Patch "of/device: Prevent buffer overflow in of_device_modalias()" has been added to the 4.13-stable tree

Patch "of/device: Prevent buffer overflow in of_device_modalias()" has been added to the 4.13-stable tree

[gregkh]

This is a note to let you know that I've just added the patch titled

    of/device: Prevent buffer overflow in of_device_modalias()

to the 4.13-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     of-device-prevent-buffer-overflow-in-of_device_modalias.patch
and it can be found in the queue-4.13 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


>From 08ab58d9de3eb8498ae0585001d0975e46217a39 Mon Sep 17 00:00:00 2001
From: Bjorn Andersson <bjorn.andersson@linaro.org>
Date: Wed, 23 Aug 2017 18:04:04 -0700
Subject: of/device: Prevent buffer overflow in of_device_modalias()

From: Bjorn Andersson <bjorn.andersson@linaro.org>

commit 08ab58d9de3eb8498ae0585001d0975e46217a39 upstream.

As of_device_get_modalias() returns the number of bytes that would have
been written to the target string, regardless of how much did fit in the
buffer, it's possible that the returned index points beyond the buffer
passed to of_device_modalias() - causing memory beyond the buffer to be
null terminated.

Fixes: 0634c2958927 ("of: Add function for generating a DT modalias with a newline")
Cc: Rob Herring <robh@kernel.org>
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Signed-off-by: Rob Herring <robh@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 drivers/of/device.c |    2 ++
 1 file changed, 2 insertions(+)

--- a/drivers/of/device.c
+++ b/drivers/of/device.c
@@ -274,6 +274,8 @@ ssize_t of_device_modalias(struct device
 	ssize_t sl = of_device_get_modalias(dev, str, len - 2);
 	if (sl < 0)
 		return sl;
+	if (sl > len - 2)
+		return -ENOMEM;
 
 	str[sl++] = '\n';
 	str[sl] = 0;


Patches currently in stable-queue which might be from bjorn.andersson@linaro.org are

queue-4.13/of-device-prevent-buffer-overflow-in-of_device_modalias.patch