From: Kees Cook <keescook@xxxxxxxxxxxx>
Subject: ubsan: entirely disable alignment checks under UBSAN_TRAP
Commit 8d58f222e85f ("ubsan: disable UBSAN_ALIGNMENT under COMPILE_TEST")
tried to fix the pathological results of UBSAN_ALIGNMENT with UBSAN_TRAP
(which objtool would rightly scream about), but it made an assumption
about how COMPILE_TEST gets set (it is not set for randconfig). As a
result, we need a bigger hammer here: just don't allow the alignment
checks with the trap mode.
Link: http://lkml.kernel.org/r/202005291236.000FCB6@keescook
Link: https://lore.kernel.org/lkml/742521db-1e8c-0d7a-1ed4-a908894fb497@xxxxxxxxxxxxx/
Fixes: 8d58f222e85f ("ubsan: disable UBSAN_ALIGNMENT under COMPILE_TEST")
Signed-off-by: Kees Cook <keescook@xxxxxxxxxxxx>
Reported-by: Randy Dunlap <rdunlap@xxxxxxxxxxxxx>
Acked-by: Randy Dunlap <rdunlap@xxxxxxxxxxxxx>
Cc: Josh Poimboeuf <jpoimboe@xxxxxxxxxx>
Cc: Dmitry Vyukov <dvyukov@xxxxxxxxxx>
Cc: Elena Petrova <lenaptr@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
lib/Kconfig.ubsan | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
--- a/lib/Kconfig.ubsan~ubsan-entirely-disable-alignment-checks-under-ubsan_trap
+++ a/lib/Kconfig.ubsan
@@ -63,7 +63,7 @@ config UBSAN_SANITIZE_ALL
config UBSAN_ALIGNMENT
bool "Enable checks for pointers alignment"
default !HAVE_EFFICIENT_UNALIGNED_ACCESS
- depends on !X86 || !COMPILE_TEST
+ depends on !UBSAN_TRAP
help
This option enables the check of unaligned memory accesses.
Enabling this option on architectures that support unaligned
_
