From e5945ef78463a2a90631c91e9f8cff109fd20625 Mon Sep 17 00:00:00 2001
From: Laszlo Ersek <lersek@redhat.com>
Date: Thu, 21 Jan 2016 18:40:09 +0000
Subject: [PATCH] ShellPkg: BcfgDisplayDump(): enforce minimum size for
Boot#### and co.
"3.1.1 Boot Manager Programming" in the UEFI 2.5 spec mandates that
Boot#### and similar options contain EFI_LOAD_OPTION structures. The
EFI_LOAD_OPTION structure encodes the fixed initial part of the payload,
and we can (and should) use it to enforce a minimum size for variable
contents.
This patch is meant as a safety improvement.
Cc: Jaben Carsey <jaben.carsey@intel.com>
Cc: Ryan Harkin <ryan.harkin@linaro.org>
Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Laszlo Ersek <lersek@redhat.com>
Reviewed-by: Jaben Carsey <jaben.carsey@intel.com>
git-svn-id: https://svn.code.sf.net/p/edk2/code/trunk/edk2@19710 6f19259b-4bc3-4df7-8a09-765794883524
---
.../UefiShellBcfgCommandLib.c | 19 +++++++++++++++++++
.../UefiShellBcfgCommandLib.uni | 1 +
2 files changed, 20 insertions(+)
diff --git a/ShellPkg/Library/UefiShellBcfgCommandLib/UefiShellBcfgCommandLib.c b/ShellPkg/Library/UefiShellBcfgCommandLib/UefiShellBcfgCommandLib.c
index 36d04d495c..9955c9e640 100644
--- a/ShellPkg/Library/UefiShellBcfgCommandLib/UefiShellBcfgCommandLib.c
+++ b/ShellPkg/Library/UefiShellBcfgCommandLib/UefiShellBcfgCommandLib.c
@@ -1052,6 +1052,7 @@ BcfgDisplayDump(
CHAR16 *DevPathString;
VOID *DevPath;
UINTN Errors;
+ EFI_LOAD_OPTION *LoadOption;
if (OrderCount == 0) {
ShellPrintHiiEx(-1, -1, NULL, STRING_TOKEN(STR_BCFG_NONE), gShellBcfgHiiHandle, L"bcfg");
@@ -1090,6 +1091,24 @@ BcfgDisplayDump(
goto Cleanup;
}
+ //
+ // We expect the Attributes, FilePathListLength, and L'\0'-terminated
+ // Description fields to be present.
+ //
+ if (BufferSize < sizeof *LoadOption + sizeof (CHAR16)) {
+ ShellPrintHiiEx (
+ -1,
+ -1,
+ NULL,
+ STRING_TOKEN (STR_BCFG_VAR_CORRUPT),
+ gShellBcfgHiiHandle,
+ L"bcfg",
+ VariableName
+ );
+ ++Errors;
+ goto Cleanup;
+ }
+
if ((*(UINT16*)(Buffer+4)) != 0) {
DevPath = AllocateZeroPool(*(UINT16*)(Buffer+4));
if (DevPath != NULL) {
diff --git a/ShellPkg/Library/UefiShellBcfgCommandLib/UefiShellBcfgCommandLib.uni b/ShellPkg/Library/UefiShellBcfgCommandLib/UefiShellBcfgCommandLib.uni
index 25bd138b2b..282494b2f4 100644
--- a/ShellPkg/Library/UefiShellBcfgCommandLib/UefiShellBcfgCommandLib.uni
+++ b/ShellPkg/Library/UefiShellBcfgCommandLib/UefiShellBcfgCommandLib.uni
@@ -37,6 +37,7 @@
#string STR_GEN_OUT_MEM #language en-US "%H%s%N: Memory allocation was not successful.\r\n"
#string STR_BCFG_WRITE_FAIL #language en-US "%H%s%N: Unable to write to '%H%s%N'\r\n"
#string STR_BCFG_READ_FAIL #language en-US "%H%s%N: Unable to read from '%H%s%N'\r\n"
+#string STR_BCFG_VAR_CORRUPT #language en-US "%H%s%N: Variable '%H%s%N' corrupt.\r\n"
#string STR_BCFG_HANDLE #language en-US "%H%s%N: The handle [%H%02x%N] does not have DevicePath.\r\n"
#string STR_BCFG_FILE #language en-US "%H%s%N: The file '%H%s%N' matches multiple files.\r\n"
#string STR_BCFG_FILE_OPEN #language en-US "%H%s%N: The file '%H%s%N' did not open.\r\n"