| Message ID | 20210818060533.3569517-26-keescook@chromium.org |
|---|---|
| State | New |
| Headers | show |
| Series | Introduce strict memcpy() bounds checking | expand |
On Wed, Aug 18, 2021 at 8:14 AM Kees Cook <keescook@chromium.org> wrote: > > Since all compilers support __builtin_object_size(), and there is only > one user of __compiletime_object_size, remove it to avoid the needless > indirection. This lets Clang reason about check_copy_size() correctly. Sounds good to me, the indirection is making things more complex than they need to be. Reviewed-by: Miguel Ojeda <ojeda@kernel.org> Cheers, Miguel
diff --git a/include/linux/compiler-gcc.h b/include/linux/compiler-gcc.h index cb9217fc60af..01985821944b 100644 --- a/include/linux/compiler-gcc.h +++ b/include/linux/compiler-gcc.h @@ -41,8 +41,6 @@ #define __UNIQUE_ID(prefix) __PASTE(__PASTE(__UNIQUE_ID_, prefix), __COUNTER__) -#define __compiletime_object_size(obj) __builtin_object_size(obj, 0) - #define __compiletime_warning(message) __attribute__((__warning__(message))) #define __compiletime_error(message) __attribute__((__error__(message))) diff --git a/include/linux/compiler_types.h b/include/linux/compiler_types.h index e4ea86fc584d..c43308b0a9a9 100644 --- a/include/linux/compiler_types.h +++ b/include/linux/compiler_types.h @@ -290,10 +290,6 @@ struct ftrace_likely_data { (sizeof(t) == sizeof(char) || sizeof(t) == sizeof(short) || \ sizeof(t) == sizeof(int) || sizeof(t) == sizeof(long)) -/* Compile time object size, -1 for unknown */ -#ifndef __compiletime_object_size -# define __compiletime_object_size(obj) -1 -#endif #ifndef __compiletime_warning # define __compiletime_warning(message) #endif diff --git a/include/linux/thread_info.h b/include/linux/thread_info.h index 0999f6317978..ad0c4e041030 100644 --- a/include/linux/thread_info.h +++ b/include/linux/thread_info.h @@ -203,7 +203,7 @@ static inline void copy_overflow(int size, unsigned long count) static __always_inline __must_check bool check_copy_size(const void *addr, size_t bytes, bool is_source) { - int sz = __compiletime_object_size(addr); + int sz = __builtin_object_size(addr, 0); if (unlikely(sz >= 0 && sz < bytes)) { if (!__builtin_constant_p(bytes)) copy_overflow(sz, bytes);
Since all compilers support __builtin_object_size(), and there is only one user of __compiletime_object_size, remove it to avoid the needless indirection. This lets Clang reason about check_copy_size() correctly. Link: https://github.com/ClangBuiltLinux/linux/issues/1179 Suggested-by: Nick Desaulniers <ndesaulniers@google.com> Cc: Nathan Chancellor <nathan@kernel.org> Cc: Nick Desaulniers <ndesaulniers@google.com> Cc: Miguel Ojeda <ojeda@kernel.org> Cc: Sedat Dilek <sedat.dilek@gmail.com> Cc: Will Deacon <will@kernel.org> Cc: Marco Elver <elver@google.com> Cc: Arvind Sankar <nivedita@alum.mit.edu> Cc: Masahiro Yamada <masahiroy@kernel.org> Cc: Luc Van Oostenryck <luc.vanoostenryck@gmail.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Sami Tolvanen <samitolvanen@google.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Gabriel Krisman Bertazi <krisman@collabora.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: Oleg Nesterov <oleg@redhat.com> Signed-off-by: Kees Cook <keescook@chromium.org> --- include/linux/compiler-gcc.h | 2 -- include/linux/compiler_types.h | 4 ---- include/linux/thread_info.h | 2 +- 3 files changed, 1 insertion(+), 7 deletions(-)