Commit 86674a97 authored Mar 28, 2018 by Harry Morris Committed by Stefan Schmidt Mar 29, 2018

ieee802154: ca8210: fix uninitialised data read



In ca8210_test_int_user_write() a user can request the transfer of a
frame with a length field (command.length) that is longer than the
actual buffer provided (len). In this scenario the driver will copy
the buffer contents into the uninitialised command[] buffer, then
transfer <data.length> bytes over the SPI even though only <len> bytes
had been populated, potentially leaking sensitive kernel memory.

Also the first 6 bytes of the command buffer must be initialised in case
a malformed, short packet is written and the uninitialised bytes are
read in ca8210_test_check_upstream.

Reported-by: Domen Puncer Kugler <domen.puncer@samsung.com>
Signed-off-by: Harry Morris <h.morris@cascoda.com>
Tested-by: Harry Morris <h.morris@cascoda.com>
Signed-off-by: Stefan Schmidt <stefan@osg.samsung.com>

parent 8fd4bc8a

drivers/net/ieee802154/ca8210.c

+11 −3

Original line number	Diff line number	Diff line
		@@ -2493,13 +2493,14 @@ static ssize_t ca8210_test_int_user_write(
		struct ca8210_priv *priv = filp->private_data;
		u8 command[CA8210_SPI_BUF_SIZE];

		if (len > CA8210_SPI_BUF_SIZE) {
		memset(command, SPI_IDLE, 6);
		if (len > CA8210_SPI_BUF_SIZE \|\| len < 2) {
		dev_warn(
		&priv->spi->dev,
		"userspace requested erroneously long write (%zu)\n",
		"userspace requested erroneous write length (%zu)\n",
		len
		);
		return -EMSGSIZE;
		return -EBADE;
		}

		ret = copy_from_user(command, in_buf, len);
		@@ -2511,6 +2512,13 @@ static ssize_t ca8210_test_int_user_write(
		);
		return -EIO;
		}
		if (len != command[1] + 2) {
		dev_err(
		&priv->spi->dev,
		"write len does not match packet length field\n"
		);
		return -EBADE;
		}

		ret = ca8210_test_check_upstream(command, priv->spi);
		if (ret == 0) {