From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: stable@vger.kernel.org
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	patches@lists.linux.dev,
	Jiri Kosina <jkosina@suse.com>,
	Benjamin Tissoires <bentiss@kernel.org>
Subject: [PATCH 6.12 309/460] HID: bpf: prevent buffer overflow in hid_hw_request
Date: Mon, 23 Mar 2026 14:45:05 +0100
Message-ID: <20260323134534.089979321@linuxfoundation.org>
In-Reply-To: <20260323134526.647552166@linuxfoundation.org>
References: <20260323134526.647552166@linuxfoundation.org>
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6.12-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Benjamin Tissoires <bentiss@kernel.org>

commit 2b658c1c442ec1cd9eec5ead98d68662c40fe645 upstream.

right now the returned value is considered to be always valid. However,
when playing with HID-BPF, the return value can be arbitrary big,
because it's the return value of dispatch_hid_bpf_raw_requests(), which
calls the struct_ops and we have no guarantees that the value makes
sense.

Fixes: 8bd0488b5ea5 ("HID: bpf: add HID-BPF hooks for hid_hw_raw_requests")
Cc: stable@vger.kernel.org
Acked-by: Jiri Kosina <jkosina@suse.com>
Signed-off-by: Benjamin Tissoires <bentiss@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 drivers/hid/bpf/hid_bpf_dispatch.c |    2 ++
 1 file changed, 2 insertions(+)

--- a/drivers/hid/bpf/hid_bpf_dispatch.c
+++ b/drivers/hid/bpf/hid_bpf_dispatch.c
@@ -450,6 +450,8 @@ hid_bpf_hw_request(struct hid_bpf_ctx *c
 					      (u64)(long)ctx,
 					      true); /* prevent infinite recursions */
 
+	if (ret > size)
+		ret = size;
 	if (ret > 0)
 		memcpy(buf, dma_data, ret);