sbpf_disassembler/
program_header.rs

1use std::fmt::Debug;
2
3use object::Endianness;
4use object::read::elf::ElfFile64;
5use serde::{Deserialize, Serialize};
6
7use crate::errors::DisassemblerError;
8
9// Program Segment Flags
10pub const PF_X: u8 = 0x01;
11pub const PF_W: u8 = 0x02;
12pub const PF_R: u8 = 0x04;
13
14#[allow(non_camel_case_types)]
15#[derive(Debug, Clone, Serialize, Deserialize)]
16#[repr(u32)]
17pub enum ProgramType {
18    PT_NULL = 0x00,    // Program header table entry unused.
19    PT_LOAD = 0x01,    // Loadable segment.
20    PT_DYNAMIC = 0x02, // Dynamic linking information.
21    PT_INTERP = 0x03,  // Interpreter information.
22    PT_NOTE = 0x04,    // Auxiliary information.
23    PT_SHLIB = 0x05,   // Reserved.
24    PT_PHDR = 0x06,    // Segment containing program header table itself.
25    PT_TLS = 0x07,     // Thread-Local Storage template.
26}
27
28impl TryFrom<u32> for ProgramType {
29    type Error = DisassemblerError;
30
31    fn try_from(value: u32) -> Result<Self, Self::Error> {
32        Ok(match value {
33            0 => Self::PT_NULL,
34            1 => Self::PT_LOAD,
35            2 => Self::PT_DYNAMIC,
36            3 => Self::PT_INTERP,
37            4 => Self::PT_NOTE,
38            5 => Self::PT_SHLIB,
39            6 => Self::PT_PHDR,
40            7 => Self::PT_TLS,
41            _ => return Err(DisassemblerError::InvalidProgramType),
42        })
43    }
44}
45
46impl From<ProgramType> for u32 {
47    fn from(val: ProgramType) -> Self {
48        match val {
49            ProgramType::PT_NULL => 0,
50            ProgramType::PT_LOAD => 1,
51            ProgramType::PT_DYNAMIC => 2,
52            ProgramType::PT_INTERP => 3,
53            ProgramType::PT_NOTE => 4,
54            ProgramType::PT_SHLIB => 5,
55            ProgramType::PT_PHDR => 6,
56            ProgramType::PT_TLS => 7,
57        }
58    }
59}
60
61impl From<ProgramType> for &str {
62    fn from(val: ProgramType) -> Self {
63        match val {
64            ProgramType::PT_NULL => "PT_NULL",
65            ProgramType::PT_LOAD => "PT_LOAD",
66            ProgramType::PT_DYNAMIC => "PT_DYNAMIC",
67            ProgramType::PT_INTERP => "PT_INTERP",
68            ProgramType::PT_NOTE => "PT_NOTE",
69            ProgramType::PT_SHLIB => "PT_SHLIB",
70            ProgramType::PT_PHDR => "PT_PHDR",
71            ProgramType::PT_TLS => "PT_TLS",
72        }
73    }
74}
75
76#[derive(Debug, Clone, Serialize, Deserialize)]
77pub struct ProgramFlags(pub u32);
78
79impl From<u32> for ProgramFlags {
80    fn from(value: u32) -> Self {
81        Self(value & 7)
82    }
83}
84
85impl std::fmt::Display for ProgramFlags {
86    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
87        let x = match self.0 & PF_X as u32 == PF_X as u32 {
88            true => "X",
89            false => "*",
90        };
91
92        let r = match self.0 & PF_R as u32 == PF_R as u32 {
93            true => "R",
94            false => "*",
95        };
96
97        let w = match self.0 & PF_W as u32 == PF_W as u32 {
98            true => "W",
99            false => "*",
100        };
101        f.write_str(&format!("{}/{}/{}", r, w, x))
102    }
103}
104
105#[derive(Debug, Clone, Serialize, Deserialize)]
106pub struct ProgramHeader {
107    pub p_type: ProgramType, // An offset to a string in the .shstrtab section that represents the name of this section.
108    pub p_flags: ProgramFlags, // Identifies the type of this header.
109    pub p_offset: u64,       // Offset of the segment in the file image.
110    pub p_vaddr: u64,        // Virtual address of the segment in memory.
111    pub p_paddr: u64, // On systems where physical address is relevant, reserved for segment's physical address.
112    pub p_filesz: u64, // Size in bytes of the section in the file image. May be 0.
113    pub p_memsz: u64, // Size in bytes of the segment in memory. May be 0.
114    pub p_align: u64, // 0 and 1 specify no alignment. Otherwise should be a positive, integral power of 2, with p_vaddr equating p_offset modulus p_align.
115}
116
117impl ProgramHeader {
118    pub fn from_elf_file(elf_file: &ElfFile64<Endianness>) -> Result<Vec<Self>, DisassemblerError> {
119        let endian = elf_file.endian();
120        let program_headers_data = elf_file.elf_program_headers();
121
122        let mut program_headers = Vec::new();
123        for ph in program_headers_data {
124            let p_type = ProgramType::try_from(ph.p_type.get(endian))?;
125            let p_flags = ProgramFlags::from(ph.p_flags.get(endian));
126            let p_offset = ph.p_offset.get(endian);
127            let p_vaddr = ph.p_vaddr.get(endian);
128            let p_paddr = ph.p_paddr.get(endian);
129            let p_filesz = ph.p_filesz.get(endian);
130            let p_memsz = ph.p_memsz.get(endian);
131            let p_align = ph.p_align.get(endian);
132
133            program_headers.push(ProgramHeader {
134                p_type,
135                p_flags,
136                p_offset,
137                p_vaddr,
138                p_paddr,
139                p_filesz,
140                p_memsz,
141                p_align,
142            });
143        }
144
145        Ok(program_headers)
146    }
147
148    pub fn to_bytes(&self) -> Vec<u8> {
149        let mut b = (self.p_type.clone() as u32).to_le_bytes().to_vec();
150        b.extend_from_slice(&self.p_flags.0.to_le_bytes());
151        b.extend_from_slice(&self.p_offset.to_le_bytes());
152        b.extend_from_slice(&self.p_vaddr.to_le_bytes());
153        b.extend_from_slice(&self.p_paddr.to_le_bytes());
154        b.extend_from_slice(&self.p_filesz.to_le_bytes());
155        b.extend_from_slice(&self.p_memsz.to_le_bytes());
156        b.extend_from_slice(&self.p_align.to_le_bytes());
157        b
158    }
159}
160
161#[cfg(test)]
162mod tests {
163    use hex_literal::hex;
164
165    use crate::program::Program;
166
167    #[test]
168    fn test_program_headers() {
169        let original_bytes = hex!(
170            "7F454C460201010000000000000000000300F700010000002001000000000000400000000000000028020000000000000000000040003800030040000600050001000000050000002001000000000000200100000000000020010000000000003000000000000000300000000000000000100000000000000100000004000000C001000000000000C001000000000000C0010000000000003C000000000000003C000000000000000010000000000000020000000600000050010000000000005001000000000000500100000000000070000000000000007000000000000000080000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000007912A000000000007911182900000000B7000000010000002D21010000000000B70000000000000095000000000000001E0000000000000004000000000000000600000000000000C0010000000000000B0000000000000018000000000000000500000000000000F0010000000000000A000000000000000C00000000000000160000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000001000000120001002001000000000000300000000000000000656E747279706F696E7400002E74657874002E64796E737472002E64796E73796D002E64796E616D6963002E73687374727461620000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000001000000010000000600000000000000200100000000000020010000000000003000000000000000000000000000000008000000000000000000000000000000170000000600000003000000000000005001000000000000500100000000000070000000000000000400000000000000080000000000000010000000000000000F0000000B0000000200000000000000C001000000000000C001000000000000300000000000000004000000010000000800000000000000180000000000000007000000030000000200000000000000F001000000000000F0010000000000000C00000000000000000000000000000001000000000000000000000000000000200000000300000000000000000000000000000000000000FC010000000000002A00000000000000000000000000000001000000000000000000000000000000"
171        );
172        let program = Program::from_bytes(&original_bytes).unwrap();
173
174        // Verify we have the expected number of program headers.
175        assert_eq!(program.program_headers.len(), 3);
176
177        // Verify that serialized program headers match the original ELF data.
178        for (i, program_header) in program.program_headers.iter().enumerate() {
179            let serialized = program_header.to_bytes();
180            let header_offset = 0x40 + (i * 56);
181            let original_header_bytes = &original_bytes[header_offset..header_offset + 56];
182            assert_eq!(serialized, original_header_bytes,);
183        }
184    }
185}
sbpf_disassembler/program_header.rs

sbpf_disassembler/
program_header.rs
