[RFC] UBSan: run-time undefined behavior sanity checker

From: Andrey Ryabinin
Date: Mon Oct 20 2014 - 06:57:12 EST


Hi

This is yet another sanitizer for linux kernel.

UBSan uses copile-time instumentation to catch undefined behavior (UB).
Compiler inserts code that perform certain kinds of
checks before operations that could cause UB.
If check fails (i.e. UB detected) __ubsan_handle_* function called.
to print error message.

Patch is also available via git:
git://github.com/aryabinin/linux --branch ubsan/v1

GCC supports this since 4.9, however upcoming GCC 5.0 has
more checkers implemented.

Different kinds of checkers could be enabled via boot parameter:
ubsan_handle=OEAINVBSLF.
If ubsan_handle not present in cmdline default options are used: ELNVBSLF

O - different kinds of overflows
E - negation overflow, division overflow, division by zero.
A - misaligned memory access.
I - load from/store to an object with insufficient space.
N - null argument declared with nonnull attribute,
returned null from function which never returns null, null ptr dereference.
V - variable size array with non-positive length
B - out-of-bounds memory accesses.
S - shifting out-of-bounds.
L - load of invalid value (value out of range for the enum type, loading other then 0/1 to bool type)
F - call to function through pointer with incorrect function type
(AFAIK this is not implemented in gcc yet, probably works with clang,
though I didn't check it).


Andrey Ryabinin (1):
UBSan: run-time undefined behavior sanity checker

Makefile | 12 +-
arch/x86/Kconfig | 1 +
arch/x86/boot/Makefile | 1 +
arch/x86/boot/compressed/Makefile | 1 +
arch/x86/realmode/rm/Makefile | 1 +
arch/x86/vdso/Makefile | 2 +
drivers/firmware/efi/libstub/Makefile | 1 +
include/linux/sched.h | 4 +
kernel/printk/Makefile | 1 +
lib/Kconfig.debug | 23 ++
lib/Makefile | 3 +
lib/ubsan.c | 559 ++++++++++++++++++++++++++++++++++
lib/ubsan.h | 84 +++++
scripts/Makefile.lib | 6 +
14 files changed, 698 insertions(+), 1 deletion(-)
create mode 100644 lib/ubsan.c
create mode 100644 lib/ubsan.h

--
2.1.2

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