From eaa5cd926345f86e9df1eb6b0490da539f5ce7d0 Mon Sep 17 00:00:00 2001
From: Vladimir Zapolskiy <vz@mleia.com>
Date: Fri, 22 May 2015 00:21:16 +0300
Subject: [PATCH] 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>
---
fs/sysfs/file.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
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;
--
GitLab