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Rollup merge of #93459 - tavianator:dirent-copy-only-reclen, r=cuviper

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fs: Don't copy d_name from struct dirent

The dirent returned from readdir() is only guaranteed to be valid for
d_reclen bytes on common platforms.  Since we copy the name separately
anyway, we can copy everything except d_name into DirEntry::entry.

Fixes #93384.
This commit is contained in:
Matthias Krüger
2022-01-30 00:04:16 +01:00
committed by GitHub
parent 605ffd6113 d0c8b29ec6
commit 0d08bbc8c8
2 changed files with 26 additions and 2 deletions
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12
library/std/src/sys/unix/fs.rs
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@@ -489,10 +489,18 @@ impl Iterator for ReadDir {
};
}
// Only d_reclen bytes of *entry_ptr are valid, so we can't just copy the
// whole thing (#93384). Instead, copy everything except the name.
let entry_bytes = entry_ptr as *const u8;
let entry_name = ptr::addr_of!((*entry_ptr).d_name) as *const u8;
let name_offset = entry_name.offset_from(entry_bytes) as usize;
let mut entry: dirent64 = mem::zeroed();
ptr::copy_nonoverlapping(entry_bytes, &mut entry as *mut _ as *mut u8, name_offset);
let ret = DirEntry {
entry: *entry_ptr,
entry,
// d_name is guaranteed to be null-terminated.
name: CStr::from_ptr((*entry_ptr).d_name.as_ptr()).to_owned(),
name: CStr::from_ptr(entry_name as *const _).to_owned(),
dir: Arc::clone(&self.inner),
};
if ret.name_bytes() != b"." && ret.name_bytes() != b".." {