[JFFS2] Fix race in setting file attributes (422138dd) · Commits · 戴 / test

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>

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));
		}

Admin message