[PATCH] DynamicTablesPkg: add validation for PcdNonBsaCompliant16550SerialHid


Joey Gouly
 

According to ACPI 6.4, 6.1.5 _HID states:

- A valid PNP ID must be of the form "AAA####" where A is an uppercase
letter and # is a hex digit.
- A valid ACPI ID must be of the form "NNNN####" where N is an uppercase
letter or a digit ('0'-'9') and # is a hex digit.

Signed-off-by: Joey Gouly <joey.goulyd@...>
---

The changes can be seen at https://github.com/jgouly/edk2/tree/1645_non_sba_compliant_validation_v1

DynamicTablesPkg/Include/Library/TableHelperLib.h | 38 +++++++++-
DynamicTablesPkg/Library/Common/SsdtSerialPortFixupLib/SsdtSerialPortFixupLib.c | 4 ++
DynamicTablesPkg/Library/Common/TableHelperLib/TableHelper.c | 73 +++++++++++++++++++-
3 files changed, 113 insertions(+), 2 deletions(-)

diff --git a/DynamicTablesPkg/Include/Library/TableHelperLib.h b/DynamicTablesPkg/Include/Library/TableHelperLib.h
index 099a0a4544e3d1f746d4be8533cb006786f11611..0f93cdbf08953af2377952ef616f760a51706170 100644
--- a/DynamicTablesPkg/Include/Library/TableHelperLib.h
+++ b/DynamicTablesPkg/Include/Library/TableHelperLib.h
@@ -1,6 +1,6 @@
/** @file

- Copyright (c) 2017 - 2020, Arm Limited. All rights reserved.<BR>
+ Copyright (c) 2017 - 2021, Arm Limited. All rights reserved.<BR>

SPDX-License-Identifier: BSD-2-Clause-Patent

@@ -12,6 +12,18 @@
#ifndef TABLE_HELPER_LIB_H_
#define TABLE_HELPER_LIB_H_

+/** Is a character upper case
+*/
+#define IS_UPPER_CHAR(x) ((x >= 'A') && (x <= 'Z'))
+
+/** Is a character a decimal digit
+*/
+#define IS_DIGIT(x) ((x >= '0') && (x <= '9'))
+
+/** Is a character an upper case hexadecimal digit
+*/
+#define IS_UPPER_HEX(x) (((x >= 'A') && (x <= 'F')) || IS_DIGIT (x))
+
/** The GetCgfMgrInfo function gets the CM_STD_OBJ_CONFIGURATION_MANAGER_INFO
object from the Configuration Manager.

@@ -120,4 +132,28 @@ AsciiFromHex (
IN UINT8 x
);

+/** Check if a HID is a valid PNP ID.
+
+ @param [in] Hid The Hid to validate.
+
+ @retval TRUE The Hid is a valid PNP ID.
+ @retval FALSE The Hid is not a valid PNP ID.
+**/
+BOOLEAN
+IsValidPnpId (
+ IN CONST CHAR8 * Hid
+ );
+
+/** Check if a HID is a valid ACPI ID.
+
+ @param [in] Hid The Hid to validate.
+
+ @retval TRUE The Hid is a valid ACPI ID.
+ @retval FALSE The Hid is not a valid ACPI ID.
+**/
+BOOLEAN
+IsValidAcpiId (
+ IN CONST CHAR8 * Hid
+ );
+
#endif // TABLE_HELPER_LIB_H_
diff --git a/DynamicTablesPkg/Library/Common/SsdtSerialPortFixupLib/SsdtSerialPortFixupLib.c b/DynamicTablesPkg/Library/Common/SsdtSerialPortFixupLib/SsdtSerialPortFixupLib.c
index 3c4356097c3bf25e8d1432b45ba8ca59d33e8d09..f2b4831ad596284476fb342148d9c1f62bc7f98b 100644
--- a/DynamicTablesPkg/Library/Common/SsdtSerialPortFixupLib/SsdtSerialPortFixupLib.c
+++ b/DynamicTablesPkg/Library/Common/SsdtSerialPortFixupLib/SsdtSerialPortFixupLib.c
@@ -148,6 +148,10 @@ FixupIds (
// If there is a non-BSA compliant HID, use that.
NonBsaHid = (CONST CHAR8*)PcdGetPtr (PcdNonBsaCompliant16550SerialHid);
if ((NonBsaHid != NULL) && (AsciiStrLen (NonBsaHid) != 0)) {
+ if (!(IsValidPnpId (NonBsaHid) || IsValidAcpiId (NonBsaHid))) {
+ return EFI_INVALID_PARAMETER;
+ }
+
HidString = NonBsaHid;
CidString = "";
} else {
diff --git a/DynamicTablesPkg/Library/Common/TableHelperLib/TableHelper.c b/DynamicTablesPkg/Library/Common/TableHelperLib/TableHelper.c
index 0d9daad3b05b6e82089f92afb6de4eeee5af9a28..9830ce62b3cb94be6d861a09d8d8356d60fdfbba 100644
--- a/DynamicTablesPkg/Library/Common/TableHelperLib/TableHelper.c
+++ b/DynamicTablesPkg/Library/Common/TableHelperLib/TableHelper.c
@@ -1,7 +1,7 @@
/** @file
Table Helper

- Copyright (c) 2017 - 2020, Arm Limited. All rights reserved.<BR>
+ Copyright (c) 2017 - 2021, Arm Limited. All rights reserved.<BR>

SPDX-License-Identifier: BSD-2-Clause-Patent
**/
@@ -270,3 +270,74 @@ AsciiFromHex (
ASSERT (FALSE);
return (UINT8)0;
}
+
+/** Check if a HID is a valid PNP ID.
+
+ @param [in] Hid The Hid to validate.
+
+ @retval TRUE The Hid is a valid PNP ID.
+ @retval FALSE The Hid is not a valid PNP ID.
+**/
+BOOLEAN
+IsValidPnpId (
+ IN CONST CHAR8 * Hid
+ )
+{
+ UINTN Index;
+
+ if (AsciiStrLen (Hid) != 7) {
+ return FALSE;
+ }
+
+ // A valid PNP ID must be of the form "AAA####"
+ // where A is an uppercase letter and # is a hex digit.
+ for (Index = 0; Index < 3; Index++) {
+ if (!IS_UPPER_CHAR (Hid[Index])) {
+ return FALSE;
+ }
+ }
+
+ for (Index = 3; Index < 7; Index++) {
+ if (!IS_UPPER_HEX (Hid[Index])) {
+ return FALSE;
+ }
+ }
+
+ return TRUE;
+}
+
+/** Check if a HID is a valid ACPI ID.
+
+ @param [in] Hid The Hid to validate.
+
+ @retval TRUE The Hid is a valid ACPI ID.
+ @retval FALSE The Hid is not a valid ACPI ID.
+**/
+BOOLEAN
+IsValidAcpiId (
+ IN CONST CHAR8 * Hid
+ )
+{
+ UINTN Index;
+
+ if (AsciiStrLen (Hid) != 8) {
+ return FALSE;
+ }
+
+ // A valid ACPI ID must be of the form "NNNN####"
+ // where N is an uppercase letter or a digit ('0'-'9')
+ // and # is a hex digit.
+ for (Index = 0; Index < 4; Index++) {
+ if (!(IS_UPPER_CHAR (Hid[Index]) || IS_DIGIT (Hid[Index]))) {
+ return FALSE;
+ }
+ }
+
+ for (Index = 4; Index < 8; Index++) {
+ if (!IS_UPPER_HEX (Hid[Index])) {
+ return FALSE;
+ }
+ }
+
+ return TRUE;
+}
--
Guid("CE165669-3EF3-493F-B85D-6190EE5B9759")

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