105 lines
4.0 KiB
Diff
105 lines
4.0 KiB
Diff
From 2f0e51dcfea6d9101c4694636a948eb4b6e6d4d4 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 14:12:57 +0200
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Subject: [PATCH 08/10] NetworkPkg/IScsiDxe: fix IScsiHexToBin() hex parsing
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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: [8/10] febb96c07dbd0e4a191e855742cb47fc6e39dfba
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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 has the following parser issues:
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(1) If the *subject sequence* in "HexStr" is empty, the function returns
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EFI_SUCCESS (with "BinLength" set to 0 on output). Such inputs should
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be rejected.
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(2) The function mis-handles a "HexStr" that ends with a stray nibble. For
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example, if "HexStr" is "0xABC", the function decodes it to the bytes
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{0xAB, 0x0C}, sets "BinLength" to 2 on output, and returns
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EFI_SUCCESS. Such inputs should be rejected.
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(3) If an invalid hex char is found in "HexStr", the function treats it as
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end-of-hex-string, and returns EFI_SUCCESS. Such inputs should be
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rejected.
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All of the above cases are remotely triggerable, as shown in a subsequent
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patch, which adds error checking to the IScsiHexToBin() call sites. While
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the initiator is not immediately compromised, incorrectly parsing CHAP_R
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from the target, in case of mutual authentication, is not great.
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Extend the interface contract of IScsiHexToBin() with
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EFI_INVALID_PARAMETER, for reporting issues (1) through (3), and implement
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the new checks.
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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: <20210608121259.32451-9-lersek@redhat.com>
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(cherry picked from commit 47b76780b487dbfde4efb6843b16064c4a97e94d)
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---
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NetworkPkg/IScsiDxe/IScsiMisc.c | 12 ++++++++++--
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NetworkPkg/IScsiDxe/IScsiMisc.h | 1 +
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2 files changed, 11 insertions(+), 2 deletions(-)
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diff --git a/NetworkPkg/IScsiDxe/IScsiMisc.c b/NetworkPkg/IScsiDxe/IScsiMisc.c
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index 014700e87a..f0f4992b07 100644
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--- a/NetworkPkg/IScsiDxe/IScsiMisc.c
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+++ b/NetworkPkg/IScsiDxe/IScsiMisc.c
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@@ -376,6 +376,7 @@ 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_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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@@ -402,14 +403,21 @@ IScsiHexToBin (
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Length = AsciiStrLen (HexStr);
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+ //
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+ // Reject an empty hex string; reject a stray nibble.
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+ //
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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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for (Index = 0; Index < Length; Index ++) {
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TemStr[0] = HexStr[Index];
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Digit = (UINT8) AsciiStrHexToUint64 (TemStr);
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if (Digit == 0 && TemStr[0] != '0') {
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//
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- // Invalid Lun Char.
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+ // Invalid Hex Char.
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//
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- break;
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+ return EFI_INVALID_PARAMETER;
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}
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if ((Index & 1) == 0) {
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BinBuffer [Index/2] = Digit;
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diff --git a/NetworkPkg/IScsiDxe/IScsiMisc.h b/NetworkPkg/IScsiDxe/IScsiMisc.h
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index 28cf408cd5..404a482e57 100644
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--- a/NetworkPkg/IScsiDxe/IScsiMisc.h
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+++ b/NetworkPkg/IScsiDxe/IScsiMisc.h
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@@ -171,6 +171,7 @@ 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_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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