From 7829a7ade9ded4a2eb981542d82a408b3ac1af82 Mon Sep 17 00:00:00 2001
From: Mateusz Tabaka <tab.debugteam@gmail.com>
Date: Tue, 29 Sep 2020 19:30:42 +0200
Subject: [PATCH] Add support for RUNPATH
---
src/ld_so/library.rs | 1 +
src/ld_so/linker.rs | 40 +++++++++++++++++++++++++++++++++-------
src/ld_so/start.rs | 7 ++-----
3 files changed, 36 insertions(+), 12 deletions(-)
diff --git a/src/ld_so/library.rs b/src/ld_so/library.rs
index 88958e01..19862f7e 100644
--- a/src/ld_so/library.rs
+++ b/src/ld_so/library.rs
@@ -36,6 +36,7 @@ pub struct Library {
pub dep_tree: DepTree,
/// A set used to detect circular dependencies in the Linker::load function
pub cir_dep: BTreeSet<String>,
+ pub runpath: Option<String>,
}
impl Library {
pub fn new() -> Library {
diff --git a/src/ld_so/linker.rs b/src/ld_so/linker.rs
index a091e857..3f6b4d4c 100644
--- a/src/ld_so/linker.rs
+++ b/src/ld_so/linker.rs
@@ -14,7 +14,7 @@ use goblin::{
elf::{
header::ET_DYN,
program_header,
- r#dyn::{Dyn, DT_DEBUG},
+ r#dyn::{Dyn, DT_DEBUG, DT_RUNPATH},
reloc, sym, Elf,
},
error::{Error, Result},
@@ -63,7 +63,8 @@ impl Symbol {
pub struct Linker {
// Used by load
/// Library path to search when loading library by name
- library_path: String,
+ default_library_path: String,
+ ld_library_path: Option<String>,
root: Library,
verbose: bool,
tls_index_offset: usize,
@@ -73,9 +74,10 @@ pub struct Linker {
}
impl Linker {
- pub fn new(library_path: &str, verbose: bool) -> Self {
+ pub fn new(ld_library_path: Option<String>, verbose: bool) -> Self {
Self {
- library_path: library_path.to_string(),
+ default_library_path: "/lib".to_string(),
+ ld_library_path: ld_library_path,
root: Library::new(),
verbose,
tls_index_offset: 0,
@@ -139,13 +141,30 @@ impl Linker {
) -> Result<Vec<DepTree>> {
let elf = Elf::parse(&data)?;
//println!("{:#?}", elf);
+
+ // search for RUNPATH
+ lib.runpath = if let Some(dynamic) = elf.dynamic {
+ let entry = dynamic.dyns.iter().find(|d| d.d_tag == DT_RUNPATH);
+ match entry {
+ Some(entry) => {
+ let path = elf
+ .dynstrtab
+ .get(entry.d_val as usize)
+ .ok_or(Error::Malformed("Missing RUNPATH in dynstrtab".to_string()))??;
+ Some(path.to_string())
+ }
+ _ => None,
+ }
+ } else {
+ None
+ };
+
let mut deps = Vec::new();
for library in elf.libraries.iter() {
if let Some(dep) = self._load_library(library, lib)? {
deps.push(dep);
}
}
- let elf = Elf::parse(&data)?;
let key = match elf.soname {
Some(soname) => soname,
_ => name,
@@ -171,8 +190,15 @@ impl Linker {
} else if name.contains('/') {
Ok(Some(self.load_recursive(name, name, lib)?))
} else {
- let library_path = self.library_path.clone();
- for part in library_path.split(PATH_SEP) {
+ let mut paths = Vec::new();
+ if let Some(ld_library_path) = &self.ld_library_path {
+ paths.push(ld_library_path);
+ }
+ if let Some(runpath) = &lib.runpath {
+ paths.push(runpath);
+ }
+ paths.push(&self.default_library_path);
+ for part in paths.iter() {
let path = if part.is_empty() {
format!("./{}", name)
} else {
diff --git a/src/ld_so/start.rs b/src/ld_so/start.rs
index 153b8992..6a9439d0 100644
--- a/src/ld_so/start.rs
+++ b/src/ld_so/start.rs
@@ -183,10 +183,7 @@ pub extern "C" fn relibc_ld_so_start(sp: &'static mut Stack, ld_entry: usize) ->
}
// Some variables that will be overridden by environment and auxiliary vectors
- let library_path = match envs.get("LD_LIBRARY_PATH") {
- Some(lib_path) => lib_path.to_owned() + ":/lib",
- None => "/lib".to_owned(),
- };
+ let ld_library_path = envs.get("LD_LIBRARY_PATH").map(|s| s.to_owned());
let name_or_path = if is_manual {
// ld.so is run directly by user and not via execve() or similar systemcall
@@ -234,7 +231,7 @@ pub extern "C" fn relibc_ld_so_start(sp: &'static mut Stack, ld_entry: usize) ->
}
pr
};
- let mut linker = Linker::new(&library_path, false);
+ let mut linker = Linker::new(ld_library_path, false);
match linker.load(&path, &path) {
Ok(()) => (),
Err(err) => {
--
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