Merge tag 'hardening-v6.3-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux

Pull hardening updates from Kees Cook:
 "Beyond some specific LoadPin, UBSAN, and fortify features, there are
  other fixes scattered around in various subsystems where maintainers
  were okay with me carrying them in my tree or were non-responsive but
  the patches were reviewed by others:

   - Replace 0-length and 1-element arrays with flexible arrays in
     various subsystems (Paulo Miguel Almeida, Stephen Rothwell, Kees
     Cook)

   - randstruct: Disable Clang 15 support (Eric Biggers)

   - GCC plugins: Drop -std=gnu++11 flag (Sam James)

   - strpbrk(): Refactor to use strchr() (Andy Shevchenko)

   - LoadPin LSM: Allow root filesystem switching when non-enforcing

   - fortify: Use dynamic object size hints when available

   - ext4: Fix CFI function prototype mismatch

   - Nouveau: Fix DP buffer size arguments

   - hisilicon: Wipe entire crypto DMA pool on error

   - coda: Fully allocate sig_inputArgs

   - UBSAN: Improve arm64 trap code reporting

   - copy_struct_from_user(): Add minimum bounds check on kernel buffer
     size"

* tag 'hardening-v6.3-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux:
  randstruct: disable Clang 15 support
  uaccess: Add minimum bounds check on kernel buffer size
  arm64: Support Clang UBSAN trap codes for better reporting
  coda: Avoid partial allocation of sig_inputArgs
  gcc-plugins: drop -std=gnu++11 to fix GCC 13 build
  lib/string: Use strchr() in strpbrk()
  crypto: hisilicon: Wipe entire pool on error
  net/i40e: Replace 0-length array with flexible array
  io_uring: Replace 0-length array with flexible array
  ext4: Fix function prototype mismatch for ext4_feat_ktype
  i915/gvt: Replace one-element array with flexible-array member
  drm/nouveau/disp: Fix nvif_outp_acquire_dp() argument size
  LoadPin: Allow filesystem switch when not enforcing
  LoadPin: Move pin reporting cleanly out of locking
  LoadPin: Refactor sysctl initialization
  LoadPin: Refactor read-only check into a helper
  ARM: ixp4xx: Replace 0-length arrays with flexible arrays
  fortify: Use __builtin_dynamic_object_size() when available
  rxrpc: replace zero-lenth array with DECLARE_FLEX_ARRAY() helper

lib/ubsan.c

@@ -14,10 +14,76 @@
 #include <linux/types.h>
 #include <linux/sched.h>
 #include <linux/uaccess.h>
+#include <linux/ubsan.h>
 #include <kunit/test-bug.h>
 
 #include "ubsan.h"
 
+#ifdef CONFIG_UBSAN_TRAP
+/*
+ * Only include matches for UBSAN checks that are actually compiled in.
+ * The mappings of struct SanitizerKind (the -fsanitize=xxx args) to
+ * enum SanitizerHandler (the traps) in Clang is in clang/lib/CodeGen/.
+ */
+const char *report_ubsan_failure(struct pt_regs *regs, u32 check_type)
+{
+	switch (check_type) {
+#ifdef CONFIG_UBSAN_BOUNDS
+	/*
+	 * SanitizerKind::ArrayBounds and SanitizerKind::LocalBounds
+	 * emit SanitizerHandler::OutOfBounds.
+	 */
+	case ubsan_out_of_bounds:
+		return "UBSAN: array index out of bounds";
+#endif
+#ifdef CONFIG_UBSAN_SHIFT
+	/*
+	 * SanitizerKind::ShiftBase and SanitizerKind::ShiftExponent
+	 * emit SanitizerHandler::ShiftOutOfBounds.
+	 */
+	case ubsan_shift_out_of_bounds:
+		return "UBSAN: shift out of bounds";
+#endif
+#ifdef CONFIG_UBSAN_DIV_ZERO
+	/*
+	 * SanitizerKind::IntegerDivideByZero emits
+	 * SanitizerHandler::DivremOverflow.
+	 */
+	case ubsan_divrem_overflow:
+		return "UBSAN: divide/remainder overflow";
+#endif
+#ifdef CONFIG_UBSAN_UNREACHABLE
+	/*
+	 * SanitizerKind::Unreachable emits
+	 * SanitizerHandler::BuiltinUnreachable.
+	 */
+	case ubsan_builtin_unreachable:
+		return "UBSAN: unreachable code";
+#endif
+#if defined(CONFIG_UBSAN_BOOL) || defined(CONFIG_UBSAN_ENUM)
+	/*
+	 * SanitizerKind::Bool and SanitizerKind::Enum emit
+	 * SanitizerHandler::LoadInvalidValue.
+	 */
+	case ubsan_load_invalid_value:
+		return "UBSAN: loading invalid value";
+#endif
+#ifdef CONFIG_UBSAN_ALIGNMENT
+	/*
+	 * SanitizerKind::Alignment emits SanitizerHandler::TypeMismatch
+	 * or SanitizerHandler::AlignmentAssumption.
+	 */
+	case ubsan_alignment_assumption:
+		return "UBSAN: alignment assumption";
+	case ubsan_type_mismatch:
+		return "UBSAN: type mismatch";
+#endif
+	default:
+		return "UBSAN: unrecognized failure code";
+	}
+}
+
+#else
 static const char * const type_check_kinds[] = {
 	"load of",
 	"store to",
@@ -387,3 +453,5 @@ void __ubsan_handle_alignment_assumption(void *_data, unsigned long ptr,
 	ubsan_epilogue();
 }
 EXPORT_SYMBOL(__ubsan_handle_alignment_assumption);
+
+#endif /* !CONFIG_UBSAN_TRAP */