From: Vladimir Zapolskiy Date: Thu, 21 May 2015 21:21:16 +0000 (+0300) Subject: fs: sysfs: don't pass count == 0 to bin file readers X-Git-Tag: firefly_0821_release~176^2~1546^2~6 X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=eaa5cd926345f86e9df1eb6b0490da539f5ce7d0;p=firefly-linux-kernel-4.4.55.git 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 Acked-by: Tejun Heo Signed-off-by: Greg Kroah-Hartman --- diff --git a/fs/sysfs/file.c b/fs/sysfs/file.c index 7c2867b44141..6c95628ea377 100644 --- a/fs/sysfs/file.c +++ b/fs/sysfs/file.c @@ -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;