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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Dan Carpenter <dan.carpenter@oracle.com>,
        =?UTF-8?q?J=C3=A9r=C3=B4me=20Pouiller?= 
        <jerome.pouiller@silabs.com>, Kalle Valo <kvalo@kernel.org>,
        Sasha Levin <sashal@kernel.org>
Subject: [PATCH 5.19 227/717] wifi: wfx: prevent underflow in wfx_send_pds()
Date:   Sat, 22 Oct 2022 09:21:46 +0200
Message-Id: <20221022072455.271461706@linuxfoundation.org>
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From: Dan Carpenter <dan.carpenter@oracle.com>

[ Upstream commit f97c81f5b7f8047810b0d79a8f759a83951210a0 ]

This does a "chunk_len - 4" subtraction later when it calls:

	ret = wfx_hif_configuration(wdev, buf + 4, chunk_len - 4);

so check for "chunk_len" is less than 4.

Fixes: dcbecb497908 ("staging: wfx: allow new PDS format")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Reviewed-by: Jérôme Pouiller <jerome.pouiller@silabs.com>
Signed-off-by: Kalle Valo <kvalo@kernel.org>
Link: https://lore.kernel.org/r/Yv8eX7Xv2ubUOvW7@kili
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/net/wireless/silabs/wfx/main.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/net/wireless/silabs/wfx/main.c b/drivers/net/wireless/silabs/wfx/main.c
index e015bfb8d221..84d82ddded56 100644
--- a/drivers/net/wireless/silabs/wfx/main.c
+++ b/drivers/net/wireless/silabs/wfx/main.c
@@ -181,7 +181,7 @@ int wfx_send_pds(struct wfx_dev *wdev, u8 *buf, size_t len)
 	while (len > 0) {
 		chunk_type = get_unaligned_le16(buf + 0);
 		chunk_len = get_unaligned_le16(buf + 2);
-		if (chunk_len > len) {
+		if (chunk_len < 4 || chunk_len > len) {
 			dev_err(wdev->dev, "PDS:%d: corrupted file\n", chunk_num);
 			return -EINVAL;
 		}
-- 
2.35.1