114 lines
4.4 KiB
Diff
114 lines
4.4 KiB
Diff
From f423b7078d291b84952464aca6930a9d772319b0 Mon Sep 17 00:00:00 2001
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From: Laszlo Ersek <lersek@redhat.com>
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Date: Tue, 8 Jun 2021 14:12:58 +0200
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Subject: [PATCH 09/10] NetworkPkg/IScsiDxe: fix IScsiHexToBin() buffer
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overflow
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MIME-Version: 1.0
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Content-Type: text/plain; charset=UTF-8
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Content-Transfer-Encoding: 8bit
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RH-Author: Laszlo Ersek <lersek@redhat.com>
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RH-MergeRequest: 5: NetworkPkg/IScsiDxe: fix IScsiHexToBin() security and functionality bugs [rhel-8.5.0, post-rebase]
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RH-Commit: [9/10] acf102203198d575a12e5257c12b8e43ccdfc589
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RH-Bugzilla: 1956408
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RH-Acked-by: Philippe Mathieu-Daudé <philmd@redhat.com>
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The IScsiHexToBin() function documents the EFI_BUFFER_TOO_SMALL return
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condition, but never actually checks whether the decoded buffer fits into
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the caller-provided room (i.e., the input value of "BinLength"), and
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EFI_BUFFER_TOO_SMALL is never returned. The decoding of "HexStr" can
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overflow "BinBuffer".
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This is remotely exploitable, as shown in a subsequent patch, which adds
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error checking to the IScsiHexToBin() call sites. This issue allows the
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target to compromise the initiator.
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Introduce EFI_BAD_BUFFER_SIZE, in addition to the existent
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EFI_BUFFER_TOO_SMALL, for reporting a special case of the buffer overflow,
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plus actually catch the buffer overflow.
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Cc: Jiaxin Wu <jiaxin.wu@intel.com>
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Cc: Maciej Rabeda <maciej.rabeda@linux.intel.com>
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Cc: Philippe Mathieu-Daudé <philmd@redhat.com>
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Cc: Siyuan Fu <siyuan.fu@intel.com>
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Ref: https://bugzilla.tianocore.org/show_bug.cgi?id=3356
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Signed-off-by: Laszlo Ersek <lersek@redhat.com>
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Reviewed-by: Maciej Rabeda <maciej.rabeda@linux.intel.com>
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Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
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Message-Id: <20210608121259.32451-10-lersek@redhat.com>
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(cherry picked from commit 54e90edaed0d7c15230902ac4d74f4304bad2ebd)
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---
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NetworkPkg/IScsiDxe/IScsiMisc.c | 20 +++++++++++++++++---
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NetworkPkg/IScsiDxe/IScsiMisc.h | 3 +++
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2 files changed, 20 insertions(+), 3 deletions(-)
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diff --git a/NetworkPkg/IScsiDxe/IScsiMisc.c b/NetworkPkg/IScsiDxe/IScsiMisc.c
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index f0f4992b07..4069547867 100644
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--- a/NetworkPkg/IScsiDxe/IScsiMisc.c
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+++ b/NetworkPkg/IScsiDxe/IScsiMisc.c
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@@ -377,6 +377,9 @@ IScsiBinToHex (
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@retval EFI_SUCCESS The hexadecimal string is converted into a
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binary encoded buffer.
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@retval EFI_INVALID_PARAMETER Invalid hex encoding found in HexStr.
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+ @retval EFI_BAD_BUFFER_SIZE The length of HexStr is too large for decoding:
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+ the decoded size cannot be expressed in
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+ BinLength on output.
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@retval EFI_BUFFER_TOO_SMALL The binary buffer is too small to hold the
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converted data.
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**/
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@@ -387,6 +390,8 @@ IScsiHexToBin (
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IN CHAR8 *HexStr
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)
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{
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+ UINTN BinLengthMin;
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+ UINT32 BinLengthProvided;
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UINTN Index;
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UINTN Length;
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UINT8 Digit;
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@@ -409,6 +414,18 @@ IScsiHexToBin (
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if (Length == 0 || Length % 2 != 0) {
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return EFI_INVALID_PARAMETER;
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}
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+ //
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+ // Check if the caller provides enough room for the decoded blob.
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+ //
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+ BinLengthMin = Length / 2;
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+ if (BinLengthMin > MAX_UINT32) {
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+ return EFI_BAD_BUFFER_SIZE;
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+ }
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+ BinLengthProvided = *BinLength;
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+ *BinLength = (UINT32)BinLengthMin;
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+ if (BinLengthProvided < BinLengthMin) {
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+ return EFI_BUFFER_TOO_SMALL;
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+ }
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for (Index = 0; Index < Length; Index ++) {
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TemStr[0] = HexStr[Index];
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@@ -425,9 +442,6 @@ IScsiHexToBin (
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BinBuffer [Index/2] = (UINT8) ((BinBuffer [Index/2] << 4) + Digit);
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}
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}
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-
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- *BinLength = (UINT32) ((Index + 1)/2);
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-
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return EFI_SUCCESS;
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}
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diff --git a/NetworkPkg/IScsiDxe/IScsiMisc.h b/NetworkPkg/IScsiDxe/IScsiMisc.h
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index 404a482e57..fddef4f466 100644
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--- a/NetworkPkg/IScsiDxe/IScsiMisc.h
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+++ b/NetworkPkg/IScsiDxe/IScsiMisc.h
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@@ -172,6 +172,9 @@ IScsiBinToHex (
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@retval EFI_SUCCESS The hexadecimal string is converted into a
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binary encoded buffer.
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@retval EFI_INVALID_PARAMETER Invalid hex encoding found in HexStr.
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+ @retval EFI_BAD_BUFFER_SIZE The length of HexStr is too large for decoding:
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+ the decoded size cannot be expressed in
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+ BinLength on output.
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@retval EFI_BUFFER_TOO_SMALL The binary buffer is too small to hold the
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converted data.
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**/
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--
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2.27.0
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