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authorLaszlo Ersek <lersek@redhat.com>2021-06-08 14:12:58 +0200
committermergify[bot] <37929162+mergify[bot]@users.noreply.github.com>2021-06-09 17:25:03 +0000
commit54e90edaed0d7c15230902ac4d74f4304bad2ebd (patch)
treef90cd8bc36744bcb6a87dc3686f6c8307245036f /NetworkPkg/IScsiDxe
parent47b76780b487dbfde4efb6843b16064c4a97e94d (diff)
downloadedk2-54e90edaed0d7c15230902ac4d74f4304bad2ebd.tar.gz
edk2-54e90edaed0d7c15230902ac4d74f4304bad2ebd.tar.bz2
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NetworkPkg/IScsiDxe: fix IScsiHexToBin() buffer overflow
The IScsiHexToBin() function documents the EFI_BUFFER_TOO_SMALL return condition, but never actually checks whether the decoded buffer fits into the caller-provided room (i.e., the input value of "BinLength"), and EFI_BUFFER_TOO_SMALL is never returned. The decoding of "HexStr" can overflow "BinBuffer". This is remotely exploitable, as shown in a subsequent patch, which adds error checking to the IScsiHexToBin() call sites. This issue allows the target to compromise the initiator. Introduce EFI_BAD_BUFFER_SIZE, in addition to the existent EFI_BUFFER_TOO_SMALL, for reporting a special case of the buffer overflow, plus actually catch the buffer overflow. 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: <20210608121259.32451-10-lersek@redhat.com>
Diffstat (limited to 'NetworkPkg/IScsiDxe')
-rw-r--r--NetworkPkg/IScsiDxe/IScsiMisc.c20
-rw-r--r--NetworkPkg/IScsiDxe/IScsiMisc.h3
2 files changed, 20 insertions, 3 deletions
diff --git a/NetworkPkg/IScsiDxe/IScsiMisc.c b/NetworkPkg/IScsiDxe/IScsiMisc.c
index f0f4992b07..4069547867 100644
--- a/NetworkPkg/IScsiDxe/IScsiMisc.c
+++ b/NetworkPkg/IScsiDxe/IScsiMisc.c
@@ -377,6 +377,9 @@ 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_BAD_BUFFER_SIZE The length of HexStr is too large for decoding:
+ the decoded size cannot be expressed in
+ BinLength on output.
@retval EFI_BUFFER_TOO_SMALL The binary buffer is too small to hold the
converted data.
**/
@@ -387,6 +390,8 @@ IScsiHexToBin (
IN CHAR8 *HexStr
)
{
+ UINTN BinLengthMin;
+ UINT32 BinLengthProvided;
UINTN Index;
UINTN Length;
UINT8 Digit;
@@ -409,6 +414,18 @@ IScsiHexToBin (
if (Length == 0 || Length % 2 != 0) {
return EFI_INVALID_PARAMETER;
}
+ //
+ // Check if the caller provides enough room for the decoded blob.
+ //
+ BinLengthMin = Length / 2;
+ if (BinLengthMin > MAX_UINT32) {
+ return EFI_BAD_BUFFER_SIZE;
+ }
+ BinLengthProvided = *BinLength;
+ *BinLength = (UINT32)BinLengthMin;
+ if (BinLengthProvided < BinLengthMin) {
+ return EFI_BUFFER_TOO_SMALL;
+ }
for (Index = 0; Index < Length; Index ++) {
TemStr[0] = HexStr[Index];
@@ -425,9 +442,6 @@ IScsiHexToBin (
BinBuffer [Index/2] = (UINT8) ((BinBuffer [Index/2] << 4) + Digit);
}
}
-
- *BinLength = (UINT32) ((Index + 1)/2);
-
return EFI_SUCCESS;
}
diff --git a/NetworkPkg/IScsiDxe/IScsiMisc.h b/NetworkPkg/IScsiDxe/IScsiMisc.h
index 404a482e57..fddef4f466 100644
--- a/NetworkPkg/IScsiDxe/IScsiMisc.h
+++ b/NetworkPkg/IScsiDxe/IScsiMisc.h
@@ -172,6 +172,9 @@ 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_BAD_BUFFER_SIZE The length of HexStr is too large for decoding:
+ the decoded size cannot be expressed in
+ BinLength on output.
@retval EFI_BUFFER_TOO_SMALL The binary buffer is too small to hold the
converted data.
**/