From d7e7ecea6c3f8360a6b1f9d817682049ee7a5bcd Mon Sep 17 00:00:00 2001
From: Omri Steiner <omri@steiners.co.il>
Date: Fri, 2 May 2025 18:24:30 +0200
Subject: [PATCH] aya: uprobe attach: use mmap instead of reading whole
 binaries to memory

---
 aya/src/programs/uprobe.rs | 10 +++++-----
 aya/src/sys/mmap.rs        | 22 ++++++++++++++++++++--
 2 files changed, 25 insertions(+), 7 deletions(-)

diff --git a/aya/src/programs/uprobe.rs b/aya/src/programs/uprobe.rs
index 116ca3d8..2ec94859 100644
--- a/aya/src/programs/uprobe.rs
+++ b/aya/src/programs/uprobe.rs
@@ -23,7 +23,7 @@ use crate::{
         perf_attach::{PerfLinkIdInner, PerfLinkInner},
         probe::{OsStringExt as _, ProbeKind, attach},
     },
-    sys::bpf_link_get_info_by_fd,
+    sys::{MMap, bpf_link_get_info_by_fd},
 };
 
 const LD_SO_CACHE_FILE: &str = "/etc/ld.so.cache";
@@ -712,15 +712,15 @@ fn symbol_translated_address(
 }
 
 fn resolve_symbol(path: &Path, symbol: &str) -> Result<u64, ResolveSymbolError> {
-    let data = fs::read(path)?;
-    let obj = object::read::File::parse(&*data)?;
+    let data = MMap::mmap_whole_file(path)?;
+    let obj = object::read::File::parse(data.as_ref())?;
 
     if let Some(sym) = find_symbol_in_object(&obj, symbol) {
         symbol_translated_address(&obj, sym, symbol)
     } else {
         // Only search in the debug object if the symbol was not found in the main object
         let debug_path = find_debug_path_in_object(&obj, path, symbol)?;
-        let debug_data = fs::read(&debug_path).map_err(|e| {
+        let debug_data = MMap::mmap_whole_file(&debug_path).map_err(|e| {
             ResolveSymbolError::DebuglinkAccessError(
                 debug_path
                     .to_str()
@@ -729,7 +729,7 @@ fn resolve_symbol(path: &Path, symbol: &str) -> Result<u64, ResolveSymbolError>
                 e,
             )
         })?;
-        let debug_obj = object::read::File::parse(&*debug_data)?;
+        let debug_obj = object::read::File::parse(debug_data.as_ref())?;
 
         verify_build_ids(&obj, &debug_obj, symbol)?;
 
diff --git a/aya/src/sys/mmap.rs b/aya/src/sys/mmap.rs
index 30ff0911..a576ab88 100644
--- a/aya/src/sys/mmap.rs
+++ b/aya/src/sys/mmap.rs
@@ -1,8 +1,13 @@
 //! Safe wrapper around memory-mapped files.
 
-use std::{io, os::fd::BorrowedFd, ptr};
+use std::{
+    fs, io,
+    os::fd::{AsFd as _, BorrowedFd},
+    path::Path,
+    ptr,
+};
 
-use libc::{MAP_FAILED, c_int, c_void, off_t};
+use libc::{MAP_FAILED, MAP_PRIVATE, PROT_READ, c_int, c_void, off_t};
 
 use super::{SyscallError, mmap, munmap};
 
@@ -46,6 +51,19 @@ impl MMap {
             }
         }
     }
+
+    /// Maps the file at `path` for reading, using `mmap` with `MAP_PRIVATE`.
+    pub(crate) fn mmap_whole_file(path: &Path) -> Result<Self, io::Error> {
+        let file = fs::File::open(path)?;
+        Self::new(
+            file.as_fd(),
+            file.metadata()?.len() as usize,
+            PROT_READ,
+            MAP_PRIVATE,
+            0,
+        )
+        .map_err(|e| e.io_error)
+    }
 }
 
 impl AsRef<[u8]> for MMap {