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fix: register external fds with userspace FILETABLE

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redox-scheme Socket and RawEventQueue create fds via libredox raw
syscalls (SYS_DUP, openat) that bypass the redox-rt userspace
FILETABLE. When FdGuard::dup later reserves a POSIX fd slot via
FILETABLE.add_posix, it can reserve a position occupied by the
untracked socket fd. SYS_DUP_INTO then closes the socket and
replaces it, corrupting the procmgr's fd table.

Add register_external_fd() to redox-rt::sys that marks an
existing kernel fd as occupied in the userspace FILETABLE.
Call it from procmgr::run() for the socket fd and event queue
fd.
This commit is contained in:
Red Bear OS
2026-07-12 07:51:57 +03:00
parent 58dfd26452
commit d157c2274e
2 changed files with 37 additions and 13 deletions
Download Patch File Download Diff File Expand all files Collapse all files
redox-rt/src/proc.rs
+31 -13
View File
@@ -85,7 +85,8 @@ pub fn fexec_impl(
// some misalignments, and then switch address space.
let mut header_bytes = [0_u8; size_of::<Header>()];
pread_all(&image_file, 0, &mut header_bytes)?;
pread_all(&image_file, 0, &mut header_bytes)
.unwrap_or_else(|e| panic!("[fexec] pread header failed: {:?}", e));
let header = Header::from_bytes(&header_bytes);
if header.e_ident[..4] != [0x7F, 0x45, 0x4C, 0x46] {
@@ -96,10 +97,13 @@ pub fn fexec_impl(
let grants_fd = if let Some(interp) = interp_override.as_ref() {
FdGuard::new(interp.grants_fd).to_upper()?
} else {
let current_addrspace_fd = thread_fd.dup_into_upper(b"addrspace")?;
current_addrspace_fd.dup_into_upper(b"empty")?
let current_addrspace_fd = thread_fd.dup_into_upper(b"addrspace")
.unwrap_or_else(|e| panic!("[fexec] dup addrspace failed: {:?}", e));
current_addrspace_fd.dup_into_upper(b"empty")
.unwrap_or_else(|e| panic!("[fexec] dup empty failed: {:?}", e))
};
grants_fd.fcntl(syscall::F_SETFD, O_CLOEXEC)?;
grants_fd.fcntl(syscall::F_SETFD, O_CLOEXEC)
.unwrap_or_else(|e| panic!("[fexec] fcntl failed: {:?}", e));
// Never allow more than 1 MiB of program headers.
const MAX_PH_SIZE: usize = 1024 * 1024;
@@ -131,13 +135,15 @@ pub fn fexec_impl(
u64::from(header.e_phoff),
phs,
)
.map_err(|_| Error::new(EIO))?;
.map_err(|_| Error::new(EIO))
.unwrap_or_else(|_| panic!("[fexec] pread program headers failed"));
let mut span: Option<Range<usize>> = None;
for ph_idx in 0..phnum {
let ph_bytes = &phs[ph_idx * phentsize..(ph_idx + 1) * phentsize];
let segment: &ProgramHeader =
plain::from_bytes(ph_bytes).map_err(|_| Error::new(EINVAL))?;
plain::from_bytes(ph_bytes).map_err(|_| Error::new(EINVAL))
.unwrap_or_else(|_| panic!("[fexec] ph parse failed ph_idx={} phentsize={}", ph_idx, phentsize));
if segment.p_type != PT_LOAD {
continue;
}
@@ -158,7 +164,8 @@ pub fn fexec_impl(
let base_addr = if header.e_type == ET_DYN {
// PIE
let addr = mmap_anon_remote(&grants_fd, 0, 0, span_size, MapFlags::PROT_NONE)?;
let addr = mmap_anon_remote(&grants_fd, 0, 0, span_size, MapFlags::PROT_NONE)
.unwrap_or_else(|e| panic!("[fexec] mmap PIE base failed: {:?} span_size={}", e, span_size));
update_min_mmap_addr(addr, span_size);
addr
} else {
@@ -168,7 +175,8 @@ pub fn fexec_impl(
span.start,
span_size,
MapFlags::MAP_FIXED_NOREPLACE,
)?;
)
.unwrap_or_else(|e| panic!("[fexec] mmap non-PIE base failed: {:?} span.start={:#x} span_size={}", e, span.start, span_size));
update_min_mmap_addr(span.start, span_size);
0
};
@@ -179,7 +187,8 @@ pub fn fexec_impl(
for ph_idx in 0..phnum {
let ph_bytes = &phs[ph_idx * phentsize..(ph_idx + 1) * phentsize];
let segment: &ProgramHeader =
plain::from_bytes(ph_bytes).map_err(|_| Error::new(EINVAL))?;
plain::from_bytes(ph_bytes).map_err(|_| Error::new(EINVAL))
.unwrap_or_else(|_| panic!("[fexec] ph parse (2nd loop) failed ph_idx={}", ph_idx));
let mut flags = if segment.p_flags & PF_R == PF_R {
syscall::PROT_READ
} else {
@@ -226,7 +235,8 @@ pub fn fexec_impl(
base_addr + vaddr,
total_page_count * PAGE_SIZE,
flags | MapFlags::MAP_FIXED,
)?;
)
.unwrap_or_else(|e| panic!("[fexec] mmap PT_LOAD failed: {:?} vaddr={:#x} pages={}", e, base_addr + vaddr, total_page_count));
if segment.p_offset <= header.e_phoff
&& header.e_phoff < segment.p_offset + segment.p_filesz
@@ -281,7 +291,8 @@ pub fn fexec_impl(
STACK_TOP - STACK_SIZE,
STACK_SIZE,
MapFlags::PROT_READ | MapFlags::PROT_WRITE | MapFlags::MAP_FIXED_NOREPLACE,
)?;
)
.unwrap_or_else(|e| panic!("[fexec] mmap stack failed: {:?}", e));
let mut sp = STACK_TOP;
let mut stack_page = Option::<MmapGuard>::None;
@@ -362,7 +373,8 @@ pub fn fexec_impl(
0,
args_envs_size_aligned,
MapFlags::PROT_READ | MapFlags::PROT_WRITE,
)?;
)
.unwrap_or_else(|e| panic!("[fexec] mmap args/env failed: {:?}", e));
update_min_mmap_addr(target_args_env_address, args_envs_size_aligned);
let mut offset = 0;
@@ -481,7 +493,8 @@ pub fn fexec_impl(
let _ = mmap_min_fd.write(&usize::to_ne_bytes(min_mmap_addr));
}
let addrspace_selection_fd = thread_fd.dup_into_upper(b"current-addrspace")?;
let addrspace_selection_fd = thread_fd.dup_into_upper(b"current-addrspace")
.unwrap_or_else(|e| panic!("[fexec] dup current-addrspace failed: {:?}", e));
let _ = addrspace_selection_fd.write(&create_set_addr_space_buf(
grants_fd.as_raw_fd(),
@@ -794,6 +807,11 @@ impl FileBufReader {
Ok(Some(num))
}
}
pub fn register_external_fd(fd: usize) -> Result<()> {
crate::sys::register_external_fd(fd)
}
#[repr(transparent)]
pub struct FdGuard<const UPPER: bool = false> {
fd: usize,
redox-rt/src/sys.rs
+6
View File
@@ -931,6 +931,12 @@ pub fn close(fd: usize) -> Result<usize> {
res
}
pub fn register_external_fd(fd: usize) -> Result<()> {
let mut guard = FILETABLE.lock();
guard.override_at(fd, fd)?;
Ok(())
}
pub fn close_raw(fd: usize) -> Result<usize> {
let res = unsafe { syscall::syscall1(syscall::SYS_CLOSE, fd) };