Commit 0a3fe972a7cb ("HID: core: Mitigate potential OOB by removing
bogus memset()") enforced the provided data to be at least the size of
the declared buffer in the report descriptor to prevent a buffer
overflow.
We only had corner cases of malicious devices exposing the OOM because
in most cases, the buffer provided by the transport layer needs to be
allocated at probe time and is large enough to handle all the possible
reports.
However, the patch from above, which enforces the spec a little bit more
introduced both regressions for devices not following the spec (not
necesserally malicious), but also a stream of errors for those devices.
Let's revert to the old behavior by giving more information to HID core
to be able to decide whether it can or not memset the rest of the buffer
to 0 and continue the processing.
Note that the first commit makes an API change, but the callers are
relatively limited, so it should be fine on its own. The second patch
can't really make the same kind of API change because we have too many
callers in various subsystems. We can switch them one by one to the safe
approach when needed.
The last 2 patches are small cleanups I initially put together with the
2 first patches, but they can be applied on their own and don't need to
be pulled in stable like the first 2.
Cheers,
Benjamin
Signed-off-by: Benjamin Tissoires <bentiss(a)kernel.org>
---
Benjamin Tissoires (4):
HID: pass the buffer size to hid_report_raw_event
HID: core: introduce hid_safe_input_report()
HID: multitouch: use __free(kfree) to clean up temporary buffers
HID: wacom: use __free(kfree) to clean up temporary buffers
drivers/hid/bpf/hid_bpf_dispatch.c | 6 ++--
drivers/hid/hid-core.c | 63 +++++++++++++++++++++++++++++---------
drivers/hid/hid-gfrm.c | 4 +--
drivers/hid/hid-logitech-hidpp.c | 2 +-
drivers/hid/hid-multitouch.c | 18 +++++------
drivers/hid/hid-primax.c | 2 +-
drivers/hid/hid-vivaldi-common.c | 2 +-
drivers/hid/i2c-hid/i2c-hid-core.c | 7 +++--
drivers/hid/usbhid/hid-core.c | 11 ++++---
drivers/hid/wacom_sys.c | 46 ++++++++++------------------
drivers/staging/greybus/hid.c | 2 +-
include/linux/hid.h | 6 ++--
include/linux/hid_bpf.h | 14 ++++++---
13 files changed, 105 insertions(+), 78 deletions(-)
---
base-commit: 7df6572f1cb381d6b89ceed58e3b076c233c2cd0
change-id: 20260415-wip-fix-core-7d85c8516ed0
Best regards,
--
Benjamin Tissoires <bentiss(a)kernel.org>
hdlc_append() calls usleep_range() to wait for circular buffer space,
but it is called with tx_producer_lock (a spinlock) held via
hdlc_tx_frames() -> hdlc_append_tx_frame()/hdlc_append_tx_u8()/etc.
Sleeping while holding a spinlock is illegal and can trigger
"BUG: scheduling while atomic".
Fix this by moving the buffer-space wait out of hdlc_append() and into
hdlc_tx_frames(), before the spinlock is acquired. The new flow:
1. Pre-calculate the worst-case encoded frame length.
2. Wait (with sleep) outside the lock until enough space is available,
kicking the TX consumer work to drain the buffer.
3. Acquire the spinlock, re-verify space, and write the entire frame
atomically.
This ensures that sleeping only happens without any lock held, and
that frames are either fully enqueued or not written at all.
This bug is found by CodeQL static analysis tool (interprocedural
sleep-in-atomic query) and my code review.
Fixes: ec558bbfea67 ("greybus: Add BeaglePlay Linux Driver")
Cc: stable(a)vger.kernel.org
Cc: Ayush Singh <ayushdevel1325(a)gmail.com>
Cc: Johan Hovold <johan(a)kernel.org>
Cc: Alex Elder <elder(a)kernel.org>
Cc: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org>
Signed-off-by: Weigang He <geoffreyhe2(a)gmail.com>
---
drivers/greybus/gb-beagleplay.c | 105 +++++++++++++++++++++++++++-----
1 file changed, 89 insertions(+), 16 deletions(-)
diff --git a/drivers/greybus/gb-beagleplay.c b/drivers/greybus/gb-beagleplay.c
index 87186f891a6ac..da1b9039fd2f3 100644
--- a/drivers/greybus/gb-beagleplay.c
+++ b/drivers/greybus/gb-beagleplay.c
@@ -242,30 +242,26 @@ static void hdlc_write(struct gb_beagleplay *bg)
}
/**
- * hdlc_append() - Queue HDLC data for sending.
+ * hdlc_append() - Queue a single HDLC byte for sending.
* @bg: beagleplay greybus driver
* @value: hdlc byte to transmit
*
- * Assumes that producer lock as been acquired.
+ * Caller must hold tx_producer_lock and must have ensured sufficient
+ * space in the circular buffer before calling (see hdlc_tx_frames()).
*/
static void hdlc_append(struct gb_beagleplay *bg, u8 value)
{
- int tail, head = bg->tx_circ_buf.head;
+ int head = bg->tx_circ_buf.head;
+ int tail = READ_ONCE(bg->tx_circ_buf.tail);
- while (true) {
- tail = READ_ONCE(bg->tx_circ_buf.tail);
-
- if (CIRC_SPACE(head, tail, TX_CIRC_BUF_SIZE) >= 1) {
- bg->tx_circ_buf.buf[head] = value;
+ lockdep_assert_held(&bg->tx_producer_lock);
+ if (WARN_ON_ONCE(CIRC_SPACE(head, tail, TX_CIRC_BUF_SIZE) < 1))
+ return;
- /* Finish producing HDLC byte */
- smp_store_release(&bg->tx_circ_buf.head,
- (head + 1) & (TX_CIRC_BUF_SIZE - 1));
- return;
- }
- dev_warn(&bg->sd->dev, "Tx circ buf full");
- usleep_range(3000, 5000);
- }
+ bg->tx_circ_buf.buf[head] = value;
+ /* Ensure buffer write is visible before advancing head. */
+ smp_store_release(&bg->tx_circ_buf.head,
+ (head + 1) & (TX_CIRC_BUF_SIZE - 1));
}
static void hdlc_append_escaped(struct gb_beagleplay *bg, u8 value)
@@ -313,13 +309,90 @@ static void hdlc_transmit(struct work_struct *work)
spin_unlock_bh(&bg->tx_consumer_lock);
}
+/**
+ * hdlc_encoded_length() - Calculate worst-case encoded length of an HDLC frame.
+ * @payloads: array of payload buffers
+ * @count: number of payloads
+ *
+ * Returns the maximum number of bytes needed in the circular buffer.
+ */
+static size_t hdlc_encoded_length(const struct hdlc_payload payloads[],
+ size_t count)
+{
+ size_t i, payload_len = 0;
+
+ for (i = 0; i < count; i++)
+ payload_len += payloads[i].len;
+
+ /*
+ * Worst case: every data byte needs escaping (doubles in size).
+ * data bytes = address(1) + control(1) + payload + crc(2)
+ * framing = opening flag(1) + closing flag(1)
+ */
+ return 2 + (1 + 1 + payload_len + 2) * 2;
+}
+
+#define HDLC_TX_BUF_WAIT_RETRIES 500
+#define HDLC_TX_BUF_WAIT_US_MIN 3000
+#define HDLC_TX_BUF_WAIT_US_MAX 5000
+
+/**
+ * hdlc_tx_frames() - Encode and queue an HDLC frame for transmission.
+ * @bg: beagleplay greybus driver
+ * @address: HDLC address field
+ * @control: HDLC control field
+ * @payloads: array of payload buffers
+ * @count: number of payloads
+ *
+ * Sleeps outside the spinlock until enough circular-buffer space is
+ * available, then verifies space under the lock and writes the entire
+ * frame atomically. Either a complete frame is enqueued or nothing is
+ * written, avoiding both sleeping in atomic context and partial frames.
+ */
static void hdlc_tx_frames(struct gb_beagleplay *bg, u8 address, u8 control,
const struct hdlc_payload payloads[], size_t count)
{
+ size_t needed = hdlc_encoded_length(payloads, count);
+ int retries = HDLC_TX_BUF_WAIT_RETRIES;
size_t i;
+ int head, tail;
+
+ /* Wait outside the lock for sufficient buffer space. */
+ while (retries--) {
+ /* Pairs with smp_store_release() in hdlc_append(). */
+ head = smp_load_acquire(&bg->tx_circ_buf.head);
+ tail = READ_ONCE(bg->tx_circ_buf.tail);
+
+ if (CIRC_SPACE(head, tail, TX_CIRC_BUF_SIZE) >= needed)
+ break;
+
+ /* Kick the consumer and sleep — no lock held. */
+ schedule_work(&bg->tx_work);
+ usleep_range(HDLC_TX_BUF_WAIT_US_MIN, HDLC_TX_BUF_WAIT_US_MAX);
+ }
+
+ if (retries < 0) {
+ dev_warn_ratelimited(&bg->sd->dev,
+ "Tx circ buf full, dropping frame\n");
+ return;
+ }
spin_lock(&bg->tx_producer_lock);
+ /*
+ * Re-check under the lock. Should not fail since
+ * tx_producer_lock serialises all producers and the
+ * consumer only frees space, but guard against it.
+ */
+ head = bg->tx_circ_buf.head;
+ tail = READ_ONCE(bg->tx_circ_buf.tail);
+ if (unlikely(CIRC_SPACE(head, tail, TX_CIRC_BUF_SIZE) < needed)) {
+ spin_unlock(&bg->tx_producer_lock);
+ dev_warn_ratelimited(&bg->sd->dev,
+ "Tx circ buf space lost, dropping frame\n");
+ return;
+ }
+
hdlc_append_tx_frame(bg);
hdlc_append_tx_u8(bg, address);
hdlc_append_tx_u8(bg, control);
--
2.34.1
cc1352_bootloader_rx() appends each serdev chunk into the fixed
rx_buffer before parsing bootloader packets. The helper can keep
leftover bytes between callbacks and may receive multiple packets in one
callback, so a single count value is not constrained by one packet
length.
Check that the incoming chunk fits in the remaining receive buffer space
before memcpy(). If it does not, drop the staged data and consume the
bytes instead of overflowing rx_buffer.
Fixes: 0cf7befa3ea2 ("greybus: gb-beagleplay: Add firmware upload API")
Cc: stable(a)vger.kernel.org
Signed-off-by: Pengpeng Hou <pengpeng(a)iscas.ac.cn>
---
drivers/greybus/gb-beagleplay.c | 7 +++++++
1 file changed, 7 insertions(+)
diff --git a/drivers/greybus/gb-beagleplay.c b/drivers/greybus/gb-beagleplay.c
index 87186f891a6a..e70787146c4f 100644
--- a/drivers/greybus/gb-beagleplay.c
+++ b/drivers/greybus/gb-beagleplay.c
@@ -535,6 +535,13 @@ static size_t cc1352_bootloader_rx(struct gb_beagleplay *bg, const u8 *data,
int ret;
size_t off = 0;
+ if (count > sizeof(bg->rx_buffer) - bg->rx_buffer_len) {
+ dev_warn(&bg->sd->dev,
+ "dropping oversized bootloader receive chunk");
+ bg->rx_buffer_len = 0;
+ return count;
+ }
+
memcpy(bg->rx_buffer + bg->rx_buffer_len, data, count);
bg->rx_buffer_len += count;
--
2.50.1 (Apple Git-155)
