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MdeModulePkg/UsbBus: Fix out-of-bound read access to descriptors 

Today's implementation reads the Type/Length field in the USB
descriptors data without checking whether the offset to read is
beyond the data boundary.

The patch fixes this issue.

Contributed-under: TianoCore Contribution Agreement 1.1
Signed-off-by: Ruiyu Ni <ruiyu.ni@intel.com>
Cc: Star Zeng <star.zeng@intel.com>
Cc: Jiewen Yao <jiewen.yao@intel.com>
Reviewed-by: Star Zeng <star.zeng@intel.com>
This commit is contained in:
Ruiyu Ni 2018-09-27 16:34:36 +08:00
parent 4f8b2f9d72
commit 4c034bf62c
1 changed files with 43 additions and 12 deletions
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57
MdeModulePkg/Bus/Usb/UsbBusDxe/UsbDesc.c
View File

@ -177,6 +177,18 @@ UsbCreateDesc (
DescLen = sizeof (EFI_USB_ENDPOINT_DESCRIPTOR);
CtrlLen = sizeof (USB_ENDPOINT_DESC);
break;
default:
ASSERT (FALSE);
return NULL;
}
//
// Total length is too small that cannot hold the single descriptor header plus data.
//
if (Len <= sizeof (USB_DESC_HEAD)) {
DEBUG ((DEBUG_ERROR, "UsbCreateDesc: met mal-format descriptor, total length = %d!\n", Len));
return NULL;
}
//
@ -184,24 +196,43 @@ UsbCreateDesc (
// format. Skip the descriptor that isn't of this Type
//
Offset = 0;
Head = (USB_DESC_HEAD*)DescBuf;
Head = (USB_DESC_HEAD *)DescBuf;
while (Offset < Len - sizeof (USB_DESC_HEAD)) {
//
// Above condition make sure Head->Len and Head->Type are safe to access
//
Head = (USB_DESC_HEAD *)&DescBuf[Offset];
while ((Offset < Len) && (Head->Type != Type)) {
Offset += Head->Len;
if (Len <= Offset) {
DEBUG (( EFI_D_ERROR, "UsbCreateDesc: met mal-format descriptor, Beyond boundary!\n"));
return NULL;
}
Head = (USB_DESC_HEAD*)(DescBuf + Offset);
if (Head->Len == 0) {
DEBUG (( EFI_D_ERROR, "UsbCreateDesc: met mal-format descriptor, Head->Len = 0!\n"));
DEBUG ((DEBUG_ERROR, "UsbCreateDesc: met mal-format descriptor, Head->Len = 0!\n"));
return NULL;
}
//
// Make sure no overflow when adding Head->Len to Offset.
//
if (Head->Len > MAX_UINTN - Offset) {
DEBUG ((DEBUG_ERROR, "UsbCreateDesc: met mal-format descriptor, Head->Len = %d!\n", Head->Len));
return NULL;
}
Offset += Head->Len;
if (Head->Type == Type) {
break;
}
}
if ((Len <= Offset) || (Len < Offset + Head->Len) ||
(Head->Type != Type) || (Head->Len < DescLen)) {
DEBUG (( EFI_D_ERROR, "UsbCreateDesc: met mal-format descriptor\n"));
//
// Head->Len is invalid resulting data beyond boundary, or
// Descriptor cannot be found: No such type.
//
if (Len < Offset) {
DEBUG ((DEBUG_ERROR, "UsbCreateDesc: met mal-format descriptor, Offset/Len = %d/%d!\n", Offset, Len));
}
if ((Head->Type != Type) || (Head->Len < DescLen)) {
DEBUG ((DEBUG_ERROR, "UsbCreateDesc: descriptor cannot be found, Header(T/L) = %d/%d!\n", Head->Type, Head->Len));
return NULL;
}
@ -212,7 +243,7 @@ UsbCreateDesc (
CopyMem (Desc, Head, (UINTN) DescLen);
*Consumed = Offset + Head->Len;
*Consumed = Offset;
return Desc;
}