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 E560E17AAD for ; Wed, 9 Aug 2023 11:38:48 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 67171C433C8; Wed, 9 Aug 2023 11:38:48 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1691581128; bh=HgdXanpae9A4yLfmWm1Mn6PUq81LO0OHa7Scf3YamQw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=eJ5VZ05qIxHr0H8LyjkHXcKMkx6KNAPiU8wcp8wFjMaf0acvIpwk7QI+wKOsDUUYQ k2RKR9H2xlAsuBF79HQ1zO6UT1L0zUwfGmkoS/9y2rzYOXgCW1IEPHRArin1yHQR6y WNqmv7K0IIZYGLox0/cqAOFews5/zYfF8NMm2nG4= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Chaoyuan Peng , stable Subject: [PATCH 5.10 085/201] tty: n_gsm: fix UAF in gsm_cleanup_mux Date: Wed, 9 Aug 2023 12:41:27 +0200 Message-ID: <20230809103646.648018179@linuxfoundation.org> X-Mailer: git-send-email 2.41.0 In-Reply-To: <20230809103643.799166053@linuxfoundation.org> References: <20230809103643.799166053@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: Chaoyuan Peng commit 9b9c8195f3f0d74a826077fc1c01b9ee74907239 upstream. In gsm_cleanup_mux() the 'gsm->dlci' pointer was not cleaned properly, leaving it a dangling pointer after gsm_dlci_release. This leads to use-after-free where 'gsm->dlci[0]' are freed and accessed by the subsequent gsm_cleanup_mux(). Such is the case in the following call trace: __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0x1e3/0x2cb lib/dump_stack.c:106 print_address_description+0x63/0x3b0 mm/kasan/report.c:248 __kasan_report mm/kasan/report.c:434 [inline] kasan_report+0x16b/0x1c0 mm/kasan/report.c:451 gsm_cleanup_mux+0x76a/0x850 drivers/tty/n_gsm.c:2397 gsm_config drivers/tty/n_gsm.c:2653 [inline] gsmld_ioctl+0xaae/0x15b0 drivers/tty/n_gsm.c:2986 tty_ioctl+0x8ff/0xc50 drivers/tty/tty_io.c:2816 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:874 [inline] __se_sys_ioctl+0xf1/0x160 fs/ioctl.c:860 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x61/0xcb Allocated by task 3501: kasan_save_stack mm/kasan/common.c:38 [inline] kasan_set_track mm/kasan/common.c:46 [inline] set_alloc_info mm/kasan/common.c:434 [inline] ____kasan_kmalloc+0xba/0xf0 mm/kasan/common.c:513 kasan_kmalloc include/linux/kasan.h:264 [inline] kmem_cache_alloc_trace+0x143/0x290 mm/slub.c:3247 kmalloc include/linux/slab.h:591 [inline] kzalloc include/linux/slab.h:721 [inline] gsm_dlci_alloc+0x53/0x3a0 drivers/tty/n_gsm.c:1932 gsm_activate_mux+0x1c/0x330 drivers/tty/n_gsm.c:2438 gsm_config drivers/tty/n_gsm.c:2677 [inline] gsmld_ioctl+0xd46/0x15b0 drivers/tty/n_gsm.c:2986 tty_ioctl+0x8ff/0xc50 drivers/tty/tty_io.c:2816 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:874 [inline] __se_sys_ioctl+0xf1/0x160 fs/ioctl.c:860 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x61/0xcb Freed by task 3501: kasan_save_stack mm/kasan/common.c:38 [inline] kasan_set_track+0x4b/0x80 mm/kasan/common.c:46 kasan_set_free_info+0x1f/0x40 mm/kasan/generic.c:360 ____kasan_slab_free+0xd8/0x120 mm/kasan/common.c:366 kasan_slab_free include/linux/kasan.h:230 [inline] slab_free_hook mm/slub.c:1705 [inline] slab_free_freelist_hook+0xdd/0x160 mm/slub.c:1731 slab_free mm/slub.c:3499 [inline] kfree+0xf1/0x270 mm/slub.c:4559 dlci_put drivers/tty/n_gsm.c:1988 [inline] gsm_dlci_release drivers/tty/n_gsm.c:2021 [inline] gsm_cleanup_mux+0x574/0x850 drivers/tty/n_gsm.c:2415 gsm_config drivers/tty/n_gsm.c:2653 [inline] gsmld_ioctl+0xaae/0x15b0 drivers/tty/n_gsm.c:2986 tty_ioctl+0x8ff/0xc50 drivers/tty/tty_io.c:2816 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:874 [inline] __se_sys_ioctl+0xf1/0x160 fs/ioctl.c:860 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x61/0xcb Fixes: aa371e96f05d ("tty: n_gsm: fix restart handling via CLD command") Signed-off-by: Chaoyuan Peng Cc: stable Signed-off-by: Greg Kroah-Hartman --- drivers/tty/n_gsm.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) --- a/drivers/tty/n_gsm.c +++ b/drivers/tty/n_gsm.c @@ -2178,8 +2178,10 @@ static void gsm_cleanup_mux(struct gsm_m /* Free up any link layer users and finally the control channel */ for (i = NUM_DLCI - 1; i >= 0; i--) - if (gsm->dlci[i]) + if (gsm->dlci[i]) { gsm_dlci_release(gsm->dlci[i]); + gsm->dlci[i] = NULL; + } mutex_unlock(&gsm->mutex); /* Now wipe the queues */ tty_ldisc_flush(gsm->tty);