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read/macho: fix data for segments in dyld caches #673

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Merged
merged 1 commit into from
Apr 30, 2024
Merged

read/macho: fix data for segments in dyld caches #673

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20 changes: 5 additions & 15 deletions src/read/macho/file.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -44,7 +44,7 @@ where
pub(super) header_offset: u64,
pub(super) header: &'data Mach,
pub(super) segments: Vec<MachOSegmentInternal<'data, Mach, R>>,
pub(super) sections: Vec<MachOSectionInternal<'data, Mach>>,
pub(super) sections: Vec<MachOSectionInternal<'data, Mach, R>>,
pub(super) symbols: SymbolTable<'data, Mach, R>,
}

Expand All @@ -65,11 +65,10 @@ where
if let Ok(mut commands) = header.load_commands(endian, data, 0) {
while let Ok(Some(command)) = commands.next() {
if let Some((segment, section_data)) = Mach::Segment::from_command(command)? {
let segment_index = segments.len();
segments.push(MachOSegmentInternal { segment, data });
for section in segment.sections(endian, section_data)? {
let index = SectionIndex(sections.len() + 1);
sections.push(MachOSectionInternal::parse(index, segment_index, section));
sections.push(MachOSectionInternal::parse(index, section, data));
}
} else if let Some(symtab) = command.symtab()? {
symbols = symtab.symbols(endian, data)?;
Expand Down Expand Up @@ -110,6 +109,7 @@ where
if let Some((segment, section_data)) = Mach::Segment::from_command(command)? {
// Each segment can be stored in a different subcache. Get the segment's
// address and look it up in the cache mappings, to find the correct cache data.
// This was observed for the arm64e __LINKEDIT segment in macOS 12.0.1.
let addr = segment.vmaddr(endian).into();
let (data, _offset) = image
.cache
Expand All @@ -118,12 +118,11 @@ where
if segment.name() == macho::SEG_LINKEDIT.as_bytes() {
linkedit_data = Some(data);
}
let segment_index = segments.len();
segments.push(MachOSegmentInternal { segment, data });

for section in segment.sections(endian, section_data)? {
let index = SectionIndex(sections.len() + 1);
sections.push(MachOSectionInternal::parse(index, segment_index, section));
sections.push(MachOSectionInternal::parse(index, section, data));
}
} else if let Some(st) = command.symtab()? {
symtab = Some(st);
Expand Down Expand Up @@ -154,23 +153,14 @@ where
pub(super) fn section_internal(
&self,
index: SectionIndex,
) -> Result<&MachOSectionInternal<'data, Mach>> {
) -> Result<&MachOSectionInternal<'data, Mach, R>> {
index
.0
.checked_sub(1)
.and_then(|index| self.sections.get(index))
.read_error("Invalid Mach-O section index")
}

pub(super) fn segment_internal(
&self,
index: usize,
) -> Result<&MachOSegmentInternal<'data, Mach, R>> {
self.segments
.get(index)
.read_error("Invalid Mach-O segment index")
}

/// Returns the endianness.
pub fn endian(&self) -> Mach::Endian {
self.endian
Expand Down
28 changes: 13 additions & 15 deletions src/read/macho/section.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -25,7 +25,7 @@ where
R: ReadRef<'data>,
{
pub(super) file: &'file MachOFile<'data, Mach, R>,
pub(super) iter: slice::Iter<'file, MachOSectionInternal<'data, Mach>>,
pub(super) iter: slice::Iter<'file, MachOSectionInternal<'data, Mach, R>>,
}

impl<'data, 'file, Mach, R> fmt::Debug for MachOSectionIterator<'data, 'file, Mach, R>
Expand Down Expand Up @@ -71,7 +71,7 @@ where
R: ReadRef<'data>,
{
pub(super) file: &'file MachOFile<'data, Mach, R>,
pub(super) internal: MachOSectionInternal<'data, Mach>,
pub(super) internal: MachOSectionInternal<'data, Mach, R>,
}

impl<'data, 'file, Mach, R> MachOSection<'data, 'file, Mach, R>
Expand All @@ -80,11 +80,9 @@ where
R: ReadRef<'data>,
{
fn bytes(&self) -> Result<&'data [u8]> {
let segment_index = self.internal.segment_index;
let segment = self.file.segment_internal(segment_index)?;
self.internal
.section
.data(self.file.endian, segment.data)
.data(self.file.endian, self.internal.data)
.read_error("Invalid Mach-O section size or offset")
}
}
Expand Down Expand Up @@ -193,7 +191,7 @@ where
relocations: self
.internal
.section
.relocations(self.file.endian, self.file.data)
.relocations(self.file.endian, self.internal.data)
.unwrap_or(&[])
.iter(),
}
Expand All @@ -211,19 +209,19 @@ where
}

#[derive(Debug, Clone, Copy)]
pub(super) struct MachOSectionInternal<'data, Mach: MachHeader> {
pub(super) struct MachOSectionInternal<'data, Mach: MachHeader, R: ReadRef<'data>> {
pub index: SectionIndex,
pub segment_index: usize,
pub kind: SectionKind,
pub section: &'data Mach::Section,
/// The data for the file that contains the section data.
///
/// This is required for dyld caches, where this may be a different subcache
/// from the file containing the Mach-O load commands.
pub data: R,
}

impl<'data, Mach: MachHeader> MachOSectionInternal<'data, Mach> {
pub(super) fn parse(
index: SectionIndex,
segment_index: usize,
section: &'data Mach::Section,
) -> Self {
impl<'data, Mach: MachHeader, R: ReadRef<'data>> MachOSectionInternal<'data, Mach, R> {
pub(super) fn parse(index: SectionIndex, section: &'data Mach::Section, data: R) -> Self {
// TODO: we don't validate flags, should we?
let kind = match (section.segment_name(), section.name()) {
(b"__TEXT", b"__text") => SectionKind::Text,
Expand All @@ -246,9 +244,9 @@ impl<'data, Mach: MachHeader> MachOSectionInternal<'data, Mach> {
};
MachOSectionInternal {
index,
segment_index,
kind,
section,
data,
}
}
}
Expand Down
8 changes: 6 additions & 2 deletions src/read/macho/segment.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -69,7 +69,7 @@ where
fn bytes(&self) -> Result<&'data [u8]> {
self.internal
.segment
.data(self.file.endian, self.file.data)
.data(self.file.endian, self.internal.data)
.read_error("Invalid Mach-O segment size or offset")
}
}
Expand Down Expand Up @@ -149,8 +149,12 @@ where

#[derive(Debug, Clone, Copy)]
pub(super) struct MachOSegmentInternal<'data, Mach: MachHeader, R: ReadRef<'data>> {
pub data: R,
pub segment: &'data Mach::Segment,
/// The data for the file that contains the segment data.
///
/// This is required for dyld caches, where this may be a different subcache
/// from the file containing the Mach-O load commands.
pub data: R,
}

/// A trait for generic access to [`macho::SegmentCommand32`] and [`macho::SegmentCommand64`].
Expand Down
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