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Refactor - Make Executable::ro_section offset explicit #606

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merged 1 commit into from
Oct 8, 2024
Merged

Refactor - Make Executable::ro_section offset explicit #606

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31 changes: 17 additions & 14 deletions src/elf.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -355,7 +355,7 @@ impl<C: ContextObject> Executable<C> {
Ok(Self {
elf_bytes,
sbpf_version,
ro_section: Section::Borrowed(0, 0..text_bytes.len()),
ro_section: Section::Borrowed(ebpf::MM_PROGRAM_START as usize, 0..text_bytes.len()),
text_section_vaddr: ebpf::MM_PROGRAM_START,
text_section_range: 0..text_bytes.len(),
entry_pc,
Expand Down Expand Up @@ -720,12 +720,12 @@ impl<C: ContextObject> Executable<C> {
// ebpf::MM_PROGRAM_START so if the linker has already put the
// sections within ebpf::MM_PROGRAM_START, we need to subtract
// it now.
lowest_addr.saturating_sub(ebpf::MM_PROGRAM_START as usize)
lowest_addr
} else {
if sbpf_version.enable_elf_vaddr() {
return Err(ElfError::ValueOutOfBounds);
}
lowest_addr
lowest_addr.saturating_add(ebpf::MM_PROGRAM_START as usize)
};

Section::Borrowed(addr_offset, buf_offset_start..buf_offset_end)
Expand Down Expand Up @@ -759,9 +759,9 @@ impl<C: ContextObject> Executable<C> {
}

let addr_offset = if lowest_addr >= ebpf::MM_PROGRAM_START as usize {
lowest_addr.saturating_sub(ebpf::MM_PROGRAM_START as usize)
} else {
lowest_addr
} else {
lowest_addr.saturating_add(ebpf::MM_PROGRAM_START as usize)
};
Section::Owned(addr_offset, ro_section)
};
Expand Down Expand Up @@ -1138,10 +1138,7 @@ pub(crate) fn get_ro_region(ro_section: &Section, elf: &[u8]) -> MemoryRegion {
// If offset > 0, the region will start at MM_PROGRAM_START + the offset of
// the first read only byte. [MM_PROGRAM_START, MM_PROGRAM_START + offset)
// will be unmappable, see MemoryRegion::vm_to_host.
MemoryRegion::new_readonly(
ro_data,
ebpf::MM_PROGRAM_START.saturating_add(offset as u64),
)
MemoryRegion::new_readonly(ro_data, offset as u64)
}

#[cfg(test)]
Expand Down Expand Up @@ -1419,7 +1416,7 @@ mod test {
sections,
&elf_bytes,
),
Ok(Section::Owned(offset, data)) if offset == 10 && data.len() == 30
Ok(Section::Owned(offset, data)) if offset == ebpf::MM_PROGRAM_START as usize + 10 && data.len() == 30
));
}

Expand All @@ -1446,7 +1443,7 @@ mod test {
sections,
&elf_bytes,
),
Ok(Section::Owned(offset, data)) if offset == 10 && data.len() == 20
Ok(Section::Owned(offset, data)) if offset == ebpf::MM_PROGRAM_START as usize + 10 && data.len() == 20
));
}

Expand Down Expand Up @@ -1543,7 +1540,10 @@ mod test {
[(Some(b".text"), &s1), (Some(b".rodata"), &s2)];
assert_eq!(
ElfExecutable::parse_ro_sections(&config, &SBPFVersion::V2, sections, &elf_bytes),
Ok(Section::Borrowed(10, 100..120))
Ok(Section::Borrowed(
ebpf::MM_PROGRAM_START as usize + 10,
100..120
))
);
}

Expand Down Expand Up @@ -1708,7 +1708,7 @@ mod test {
sections,
&elf_bytes,
),
Ok(Section::Owned(offset, data)) if offset == 0 && data.len() == 20
Ok(Section::Owned(offset, data)) if offset == ebpf::MM_PROGRAM_START as usize && data.len() == 20
));
}

Expand All @@ -1732,7 +1732,10 @@ mod test {
];
assert_eq!(
ElfExecutable::parse_ro_sections(&config, &sbpf_version, sections, &elf_bytes),
Ok(Section::Borrowed(20, 20..50))
Ok(Section::Borrowed(
ebpf::MM_PROGRAM_START as usize + 20,
20..50
))
);
}
}
Expand Down