On Fri, 2016-08-26 at 18:02 +0000, Binyamin Sharet (bsharet) wrote: > I think the reason is that in case of quirks == NO_UNION_NORMAL it gets the data > and control interfaces and then jumps to skip_normal probe, in which case there are no > checks whether data_interface, data_interface->cur_altsetting or control_interface are NULL. > > Also, even in the case where quirks != NO_UNION_NORMAL, if the control and the data > interfaces are not the same, there is no check whether data_interface->cur_altsetting is NULL. > (before the first line of code in skip_normal_probe) which may cause the first check to dereference > a NULL pointer. Hi, could you test this updated patch? Regards Oliver
From 4274cf2a7f8bf0b97b6d5ecc27882b9d946bf7f0 Mon Sep 17 00:00:00 2001 From: Oliver Neukum <oneukum@xxxxxxxx> Date: Wed, 17 Aug 2016 15:19:28 +0200 Subject: [PATCH] cdc-acm: added sanity checking for probe() This is analternative to eccf2a4e6b64d249929acc1f7aaa2ab0fb199d3d which inadvertedly fixes an oops in probe by malformed descriptors. The patch is too extensive to backport to stable. Signed-off-by: Oliver Neukum <oneukum@xxxxxxxx> --- drivers/usb/class/cdc-acm.c | 18 ++++++++++++++++++ 1 file changed, 18 insertions(+) diff --git a/drivers/usb/class/cdc-acm.c b/drivers/usb/class/cdc-acm.c index ba6b978..d54e2c7 100644 --- a/drivers/usb/class/cdc-acm.c +++ b/drivers/usb/class/cdc-acm.c @@ -1002,6 +1002,8 @@ static int acm_probe(struct usb_interface *intf, } if (!buflen) { + if (!intf->cur_altsetting || !intf->cur_altsetting->endpoint) + return -EINVAL; if (intf->cur_altsetting->endpoint && intf->cur_altsetting->endpoint->extralen && intf->cur_altsetting->endpoint->extra) { @@ -1069,6 +1071,8 @@ next_desc: data_interface = usb_ifnum_to_if(usb_dev, (data_interface_num = call_interface_num)); control_interface = intf; } else { + if (!intf->cur_altsetting) + return -ENODEV; if (intf->cur_altsetting->desc.bNumEndpoints != 3) { dev_dbg(&intf->dev,"No union descriptor, giving up\n"); return -ENODEV; @@ -1098,15 +1102,22 @@ next_desc: combined_interfaces = 1; /* a popular other OS doesn't use it */ quirks |= NO_CAP_LINE; + if (!data_interface->cur_altsetting) + return -EINVAL; if (data_interface->cur_altsetting->desc.bNumEndpoints != 3) { dev_err(&intf->dev, "This needs exactly 3 endpoints\n"); return -EINVAL; } look_for_collapsed_interface: + if (!data_interface->cur_altsetting) + return -EINVAL; for (i = 0; i < 3; i++) { struct usb_endpoint_descriptor *ep; ep = &data_interface->cur_altsetting->endpoint[i].desc; + if (!ep) + return -ENODEV; + if (usb_endpoint_is_int_in(ep)) epctrl = ep; else if (usb_endpoint_is_bulk_out(ep)) @@ -1125,8 +1136,12 @@ look_for_collapsed_interface: skip_normal_probe: /*workaround for switched interfaces */ + if (!data_interface->cur_altsetting) + return -EINVAL; if (data_interface->cur_altsetting->desc.bInterfaceClass != CDC_DATA_INTERFACE_TYPE) { + if (!control_interface->cur_altsetting) + return -EINVAL; if (control_interface->cur_altsetting->desc.bInterfaceClass == CDC_DATA_INTERFACE_TYPE) { struct usb_interface *t; @@ -1152,6 +1167,7 @@ skip_normal_probe: if (data_interface->cur_altsetting->desc.bNumEndpoints < 2 || + !control_interface->cur_altsetting || control_interface->cur_altsetting->desc.bNumEndpoints == 0) return -EINVAL; @@ -1159,6 +1175,8 @@ skip_normal_probe: epread = &data_interface->cur_altsetting->endpoint[0].desc; epwrite = &data_interface->cur_altsetting->endpoint[1].desc; + if (!epctrl || !epread || !epwrite) + return -ENODEV; /* workaround for switched endpoints */ if (!usb_endpoint_dir_in(epread)) { -- 2.1.4