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Properly handle reading section header tables with > SHN_LORESERVE number of sections

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This commit is contained in:
Christopher Cole 2022-10-21 11:20:28 -07:00
parent 5a4e556d68
commit 5469c59037
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GPG Key ID: 0AC856975983E9DB
1 changed files with 13 additions and 3 deletions
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16
src/file.rs
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@ -61,7 +61,8 @@ impl<R: ReadBytesAt> File<R> {
/// [e_shentsize](FileHeader#structfield.e_shentsize) are invalid and point
/// to a range in the file data that does not actually exist.
pub fn section_headers(&mut self) -> Result<section::SectionHeaderIterator, ParseError> {
if self.ehdr.e_shnum == 0 {
// It's Ok to have no section headers
if self.ehdr.e_shoff == 0 {
return Ok(section::SectionHeaderIterator::new(
self.ehdr.endianness,
self.ehdr.class,
@ -69,8 +70,17 @@ impl<R: ReadBytesAt> File<R> {
));
}
// If the number of sections is greater than or equal to SHN_LORESERVE (0xff00),
// e_shnum is zero and the actual number of section header table entries
// is contained in the sh_size field of the section header at index 0.
let mut shnum = self.ehdr.e_shnum as u64;
if self.ehdr.e_shoff > 0 && self.ehdr.e_shnum == 0 {
let shdr_0 = self.section_header_by_index(0)?;
shnum = shdr_0.sh_size;
}
let start = self.ehdr.e_shoff as usize;
let size = self.ehdr.e_shentsize as usize * self.ehdr.e_shnum as usize;
let size = self.ehdr.e_shentsize as usize * shnum as usize;
let buf = self.reader.read_bytes_at(start..start + size)?;
Ok(section::SectionHeaderIterator::new(
self.ehdr.endianness,
@ -85,7 +95,7 @@ impl<R: ReadBytesAt> File<R> {
&mut self,
index: usize,
) -> Result<section::SectionHeader, ParseError> {
if self.ehdr.e_shnum == 0 || index >= self.ehdr.e_shnum as usize {
if self.ehdr.e_shnum > 0 && index >= self.ehdr.e_shnum as usize {
return Err(ParseError::BadOffset(index as u64));
}