On Fri, Dec 25, 2020 at 12:05:22PM -0800, syzbot wrote: > Hello, > > syzbot found the following issue on: > > HEAD commit: e37b12e4 Merge tag 'for-linus-5.11-ofs1' of git://git.kern.. > git tree: upstream > console output: https://syzkaller.appspot.com/x/log.txt?x=17429937500000 > kernel config: https://syzkaller.appspot.com/x/.config?x=98408202fed1f636 > dashboard link: https://syzkaller.appspot.com/bug?extid=5925509f78293baa7331 > compiler: gcc (GCC) 10.1.0-syz 20200507 > syz repro: https://syzkaller.appspot.com/x/repro.syz?x=1781fc5b500000 > C reproducer: https://syzkaller.appspot.com/x/repro.c?x=157cd123500000 > > The issue was bisected to: > > commit 8442b02bf3c6770e0d7e7ea17be36c30e95987b6 > Author: Andrey Konovalov <andreyknvl@xxxxxxxxxx> > Date: Mon Oct 21 14:20:58 2019 +0000 > > USB: dummy-hcd: increase max number of devices to 32 > > bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=1631d0db500000 > final oops: https://syzkaller.appspot.com/x/report.txt?x=1531d0db500000 > console output: https://syzkaller.appspot.com/x/log.txt?x=1131d0db500000 > > IMPORTANT: if you fix the issue, please add the following tag to the commit: > Reported-by: syzbot+5925509f78293baa7331@xxxxxxxxxxxxxxxxxxxxxxxxx > Fixes: 8442b02bf3c6 ("USB: dummy-hcd: increase max number of devices to 32") > > ================================================================================ > UBSAN: shift-out-of-bounds in drivers/usb/gadget/udc/dummy_hcd.c:2293:33 > shift exponent 257 is too large for 32-bit type 'int' > CPU: 0 PID: 8526 Comm: syz-executor949 Not tainted 5.10.0-syzkaller #0 > Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 > Call Trace: > __dump_stack lib/dump_stack.c:79 [inline] > dump_stack+0x107/0x163 lib/dump_stack.c:120 > ubsan_epilogue+0xb/0x5a lib/ubsan.c:148 > __ubsan_handle_shift_out_of_bounds.cold+0xb1/0x181 lib/ubsan.c:395 > dummy_hub_control.cold+0x1a/0xbc drivers/usb/gadget/udc/dummy_hcd.c:2293 > rh_call_control drivers/usb/core/hcd.c:683 [inline] > rh_urb_enqueue drivers/usb/core/hcd.c:841 [inline] > usb_hcd_submit_urb+0xcaa/0x22d0 drivers/usb/core/hcd.c:1544 > usb_submit_urb+0x6e4/0x1560 drivers/usb/core/urb.c:585 > usb_start_wait_urb+0x101/0x4c0 drivers/usb/core/message.c:58 > usb_internal_control_msg drivers/usb/core/message.c:102 [inline] > usb_control_msg+0x31c/0x4a0 drivers/usb/core/message.c:153 > do_proc_control+0x4cb/0x9c0 drivers/usb/core/devio.c:1165 > proc_control drivers/usb/core/devio.c:1191 [inline] > usbdev_do_ioctl drivers/usb/core/devio.c:2535 [inline] > usbdev_ioctl+0x12c1/0x3b20 drivers/usb/core/devio.c:2708 > vfs_ioctl fs/ioctl.c:48 [inline] > __do_sys_ioctl fs/ioctl.c:753 [inline] > __se_sys_ioctl fs/ioctl.c:739 [inline] > __x64_sys_ioctl+0x193/0x200 fs/ioctl.c:739 > do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46 > entry_SYSCALL_64_after_hwframe+0x44/0xa9 > RIP: 0033:0x443f29 > Code: 18 89 d0 c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 0f 83 fb d7 fb ff c3 66 2e 0f 1f 84 00 00 00 00 > RSP: 002b:00007ffc10df4328 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 > RAX: ffffffffffffffda RBX: 00000000004002e0 RCX: 0000000000443f29 > RDX: 0000000020000000 RSI: 00000000c0185500 RDI: 0000000000000003 > RBP: 00000000006ce018 R08: 0000000000000000 R09: 00000000004002e0 > R10: 000000000000000f R11: 0000000000000246 R12: 0000000000401bb0 > R13: 0000000000401c40 R14: 0000000000000000 R15: 0000000000000000 > ================================================================================ The cause is pretty obvious. dummy-hcd assumes that requests sent to the root hub are always valid, which isn't always true when they come from userspace. Alan Stern #syz test: upstream e37b12e4 Index: usb-devel/drivers/usb/gadget/udc/dummy_hcd.c =================================================================== --- usb-devel.orig/drivers/usb/gadget/udc/dummy_hcd.c +++ usb-devel/drivers/usb/gadget/udc/dummy_hcd.c @@ -2114,9 +2114,21 @@ static int dummy_hub_control( dum_hcd->port_status &= ~USB_PORT_STAT_POWER; set_link_state(dum_hcd); break; - default: + case USB_PORT_FEAT_ENABLE: + case USB_PORT_FEAT_C_ENABLE: + case USB_PORT_FEAT_C_SUSPEND: + /* Not allowed for USB-3 */ + if (hcd->speed == HCD_USB3) + goto error; + fallthrough; + case USB_PORT_FEAT_C_CONNECTION: + case USB_PORT_FEAT_C_RESET: dum_hcd->port_status &= ~(1 << wValue); set_link_state(dum_hcd); + break; + default: + /* Disallow INDICATOR and C_OVER_CURRENT */ + goto error; } break; case GetHubDescriptor: @@ -2277,18 +2289,17 @@ static int dummy_hub_control( */ dum_hcd->re_timeout = jiffies + msecs_to_jiffies(50); fallthrough; + case USB_PORT_FEAT_C_CONNECTION: + case USB_PORT_FEAT_C_RESET: + case USB_PORT_FEAT_C_ENABLE: + case USB_PORT_FEAT_C_SUSPEND: + /* Not allowed for USB-3, and ignored for USB-2 */ + if (hcd->speed == HCD_USB3) + goto error; + break; default: - if (hcd->speed == HCD_USB3) { - if ((dum_hcd->port_status & - USB_SS_PORT_STAT_POWER) != 0) { - dum_hcd->port_status |= (1 << wValue); - } - } else - if ((dum_hcd->port_status & - USB_PORT_STAT_POWER) != 0) { - dum_hcd->port_status |= (1 << wValue); - } - set_link_state(dum_hcd); + /* Disallow TEST, INDICATOR, and C_OVER_CURRENT */ + goto error; } break; case GetPortErrorCount:
