wifi: wcn36xx: fix OOB read from firmware count in PRINT_REG_INFO indication

[ Upstream commit df2187a ]

The firmware-controlled rsp->count field is used as the loop bound for
indexing into the flexible rsp->regs[] array without validation against
the message length. A count exceeding the actual data causes out-of-
bounds reads from the heap-allocated message buffer.

Add a check that count fits within the received message.

Fixes: 43efa3c ("wcn36xx: Implement print_reg indication")
Signed-off-by: Tristan Madani <tristan@talencesecurity.com>
Reviewed-by: Loic Poulain <loic.poulain@oss.qualcomm.com>
Link: https://patch.msgid.link/20260421135018.352774-3-tristmd@gmail.com
Signed-off-by: Jeff Johnson <jeff.johnson@oss.qualcomm.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>

Author: Tristan Madani

drivers/net/wireless/ath/wcn36xx/smd.c

@@ -2865,6 +2865,12 @@ static int wcn36xx_smd_print_reg_info_ind(struct wcn36xx *wcn,
 		return -EIO;
 	}
 
+	if (rsp->count > (len - sizeof(*rsp)) / sizeof(rsp->regs[0])) {
+		wcn36xx_warn("Truncated print reg info indication: count %u, len %zu\n",
+			     rsp->count, len);
+		return -EIO;
+	}
+
 	wcn36xx_dbg(WCN36XX_DBG_HAL,
 		    "reginfo indication, scenario: 0x%x reason: 0x%x\n",
 		    rsp->scenario, rsp->reason);