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eif_reader: Parse eif sections according to EifHeader #26

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eif_reader: Parse eif sections according to EifHeader #26

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51 changes: 34 additions & 17 deletions src/utils/eif_reader.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -101,9 +101,6 @@ impl EifReader {
let header = EifHeader::from_be_bytes(&header_buf)
.map_err(|e| format!("Error while parsing EIF header: {:?}", e))?;
curr_seek += EifHeader::size();
eif_file
.seek(SeekFrom::Start(curr_seek as u64))
.map_err(|e| format!("Failed to seek file from start: {:?}", e))?;

let mut section_buf = vec![0u8; EifSectionHeader::size()];
let mut image_hasher = EifHasher::new_without_cache(Sha384::new())
Expand All @@ -118,18 +115,41 @@ impl EifReader {
let mut signature_section = None;
let mut metadata = None;

// Read all section headers and treat by type
while eif_file
.read_exact(&mut section_buf)
.map_err(|e| format!("Error while reading EIF header: {:?}", e))
.is_ok()
{
let section = EifSectionHeader::from_be_bytes(&section_buf)
for iter in 0..header.num_sections {
let section_offset = header.section_offsets[iter as usize];
let section_size = header.section_sizes[iter as usize];

// Consider data in any potential gaps between sections for CRC calculation
if section_offset > curr_seek as u64 {
let gap_size = section_offset - curr_seek as u64;
let mut buf_gap = vec![0u8; gap_size as usize];
eif_file
.seek(SeekFrom::Start(curr_seek as u64))
.map_err(|e| format!("Failed to seek file from start: {:?}", e))?;
eif_file
.read_exact(&mut buf_gap)
.map_err(|e| format!("Error while reading EIF file: {:?}", e))?;
eif_crc.write(&buf_gap);
curr_seek += gap_size as usize;
}

eif_file
.seek(SeekFrom::Start(curr_seek as u64))
.map_err(|e| format!("Failed to seek file from start: {:?}", e))?;
eif_file
.read_exact(&mut section_buf)
.map_err(|e| format!("Error while reading EIF header: {:?}", e))?;
let section_header = EifSectionHeader::from_be_bytes(&section_buf)
.map_err(|e| format!("Error extracting EIF section header: {:?}", e))?;
eif_crc.write(&section_buf);

let mut buf = vec![0u8; section.section_size as usize];
eif_crc.write(&section_buf);
curr_seek += EifSectionHeader::size();

if section_header.section_size != section_size {
return Err(format!("Error while parsing EIF file: EifHeader::section_sizes[{:?}] does not match EifSectionHeader::size", iter));
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@sabin-rapan sabin-rapan Aug 6, 2024

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maybe the string can be massaged to print both section_header.section_size and section_size to make debugging easier

}

let mut buf = vec![0u8; section_size as usize];
eif_file
.seek(SeekFrom::Start(curr_seek as u64))
.map_err(|e| format!("Failed to seek after EIF header: {:?}", e))?;
Expand All @@ -138,12 +158,9 @@ impl EifReader {
.map_err(|e| format!("Error while reading kernel from EIF: {:?}", e))?;
eif_crc.write(&buf);

curr_seek += section.section_size as usize;
eif_file
.seek(SeekFrom::Start(curr_seek as u64))
.map_err(|e| format!("Failed to seek after EIF section: {:?}", e))?;
curr_seek += section_size as usize;

match section.section_type {
match section_header.section_type {
EifSectionType::EifSectionKernel | EifSectionType::EifSectionCmdline => {
image_hasher.write_all(&buf).map_err(|e| {
format!("Failed to write EIF section to image_hasher: {:?}", e)
Expand Down