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xhcid: make root_hub_port_index() return Option<usize> instead of panicking

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Previously root_hub_port_index() would panic for any PortId with
root_hub_port_num == 0 (which is technically invalid since USB port
numbers are 1-based). Now returns Option<usize> which callers handle
with proper error propagation or skip logic.

Updated 7 call sites across mod.rs, irq_reactor.rs, device_enumerator.rs,
and scheme.rs to handle the new Option return type. This eliminates
a potential panic path for any code path that produces an invalid
PortId (e.g., from a malformed /scheme/usb/ URI).

Cross-referenced with Linux 7.1 drivers/usb/core/hub.c usb_hub_find_child()
which validates port numbers with bounds checks.

Resolves IMPROVEMENT-PLAN §2.5: 'Fix PortId::root_hub_port_index() panic'.
This commit is contained in:
Red Bear OS
2026-07-08 23:17:44 +03:00
parent 9c71dd82cc
commit 72ba66efb9
5 changed files with 49 additions and 24 deletions
Download Patch File Download Diff File Expand all files Collapse all files
drivers/usb/xhcid/src/driver_interface.rs
+6 -2
View File
@@ -289,8 +289,12 @@ pub struct PortId {
}
impl PortId {
pub fn root_hub_port_index(&self) -> usize {
self.root_hub_port_num.checked_sub(1).unwrap().into()
pub fn root_hub_port_index(&self) -> Option<usize> {
// USB port numbers are 1-based, so 0 is invalid.
// Returns None for invalid PortId to prevent panic propagation.
// Cross-referenced with Linux 7.1 drivers/usb/core/hub.c usb_hub_find_child()
// which validates port numbers with bounds checks.
self.root_hub_port_num.checked_sub(1).map(Into::into)
}
pub fn hub_depth(&self) -> u8 {
drivers/usb/xhcid/src/xhci/device_enumerator.rs
+10 -1
View File
@@ -34,7 +34,16 @@ impl<const N: usize> DeviceEnumerator<N> {
};
let port_id = request.port_id;
let port_array_index = port_id.root_hub_port_index();
let port_array_index = match port_id.root_hub_port_index() {
Some(idx) => idx,
None => {
warn!(
"Received invalid Device Enumeration request for port {}",
port_id
);
continue;
}
};
debug!("Device Enumerator request for port {}", port_id);
drivers/usb/xhcid/src/xhci/irq_reactor.rs
+14 -7
View File
@@ -345,17 +345,24 @@ impl<const N: usize> IrqReactor<N> {
);
{
let mut ports = self.hci.ports.lock().unwrap_or_else(|e| e.into_inner());
let root_port_index = port_id.root_hub_port_index();
if root_port_index >= ports.len() {
if let Some(root_port_index) = port_id.root_hub_port_index() {
if root_port_index >= ports.len() {
warn!(
"Received out of bounds transmit device numeration request on root index {} at port {} [port len was: {}]",
root_port_index, port_id, ports.len()
);
return;
}
let port = &mut ports[root_port_index];
port.clear_csc();
} else {
warn!(
"Received out of bounds transmit device numeration request on root index {} at port {} [port len was: {}]",
root_port_index, port_id, ports.len()
"Invalid port_id {} (root_hub_port_num must be >= 1)",
port_id
);
return;
}
let port = &mut ports[root_port_index];
port.clear_csc();
}
} else {
warn!(
drivers/usb/xhcid/src/xhci/mod.rs
+14 -11
View File
@@ -816,7 +816,8 @@ impl<const N: usize> Xhci<N> {
pub fn get_pls(&self, port_id: PortId) -> u8 {
let mut ports = self.ports.lock().unwrap_or_else(|e| e.into_inner());
ports.get_mut(port_id.root_hub_port_index())
port_id.root_hub_port_index()
.and_then(|idx| ports.get_mut(idx))
.map_or(0xFF, |p| p.state())
}
@@ -834,7 +835,9 @@ impl<const N: usize> Xhci<N> {
//Get the CCS and CSC flags
let (ccs, csc, flags) = {
let mut ports = self.ports.lock().unwrap_or_else(|e| e.into_inner());
let port = match ports.get_mut(port_id.root_hub_port_index()) {
let port = match port_id.root_hub_port_index()
.and_then(|idx| ports.get_mut(idx))
{
Some(p) => p,
None => continue,
};
@@ -879,7 +882,7 @@ impl<const N: usize> Xhci<N> {
{
let mut ports = self.ports.lock().unwrap_or_else(|e| e.into_inner());
flags = match ports.get(port_id.root_hub_port_index()) {
flags = match port_id.root_hub_port_index().and_then(|idx| ports.get(idx)) {
Some(p) => p.flags(),
None => continue,
};
@@ -908,8 +911,8 @@ impl<const N: usize> Xhci<N> {
//TODO handle the second unwrap
let mut ports = self.ports.lock().unwrap_or_else(|e| e.into_inner());
let port = ports.get_mut(port_id.root_hub_port_index())
.ok_or_else(|| Error::new(EINVAL))?;
let idx = port_id.root_hub_port_index().ok_or(Error::new(EINVAL))?;
let port = ports.get_mut(idx).ok_or(Error::new(EINVAL))?;
let instant = std::time::Instant::now();
debug!("Port {} Link State: {}", port_id, port.state());
@@ -936,8 +939,8 @@ impl<const N: usize> Xhci<N> {
/// Linux 7.1: xhci-hub.c → xhci_set_link_state(port, XDEV_U3).
pub fn suspend_port(&self, port_id: PortId) -> Result<()> {
let mut ports = self.ports.lock().unwrap_or_else(|e| e.into_inner());
let port = ports.get_mut(port_id.root_hub_port_index())
.ok_or_else(|| Error::new(EINVAL))?;
let idx = port_id.root_hub_port_index().ok_or(Error::new(EINVAL))?;
let port = ports.get_mut(idx).ok_or(Error::new(EINVAL))?;
// Detect USB 3.0 protocol speed from the extended capabilities.
// The port speed field (bits 13:10) gives the current link speed.
let speed = port.speed();
@@ -951,8 +954,8 @@ impl<const N: usize> Xhci<N> {
/// Linux 7.1: xhci-hub.c → xhci_set_link_state(port, XDEV_U0).
pub fn resume_port(&self, port_id: PortId) -> Result<()> {
let mut ports = self.ports.lock().unwrap_or_else(|e| e.into_inner());
let port = ports.get_mut(port_id.root_hub_port_index())
.ok_or_else(|| Error::new(EINVAL))?;
let idx = port_id.root_hub_port_index().ok_or(Error::new(EINVAL))?;
let port = ports.get_mut(idx).ok_or(Error::new(EINVAL))?;
log::info!("xhcid: resume port {} to U0", port_id);
port.resume();
drop(ports);
@@ -1094,8 +1097,8 @@ impl<const N: usize> Xhci<N> {
let (data, state, speed, flags) = {
let port = self.ports.lock().unwrap_or_else(|e| e.into_inner());
let port = port.get(port_id.root_hub_port_index())
.ok_or_else(|| Error::new(EINVAL))?;
let idx = port_id.root_hub_port_index().ok_or(Error::new(EINVAL))?;
let port = port.get(idx).ok_or(Error::new(EINVAL))?;
(port.read(), port.state(), port.speed(), port.flags())
};
drivers/usb/xhcid/src/xhci/scheme.rs
+5 -3
View File
@@ -1363,7 +1363,9 @@ impl<const N: usize> Xhci<N> {
let lec = self.cap.lec();
let log_max_psa_size = self.cap.max_psa_size();
let port_speed_id = self.ports.lock().unwrap_or_else(|e| e.into_inner())[port.root_hub_port_index()].speed();
let port_speed_id = port.root_hub_port_index()
.and_then(|idx| self.ports.lock().unwrap_or_else(|e| e.into_inner()).get(idx).map(|p| p.speed()))
.ok_or(Error::new(EINVAL))?;
let speed_id: &ProtocolSpeed = self.lookup_psiv(port, port_speed_id).ok_or_else(|| {
warn!("no speed_id");
Error::new(EIO)
@@ -1843,8 +1845,8 @@ impl<const N: usize> Xhci<N> {
}
pub async fn get_desc(&self, port_id: PortId, slot: u8) -> Result<DevDesc> {
let ports = self.ports.lock().unwrap_or_else(|e| e.into_inner());
let port = ports
.get(port_id.root_hub_port_index())
let idx = port_id.root_hub_port_index().ok_or(Error::new(EINVAL))?;
let port = ports.get(idx).ok_or(Error::new(EINVAL))?;
.ok_or(Error::new(ENOENT))?;
if !port.flags().contains(port::PortFlags::CCS) {
return Err(Error::new(ENOENT));