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: Nathan Chancellor <nathan@kernel.org>
Closes: https://lore.kernel.org/lkml/20240411-fix-ubsan-in-hardening-config-v1-0-e0177c80ffaa@kernel.org
Fixes: 557f8c582a9b ("ubsan: Reintroduce signed overflow sanitizer")
Tested-by: Nathan Chancellor <nathan@kernel.org>
Link: https://lore.kernel.org/r/20240415182832.work.932-kees@kernel.org
Signed-off-by: Kees Cook <keescook@chromium.org>

diff --git a/lib/ubsan.c b/lib/ubsan.c
index 5fc107f61934c28bd38b6997cd070ee8a25185b5..a1c983d148f16fe34493d6b933577556832bcdf6 100644 (file)
--- a/lib/ubsan.c
+++ b/lib/ubsan.c
@@ -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";