* [edk2-devel] [PATCH 1/1] MdePkg/UefiDevicePathLib: Fix AcpiEx print logic
2023-09-26 15:28 [edk2-devel] [PATCH 0/1] MdePkg/UefiDevicePathLib: Fix buffer overflows in DevPathToTextAcpiEx Albecki, Mateusz
@ 2023-09-26 15:28 ` Albecki, Mateusz
2023-09-27 11:33 ` Albecki, Mateusz
0 siblings, 1 reply; 3+ messages in thread
From: Albecki, Mateusz @ 2023-09-26 15:28 UTC (permalink / raw)
To: devel; +Cc: Mateusz Albecki, Michael D Kinney, Liming Gao, Zhiguang Liu
BZ: https://bugzilla.tianocore.org/show_bug.cgi?id=4555
Add logic that checks if the code doesn't overflow
ACPI_EXTENDED_HID_DEVICE_PATH node when searching for optional
strings. If the string is not provided in the device path node
default value of "\0" is used.
Cc: Michael D Kinney <michael.d.kinney@intel.com>
Cc: Liming Gao <gaoliming@byosoft.com.cn>
Cc: Zhiguang Liu <zhiguang.liu@intel.com>
Signed-off-by: Mateusz Albecki <mateusz.albecki@intel.com>
---
.../UefiDevicePathLib/DevicePathToText.c | 66 +++++++++++--------
1 file changed, 39 insertions(+), 27 deletions(-)
diff --git a/MdePkg/Library/UefiDevicePathLib/DevicePathToText.c b/MdePkg/Library/UefiDevicePathLib/DevicePathToText.c
index dd90dfa58e..5012dfef6b 100644
--- a/MdePkg/Library/UefiDevicePathLib/DevicePathToText.c
+++ b/MdePkg/Library/UefiDevicePathLib/DevicePathToText.c
@@ -418,23 +418,38 @@ DevPathToTextAcpiEx (
)
{
ACPI_EXTENDED_HID_DEVICE_PATH *AcpiEx;
- CHAR8 *HIDStr;
- CHAR8 *UIDStr;
- CHAR8 *CIDStr;
CHAR16 HIDText[11];
CHAR16 CIDText[11];
-
- AcpiEx = DevPath;
- HIDStr = (CHAR8 *)(((UINT8 *)AcpiEx) + sizeof (ACPI_EXTENDED_HID_DEVICE_PATH));
- UIDStr = HIDStr + AsciiStrLen (HIDStr) + 1;
- CIDStr = UIDStr + AsciiStrLen (UIDStr) + 1;
+ UINTN CurrentLength;
+ CHAR8 *CurrentPos;
+ UINTN NextStringOffset;
+ CHAR8 *Strings[3];
+ CONST UINT8 HidStrIndex = 0;
+ CONST UINT8 UidStrIndex = 1;
+ CONST UINT8 CidStrIndex = 2;
+ UINT8 StrIndex;
+
+ AcpiEx = DevPath;
+ Strings[HidStrIndex] = NULL;
+ Strings[UidStrIndex] = NULL;
+ Strings[CidStrIndex] = NULL;
+ CurrentLength = sizeof (ACPI_EXTENDED_HID_DEVICE_PATH);
+ CurrentPos = (CHAR8 *)(((UINT8 *)AcpiEx) + sizeof (ACPI_EXTENDED_HID_DEVICE_PATH));
+ StrIndex = 0;
+ while (CurrentLength < AcpiEx->Header.Length[0] && StrIndex < ARRAY_SIZE (Strings)) {
+ Strings[StrIndex] = CurrentPos;
+ NextStringOffset = AsciiStrLen (CurrentPos) + 1;
+ CurrentLength += NextStringOffset;
+ CurrentPos += NextStringOffset;
+ StrIndex++;
+ }
if (DisplayOnly) {
if ((EISA_ID_TO_NUM (AcpiEx->HID) == 0x0A03) ||
((EISA_ID_TO_NUM (AcpiEx->CID) == 0x0A03) && (EISA_ID_TO_NUM (AcpiEx->HID) != 0x0A08)))
{
- if (AcpiEx->UID == 0) {
- UefiDevicePathLibCatPrint (Str, L"PciRoot(%a)", UIDStr);
+ if (Strings[UidStrIndex] != NULL) {
+ UefiDevicePathLibCatPrint (Str, L"PciRoot(%a)", Strings[UidStrIndex]);
} else {
UefiDevicePathLibCatPrint (Str, L"PciRoot(0x%x)", AcpiEx->UID);
}
@@ -443,8 +458,8 @@ DevPathToTextAcpiEx (
}
if ((EISA_ID_TO_NUM (AcpiEx->HID) == 0x0A08) || (EISA_ID_TO_NUM (AcpiEx->CID) == 0x0A08)) {
- if (AcpiEx->UID == 0) {
- UefiDevicePathLibCatPrint (Str, L"PcieRoot(%a)", UIDStr);
+ if (Strings[UidStrIndex] != NULL) {
+ UefiDevicePathLibCatPrint (Str, L"PcieRoot(%a)", Strings[UidStrIndex]);
} else {
UefiDevicePathLibCatPrint (Str, L"PcieRoot(0x%x)", AcpiEx->UID);
}
@@ -475,7 +490,7 @@ DevPathToTextAcpiEx (
(AcpiEx->CID >> 16) & 0xFFFF
);
- if ((*HIDStr == '\0') && (*CIDStr == '\0') && (*UIDStr != '\0')) {
+ if ((Strings[HidStrIndex] == NULL) && (Strings[CidStrIndex] == NULL) && (Strings[UidStrIndex] != NULL)) {
//
// use AcpiExp()
//
@@ -484,7 +499,7 @@ DevPathToTextAcpiEx (
Str,
L"AcpiExp(%s,0,%a)",
HIDText,
- UIDStr
+ Strings[UidStrIndex]
);
} else {
UefiDevicePathLibCatPrint (
@@ -492,28 +507,25 @@ DevPathToTextAcpiEx (
L"AcpiExp(%s,%s,%a)",
HIDText,
CIDText,
- UIDStr
+ Strings[UidStrIndex]
);
}
} else {
if (DisplayOnly) {
- //
- // display only
- //
- if (AcpiEx->HID == 0) {
- UefiDevicePathLibCatPrint (Str, L"AcpiEx(%a,", HIDStr);
+ if (Strings[HidStrIndex] != NULL) {
+ UefiDevicePathLibCatPrint (Str, L"AcpiEx(%a,", Strings[HidStrIndex]);
} else {
UefiDevicePathLibCatPrint (Str, L"AcpiEx(%s,", HIDText);
}
- if (AcpiEx->CID == 0) {
- UefiDevicePathLibCatPrint (Str, L"%a,", CIDStr);
+ if (Strings[CidStrIndex] != NULL) {
+ UefiDevicePathLibCatPrint (Str, L"%a,", Strings[CidStrIndex]);
} else {
UefiDevicePathLibCatPrint (Str, L"%s,", CIDText);
}
- if (AcpiEx->UID == 0) {
- UefiDevicePathLibCatPrint (Str, L"%a)", UIDStr);
+ if (Strings[UidStrIndex] != NULL) {
+ UefiDevicePathLibCatPrint (Str, L"%a)", Strings[UidStrIndex]);
} else {
UefiDevicePathLibCatPrint (Str, L"0x%x)", AcpiEx->UID);
}
@@ -524,9 +536,9 @@ DevPathToTextAcpiEx (
HIDText,
CIDText,
AcpiEx->UID,
- HIDStr,
- CIDStr,
- UIDStr
+ Strings[HidStrIndex],
+ Strings[CidStrIndex],
+ Strings[UidStrIndex]
);
}
}
--
2.39.2
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