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From: Sasha Levin <sashal@kernel.org>
To: linux-kernel@vger.kernel.org,
	stable@vger.kernel.org
Cc: Edward Adam Davis <eadavis@qq.com>,
	syzbot+71bfed2b2bcea46c98f2@syzkaller.appspotmail.com,
	"David S . Miller" <davem@davemloft.net>,
	Sasha Levin <sashal@kernel.org>,
	bongsu.jeon@samsung.com,
	krzk@kernel.org,
	netdev@vger.kernel.org
Subject: [PATCH AUTOSEL 5.15 11/12] nfc/nci: Add the inconsistency check between the input data length and count
Date: Wed,  5 Jun 2024 08:05:21 -0400
Message-ID: <20240605120528.2967750-11-sashal@kernel.org>
In-Reply-To: <20240605120528.2967750-1-sashal@kernel.org>
References: <20240605120528.2967750-1-sashal@kernel.org>
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From: Edward Adam Davis <eadavis@qq.com>

[ Upstream commit 068648aab72c9ba7b0597354ef4d81ffaac7b979 ]

write$nci(r0, &(0x7f0000000740)=ANY=[@ANYBLOB="610501"], 0xf)

Syzbot constructed a write() call with a data length of 3 bytes but a count value
of 15, which passed too little data to meet the basic requirements of the function
nci_rf_intf_activated_ntf_packet().

Therefore, increasing the comparison between data length and count value to avoid
problems caused by inconsistent data length and count.

Reported-and-tested-by: syzbot+71bfed2b2bcea46c98f2@syzkaller.appspotmail.com
Signed-off-by: Edward Adam Davis <eadavis@qq.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/nfc/virtual_ncidev.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/drivers/nfc/virtual_ncidev.c b/drivers/nfc/virtual_ncidev.c
index 6317e8505aaad..09d4ab0e63b1a 100644
--- a/drivers/nfc/virtual_ncidev.c
+++ b/drivers/nfc/virtual_ncidev.c
@@ -121,6 +121,10 @@ static ssize_t virtual_ncidev_write(struct file *file,
 		kfree_skb(skb);
 		return -EFAULT;
 	}
+	if (strnlen(skb->data, count) != count) {
+		kfree_skb(skb);
+		return -EINVAL;
+	}
 
 	nci_recv_frame(ndev, skb);
 	return count;
-- 
2.43.0