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Commit 422138dd authored by Dmitry Bazhenov's avatar Dmitry Bazhenov Committed by David Woodhouse
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[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: default avatarDmitry Bazhenov <atrey@emcraft.com>
Signed-off-by: default avatarDavid Woodhouse <dwmw2@infradead.org>
parent edc4ff7c

fs/jffs2/fs.c

+6 −1
Original line number Diff line number Diff line
@@ -56,15 +56,20 @@ static int jffs2_do_setattr (struct inode *inode, struct iattr *iattr) 
		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));

	}