From: Bjorn Andersson Date: Thu, 24 Aug 2017 01:04:04 +0000 (-0700) Subject: of/device: Prevent buffer overflow in of_device_modalias() X-Git-Tag: v4.14-rc1~105^2~12 X-Git-Url: https://asedeno.scripts.mit.edu/gitweb/?a=commitdiff_plain;h=08ab58d9de3eb8498ae0585001d0975e46217a39;p=linux.git 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 --- 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;