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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, Khalil Blaiech <kblaiech@nvidia.com>,
        Asmaa Mnebhi <asmaa@nvidia.com>, Wolfram Sang <wsa@kernel.org>,
        Sasha Levin <sashal@kernel.org>
Subject: [PATCH 5.10 136/141] i2c: mlxbf: prevent stack overflow in mlxbf_i2c_smbus_start_transaction()
Date:   Mon, 26 Sep 2022 12:12:42 +0200
Message-Id: <20220926100759.383918686@linuxfoundation.org>
In-Reply-To: <20220926100754.639112000@linuxfoundation.org>
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From: Asmaa Mnebhi <asmaa@nvidia.com>

[ Upstream commit de24aceb07d426b6f1c59f33889d6a964770547b ]

memcpy() is called in a loop while 'operation->length' upper bound
is not checked and 'data_idx' also increments.

Fixes: b5b5b32081cd206b ("i2c: mlxbf: I2C SMBus driver for Mellanox BlueField SoC")
Reviewed-by: Khalil Blaiech <kblaiech@nvidia.com>
Signed-off-by: Asmaa Mnebhi <asmaa@nvidia.com>
Signed-off-by: Wolfram Sang <wsa@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/i2c/busses/i2c-mlxbf.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/i2c/busses/i2c-mlxbf.c b/drivers/i2c/busses/i2c-mlxbf.c
index 042c83b90734..d78fb24d5588 100644
--- a/drivers/i2c/busses/i2c-mlxbf.c
+++ b/drivers/i2c/busses/i2c-mlxbf.c
@@ -744,6 +744,9 @@ mlxbf_i2c_smbus_start_transaction(struct mlxbf_i2c_priv *priv,
 		if (flags & MLXBF_I2C_F_WRITE) {
 			write_en = 1;
 			write_len += operation->length;
+			if (data_idx + operation->length >
+					MLXBF_I2C_MASTER_DATA_DESC_SIZE)
+				return -ENOBUFS;
 			memcpy(data_desc + data_idx,
 			       operation->buffer, operation->length);
 			data_idx += operation->length;
-- 
2.35.1