[JFFS2] Fix race in setting file attributes
It seems like there is a potential race in the function jffs2_do_setattr()
in the case when attributes of a symlink are updated. The symlink metadata
is read without having f->sem locked.
The following patch should fix the race.
Signed-off-by: Dmitry Bazhenov <atrey@emcraft.com>
Signed-off-by: David Woodhouse <dwmw2@infradead.org>
diff --git a/fs/jffs2/fs.c b/fs/jffs2/fs.c
index 09e5d10..ea1f37d 100644
--- a/fs/jffs2/fs.c
+++ b/fs/jffs2/fs.c
@@ -56,15 +56,20 @@
mdatalen = sizeof(dev);
D1(printk(KERN_DEBUG "jffs2_setattr(): Writing %d bytes of kdev_t\n", mdatalen));
} else if (S_ISLNK(inode->i_mode)) {
+ down(&f->sem);
mdatalen = f->metadata->size;
mdata = kmalloc(f->metadata->size, GFP_USER);
- if (!mdata)
+ if (!mdata) {
+ up(&f->sem);
return -ENOMEM;
+ }
ret = jffs2_read_dnode(c, f, f->metadata, mdata, 0, mdatalen);
if (ret) {
+ up(&f->sem);
kfree(mdata);
return ret;
}
+ up(&f->sem);
D1(printk(KERN_DEBUG "jffs2_setattr(): Writing %d bytes of symlink target\n", mdatalen));
}