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 DC38D17731 for ; Wed, 9 Aug 2023 11:07:23 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 5D1DFC433C7; Wed, 9 Aug 2023 11:07:23 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1691579243; bh=+4F+jbmnDb7dGt24n8kG/y50S1oILj5eCJueOyqEqKM=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=MuWDCiceY9sOgPQXoEwwakpRms8PujfFrGWhYIMYaXO0vgC8MBO/w1ZF9fC12piZz y62CwqogQBy1dHp2y67+uAhvYE9BXlakkR6kESh8XJ41jMj/ufLp665/c7l2hLClS9 +n51vXEYGdoU9OGNlyvzmwe++YXQf9xMcv3JoUao= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, YueHaibing , Oliver Hartkopp , Marc Kleine-Budde Subject: [PATCH 4.14 126/204] can: bcm: Fix UAF in bcm_proc_show() Date: Wed, 9 Aug 2023 12:41:04 +0200 Message-ID: <20230809103646.820800527@linuxfoundation.org> X-Mailer: git-send-email 2.41.0 In-Reply-To: <20230809103642.552405807@linuxfoundation.org> References: <20230809103642.552405807@linuxfoundation.org> User-Agent: quilt/0.67 Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit From: YueHaibing commit 55c3b96074f3f9b0aee19bf93cd71af7516582bb upstream. BUG: KASAN: slab-use-after-free in bcm_proc_show+0x969/0xa80 Read of size 8 at addr ffff888155846230 by task cat/7862 CPU: 1 PID: 7862 Comm: cat Not tainted 6.5.0-rc1-00153-gc8746099c197 #230 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.15.0-1 04/01/2014 Call Trace: dump_stack_lvl+0xd5/0x150 print_report+0xc1/0x5e0 kasan_report+0xba/0xf0 bcm_proc_show+0x969/0xa80 seq_read_iter+0x4f6/0x1260 seq_read+0x165/0x210 proc_reg_read+0x227/0x300 vfs_read+0x1d5/0x8d0 ksys_read+0x11e/0x240 do_syscall_64+0x35/0xb0 entry_SYSCALL_64_after_hwframe+0x63/0xcd Allocated by task 7846: kasan_save_stack+0x1e/0x40 kasan_set_track+0x21/0x30 __kasan_kmalloc+0x9e/0xa0 bcm_sendmsg+0x264b/0x44e0 sock_sendmsg+0xda/0x180 ____sys_sendmsg+0x735/0x920 ___sys_sendmsg+0x11d/0x1b0 __sys_sendmsg+0xfa/0x1d0 do_syscall_64+0x35/0xb0 entry_SYSCALL_64_after_hwframe+0x63/0xcd Freed by task 7846: kasan_save_stack+0x1e/0x40 kasan_set_track+0x21/0x30 kasan_save_free_info+0x27/0x40 ____kasan_slab_free+0x161/0x1c0 slab_free_freelist_hook+0x119/0x220 __kmem_cache_free+0xb4/0x2e0 rcu_core+0x809/0x1bd0 bcm_op is freed before procfs entry be removed in bcm_release(), this lead to bcm_proc_show() may read the freed bcm_op. Fixes: ffd980f976e7 ("[CAN]: Add broadcast manager (bcm) protocol") Signed-off-by: YueHaibing Reviewed-by: Oliver Hartkopp Acked-by: Oliver Hartkopp Link: https://lore.kernel.org/all/20230715092543.15548-1-yuehaibing@huawei.com Cc: stable@vger.kernel.org Signed-off-by: Marc Kleine-Budde Signed-off-by: Greg Kroah-Hartman --- net/can/bcm.c | 12 ++++++------ 1 file changed, 6 insertions(+), 6 deletions(-) --- a/net/can/bcm.c +++ b/net/can/bcm.c @@ -1572,6 +1572,12 @@ static int bcm_release(struct socket *so lock_sock(sk); +#if IS_ENABLED(CONFIG_PROC_FS) + /* remove procfs entry */ + if (net->can.bcmproc_dir && bo->bcm_proc_read) + remove_proc_entry(bo->procname, net->can.bcmproc_dir); +#endif /* CONFIG_PROC_FS */ + list_for_each_entry_safe(op, next, &bo->tx_ops, list) bcm_remove_op(op); @@ -1607,12 +1613,6 @@ static int bcm_release(struct socket *so list_for_each_entry_safe(op, next, &bo->rx_ops, list) bcm_remove_op(op); -#if IS_ENABLED(CONFIG_PROC_FS) - /* remove procfs entry */ - if (net->can.bcmproc_dir && bo->bcm_proc_read) - remove_proc_entry(bo->procname, net->can.bcmproc_dir); -#endif /* CONFIG_PROC_FS */ - /* remove device reference */ if (bo->bound) { bo->bound = 0;