"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.car...@intel.com>
Cc: Ryan Harkin <ryan.har...@linaro.org>
Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Laszlo Ersek <ler...@redhat.com>
---
ShellPkg/Library/UefiShellBcfgCommandLib/UefiShellBcfgCommandLib.c | 19
+++++++++++++++++++
ShellPkg/Library/UefiShellBcfgCommandLib/UefiShellBcfgCommandLib.uni | 1 +
2 files changed, 20 insertions(+)
diff --git a/ShellPkg/Library/UefiShellBcfgCommandLib/UefiShellBcfgCommandLib.c
b/ShellPkg/Library/UefiShellBcfgCommandLib/UefiShellBcfgCommandLib.c
index 36d04d4..9955c9e 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 25bd138..282494b 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"
--
1.8.3.1
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