1
  2
  3
  4
  5
  6
  7
  8
  9
 10
 11
 12
 13
 14
 15
 16
 17
 18
 19
 20
 21
 22
 23
 24
 25
 26
 27
 28
 29
 30
 31
 32
 33
 34
 35
 36
 37
 38
 39
 40
 41
 42
 43
 44
 45
 46
 47
 48
 49
 50
 51
 52
 53
 54
 55
 56
 57
 58
 59
 60
 61
 62
 63
 64
 65
 66
 67
 68
 69
 70
 71
 72
 73
 74
 75
 76
 77
 78
 79
 80
 81
 82
 83
 84
 85
 86
 87
 88
 89
 90
 91
 92
 93
 94
 95
 96
 97
 98
 99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179

use core::fmt::Debug;

use crate::elf;
use crate::endian::{self, Endianness};
use crate::pod::{Bytes, Pod};
use crate::read::util;
use crate::read::{self, Error, ReadError};

use super::FileHeader;

/// An iterator over the notes in an `ElfSegment` or `ElfSection`.
#[derive(Debug)]
pub struct ElfNoteIterator<'data, Elf>
where
    Elf: FileHeader,
{
    endian: Elf::Endian,
    align: usize,
    data: Bytes<'data>,
}

impl<'data, Elf> ElfNoteIterator<'data, Elf>
where
    Elf: FileHeader,
{
    /// Returns `Err` if `align` is invalid.
    pub(super) fn new(
        endian: Elf::Endian,
        align: Elf::Word,
        data: Bytes<'data>,
    ) -> read::Result<Self> {
        let align = match align.into() {
            0u64..=4 => 4,
            8 => 8,
            _ => return Err(Error("Invalid ELF note alignment")),
        };
        // TODO: check data alignment?
        Ok(ElfNoteIterator {
            endian,
            align,
            data,
        })
    }

    /// Returns the next note.
    pub(super) fn next(&mut self) -> read::Result<Option<ElfNote<'data, Elf>>> {
        let mut data = self.data;
        if data.is_empty() {
            return Ok(None);
        }

        let header = data
            .read::<Elf::NoteHeader>()
            .read_error("ELF note is too short")?;

        let namesz = header.n_namesz(self.endian) as usize;
        let name = data
            .read_bytes_at(0, namesz)
            .read_error("Invalid ELF note namesz")?
            .0;

        // Skip both the name and the alignment padding.
        data.skip(util::align(namesz, self.align))
            .read_error("ELF note is too short")?;

        let descsz = header.n_descsz(self.endian) as usize;
        let desc = data
            .read_bytes_at(0, descsz)
            .read_error("Invalid ELF note descsz")?
            .0;

        // Skip both the descriptor and the alignment padding (if any).
        if data.skip(util::align(descsz, self.align)).is_err() {
            data = Bytes(&[]);
        }
        self.data = data;

        Ok(Some(ElfNote { header, name, desc }))
    }
}

/// A parsed `NoteHeader32`.
pub type ElfNote32<'data, Endian = Endianness> = ElfNote<'data, elf::FileHeader32<Endian>>;
/// A parsed `NoteHeader64`.
pub type ElfNote64<'data, Endian = Endianness> = ElfNote<'data, elf::FileHeader64<Endian>>;

/// A parsed `NoteHeader`.
#[derive(Debug)]
pub struct ElfNote<'data, Elf>
where
    Elf: FileHeader,
{
    header: &'data Elf::NoteHeader,
    name: &'data [u8],
    desc: &'data [u8],
}

impl<'data, Elf: FileHeader> ElfNote<'data, Elf> {
    /// Return the `n_type` field of the `NoteHeader`.
    ///
    /// The meaning of this field is determined by `name`.
    pub fn n_type(&self, endian: Elf::Endian) -> u32 {
        self.header.n_type(endian)
    }

    /// Return the `n_namesz` field of the `NoteHeader`.
    pub fn n_namesz(&self, endian: Elf::Endian) -> u32 {
        self.header.n_namesz(endian)
    }

    /// Return the `n_descsz` field of the `NoteHeader`.
    pub fn n_descsz(&self, endian: Elf::Endian) -> u32 {
        self.header.n_descsz(endian)
    }

    /// Return the bytes for the name field following the `NoteHeader`.
    ///
    /// The length of this field is given by `n_namesz`. This field is usually a
    /// string including a null terminator (but it is not required to be).
    pub fn name(&self) -> &'data [u8] {
        self.name
    }

    /// Return the bytes for the desc field following the `NoteHeader`.
    ///
    /// The length of this field is given by `n_descsz`. The meaning
    /// of this field is determined by `name` and `n_type`.
    pub fn desc(&self) -> &'data [u8] {
        self.desc
    }
}

/// A trait for generic access to `NoteHeader32` and `NoteHeader64`.
#[allow(missing_docs)]
pub trait NoteHeader: Debug + Pod {
    type Endian: endian::Endian;

    fn n_namesz(&self, endian: Self::Endian) -> u32;
    fn n_descsz(&self, endian: Self::Endian) -> u32;
    fn n_type(&self, endian: Self::Endian) -> u32;
}

impl<Endian: endian::Endian> NoteHeader for elf::NoteHeader32<Endian> {
    type Endian = Endian;

    #[inline]
    fn n_namesz(&self, endian: Self::Endian) -> u32 {
        self.n_namesz.get(endian)
    }

    #[inline]
    fn n_descsz(&self, endian: Self::Endian) -> u32 {
        self.n_descsz.get(endian)
    }

    #[inline]
    fn n_type(&self, endian: Self::Endian) -> u32 {
        self.n_type.get(endian)
    }
}

impl<Endian: endian::Endian> NoteHeader for elf::NoteHeader64<Endian> {
    type Endian = Endian;

    #[inline]
    fn n_namesz(&self, endian: Self::Endian) -> u32 {
        self.n_namesz.get(endian)
    }

    #[inline]
    fn n_descsz(&self, endian: Self::Endian) -> u32 {
        self.n_descsz.get(endian)
    }

    #[inline]
    fn n_type(&self, endian: Self::Endian) -> u32 {
        self.n_type.get(endian)
    }
}