On Mon, Aug 10, 2020 at 02:12:23PM +0200, Christoph Hellwig wrote: > As far as I can tell the warning is valid as we copy a user controlled > amount into a fixed sized buffer. But this an old condition not actually > created by this commit..
Actually, is is not. do_proc_control checks the legnth, but does it using a somewhat pointless local variable, which might have confused smatch. > > On Sat, Aug 08, 2020 at 01:26:39PM +0800, kernel test robot wrote: > > tree: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git > > master > > head: 049eb096da48db0421dd5e358b9b082a1a8a2025 > > commit: c17536d0abde2fd24afca542e3bb73b45a299633 usb: usbfs: stop using > > compat_alloc_user_space > > date: 2 weeks ago > > config: nds32-randconfig-m031-20200808 (attached as .config) > > compiler: nds32le-linux-gcc (GCC) 9.3.0 > > > > If you fix the issue, kindly add following tag as appropriate > > Reported-by: kernel test robot <l...@intel.com> > > > > smatch warnings: > > drivers/usb/core/devio.c:1155 do_proc_control() error: copy_from_user() > > 'tbuf' too small (4096 vs 8192) > > > > vim +/tbuf +1155 drivers/usb/core/devio.c > > > > 1104 > > 1105 static int do_proc_control(struct usb_dev_state *ps, > > 1106 struct usbdevfs_ctrltransfer *ctrl) > > 1107 { > > 1108 struct usb_device *dev = ps->dev; > > 1109 unsigned int tmo; > > 1110 unsigned char *tbuf; > > 1111 unsigned wLength; > > 1112 int i, pipe, ret; > > 1113 > > 1114 ret = check_ctrlrecip(ps, ctrl->bRequestType, > > ctrl->bRequest, > > 1115 ctrl->wIndex); > > 1116 if (ret) > > 1117 return ret; > > 1118 wLength = ctrl->wLength; /* To suppress 64k > > PAGE_SIZE warning */ > > 1119 if (wLength > PAGE_SIZE) > > 1120 return -EINVAL; > > 1121 ret = usbfs_increase_memory_usage(PAGE_SIZE + > > sizeof(struct urb) + > > 1122 sizeof(struct usb_ctrlrequest)); > > 1123 if (ret) > > 1124 return ret; > > 1125 tbuf = (unsigned char *)__get_free_page(GFP_KERNEL); > > 1126 if (!tbuf) { > > 1127 ret = -ENOMEM; > > 1128 goto done; > > 1129 } > > 1130 tmo = ctrl->timeout; > > 1131 snoop(&dev->dev, "control urb: bRequestType=%02x " > > 1132 "bRequest=%02x wValue=%04x " > > 1133 "wIndex=%04x wLength=%04x\n", > > 1134 ctrl->bRequestType, ctrl->bRequest, > > ctrl->wValue, > > 1135 ctrl->wIndex, ctrl->wLength); > > 1136 if (ctrl->bRequestType & 0x80) { > > 1137 pipe = usb_rcvctrlpipe(dev, 0); > > 1138 snoop_urb(dev, NULL, pipe, ctrl->wLength, tmo, > > SUBMIT, NULL, 0); > > 1139 > > 1140 usb_unlock_device(dev); > > 1141 i = usb_control_msg(dev, pipe, ctrl->bRequest, > > 1142 ctrl->bRequestType, > > ctrl->wValue, ctrl->wIndex, > > 1143 tbuf, ctrl->wLength, tmo); > > 1144 usb_lock_device(dev); > > 1145 snoop_urb(dev, NULL, pipe, max(i, 0), min(i, > > 0), COMPLETE, > > 1146 tbuf, max(i, 0)); > > 1147 if ((i > 0) && ctrl->wLength) { > > 1148 if (copy_to_user(ctrl->data, tbuf, i)) { > > 1149 ret = -EFAULT; > > 1150 goto done; > > 1151 } > > 1152 } > > 1153 } else { > > 1154 if (ctrl->wLength) { > > > 1155 if (copy_from_user(tbuf, ctrl->data, > > > ctrl->wLength)) { > > 1156 ret = -EFAULT; > > 1157 goto done; > > 1158 } > > 1159 } > > 1160 pipe = usb_sndctrlpipe(dev, 0); > > 1161 snoop_urb(dev, NULL, pipe, ctrl->wLength, tmo, > > SUBMIT, > > 1162 tbuf, ctrl->wLength); > > 1163 > > 1164 usb_unlock_device(dev); > > 1165 i = usb_control_msg(dev, usb_sndctrlpipe(dev, > > 0), ctrl->bRequest, > > 1166 ctrl->bRequestType, > > ctrl->wValue, ctrl->wIndex, > > 1167 tbuf, ctrl->wLength, tmo); > > 1168 usb_lock_device(dev); > > 1169 snoop_urb(dev, NULL, pipe, max(i, 0), min(i, > > 0), COMPLETE, NULL, 0); > > 1170 } > > 1171 if (i < 0 && i != -EPIPE) { > > 1172 dev_printk(KERN_DEBUG, &dev->dev, "usbfs: > > USBDEVFS_CONTROL " > > 1173 "failed cmd %s rqt %u rq %u len %u > > ret %d\n", > > 1174 current->comm, ctrl->bRequestType, > > ctrl->bRequest, > > 1175 ctrl->wLength, i); > > 1176 } > > 1177 ret = i; > > 1178 done: > > 1179 free_page((unsigned long) tbuf); > > 1180 usbfs_decrease_memory_usage(PAGE_SIZE + sizeof(struct > > urb) + > > 1181 sizeof(struct usb_ctrlrequest)); > > 1182 return ret; > > 1183 } > > 1184 > > > > --- > > 0-DAY CI Kernel Test Service, Intel Corporation > > https://lists.01.org/hyperkitty/list/kbuild-...@lists.01.org > > > ---end quoted text--- ---end quoted text---
