> -----Original Message----- > From: arndbergmann@xxxxxxxxx [mailto:arndbergmann@xxxxxxxxx] On > Behalf Of Arnd Bergmann > Sent: Tuesday, August 15, 2017 2:16 PM > To: Oleksandr Shamray <oleksandrs@xxxxxxxxxxxx> > Cc: gregkh <gregkh@xxxxxxxxxxxxxxxxxxx>; Linux Kernel Mailing List <linux- > kernel@xxxxxxxxxxxxxxx>; Linux ARM <linux-arm-kernel@xxxxxxxxxxxxxxxxxxx>; > devicetree@xxxxxxxxxxxxxxx; OpenBMC Maillist <openbmc@xxxxxxxxxxxxxxxx>; > Joel Stanley <joel@xxxxxxxxx>; Jiří Pírko <jiri@xxxxxxxxxxx>; Tobias Klauser > <tklauser@xxxxxxxxxx>; linux-serial@xxxxxxxxxxxxxxx; mec@xxxxxxxxx; > vadimp@xxxxxxxxxxxxx; system-sw-low-level <system-sw-low- > level@xxxxxxxxxxxx>; Rob Herring <robh+dt@xxxxxxxxxx>; openocd-devel- > owner@xxxxxxxxxxxxxxxxxxxxx; Jiri Pirko <jiri@xxxxxxxxxxxx> > Subject: Re: [patch v3 1/3] drivers: jtag: Add JTAG core driver > > On Tue, Aug 15, 2017 at 12:00 PM, Oleksandr Shamray > <oleksandrs@xxxxxxxxxxxx> wrote: > > > + case JTAG_IOCXFER: > > + if (copy_from_user(&xfer, varg, sizeof(struct jtag_xfer))) > > + return -EFAULT; > > + > > + if (xfer.length >= JTAG_MAX_XFER_DATA_LEN) > > + return -EFAULT; > > + > > + user_tdio_data = xfer.tdio; > > + xfer.tdio = jtag_copy_from_user((void __user *)user_tdio_data, > > + xfer.length); > > + if (!xfer.tdio) > > + return -ENOMEM; > > This is not safe for 32-bit processes on 64-bit kernels, since the structure layout > differs for the pointer member. It's better to always use either rework the > structure to avoid the pointer, or to use a > __u64 member to store it, and then use u64_to_user_ptr() to convert it in the > kernel. Thanks, I think using __u64 instead of pointer will be a good solution. > > > + case JTAG_GIOCSTATUS: > > + if (jtag->ops->status_get) > > + err = jtag->ops->status_get(jtag, > > + (enum jtag_endstate > > + *)&value); > > This pointer cast is also not safe, as an enum might have a different size than > the 'value' variable that is not an enum. I think you need to change the > argument type for the callback, or maybe use another intermediate. > > > +static int jtag_open(struct inode *inode, struct file *file) { > > + struct jtag *jtag = container_of(inode->i_cdev, struct jtag, > > +cdev); > > + > > + spin_lock(&jtag->lock); > > + > > + if (jtag->is_open) { > > + dev_info(NULL, "jtag already opened\n"); > > + spin_unlock(&jtag->lock); > > + return -EBUSY; > > + } > > + > > + jtag->is_open = true; > > + file->private_data = jtag; > > + spin_unlock(&jtag->lock); > > + return 0; > > +} > > Does the 'is_open' flag protect you from something that doesn't also happen > after a 'dup()' call on the file descriptor? is_open flag protects from the opening file more than one time. > > > + * @mode: access mode > > + * @type: transfer type > > + * @direction: xfer direction > > + * @length: xfer bits len > > + * @tdio : xfer data array > > + * @endir: xfer end state > > + * > > + * Structure represents interface to Aspeed JTAG device for jtag sdr > > +xfer > > + * execution. > > + */ > > +struct jtag_xfer { > > + __u8 mode; > > + __u8 type; > > + __u8 direction; > > + __u32 length; > > + __u8 *tdio; > > + __u8 endstate; > > +}; > > As mentioned above, the pointer in here makes it incompatible. Also, you > should reorder the members to avoid the implied padding. > Moving the 'endstate' before 'length' is sufficient. > Thank. I will do it. > Arnd ��.n��������+%������w��{.n�����{��ǫ����{ay� ʇڙ���f���h������_�(�階�ݢj"��������G����?���&��
