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BaseTools: GenFw: auto-set nxcompat flag

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Automatically set the nxcompat flag in the DLL Characteristics field of
the Optional Header of the PE32+ image. For this flag to be set
automatically, the section alignment must be evenly divisible
by 4K (EFI_PAGE_SIZE) and no section must be executable and writable.

Adds a command line flag to GenFw, --nonxcompat, to ensure the
IMAGE_DLLCHARACTERISTICS_NX_COMPAT bit is not set, even if all
requirements are met. Updates the manual for GenFw to include the new
flag.

Cc: Rebecca Cran <rebecca@bsdio.com>
Cc: Liming Gao <gaoliming@byosoft.com.cn>
Cc: Bob Feng <bob.c.feng@intel.com>
Cc: Yuwei Chen <yuwei.chen@intel.com>
Signed-off-by: Joey Vagedes <joeyvagedes@gmail.com>
Acked-by: Liming Gao <gaoliming@byosoft.com.cn>
Reviewed-by: Rebecca Cran <rebecca@bsdio.com>
This commit is contained in:
Joey Vagedes
2023-07-13 08:24:36 -07:00
committed by mergify[bot]
parent e53c618ea4
commit da21991953
2 changed files with 245 additions and 378 deletions
Download Patch File Download Diff File Expand all files Collapse all files

69
BaseTools/Source/C/GenFw/GenFw.c
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@@ -86,6 +86,7 @@ UINT32 mImageSize = 0;
UINT32 mOutImageType = FW_DUMMY_IMAGE;
BOOLEAN mIsConvertXip = FALSE;
BOOLEAN mExportFlag = FALSE;
BOOLEAN mNoNxCompat = FALSE;
STATIC
EFI_STATUS
@@ -281,6 +282,9 @@ Returns:
write export table into PE-COFF.\n\
This option can be used together with -e.\n\
It doesn't work for other options.\n");
fprintf (stdout, " --nonxcompat Do not set the IMAGE_DLLCHARACTERISTICS_NX_COMPAT bit \n\
of the optional header in the PE header even if the \n\
requirements are met.\n");
fprintf (stdout, " -v, --verbose Turn on verbose output with informational messages.\n");
fprintf (stdout, " -q, --quiet Disable all messages except key message and fatal error\n");
fprintf (stdout, " -d, --debug level Enable debug messages, at input debug level.\n");
@@ -441,6 +445,59 @@ Returns:
return STATUS_SUCCESS;
}
/**
Checks if the Pe image is nxcompat compliant.
Must meet the following conditions:
1. The PE is 64bit
2. The section alignment is evenly divisible by 4k
3. No section is writable and executable.
@param PeHdr - The PE header
@retval TRUE - The PE is nx compat compliant
@retval FALSE - The PE is not nx compat compliant
**/
STATIC
BOOLEAN
IsNxCompatCompliant (
EFI_IMAGE_OPTIONAL_HEADER_UNION *PeHdr
)
{
EFI_IMAGE_SECTION_HEADER *SectionHeader;
UINT32 Index;
UINT32 Mask;
// Must have an optional header to perform verification
if (PeHdr->Pe32.FileHeader.SizeOfOptionalHeader == 0) {
return FALSE;
}
// Verify PE is 64 bit
if (!(PeHdr->Pe32.OptionalHeader.Magic == EFI_IMAGE_NT_OPTIONAL_HDR64_MAGIC)) {
return FALSE;
}
// Verify Section Alignment is divisible by 4K
if (!((PeHdr->Pe32Plus.OptionalHeader.SectionAlignment % EFI_PAGE_SIZE) == 0)) {
return FALSE;
}
// Verify sections are not Write & Execute
Mask = EFI_IMAGE_SCN_MEM_EXECUTE | EFI_IMAGE_SCN_MEM_WRITE;
SectionHeader = (EFI_IMAGE_SECTION_HEADER *) ((UINT8 *) &(PeHdr->Pe32Plus.OptionalHeader) + PeHdr->Pe32Plus.FileHeader.SizeOfOptionalHeader);
for (Index = 0; Index < PeHdr->Pe32Plus.FileHeader.NumberOfSections; Index ++, SectionHeader ++) {
if ((SectionHeader->Characteristics & Mask) == Mask) {
return FALSE;
}
}
// Passed all requirements, return TRUE
return TRUE;
}
VOID
SetHiiResourceHeader (
UINT8 *HiiBinData,
@@ -1452,6 +1509,13 @@ Returns:
continue;
}
if (stricmp (argv[0], "--nonxcompat") == 0) {
mNoNxCompat = TRUE;
argc --;
argv ++;
continue;
}
if (argv[0][0] == '-') {
Error (NULL, 0, 1000, "Unknown option", argv[0]);
goto Finish;
@@ -2458,6 +2522,11 @@ Returns:
TEImageHeader.BaseOfCode = Optional64->BaseOfCode;
TEImageHeader.ImageBase = (UINT64) (Optional64->ImageBase);
// Set NxCompat flag
if (IsNxCompatCompliant (PeHdr) && !mNoNxCompat) {
Optional64->DllCharacteristics |= IMAGE_DLLCHARACTERISTICS_NX_COMPAT;
}
if (Optional64->NumberOfRvaAndSizes > EFI_IMAGE_DIRECTORY_ENTRY_BASERELOC) {
TEImageHeader.DataDirectory[EFI_TE_IMAGE_DIRECTORY_ENTRY_BASERELOC].VirtualAddress = Optional64->DataDirectory[EFI_IMAGE_DIRECTORY_ENTRY_BASERELOC].VirtualAddress;
TEImageHeader.DataDirectory[EFI_TE_IMAGE_DIRECTORY_ENTRY_BASERELOC].Size = Optional64->DataDirectory[EFI_IMAGE_DIRECTORY_ENTRY_BASERELOC].Size;