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 36DA512E1D7; Tue, 14 May 2024 11:49:49 +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=1715687389; cv=none; b=J8X00wIc8rCnFT1f6aN1S7j1syla6un69pIYHD/IxUVJC8jOyZ/B1Qu6ZgRtk762MSkbI3xbGK8UmYt70vEuPTUhOdIXTZ2sOaVA/kkpoJSW6KZjOA+FdrhMgPmmKo/7b3J5EUJAINVsUa6SZCxaKnLF0zY5Zlt+yYgraPyFH9o= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1715687389; c=relaxed/simple; bh=UAkqzSz02bHKv4gcgliP+1IoXJl6wlrkiTQAhu3tmjI=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=Fc1L3tv736xhmynI/z7b8w3mlefyLJZYuUCWJqLecK1s9BWkM0VNBwr/l4dq6uHW4e3nhbABst7sFK6VUk1F9RqYB4rr6PVfj3FgMByQY6HNR4fF3CNSPTrpGBUPTOSu5/CjKthd6hXJhTUb2jkw+m3NopTVejmhf90WbXJ/3+o= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=Fbv9a3Yu; 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="Fbv9a3Yu" Received: by smtp.kernel.org (Postfix) with ESMTPSA id B1B21C2BD10; Tue, 14 May 2024 11:49:48 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1715687389; bh=UAkqzSz02bHKv4gcgliP+1IoXJl6wlrkiTQAhu3tmjI=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Fbv9a3YuA1hi1x+/7BPz4x1CseLuGHW6WmjEYLvuF1wKMTIPRnTciRdcByd93RGSZ rVL8rKrf8giGVD3NnjinK2fO4PCP5MMADPMfeZ8AI6LI/piUpNJ3kEJqFFTHlOo1tD QMRCvSLwefTwCgCIE4tDcrs2zouIKRTKOj/HYk6M= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Duoming Zhou , Luiz Augusto von Dentz , Sasha Levin Subject: [PATCH 5.10 079/111] Bluetooth: l2cap: fix null-ptr-deref in l2cap_chan_timeout Date: Tue, 14 May 2024 12:20:17 +0200 Message-ID: <20240514101000.136033625@linuxfoundation.org> X-Mailer: git-send-email 2.45.0 In-Reply-To: <20240514100957.114746054@linuxfoundation.org> References: <20240514100957.114746054@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 5.10-stable review patch. If anyone has any objections, please let me know. ------------------ From: Duoming Zhou [ Upstream commit adf0398cee86643b8eacde95f17d073d022f782c ] There is a race condition between l2cap_chan_timeout() and l2cap_chan_del(). When we use l2cap_chan_del() to delete the channel, the chan->conn will be set to null. But the conn could be dereferenced again in the mutex_lock() of l2cap_chan_timeout(). As a result the null pointer dereference bug will happen. The KASAN report triggered by POC is shown below: [ 472.074580] ================================================================== [ 472.075284] BUG: KASAN: null-ptr-deref in mutex_lock+0x68/0xc0 [ 472.075308] Write of size 8 at addr 0000000000000158 by task kworker/0:0/7 [ 472.075308] [ 472.075308] CPU: 0 PID: 7 Comm: kworker/0:0 Not tainted 6.9.0-rc5-00356-g78c0094a146b #36 [ 472.075308] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.14.0-0-g155821a1990b-prebuilt.qemu4 [ 472.075308] Workqueue: events l2cap_chan_timeout [ 472.075308] Call Trace: [ 472.075308] [ 472.075308] dump_stack_lvl+0x137/0x1a0 [ 472.075308] print_report+0x101/0x250 [ 472.075308] ? __virt_addr_valid+0x77/0x160 [ 472.075308] ? mutex_lock+0x68/0xc0 [ 472.075308] kasan_report+0x139/0x170 [ 472.075308] ? mutex_lock+0x68/0xc0 [ 472.075308] kasan_check_range+0x2c3/0x2e0 [ 472.075308] mutex_lock+0x68/0xc0 [ 472.075308] l2cap_chan_timeout+0x181/0x300 [ 472.075308] process_one_work+0x5d2/0xe00 [ 472.075308] worker_thread+0xe1d/0x1660 [ 472.075308] ? pr_cont_work+0x5e0/0x5e0 [ 472.075308] kthread+0x2b7/0x350 [ 472.075308] ? pr_cont_work+0x5e0/0x5e0 [ 472.075308] ? kthread_blkcg+0xd0/0xd0 [ 472.075308] ret_from_fork+0x4d/0x80 [ 472.075308] ? kthread_blkcg+0xd0/0xd0 [ 472.075308] ret_from_fork_asm+0x11/0x20 [ 472.075308] [ 472.075308] ================================================================== [ 472.094860] Disabling lock debugging due to kernel taint [ 472.096136] BUG: kernel NULL pointer dereference, address: 0000000000000158 [ 472.096136] #PF: supervisor write access in kernel mode [ 472.096136] #PF: error_code(0x0002) - not-present page [ 472.096136] PGD 0 P4D 0 [ 472.096136] Oops: 0002 [#1] PREEMPT SMP KASAN NOPTI [ 472.096136] CPU: 0 PID: 7 Comm: kworker/0:0 Tainted: G B 6.9.0-rc5-00356-g78c0094a146b #36 [ 472.096136] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.14.0-0-g155821a1990b-prebuilt.qemu4 [ 472.096136] Workqueue: events l2cap_chan_timeout [ 472.096136] RIP: 0010:mutex_lock+0x88/0xc0 [ 472.096136] Code: be 08 00 00 00 e8 f8 23 1f fd 4c 89 f7 be 08 00 00 00 e8 eb 23 1f fd 42 80 3c 23 00 74 08 48 88 [ 472.096136] RSP: 0018:ffff88800744fc78 EFLAGS: 00000246 [ 472.096136] RAX: 0000000000000000 RBX: 1ffff11000e89f8f RCX: ffffffff8457c865 [ 472.096136] RDX: 0000000000000001 RSI: 0000000000000008 RDI: ffff88800744fc78 [ 472.096136] RBP: 0000000000000158 R08: ffff88800744fc7f R09: 1ffff11000e89f8f [ 472.096136] R10: dffffc0000000000 R11: ffffed1000e89f90 R12: dffffc0000000000 [ 472.096136] R13: 0000000000000158 R14: ffff88800744fc78 R15: ffff888007405a00 [ 472.096136] FS: 0000000000000000(0000) GS:ffff88806d200000(0000) knlGS:0000000000000000 [ 472.096136] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 472.096136] CR2: 0000000000000158 CR3: 000000000da32000 CR4: 00000000000006f0 [ 472.096136] Call Trace: [ 472.096136] [ 472.096136] ? __die_body+0x8d/0xe0 [ 472.096136] ? page_fault_oops+0x6b8/0x9a0 [ 472.096136] ? kernelmode_fixup_or_oops+0x20c/0x2a0 [ 472.096136] ? do_user_addr_fault+0x1027/0x1340 [ 472.096136] ? _printk+0x7a/0xa0 [ 472.096136] ? mutex_lock+0x68/0xc0 [ 472.096136] ? add_taint+0x42/0xd0 [ 472.096136] ? exc_page_fault+0x6a/0x1b0 [ 472.096136] ? asm_exc_page_fault+0x26/0x30 [ 472.096136] ? mutex_lock+0x75/0xc0 [ 472.096136] ? mutex_lock+0x88/0xc0 [ 472.096136] ? mutex_lock+0x75/0xc0 [ 472.096136] l2cap_chan_timeout+0x181/0x300 [ 472.096136] process_one_work+0x5d2/0xe00 [ 472.096136] worker_thread+0xe1d/0x1660 [ 472.096136] ? pr_cont_work+0x5e0/0x5e0 [ 472.096136] kthread+0x2b7/0x350 [ 472.096136] ? pr_cont_work+0x5e0/0x5e0 [ 472.096136] ? kthread_blkcg+0xd0/0xd0 [ 472.096136] ret_from_fork+0x4d/0x80 [ 472.096136] ? kthread_blkcg+0xd0/0xd0 [ 472.096136] ret_from_fork_asm+0x11/0x20 [ 472.096136] [ 472.096136] Modules linked in: [ 472.096136] CR2: 0000000000000158 [ 472.096136] ---[ end trace 0000000000000000 ]--- [ 472.096136] RIP: 0010:mutex_lock+0x88/0xc0 [ 472.096136] Code: be 08 00 00 00 e8 f8 23 1f fd 4c 89 f7 be 08 00 00 00 e8 eb 23 1f fd 42 80 3c 23 00 74 08 48 88 [ 472.096136] RSP: 0018:ffff88800744fc78 EFLAGS: 00000246 [ 472.096136] RAX: 0000000000000000 RBX: 1ffff11000e89f8f RCX: ffffffff8457c865 [ 472.096136] RDX: 0000000000000001 RSI: 0000000000000008 RDI: ffff88800744fc78 [ 472.096136] RBP: 0000000000000158 R08: ffff88800744fc7f R09: 1ffff11000e89f8f [ 472.132932] R10: dffffc0000000000 R11: ffffed1000e89f90 R12: dffffc0000000000 [ 472.132932] R13: 0000000000000158 R14: ffff88800744fc78 R15: ffff888007405a00 [ 472.132932] FS: 0000000000000000(0000) GS:ffff88806d200000(0000) knlGS:0000000000000000 [ 472.132932] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 472.132932] CR2: 0000000000000158 CR3: 000000000da32000 CR4: 00000000000006f0 [ 472.132932] Kernel panic - not syncing: Fatal exception [ 472.132932] Kernel Offset: disabled [ 472.132932] ---[ end Kernel panic - not syncing: Fatal exception ]--- Add a check to judge whether the conn is null in l2cap_chan_timeout() in order to mitigate the bug. Fixes: 3df91ea20e74 ("Bluetooth: Revert to mutexes from RCU list") Signed-off-by: Duoming Zhou Signed-off-by: Luiz Augusto von Dentz Signed-off-by: Sasha Levin --- net/bluetooth/l2cap_core.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/net/bluetooth/l2cap_core.c b/net/bluetooth/l2cap_core.c index 580b6d6b970d2..da03ca6dd9221 100644 --- a/net/bluetooth/l2cap_core.c +++ b/net/bluetooth/l2cap_core.c @@ -435,6 +435,9 @@ static void l2cap_chan_timeout(struct work_struct *work) BT_DBG("chan %p state %s", chan, state_to_string(chan->state)); + if (!conn) + return; + mutex_lock(&conn->chan_lock); /* __set_chan_timer() calls l2cap_chan_hold(chan) while scheduling * this work. No need to call l2cap_chan_hold(chan) here again. -- 2.43.0