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authorLaszlo Ersek <lersek@redhat.com>2021-06-08 14:12:57 +0200
committermergify[bot] <37929162+mergify[bot]@users.noreply.github.com>2021-06-09 17:25:03 +0000
commit47b76780b487dbfde4efb6843b16064c4a97e94d (patch)
tree862c955dbbf9df6686a14dc8a50b8232802766d2 /NetworkPkg
parentdc469f137110fe79704b8b92c552972c739bb915 (diff)
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NetworkPkg/IScsiDxe: fix IScsiHexToBin() hex parsing
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> Message-Id: <20210608121259.32451-9-lersek@redhat.com>
Diffstat (limited to 'NetworkPkg')
-rw-r--r--NetworkPkg/IScsiDxe/IScsiMisc.c12
-rw-r--r--NetworkPkg/IScsiDxe/IScsiMisc.h1
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.
**/