1 files changed, 177 insertions, 0 deletions
diff --git a/third_party/rust/goblin/src/pe/utils.rs b/third_party/rust/goblin/src/pe/utils.rs
new file mode 100644
index 0000000000..c8228fce3f
--- /dev/null
+++ b/third_party/rust/goblin/src/pe/utils.rs
@@ -0,0 +1,177 @@
+use crate::error;
+use alloc::string::ToString;
+use scroll::Pread;
+
+use super::options;
+use super::section_table;
+
+use crate::pe::data_directories::DataDirectory;
+use core::cmp;
+
+use log::debug;
+
+pub fn is_in_range(rva: usize, r1: usize, r2: usize) -> bool {
+    r1 <= rva && rva < r2
+}
+
+// reference: Peter Ferrie. Reliable algorithm to extract overlay of a PE. https://bit.ly/2vBX2bR
+#[inline]
+fn aligned_pointer_to_raw_data(pointer_to_raw_data: usize) -> usize {
+    const PHYSICAL_ALIGN: usize = 0x1ff;
+    pointer_to_raw_data & !PHYSICAL_ALIGN
+}
+
+#[inline]
+fn section_read_size(section: &section_table::SectionTable, file_alignment: u32) -> usize {
+    fn round_size(size: usize) -> usize {
+        const PAGE_MASK: usize = 0xfff;
+        (size + PAGE_MASK) & !PAGE_MASK
+    }
+
+    // Paraphrased from https://reverseengineering.stackexchange.com/a/4326 (by Peter Ferrie).
+    //
+    // Handles the corner cases such as mis-aligned pointers (round down) and sizes (round up)
+    // Further rounding corner cases:
+    // - the physical pointer should be rounded down to a multiple of 512, regardless of the value in the header
+    // - the read size is rounded up by using a combination of the file alignment and 4kb
+    // - the virtual size is always rounded up to a multiple of 4kb, regardless of the value in the header.
+    //
+    // Reference C implementation:
+    //
+    // long pointerToRaw = section.get(POINTER_TO_RAW_DATA);
+    // long alignedpointerToRaw = pointerToRaw & ~0x1ff;
+    // long sizeOfRaw = section.get(SIZE_OF_RAW_DATA);
+    // long readsize = ((pointerToRaw + sizeOfRaw) + filealign - 1) & ~(filealign - 1)) - alignedpointerToRaw;
+    // readsize = min(readsize, (sizeOfRaw + 0xfff) & ~0xfff);
+    // long virtsize = section.get(VIRTUAL_SIZE);
+    //
+    // if (virtsize)
+    // {
+    //     readsize = min(readsize, (virtsize + 0xfff) & ~0xfff);
+    // }
+
+    let file_alignment = file_alignment as usize;
+    let size_of_raw_data = section.size_of_raw_data as usize;
+    let virtual_size = section.virtual_size as usize;
+    let read_size = {
+        let read_size =
+            ((section.pointer_to_raw_data as usize + size_of_raw_data + file_alignment - 1)
+                & !(file_alignment - 1))
+                - aligned_pointer_to_raw_data(section.pointer_to_raw_data as usize);
+        cmp::min(read_size, round_size(size_of_raw_data))
+    };
+
+    if virtual_size == 0 {
+        read_size
+    } else {
+        cmp::min(read_size, round_size(virtual_size))
+    }
+}
+
+fn rva2offset(rva: usize, section: &section_table::SectionTable) -> usize {
+    (rva - section.virtual_address as usize)
+        + aligned_pointer_to_raw_data(section.pointer_to_raw_data as usize)
+}
+
+fn is_in_section(rva: usize, section: &section_table::SectionTable, file_alignment: u32) -> bool {
+    let section_rva = section.virtual_address as usize;
+    is_in_range(
+        rva,
+        section_rva,
+        section_rva + section_read_size(section, file_alignment),
+    )
+}
+
+pub fn find_offset(
+    rva: usize,
+    sections: &[section_table::SectionTable],
+    file_alignment: u32,
+    opts: &options::ParseOptions,
+) -> Option<usize> {
+    if opts.resolve_rva {
+        for (i, section) in sections.iter().enumerate() {
+            debug!(
+                "Checking {} for {:#x} ∈ {:#x}..{:#x}",
+                section.name().unwrap_or(""),
+                rva,
+                section.virtual_address,
+                section.virtual_address + section.virtual_size
+            );
+            if is_in_section(rva, &section, file_alignment) {
+                let offset = rva2offset(rva, &section);
+                debug!(
+                    "Found in section {}({}), remapped into offset {:#x}",
+                    section.name().unwrap_or(""),
+                    i,
+                    offset
+                );
+                return Some(offset);
+            }
+        }
+        None
+    } else {
+        Some(rva)
+    }
+}
+
+pub fn find_offset_or(
+    rva: usize,
+    sections: &[section_table::SectionTable],
+    file_alignment: u32,
+    opts: &options::ParseOptions,
+    msg: &str,
+) -> error::Result<usize> {
+    find_offset(rva, sections, file_alignment, opts)
+        .ok_or_else(|| error::Error::Malformed(msg.to_string()))
+}
+
+pub fn try_name<'a>(
+    bytes: &'a [u8],
+    rva: usize,
+    sections: &[section_table::SectionTable],
+    file_alignment: u32,
+    opts: &options::ParseOptions,
+) -> error::Result<&'a str> {
+    match find_offset(rva, sections, file_alignment, opts) {
+        Some(offset) => Ok(bytes.pread::<&str>(offset)?),
+        None => Err(error::Error::Malformed(format!(
+            "Cannot find name from rva {:#x} in sections: {:?}",
+            rva, sections
+        ))),
+    }
+}
+
+pub fn get_data<'a, T>(
+    bytes: &'a [u8],
+    sections: &[section_table::SectionTable],
+    directory: DataDirectory,
+    file_alignment: u32,
+) -> error::Result<T>
+where
+    T: scroll::ctx::TryFromCtx<'a, scroll::Endian, Error = scroll::Error>,
+{
+    get_data_with_opts(
+        bytes,
+        sections,
+        directory,
+        file_alignment,
+        &options::ParseOptions::default(),
+    )
+}
+
+pub fn get_data_with_opts<'a, T>(
+    bytes: &'a [u8],
+    sections: &[section_table::SectionTable],
+    directory: DataDirectory,
+    file_alignment: u32,
+    opts: &options::ParseOptions,
+) -> error::Result<T>
+where
+    T: scroll::ctx::TryFromCtx<'a, scroll::Endian, Error = scroll::Error>,
+{
+    let rva = directory.virtual_address as usize;
+    let offset = find_offset(rva, sections, file_alignment, opts)
+        .ok_or_else(|| error::Error::Malformed(directory.virtual_address.to_string()))?;
+    let result: T = bytes.pread_with(offset, scroll::LE)?;
+    Ok(result)
+}