From: Al Viro viro@zeniv.linux.org.uk
[ Upstream commit 6595d144decec396bf2e2efee27e50634a4b627f ]
First of all, on short copies __copy_{to,from}_user() return the amount of bytes left uncopied, *not* -EFAULT. get_user() and put_user() are expected to return -EFAULT on failure.
Another problem is get_user(v32, (__u64 __user *)p); that should fetch 64bit value and the assign it to v32, truncating it in process. Current code, OTOH, reads 8 bytes of data and stores them at the address of v32, stomping on the 4 bytes that follow v32 itself.
Signed-off-by: Al Viro viro@zeniv.linux.org.uk Signed-off-by: Max Filippov jcmvbkbc@gmail.com Signed-off-by: Sasha Levin sashal@kernel.org --- arch/xtensa/include/asm/uaccess.h | 13 +++++++++++-- 1 file changed, 11 insertions(+), 2 deletions(-)
diff --git a/arch/xtensa/include/asm/uaccess.h b/arch/xtensa/include/asm/uaccess.h index 147b26ed9c91f..42133985a19a1 100644 --- a/arch/xtensa/include/asm/uaccess.h +++ b/arch/xtensa/include/asm/uaccess.h @@ -245,7 +245,7 @@ do { \ case 4: __put_user_asm(x, ptr, retval, 4, "s32i", __cb); break; \ case 8: { \ __typeof__(*ptr) __v64 = x; \ - retval = __copy_to_user(ptr, &__v64, 8); \ + retval = __copy_to_user(ptr, &__v64, 8) ? -EFAULT : 0; \ break; \ } \ default: __put_user_bad(); \ @@ -344,7 +344,16 @@ do { \ case 1: __get_user_asm(x, ptr, retval, 1, "l8ui", __cb); break;\ case 2: __get_user_asm(x, ptr, retval, 2, "l16ui", __cb); break;\ case 4: __get_user_asm(x, ptr, retval, 4, "l32i", __cb); break;\ - case 8: retval = __copy_from_user(&x, ptr, 8); break; \ + case 8: { \ + u64 __x; \ + if (unlikely(__copy_from_user(&__x, ptr, 8))) { \ + retval = -EFAULT; \ + (x) = 0; \ + } else { \ + (x) = *(__force __typeof__((ptr)))&__x; \ + } \ + break; \ + } \ default: (x) = __get_user_bad(); \ } \ } while (0)