Commit eaa5cd92 authored May 22, 2015 by Vladimir Zapolskiy Committed by Greg Kroah-Hartman Jun 01, 2015

fs: sysfs: don't pass count == 0 to bin file readers



If count == 0 bytes are requested by a reader, sysfs_kf_bin_read()
deliberately returns 0 without passing a potentially harmful value to
some externally defined underlying battr->read() function.

However in case of (pos == size && count) the next clause always sets
count to 0 and this value is handed over to battr->read().

The change intends to make obsolete (and remove later) a redundant
sanity check in battr->read(), if it is present, or add more
protection to struct bin_attribute users, who does not care about
input arguments.

Signed-off-by: Vladimir Zapolskiy <vz@mleia.com>
Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

parent 9ba8af66

fs/sysfs/file.c

+1 −1

Original line number	Diff line number	Diff line
		@@ -90,7 +90,7 @@ static ssize_t sysfs_kf_bin_read(struct kernfs_open_file of, char buf,
		return 0;

		if (size) {
		if (pos > size)
		if (pos >= size)
		return 0;
		if (pos + count > size)
		count = size - pos;

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