From b6af0800ff8da6cc0862ef377378e01c5d6b49fa 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() BugLink: http://bugs.launchpad.net/bugs/1716284 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 Signed-off-by: Bjorn Andersson Signed-off-by: Rob Herring Signed-off-by: Greg Kroah-Hartman Signed-off-by: Seth Forshee --- drivers/of/device.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/drivers/of/device.c b/drivers/of/device.c index e0a28ea341fe..eabfa36383ce 100644 --- a/drivers/of/device.c +++ b/drivers/of/device.c @@ -274,6 +274,8 @@ 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; -- 2.39.5