edk2/SOURCES/edk2-NetworkPkg-IScsiDxe-fix-IScsiHexToBin-hex-parsing.patch
2021-09-09 16:18:24 +00:00

104 lines
4.0 KiB
Diff

From fd7e1858bc0e538e9af42b9f0514553da9533553 Mon Sep 17 00:00:00 2001
From: Laszlo Ersek <lersek@redhat.com>
Date: Tue, 27 Apr 2021 11:02:51 +0200
Subject: [PATCH 08/10] NetworkPkg/IScsiDxe: fix IScsiHexToBin() hex parsing
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
RH-Author: Laszlo Ersek <lersek@redhat.com>
RH-MergeRequest: 3: NetworkPkg/IScsiDxe: fix IScsiHexToBin() security and functionality bugs [rhel-8.4.0.z]
RH-Commit: [8/10] f77fc01700564c5e15027bd902a846102d488bf6
RH-Bugzilla: 1956676
RH-Acked-by: Philippe Mathieu-Daudé <philmd@redhat.com>
The IScsiHexToBin() function has the following parser issues:
(1) If the *subject sequence* in "HexStr" is empty, the function returns
EFI_SUCCESS (with "BinLength" set to 0 on output). Such inputs should
be rejected.
(2) The function mis-handles a "HexStr" that ends with a stray nibble. For
example, if "HexStr" is "0xABC", the function decodes it to the bytes
{0xAB, 0x0C}, sets "BinLength" to 2 on output, and returns
EFI_SUCCESS. Such inputs should be rejected.
(3) If an invalid hex char is found in "HexStr", the function treats it as
end-of-hex-string, and returns EFI_SUCCESS. Such inputs should be
rejected.
All of the above cases are remotely triggerable, as shown in a subsequent
patch, which adds error checking to the IScsiHexToBin() call sites. While
the initiator is not immediately compromised, incorrectly parsing CHAP_R
from the target, in case of mutual authentication, is not great.
Extend the interface contract of IScsiHexToBin() with
EFI_INVALID_PARAMETER, for reporting issues (1) through (3), and implement
the new checks.
Cc: Jiaxin Wu <jiaxin.wu@intel.com>
Cc: Maciej Rabeda <maciej.rabeda@linux.intel.com>
Cc: Philippe Mathieu-Daudé <philmd@redhat.com>
Cc: Siyuan Fu <siyuan.fu@intel.com>
Ref: https://bugzilla.tianocore.org/show_bug.cgi?id=3356
Signed-off-by: Laszlo Ersek <lersek@redhat.com>
Reviewed-by: Maciej Rabeda <maciej.rabeda@linux.intel.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Upstream: https://bugzilla.tianocore.org/show_bug.cgi?id=3356, c#17...c#22
---
NetworkPkg/IScsiDxe/IScsiMisc.c | 12 ++++++++++--
NetworkPkg/IScsiDxe/IScsiMisc.h | 1 +
2 files changed, 11 insertions(+), 2 deletions(-)
diff --git a/NetworkPkg/IScsiDxe/IScsiMisc.c b/NetworkPkg/IScsiDxe/IScsiMisc.c
index 014700e87a..f0f4992b07 100644
--- a/NetworkPkg/IScsiDxe/IScsiMisc.c
+++ b/NetworkPkg/IScsiDxe/IScsiMisc.c
@@ -376,6 +376,7 @@ IScsiBinToHex (
@retval EFI_SUCCESS The hexadecimal string is converted into a
binary encoded buffer.
+ @retval EFI_INVALID_PARAMETER Invalid hex encoding found in HexStr.
@retval EFI_BUFFER_TOO_SMALL The binary buffer is too small to hold the
converted data.
**/
@@ -402,14 +403,21 @@ IScsiHexToBin (
Length = AsciiStrLen (HexStr);
+ //
+ // Reject an empty hex string; reject a stray nibble.
+ //
+ if (Length == 0 || Length % 2 != 0) {
+ return EFI_INVALID_PARAMETER;
+ }
+
for (Index = 0; Index < Length; Index ++) {
TemStr[0] = HexStr[Index];
Digit = (UINT8) AsciiStrHexToUint64 (TemStr);
if (Digit == 0 && TemStr[0] != '0') {
//
- // Invalid Lun Char.
+ // Invalid Hex Char.
//
- break;
+ return EFI_INVALID_PARAMETER;
}
if ((Index & 1) == 0) {
BinBuffer [Index/2] = Digit;
diff --git a/NetworkPkg/IScsiDxe/IScsiMisc.h b/NetworkPkg/IScsiDxe/IScsiMisc.h
index 28cf408cd5..404a482e57 100644
--- a/NetworkPkg/IScsiDxe/IScsiMisc.h
+++ b/NetworkPkg/IScsiDxe/IScsiMisc.h
@@ -171,6 +171,7 @@ IScsiBinToHex (
@retval EFI_SUCCESS The hexadecimal string is converted into a
binary encoded buffer.
+ @retval EFI_INVALID_PARAMETER Invalid hex encoding found in HexStr.
@retval EFI_BUFFER_TOO_SMALL The binary buffer is too small to hold the
converted data.
**/
--
2.27.0