From e4160b2e4b02377c67f8ecd05786811598f39acd Mon Sep 17 00:00:00 2001 From: Hans de Goede Date: Tue, 17 Mar 2020 14:08:41 +0100 Subject: x86/purgatory: Fail the build if purgatory.ro has missing symbols Linking purgatory.ro with -r enables "incremental linking"; this means no checks for unresolved symbols are done while linking purgatory.ro. A change to the sha256 code has caused the purgatory in 5.4-rc1 to have a missing symbol on memzero_explicit(), yet things still happily build. Add an extra check for unresolved symbols by calling ld without -r before running bin2c to generate kexec-purgatory.c. This causes a build of 5.4-rc1 with this patch added to fail as it should: CHK arch/x86/purgatory/purgatory.ro ld: arch/x86/purgatory/purgatory.ro: in function `sha256_transform': sha256.c:(.text+0x1c0c): undefined reference to `memzero_explicit' make[2]: *** [arch/x86/purgatory/Makefile:72: arch/x86/purgatory/kexec-purgatory.c] Error 1 make[1]: *** [scripts/Makefile.build:509: arch/x86/purgatory] Error 2 make: *** [Makefile:1650: arch/x86] Error 2 Also remove --no-undefined from LDFLAGS_purgatory.ro as that has no effect. Signed-off-by: Hans de Goede Signed-off-by: Borislav Petkov Link: https://lkml.kernel.org/r/20200317130841.290418-2-hdegoede@redhat.com --- arch/x86/purgatory/.gitignore | 1 + arch/x86/purgatory/Makefile | 13 ++++++++++--- 2 files changed, 11 insertions(+), 3 deletions(-) create mode 100644 arch/x86/purgatory/.gitignore diff --git a/arch/x86/purgatory/.gitignore b/arch/x86/purgatory/.gitignore new file mode 100644 index 000000000000..d2be1500671d --- /dev/null +++ b/arch/x86/purgatory/.gitignore @@ -0,0 +1 @@ +purgatory.chk diff --git a/arch/x86/purgatory/Makefile b/arch/x86/purgatory/Makefile index 9733d1cc791d..54aadbb7e0b6 100644 --- a/arch/x86/purgatory/Makefile +++ b/arch/x86/purgatory/Makefile @@ -14,8 +14,12 @@ $(obj)/sha256.o: $(srctree)/lib/crypto/sha256.c FORCE CFLAGS_sha256.o := -D__DISABLE_EXPORTS -LDFLAGS_purgatory.ro := -e purgatory_start -r --no-undefined -nostdlib -z nodefaultlib -targets += purgatory.ro +# When linking purgatory.ro with -r unresolved symbols are not checked, +# also link a purgatory.chk binary without -r to check for unresolved symbols. +PURGATORY_LDFLAGS := -e purgatory_start -nostdlib -z nodefaultlib +LDFLAGS_purgatory.ro := -r $(PURGATORY_LDFLAGS) +LDFLAGS_purgatory.chk := $(PURGATORY_LDFLAGS) +targets += purgatory.ro purgatory.chk # Sanitizer, etc. runtimes are unavailable and cannot be linked here. GCOV_PROFILE := n @@ -61,12 +65,15 @@ CFLAGS_string.o += $(PURGATORY_CFLAGS) $(obj)/purgatory.ro: $(PURGATORY_OBJS) FORCE $(call if_changed,ld) +$(obj)/purgatory.chk: $(obj)/purgatory.ro FORCE + $(call if_changed,ld) + targets += kexec-purgatory.c quiet_cmd_bin2c = BIN2C $@ cmd_bin2c = $(objtree)/scripts/bin2c kexec_purgatory < $< > $@ -$(obj)/kexec-purgatory.c: $(obj)/purgatory.ro FORCE +$(obj)/kexec-purgatory.c: $(obj)/purgatory.ro $(obj)/purgatory.chk FORCE $(call if_changed,bin2c) obj-$(CONFIG_KEXEC_FILE) += kexec-purgatory.o -- cgit