powerpc/ptrace: Fix out of bounds array access warning

gcc-6 correctly warns about a out of bounds access

arch/powerpc/kernel/ptrace.c:407:24: warning: index 32 denotes an offset greater than size of 'u64[32][1] {aka long long unsigned int[32][1]}' [-Warray-bounds]
        offsetof(struct thread_fp_state, fpr[32][0]));
                        ^

check the end of array instead of beginning of next element to fix this

Signed-off-by: Khem Raj <raj.khem@gmail.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Segher Boessenkool <segher@kernel.crashing.org>
Tested-by: Aaro Koskinen <aaro.koskinen@iki.fi>
Acked-by: Olof Johansson <olof@lixom.net>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

diff --git a/arch/powerpc/kernel/ptrace.c b/arch/powerpc/kernel/ptrace.c
index 30a03c03fe734a8c80828fc4260fe3679ab63e85..060b140f03c69de424e40e4dcdb5064d832ce889 100644 (file)
--- a/arch/powerpc/kernel/ptrace.c
+++ b/arch/powerpc/kernel/ptrace.c
@@ -377,7 +377,7 @@ static int fpr_get(struct task_struct *target, const struct user_regset *regset,
 
 #else
        BUILD_BUG_ON(offsetof(struct thread_fp_state, fpscr) !=
-                    offsetof(struct thread_fp_state, fpr[32][0]));
+                    offsetof(struct thread_fp_state, fpr[32]));
 
        return user_regset_copyout(&pos, &count, &kbuf, &ubuf,
                                   &target->thread.fp_state, 0, -1);
@@ -405,7 +405,7 @@ static int fpr_set(struct task_struct *target, const struct user_regset *regset,
        return 0;
 #else
        BUILD_BUG_ON(offsetof(struct thread_fp_state, fpscr) !=
-                    offsetof(struct thread_fp_state, fpr[32][0]));
+                    offsetof(struct thread_fp_state, fpr[32]));
 
        return user_regset_copyin(&pos, &count, &kbuf, &ubuf,
                                  &target->thread.fp_state, 0, -1);