[PATCH v3] Bluetooth: HIDP: fix missing length checks in hidp_input_report()
From: Muhammad Bilal <hidden>
Date: 2026-05-20 22:57:20
Also in:
lkml, stable
Subsystem:
bluetooth subsystem, the rest · Maintainers:
Marcel Holtmann, Luiz Augusto von Dentz, Linus Torvalds
hidp_input_report() reads keyboard and mouse payload data from an skb
without first verifying that skb->len contains enough data.
hidp_recv_intr_frame() pulls the 1-byte HIDP header before dispatching
to hidp_input_report(). If a paired device sends a truncated packet,
the handler reads beyond the valid skb data, resulting in an
out-of-bounds read of skb data. The OOB bytes may be interpreted as
phantom key presses or spurious mouse movement.
Replace the open-coded length tracking and pointer arithmetic with
skb_pull_data() calls. skb_pull_data() returns NULL if the requested
bytes are not present, eliminating the need for a manual size variable
and the separate skb->len guard.
Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Cc: stable@vger.kernel.org
Signed-off-by: Muhammad Bilal <redacted>
---
v3:
- Replace manual length checks and pointer arithmetic with
skb_pull_data() per Luiz's review
v2:
- Add Cc: stable@vger.kernel.org per Greg KH's note
---
net/bluetooth/hidp/core.c | 23 ++++++++++++++++++-----
1 file changed, 18 insertions(+), 5 deletions(-)
diff --git a/net/bluetooth/hidp/core.c b/net/bluetooth/hidp/core.c
index 976f91eeb..70344bd32 100644
--- a/net/bluetooth/hidp/core.c
+++ b/net/bluetooth/hidp/core.c@@ -179,12 +179,21 @@ static void hidp_input_report(struct hidp_session *session, struct sk_buff *skb) { struct input_dev *dev = session->input; unsigned char *keys = session->keys; - unsigned char *udata = skb->data + 1; - signed char *sdata = skb->data + 1; - int i, size = skb->len - 1; + unsigned char *udata; + signed char *sdata; + u8 *hdr; + int i; + + hdr = skb_pull_data(skb, 1); + if (!hdr) + return; - switch (skb->data[0]) { + switch (*hdr) { case 0x01: /* Keyboard report */ + udata = skb_pull_data(skb, 8); + if (!udata) + break; + for (i = 0; i < 8; i++) input_report_key(dev, hidp_keycode[i + 224], (udata[0] >> i) & 1);
@@ -213,6 +222,10 @@ static void hidp_input_report(struct hidp_session *session, struct sk_buff *skb) break; case 0x02: /* Mouse report */ + sdata = skb_pull_data(skb, 3); + if (!sdata) + break; + input_report_key(dev, BTN_LEFT, sdata[0] & 0x01); input_report_key(dev, BTN_RIGHT, sdata[0] & 0x02); input_report_key(dev, BTN_MIDDLE, sdata[0] & 0x04);
@@ -222,7 +235,7 @@ static void hidp_input_report(struct hidp_session *session, struct sk_buff *skb) input_report_rel(dev, REL_X, sdata[1]); input_report_rel(dev, REL_Y, sdata[2]); - if (size > 3) + if (skb->len > 0) input_report_rel(dev, REL_WHEEL, sdata[3]); break; }
--
2.54.0