+#   ZRELADDR == virt_to_phys(PAGE_OFFSET + TEXT_OFFSET)
+ifdef CONFIG_PHYS_OFFSET
+add_hex = $(shell printf 0x%x $$(( $(1) + $(2) )) )
+ZRELADDR    := $(call add_hex, $(CONFIG_PHYS_OFFSET), $(TEXT_OFFSET))
+endif
+
+PHYS_OFFSET := $(CONFIG_PHYS_OFFSET)
+export ZRELADDR PARAMS_PHYS PHYS_OFFSET
+
+targets := Image zImage xipImage bootpImage uImage
+
+ifeq ($(CONFIG_XIP_KERNEL),y)
+
+cmd_deflate_xip_data = $(CONFIG_SHELL) -c '$(src)/deflate_xip_data.sh $< $@'
+
+ifeq ($(CONFIG_XIP_DEFLATED_DATA),y)
+quiet_cmd_mkxip = XIPZ    $@
+cmd_mkxip = $(cmd_objcopy) && $(cmd_deflate_xip_data)
+else
+quiet_cmd_mkxip = $(quiet_cmd_objcopy)
+cmd_mkxip = $(cmd_objcopy)
+endif
+
+$(obj)/xipImage: vmlinux FORCE
+	$(call if_changed,mkxip)
+	@$(kecho) '  Physical Address of xipImage: $(CONFIG_XIP_PHYS_ADDR)'
+
+$(obj)/Image $(obj)/zImage: FORCE
+	@echo 'Kernel configured for XIP (CONFIG_XIP_KERNEL=y)'
+	@echo 'Only the xipImage target is available in this case'
+	@false
+
+else
+
+$(obj)/xipImage: FORCE
+	@echo 'Kernel not configured for XIP (CONFIG_XIP_KERNEL!=y)'
+	@false
+
+$(obj)/Image: vmlinux FORCE
+	$(call if_changed,objcopy)
+
+$(obj)/compressed/vmlinux: $(obj)/Image FORCE
+	$(Q)$(MAKE) $(build)=$(obj)/compressed $@
+
+$(obj)/zImage:	$(obj)/compressed/vmlinux FORCE
+	$(call if_changed,objcopy)
+
+endif
+
+ifneq ($(LOADADDR),)
+  UIMAGE_LOADADDR=$(LOADADDR)
+else
+  ifeq ($(CONFIG_ZBOOT_ROM),y)
+    UIMAGE_LOADADDR=$(CONFIG_ZBOOT_ROM_TEXT)
+  else
+    UIMAGE_LOADADDR=$(ZRELADDR)
+  endif
+endif
+
+check_for_multiple_loadaddr = \
+if [ $(words $(UIMAGE_LOADADDR)) -ne 1 ]; then \
+	echo 'multiple (or no) load addresses: $(UIMAGE_LOADADDR)'; \
+	echo 'This is incompatible with uImages'; \
+	echo 'Specify LOADADDR on the commandline to build an uImage'; \
+	false; \
+fi
+
+$(obj)/uImage:	$(obj)/zImage FORCE
+	@$(check_for_multiple_loadaddr)
+	$(call if_changed,uimage)
+
+$(obj)/bootp/bootp: $(obj)/zImage FORCE
+	$(Q)$(MAKE) $(build)=$(obj)/bootp $@
+
+$(obj)/bootpImage: $(obj)/bootp/bootp FORCE
+	$(call if_changed,objcopy)
+
+subdir-	    := bootp compressed dts