[PATCH 3.12 29/84] powerpc/ptrace: Fix out of bounds array access warning

[Jiri Slaby]

From: Khem Raj <raj.khem@xxxxxxxxx>

3.12-stable review patch.  If anyone has any objections, please let me know.

===============

commit 1e407ee3b21f981140491d5b8a36422979ca246f upstream.

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@xxxxxxxxx>
Cc: Kees Cook <keescook@xxxxxxxxxxxx>
Cc: Michael Ellerman <mpe@xxxxxxxxxxxxxx>
Cc: Segher Boessenkool <segher@xxxxxxxxxxxxxxxxxxx>
Tested-by: Aaro Koskinen <aaro.koskinen@xxxxxx>
Acked-by: Olof Johansson <olof@xxxxxxxxx>
Signed-off-by: Michael Ellerman <mpe@xxxxxxxxxxxxxx>
Signed-off-by: Jiri Slaby <jslaby@xxxxxxx>
---
 arch/powerpc/kernel/ptrace.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/powerpc/kernel/ptrace.c b/arch/powerpc/kernel/ptrace.c
index 9a0d24c390a3..929cdc0f34f5 100644
--- a/arch/powerpc/kernel/ptrace.c
+++ b/arch/powerpc/kernel/ptrace.c
@@ -376,7 +376,7 @@ static int fpr_get(struct task_struct *target, const struct user_regset *regset,
 
 #else
 	BUILD_BUG_ON(offsetof(struct thread_struct, fpscr) !=
-		     offsetof(struct thread_struct, TS_FPR(32)));
+		     offsetof(struct thread_struct, fpr[32]));
 
 	return user_regset_copyout(&pos, &count, &kbuf, &ubuf,
 				   &target->thread.fpr, 0, -1);
@@ -404,7 +404,7 @@ static int fpr_set(struct task_struct *target, const struct user_regset *regset,
 	return 0;
 #else
 	BUILD_BUG_ON(offsetof(struct thread_struct, fpscr) !=
-		     offsetof(struct thread_struct, TS_FPR(32)));
+		     offsetof(struct thread_struct, fpr[32]));
 
 	return user_regset_copyin(&pos, &count, &kbuf, &ubuf,
 				  &target->thread.fpr, 0, -1);
-- 
2.10.1