From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 3598E1C3F17; Tue, 27 Aug 2024 15:24:21 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1724772261; cv=none; b=f0UWACK2n1mDDe/3Z1nEbQKoJMqFgRWe/b2HVSreqSuoZ6BiRVv9SHA/8ucaSqrF90OOYWXwDWpnSf7VZhTMpP8KtHff13Y0N/MPEJsSyuegrZI4BWuQ4BdaA/kv8ZkzfQS8JeeBM75qtn9YCFi0f1wNLELNJbZg6PMzlIGpxW8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1724772261; c=relaxed/simple; bh=+80s9FWsOsH8/UJemULJ7cV55rNNvSfXnKxwZ3ENxp4=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=VkKkioWkUbKYGCtnRCT3ABMn/v/5J68XDyzP946osRHcNCvFfbLteroRvO2SWyBJLy03v2kuZilTC6BQ87Qfax2Lyx/InLUanYP7WIqn5p5caG+fjuV/qkiUxyP3j7hWQAF7bHs/awWReLZTsr33/6JJ3VXanBFSdoXTPgpl17Y= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=C5KsCf7X; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="C5KsCf7X" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 95E0CC61069; Tue, 27 Aug 2024 15:24:20 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1724772261; bh=+80s9FWsOsH8/UJemULJ7cV55rNNvSfXnKxwZ3ENxp4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=C5KsCf7X2KVpNkRSbyYT4TLDGQ0OsmQpfeUuKLE+sS0kvdw4GxSdf8drpq+Iujnxy 9nePhGUJFfzacvODb5rk+PZpx9v4VSxGeCg3+eOWzj6lrJX3dAIQukJiv+W9rQkp7x qOBbfulbBbp9cA2dSE4YZXqZBFlSr9t1zSXFkpto= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Al Viro , Sasha Levin Subject: [PATCH 6.1 161/321] fuse: fix UAF in rcu pathwalks Date: Tue, 27 Aug 2024 16:37:49 +0200 Message-ID: <20240827143844.359694392@linuxfoundation.org> X-Mailer: git-send-email 2.46.0 In-Reply-To: <20240827143838.192435816@linuxfoundation.org> References: <20240827143838.192435816@linuxfoundation.org> User-Agent: quilt/0.67 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.1-stable review patch. If anyone has any objections, please let me know. ------------------ From: Al Viro [ Upstream commit 053fc4f755ad43cf35210677bcba798ccdc48d0c ] ->permission(), ->get_link() and ->inode_get_acl() might dereference ->s_fs_info (and, in case of ->permission(), ->s_fs_info->fc->user_ns as well) when called from rcu pathwalk. Freeing ->s_fs_info->fc is rcu-delayed; we need to make freeing ->s_fs_info and dropping ->user_ns rcu-delayed too. Signed-off-by: Al Viro Signed-off-by: Sasha Levin --- fs/fuse/cuse.c | 3 +-- fs/fuse/fuse_i.h | 1 + fs/fuse/inode.c | 15 +++++++++++---- 3 files changed, 13 insertions(+), 6 deletions(-) diff --git a/fs/fuse/cuse.c b/fs/fuse/cuse.c index c7d882a9fe339..295344a462e1d 100644 --- a/fs/fuse/cuse.c +++ b/fs/fuse/cuse.c @@ -474,8 +474,7 @@ static int cuse_send_init(struct cuse_conn *cc) static void cuse_fc_release(struct fuse_conn *fc) { - struct cuse_conn *cc = fc_to_cc(fc); - kfree_rcu(cc, fc.rcu); + kfree(fc_to_cc(fc)); } /** diff --git a/fs/fuse/fuse_i.h b/fs/fuse/fuse_i.h index 253b9b78d6f13..66c2a99994683 100644 --- a/fs/fuse/fuse_i.h +++ b/fs/fuse/fuse_i.h @@ -872,6 +872,7 @@ struct fuse_mount { /* Entry on fc->mounts */ struct list_head fc_entry; + struct rcu_head rcu; }; static inline struct fuse_mount *get_fuse_mount_super(struct super_block *sb) diff --git a/fs/fuse/inode.c b/fs/fuse/inode.c index f19bdd7cbd779..64618548835b4 100644 --- a/fs/fuse/inode.c +++ b/fs/fuse/inode.c @@ -925,6 +925,14 @@ void fuse_conn_init(struct fuse_conn *fc, struct fuse_mount *fm, } EXPORT_SYMBOL_GPL(fuse_conn_init); +static void delayed_release(struct rcu_head *p) +{ + struct fuse_conn *fc = container_of(p, struct fuse_conn, rcu); + + put_user_ns(fc->user_ns); + fc->release(fc); +} + void fuse_conn_put(struct fuse_conn *fc) { if (refcount_dec_and_test(&fc->count)) { @@ -936,13 +944,12 @@ void fuse_conn_put(struct fuse_conn *fc) if (fiq->ops->release) fiq->ops->release(fiq); put_pid_ns(fc->pid_ns); - put_user_ns(fc->user_ns); bucket = rcu_dereference_protected(fc->curr_bucket, 1); if (bucket) { WARN_ON(atomic_read(&bucket->count) != 1); kfree(bucket); } - fc->release(fc); + call_rcu(&fc->rcu, delayed_release); } } EXPORT_SYMBOL_GPL(fuse_conn_put); @@ -1356,7 +1363,7 @@ EXPORT_SYMBOL_GPL(fuse_send_init); void fuse_free_conn(struct fuse_conn *fc) { WARN_ON(!list_empty(&fc->devices)); - kfree_rcu(fc, rcu); + kfree(fc); } EXPORT_SYMBOL_GPL(fuse_free_conn); @@ -1895,7 +1902,7 @@ static void fuse_sb_destroy(struct super_block *sb) void fuse_mount_destroy(struct fuse_mount *fm) { fuse_conn_put(fm->fc); - kfree(fm); + kfree_rcu(fm, rcu); } EXPORT_SYMBOL(fuse_mount_destroy); -- 2.43.0