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| author | Rasmus Villemoes <linux@rasmusvillemoes.dk> | 2019-03-14 17:06:14 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2019-05-04 10:20:22 +0300 |
| commit | ee096f0dc4a44a3d6cae27dce87abeea71b4680f (patch) | |
| tree | be2206102110419e2bdbe67c0f3884b9f1b2bfba | |
| parent | 2663959af22c485a5ee662f8189075912e3280b3 (diff) | |
| download | linux-ee096f0dc4a44a3d6cae27dce87abeea71b4680f.tar.xz | |
leds: trigger: netdev: use memcpy in device_name_store
[ Upstream commit 909346433064b8d840dc82af26161926b8d37558 ]
If userspace doesn't end the input with a newline (which can easily
happen if the write happens from a C program that does write(fd,
iface, strlen(iface))), we may end up including garbage from a
previous, longer value in the device_name. For example
# cat device_name
# printf 'eth12' > device_name
# cat device_name
eth12
# printf 'eth3' > device_name
# cat device_name
eth32
I highly doubt anybody is relying on this behaviour, so switch to
simply copying the bytes (we've already checked that size is <
IFNAMSIZ) and unconditionally zero-terminate it; of course, we also
still have to strip a trailing newline.
This is also preparation for future patches.
Fixes: 06f502f57d0d ("leds: trigger: Introduce a NETDEV trigger")
Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Acked-by: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Jacek Anaszewski <jacek.anaszewski@gmail.com>
Signed-off-by: Sasha Levin (Microsoft) <sashal@kernel.org>
| -rw-r--r-- | drivers/leds/trigger/ledtrig-netdev.c | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/drivers/leds/trigger/ledtrig-netdev.c b/drivers/leds/trigger/ledtrig-netdev.c index 167a94c02d05..136f86a1627d 100644 --- a/drivers/leds/trigger/ledtrig-netdev.c +++ b/drivers/leds/trigger/ledtrig-netdev.c @@ -122,7 +122,8 @@ static ssize_t device_name_store(struct device *dev, trigger_data->net_dev = NULL; } - strncpy(trigger_data->device_name, buf, size); + memcpy(trigger_data->device_name, buf, size); + trigger_data->device_name[size] = 0; if (size > 0 && trigger_data->device_name[size - 1] == '\n') trigger_data->device_name[size - 1] = 0; |