1. 27 May, 2020 2 commits
    • Arnd Bergmann's avatar
      ubsan: build ubsan.c more conservatively · f5a8138c
      Arnd Bergmann authored
      commit af700eae upstream.
      
      objtool points out several conditions that it does not like, depending
      on the combination with other configuration options and compiler
      variants:
      
      stack protector:
        lib/ubsan.o: warning: objtool: __ubsan_handle_type_mismatch()+0xbf: call to __stack_chk_fail() with UACCESS enabled
        lib/ubsan.o: warning: objtool: __ubsan_handle_type_mismatch_v1()+0xbe: call to __stack_chk_fail() with UACCESS enabled
      
      stackleak plugin:
        lib/ubsan.o: warning: objtool: __ubsan_handle_type_mismatch()+0x4a: call to stackleak_track_stack() with UACCESS enabled
        lib/ubsan.o: warning: objtool: __ubsan_handle_type_mismatch_v1()+0x4a: call to stackleak_track_stack() with UACCESS enabled
      
      kasan:
        lib/ubsan.o: warning: objtool: __ubsan_handle_type_mismatch()+0x25: call to memcpy() with UACCESS enabled
        lib/ubsan.o: warning: objtool: __ubsan_handle_type_mismatch_v1()+0x25: call to memcpy() with UACCESS enabled
      
      The stackleak and kasan options just need to be disabled for this file
      as we do for other files already.  For the stack protector, we already
      attempt to disable it, but this fails on clang because the check is
      mixed with the gcc specific -fno-conserve-stack option.  According to
      Andrey Ryabinin, that option is not even needed, dropping it here fixes
      the stackprotector issue.
      
      Link: http://lkml.kernel.org/r/20190722125139.1335385-1-arnd@arndb.de
      Link: https://lore.kernel.org/lkml/20190617123109.667090-1-arnd@arndb.de/t/
      Link: https://lore.kernel.org/lkml/20190722091050.2188664-1-arnd@arndb.de/t/
      Fixes: d08965a2 ("x86/uaccess, ubsan: Fix UBSAN vs. SMAP")
      Signed-off-by: default avatarArnd Bergmann <arnd@arndb.de>
      Reviewed-by: default avatarAndrey Ryabinin <aryabinin@virtuozzo.com>
      Cc: Josh Poimboeuf <jpoimboe@redhat.com>
      Cc: Peter Zijlstra <peterz@infradead.org>
      Cc: Arnd Bergmann <arnd@arndb.de>
      Cc: Borislav Petkov <bp@alien8.de>
      Cc: Dmitry Vyukov <dvyukov@google.com>
      Cc: Thomas Gleixner <tglx@linutronix.de>
      Cc: Ingo Molnar <mingo@kernel.org>
      Cc: Kees Cook <keescook@chromium.org>
      Cc: Matthew Wilcox <willy@infradead.org>
      Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
      Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
      Cc: <stable@vger.kernel.org>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      f5a8138c
    • Peter Zijlstra's avatar
      x86/uaccess, ubsan: Fix UBSAN vs. SMAP · ce1cc0d8
      Peter Zijlstra authored
      commit d08965a2 upstream.
      
      UBSAN can insert extra code in random locations; including AC=1
      sections. Typically this code is not safe and needs wrapping.
      
      So far, only __ubsan_handle_type_mismatch* have been observed in AC=1
      sections and therefore only those are annotated.
      Signed-off-by: default avatarPeter Zijlstra (Intel) <peterz@infradead.org>
      Cc: Borislav Petkov <bp@alien8.de>
      Cc: Dmitry Vyukov <dvyukov@google.com>
      Cc: Josh Poimboeuf <jpoimboe@redhat.com>
      Cc: Linus Torvalds <torvalds@linux-foundation.org>
      Cc: Peter Zijlstra <peterz@infradead.org>
      Cc: Thomas Gleixner <tglx@linutronix.de>
      Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
      [stable backport: only take the lib/Makefile change to resolve gcc-10
       build issues]
      Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      ce1cc0d8
  2. 20 May, 2020 38 commits