Commit eaa5cd92 authored by Vladimir Zapolskiy's avatar Vladimir Zapolskiy Committed by Greg Kroah-Hartman

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: 's avatarVladimir Zapolskiy <vz@mleia.com>
Acked-by: 's avatarTejun Heo <tj@kernel.org>
Signed-off-by: 's avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 9ba8af66
......@@ -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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