[PATCH] greybus: gb-beagleplay: bound bootloader receive buffering

[Pengpeng Hou]

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@xxxxxxxxxxxxxxx
Signed-off-by: Pengpeng Hou <pengpeng@xxxxxxxxxxx>
---
 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)