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td-shim-interface: support large ffs header and section header
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Add support for parsing ffs and sections that have size larger than
16MiB.

Signed-off-by: Jiaqi Gao <[email protected]>
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@gaojiaqi7
gaojiaqi7 committed May 10, 2024
1 parent 0439e3e commit 5111ef7
Showing 1 changed file with 98 additions and 23 deletions.
121 changes: 98 additions & 23 deletions td-shim-interface/src/td_uefi_pi/fv.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -43,7 +43,7 @@ pub fn validate_ffs_file_header(header: FfsFileHeader) -> bool {
// Do the sanity check for Ffs header.
// Verify the header integrity,
//
if !header.validate_checksum() {
if ffs_header_validate_checksum(header.as_bytes()) {
return false;
}
true
Expand All @@ -58,10 +58,10 @@ pub fn get_image_from_fv(

let files = Files::parse(fv_data, fv_header.header_length as usize)?;
for (file_header, file_data) in files {
if !validate_ffs_file_header(file_header) {
if !file_header.validate() {
return None;
}
if file_header.r#type == fv_file_type {
if file_header.r#type() == fv_file_type {
return get_image_from_sections(file_data, section_type);
}
}
Expand All @@ -78,10 +78,10 @@ pub fn get_file_from_fv(

let files = Files::parse(fv_data, fv_header.header_length as usize)?;
for (file_header, file_data) in files {
if !validate_ffs_file_header(file_header) {
if !file_header.validate() {
return None;
}
if file_header.r#type == fv_file_type && &file_header.name == file_name.as_bytes() {
if file_header.r#type() == fv_file_type && file_header.name() == file_name.as_bytes() {
return Some(file_data);
}
}
Expand All @@ -93,14 +93,28 @@ fn get_image_from_sections(sections_data: &[u8], section_type: SectionType) -> O
let sections = Sections::parse(sections_data, 0)?;

for (section_header, section_data) in sections {
if section_header.r#type == section_type {
if section_header.r#type() == section_type {
return Some(section_data);
}
}

None
}

enum CommonSectionHeaderType {
Header(CommonSectionHeader),
Header2(CommonSectionHeader2),
}

impl CommonSectionHeaderType {
fn r#type(&self) -> FvFileType {
match self {
Self::Header(header) => header.r#type,
Self::Header2(header2) => header2.r#type,
}
}
}

struct Sections<'a> {
buffer: &'a [u8],
}
Expand All @@ -118,17 +132,32 @@ impl<'a> Sections<'a> {
}

impl<'a> Iterator for Sections<'a> {
type Item = (CommonSectionHeader, &'a [u8]);
type Item = (CommonSectionHeaderType, &'a [u8]);

fn next(&mut self) -> Option<Self::Item> {
const HEADER_SIZE: usize = core::mem::size_of::<CommonSectionHeader>();
let header: CommonSectionHeader = self.buffer.pread(0).ok()?;
let section_size = header.size[0] as usize
+ ((header.size[1] as usize) << 8)
+ ((header.size[2] as usize) << 16);
section_size.checked_sub(HEADER_SIZE)?;
let is_large_section = header.size == [0xff, 0xff, 0xff];

let (section_size, section_header, header_size) = if is_large_section {
let header2: CommonSectionHeader2 = self.buffer.pread(0).ok()?;
(
header2.extended_size as usize,
CommonSectionHeaderType::Header2(header2),
core::mem::size_of::<CommonSectionHeader2>(),
)
} else {
(
header.size[0] as usize
+ ((header.size[1] as usize) << 8)
+ ((header.size[2] as usize) << 16),
CommonSectionHeaderType::Header(header),
core::mem::size_of::<CommonSectionHeader>(),
)
};

section_size.checked_sub(header_size)?;
self.buffer.len().checked_sub(section_size)?;
let buf = &self.buffer[HEADER_SIZE..section_size];
let buf = &self.buffer[header_size..section_size];

// Align to 4 bytes.
let section_size = (section_size + 3) & !3;
Expand All @@ -138,7 +167,39 @@ impl<'a> Iterator for Sections<'a> {
self.buffer = &self.buffer[0..0];
}

Some((header, buf))
Some((section_header, buf))
}
}

enum FfsFileHeaderType {
Header(FfsFileHeader),
Header2(FfsFileHeader2),
}

impl FfsFileHeaderType {
fn r#type(&self) -> FvFileType {
match self {
FfsFileHeaderType::Header(header) => header.r#type,
FfsFileHeaderType::Header2(header2) => header2.r#type,
}
}

fn name(&self) -> &[u8] {
match self {
FfsFileHeaderType::Header(header) => &header.name,
FfsFileHeaderType::Header2(header2) => &header2.name,
}
}

// Validate Ffs File header
fn validate(&self) -> bool {
// Do the sanity check for Ffs header.
// Verify the header integrity,
//
match self {
FfsFileHeaderType::Header(header) => ffs_header_validate_checksum(header.as_bytes()),
FfsFileHeaderType::Header2(header2) => ffs_header_validate_checksum(header2.as_bytes()),
}
}
}

Expand All @@ -159,18 +220,32 @@ impl<'a> Files<'a> {
}

impl<'a> Iterator for Files<'a> {
type Item = (FfsFileHeader, &'a [u8]);
type Item = (FfsFileHeaderType, &'a [u8]);

fn next(&mut self) -> Option<Self::Item> {
const HEADER_SIZE: usize = core::mem::size_of::<FfsFileHeader>();

let header: FfsFileHeader = self.buffer.pread(0).ok()?;
let data_size = header.size[0] as usize
+ ((header.size[1] as usize) << 8)
+ ((header.size[2] as usize) << 16);
data_size.checked_sub(HEADER_SIZE)?;
let is_large_file = header.attributes & FFS_ATTRIB_LARGE_FILE != 0;

let (data_size, ffs_header, header_size) = if is_large_file {
let header2: FfsFileHeader2 = self.buffer.pread(0).ok()?;
(
header2.extended_size as usize,
FfsFileHeaderType::Header2(header2),
core::mem::size_of::<FfsFileHeader2>(),
)
} else {
(
header.size[0] as usize
+ ((header.size[1] as usize) << 8)
+ ((header.size[2] as usize) << 16),
FfsFileHeaderType::Header(header),
core::mem::size_of::<FfsFileHeader>(),
)
};

data_size.checked_sub(header_size)?;
self.buffer.len().checked_sub(data_size)?;
let buf = &self.buffer[HEADER_SIZE..data_size];
let buf = &self.buffer[header_size..data_size];

// Align to 8 bytes.
let data_size = (data_size + 7) & !7;
Expand All @@ -180,7 +255,7 @@ impl<'a> Iterator for Files<'a> {
self.buffer = &self.buffer[0..0];
}

Some((header, buf))
Some((ffs_header, buf))
}
}

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