ping? 2016-06-29 14:54 GMT+03:00 Evgeny Yakovlev <[email protected]>:
> Consider the following course of action When enumerating new USB device: > > 1. UsbParseConfigDesc is called during new device enumeration process. > It allocates an array of USB_INTERFACE_DESC pointers in Config->Interfaces. > Each of those structures have an array of pointers to USB_INTERFACE_SETTING > which are currently set to NULL. > > 2. Then UsbParseConfigDesc calls UsbParseInterfaceDesc as long as there is > data left in buffer. Each call parses an interface setting and sets > appropriate pointer in Interface->Settings for related interface desc. > > 3. Later UsbSelectConfig traverses Config->Interfaces[NumIf]->Settings > to pick appropriate interface configuration. > > However if during step 2 UsbParseInterfaceDesc returns NULL (i.e. > because UsbCreateDesc returned NULL, see f89f1db) then config will be > not fully initialized by the time it is returned to caller. Some pointers > in > Config->Interfaces->Settings are still set to NULL and will be possibly > dereferenced in UsbSelectConfig. > > This patch treats this situation as an error and returns NULL > instead if incompletely initialized config descriptor. > > Contributed-under: TianoCore Contribution Agreement 1.0 > Signed-off-by: Evgeny Yakovlev <[email protected]> > CC: Feng Tian <[email protected]> > --- > MdeModulePkg/Bus/Usb/UsbBusDxe/UsbDesc.c | 4 ++-- > MdeModulePkg/Bus/Usb/UsbBusDxe/UsbEnumer.c | 3 +++ > 2 files changed, 5 insertions(+), 2 deletions(-) > > diff --git a/MdeModulePkg/Bus/Usb/UsbBusDxe/UsbDesc.c > b/MdeModulePkg/Bus/Usb/UsbBusDxe/UsbDesc.c > index fba60da..20e6ca3 100644 > --- a/MdeModulePkg/Bus/Usb/UsbBusDxe/UsbDesc.c > +++ b/MdeModulePkg/Bus/Usb/UsbBusDxe/UsbDesc.c > @@ -368,8 +368,8 @@ UsbParseConfigDesc ( > Setting = UsbParseInterfaceDesc (DescBuf, Len, &Consumed); > > if (Setting == NULL) { > - DEBUG (( EFI_D_ERROR, "UsbParseConfigDesc: warning: failed to get > interface setting, stop parsing now.\n")); > - break; > + DEBUG (( EFI_D_ERROR, "UsbParseConfigDesc: failed to get interface > setting, stop parsing now.\n")); > + goto ON_ERROR; > > } else if (Setting->Desc.InterfaceNumber >= NumIf) { > DEBUG (( EFI_D_ERROR, "UsbParseConfigDesc: mal-formated interface > descriptor\n")); > diff --git a/MdeModulePkg/Bus/Usb/UsbBusDxe/UsbEnumer.c > b/MdeModulePkg/Bus/Usb/UsbBusDxe/UsbEnumer.c > index 79453fe..57199a0 100644 > --- a/MdeModulePkg/Bus/Usb/UsbBusDxe/UsbEnumer.c > +++ b/MdeModulePkg/Bus/Usb/UsbBusDxe/UsbEnumer.c > @@ -412,6 +412,9 @@ UsbSelectConfig ( > // the endpoint toggles to zero for its endpoints. > // > IfDesc = ConfigDesc->Interfaces[Index]; > + ASSERT (IfDesc != NULL); > + ASSERT (IfDesc->Settings[0] != NULL); > + > UsbSelectSetting (IfDesc, IfDesc->Settings[0]->Desc.AlternateSetting); > > // > -- > 2.7.4 (Apple Git-66) > > _______________________________________________ edk2-devel mailing list [email protected] https://lists.01.org/mailman/listinfo/edk2-devel
