Commit f4626c12 authored by Kees Cook's avatar Kees Cook
Browse files

ubsan: Add awareness of signed integer overflow traps 



On arm64, UBSAN traps can be decoded from the trap instruction. Add the
add, sub, and mul overflow trap codes now that CONFIG_UBSAN_SIGNED_WRAP
exists. Seen under clang 19:

  Internal error: UBSAN: unrecognized failure code: 00000000f2005515 [#1] PREEMPT SMP

Reported-by: default avatarNathan Chancellor <nathan@kernel.org>
Closes: https://lore.kernel.org/lkml/20240411-fix-ubsan-in-hardening-config-v1-0-e0177c80ffaa@kernel.org


Fixes: 557f8c58 ("ubsan: Reintroduce signed overflow sanitizer")
Tested-by: default avatarNathan Chancellor <nathan@kernel.org>
Link: https://lore.kernel.org/r/20240415182832.work.932-kees@kernel.org


Signed-off-by: default avatarKees Cook <keescook@chromium.org>
parent 7fcb91d9

lib/ubsan.c

+16 −2
Original line number Diff line number Diff line
@@ -44,9 +44,10 @@ const char *report_ubsan_failure(struct pt_regs *regs, u32 check_type) 
	case ubsan_shift_out_of_bounds:

		return "UBSAN: shift out of bounds";

#endif

#ifdef CONFIG_UBSAN_DIV_ZERO

#if defined(CONFIG_UBSAN_DIV_ZERO) || defined(CONFIG_UBSAN_SIGNED_WRAP)

	/*

	 * SanitizerKind::IntegerDivideByZero emits

	 * SanitizerKind::IntegerDivideByZero and

	 * SanitizerKind::SignedIntegerOverflow emit

	 * SanitizerHandler::DivremOverflow.

	 */

	case ubsan_divrem_overflow:
@@ -77,6 +78,19 @@ const char *report_ubsan_failure(struct pt_regs *regs, u32 check_type) 
		return "UBSAN: alignment assumption";

	case ubsan_type_mismatch:

		return "UBSAN: type mismatch";

#endif

#ifdef CONFIG_UBSAN_SIGNED_WRAP

	/*

	 * SanitizerKind::SignedIntegerOverflow emits

	 * SanitizerHandler::AddOverflow, SanitizerHandler::SubOverflow,

	 * or SanitizerHandler::MulOverflow.

	 */

	case ubsan_add_overflow:

		return "UBSAN: integer addition overflow";

	case ubsan_sub_overflow:

		return "UBSAN: integer subtraction overflow";

	case ubsan_mul_overflow:

		return "UBSAN: integer multiplication overflow";

#endif

	default:

		return "UBSAN: unrecognized failure code";