Commit e9e360b0 authored Oct 19, 2016 by Namhyung Kim Committed by Kees Cook Nov 15, 2016

pstore: Protect unlink with read_mutex



When update_ms is set, pstore_get_records() will be called when there's
a new entry.  But unlink can be called at the same time and might
contend with the open-read-close loop.  Depending on the implementation
of platform driver, it may be safe or not.  But I think it'd be better
to protect those race in the first place.

Cc: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Signed-off-by: Kees Cook <keescook@chromium.org>

parent 7a0032f5

fs/pstore/inode.c

+5 −2

Original line number	Diff line number	Diff line
		@@ -199,11 +199,14 @@ static int pstore_unlink(struct inode dir, struct dentry dentry)
		if (err)
		return err;

		if (p->psi->erase)
		if (p->psi->erase) {
		mutex_lock(&p->psi->read_mutex);
		p->psi->erase(p->type, p->id, p->count,
		d_inode(dentry)->i_ctime, p->psi);
		else
		mutex_unlock(&p->psi->read_mutex);
		} else {
		return -EPERM;
		}

		return simple_unlink(dir, dentry);
		}