From 08ab58d9de3eb8498ae0585001d0975e46217a39 Mon Sep 17 00:00:00 2001 From: Bjorn Andersson Date: Wed, 23 Aug 2017 18:04:04 -0700 Subject: [PATCH] of/device: Prevent buffer overflow in of_device_modalias() 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 Cc: stable@vger.kernel.org Signed-off-by: Bjorn Andersson Signed-off-by: Rob Herring --- drivers/of/device.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/drivers/of/device.c b/drivers/of/device.c index 9d0895fb53b5..c5c06997fdd2 100644 --- a/drivers/of/device.c +++ b/drivers/of/device.c @@ -257,6 +257,8 @@ ssize_t of_device_modalias(struct device *dev, char *str, ssize_t len) 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; -- 2.20.1