[PATCH 5.15 50/75] dpaa2-switch: add bounds check for if_id in IRQ handler

[Greg Kroah-Hartman <gregkh@linuxfoundation.org>]

5.15-stable review patch.  If anyone has any objections, please let me know.

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

From: Junrui Luo <moonafterrain@outlook.com>

[ Upstream commit 31a7a0bbeb006bac2d9c81a2874825025214b6d8 ]

The IRQ handler extracts if_id from the upper 16 bits of the hardware
status register and uses it to index into ethsw->ports[] without
validation. Since if_id can be any 16-bit value (0-65535) but the ports
array is only allocated with sw_attr.num_ifs elements, this can lead to
an out-of-bounds read potentially.

Add a bounds check before accessing the array, consistent with the
existing validation in dpaa2_switch_rx().

Reported-by: Yuhao Jiang <danisjiang@gmail.com>
Reported-by: Junrui Luo <moonafterrain@outlook.com>
Fixes: 24ab724f8a46 ("dpaa2-switch: use the port index in the IRQ handler")
Signed-off-by: Junrui Luo <moonafterrain@outlook.com>
Link: https://patch.msgid.link/SYBPR01MB7881D420AB43FF1A227B84AFAF91A@SYBPR01MB7881.ausprd01.prod.outlook.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/net/ethernet/freescale/dpaa2/dpaa2-switch.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/drivers/net/ethernet/freescale/dpaa2/dpaa2-switch.c b/drivers/net/ethernet/freescale/dpaa2/dpaa2-switch.c
index dcb96c2b2820a..5c7055a4acc6f 100644
--- a/drivers/net/ethernet/freescale/dpaa2/dpaa2-switch.c
+++ b/drivers/net/ethernet/freescale/dpaa2/dpaa2-switch.c
@@ -1509,6 +1509,10 @@ static irqreturn_t dpaa2_switch_irq0_handler_thread(int irq_num, void *arg)
 	}
 
 	if_id = (status & 0xFFFF0000) >> 16;
+	if (if_id >= ethsw->sw_attr.num_ifs) {
+		dev_err(dev, "Invalid if_id %d in IRQ status\n", if_id);
+		goto out;
+	}
 	port_priv = ethsw->ports[if_id];
 
 	if (status & DPSW_IRQ_EVENT_LINK_CHANGED) {
-- 
2.51.0