From patchwork Thu Dec 14 01:21:53 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Zheng Yejian X-Patchwork-Id: 13492159 Received: from szxga07-in.huawei.com (szxga07-in.huawei.com [45.249.212.35]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 5B7BBD62; Wed, 13 Dec 2023 17:21:10 -0800 (PST) Received: from mail.maildlp.com (unknown [172.19.88.163]) by szxga07-in.huawei.com (SkyGuard) with ESMTP id 4SrDzh0kCQz1Q6Pg; Thu, 14 Dec 2023 09:20:00 +0800 (CST) Received: from dggpeml500012.china.huawei.com (unknown [7.185.36.15]) by mail.maildlp.com (Postfix) with ESMTPS id 749E018001A; Thu, 14 Dec 2023 09:21:08 +0800 (CST) Received: from localhost.localdomain (10.67.175.61) by dggpeml500012.china.huawei.com (7.185.36.15) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2507.35; Thu, 14 Dec 2023 09:21:08 +0800 From: Zheng Yejian To: CC: , , , , , Subject: [PATCH v3] tracing: Fix uaf issue when open the hist or hist_debug file Date: Thu, 14 Dec 2023 09:21:53 +0800 Message-ID: <20231214012153.676155-1-zhengyejian1@huawei.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20231213080127.6ef26247@gandalf.local.home> References: <20231213080127.6ef26247@gandalf.local.home> Precedence: bulk X-Mailing-List: linux-trace-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-ClientProxiedBy: dggems702-chm.china.huawei.com (10.3.19.179) To dggpeml500012.china.huawei.com (7.185.36.15) KASAN report following issue. The root cause is when opening 'hist' file of an instance and accessing 'trace_event_file' in hist_show(), but 'trace_event_file' has been freed due to the instance being removed. 'hist_debug' file has the same problem. To fix it, call tracing_{open,release}_file_tr() in file_operations callback to have the ref count and avoid 'trace_event_file' being freed. BUG: KASAN: slab-use-after-free in hist_show+0x11e0/0x1278 Read of size 8 at addr ffff242541e336b8 by task head/190 CPU: 4 PID: 190 Comm: head Not tainted 6.7.0-rc5-g26aff849438c #133 Hardware name: linux,dummy-virt (DT) Call trace: dump_backtrace+0x98/0xf8 show_stack+0x1c/0x30 dump_stack_lvl+0x44/0x58 print_report+0xf0/0x5a0 kasan_report+0x80/0xc0 __asan_report_load8_noabort+0x1c/0x28 hist_show+0x11e0/0x1278 seq_read_iter+0x344/0xd78 seq_read+0x128/0x1c0 vfs_read+0x198/0x6c8 ksys_read+0xf4/0x1e0 __arm64_sys_read+0x70/0xa8 invoke_syscall+0x70/0x260 el0_svc_common.constprop.0+0xb0/0x280 do_el0_svc+0x44/0x60 el0_svc+0x34/0x68 el0t_64_sync_handler+0xb8/0xc0 el0t_64_sync+0x168/0x170 Allocated by task 188: kasan_save_stack+0x28/0x50 kasan_set_track+0x28/0x38 kasan_save_alloc_info+0x20/0x30 __kasan_slab_alloc+0x6c/0x80 kmem_cache_alloc+0x15c/0x4a8 trace_create_new_event+0x84/0x348 __trace_add_new_event+0x18/0x88 event_trace_add_tracer+0xc4/0x1a0 trace_array_create_dir+0x6c/0x100 trace_array_create+0x2e8/0x568 instance_mkdir+0x48/0x80 tracefs_syscall_mkdir+0x90/0xe8 vfs_mkdir+0x3c4/0x610 do_mkdirat+0x144/0x200 __arm64_sys_mkdirat+0x8c/0xc0 invoke_syscall+0x70/0x260 el0_svc_common.constprop.0+0xb0/0x280 do_el0_svc+0x44/0x60 el0_svc+0x34/0x68 el0t_64_sync_handler+0xb8/0xc0 el0t_64_sync+0x168/0x170 Freed by task 191: kasan_save_stack+0x28/0x50 kasan_set_track+0x28/0x38 kasan_save_free_info+0x34/0x58 __kasan_slab_free+0xe4/0x158 kmem_cache_free+0x19c/0x508 event_file_put+0xa0/0x120 remove_event_file_dir+0x180/0x320 event_trace_del_tracer+0xb0/0x180 __remove_instance+0x224/0x508 instance_rmdir+0x44/0x78 tracefs_syscall_rmdir+0xbc/0x140 vfs_rmdir+0x1cc/0x4c8 do_rmdir+0x220/0x2b8 __arm64_sys_unlinkat+0xc0/0x100 invoke_syscall+0x70/0x260 el0_svc_common.constprop.0+0xb0/0x280 do_el0_svc+0x44/0x60 el0_svc+0x34/0x68 el0t_64_sync_handler+0xb8/0xc0 el0t_64_sync+0x168/0x170 Suggested-by: Steven Rostedt Signed-off-by: Zheng Yejian --- kernel/trace/trace.c | 6 ++++++ kernel/trace/trace.h | 1 + kernel/trace/trace_events_hist.c | 12 ++++++++---- 3 files changed, 15 insertions(+), 4 deletions(-) v3: - As suggested by Steve, put the tracing_single_release_file_tr() into trace.c as a non static function, put the prototype in trace.h. Link: https://lore.kernel.org/all/20231213080127.6ef26247@gandalf.local.home/ v2: - Introduce tracing_single_release_file_tr() to add the missing call for single_release() as suggested by Steve; Link: https://lore.kernel.org/all/20231212113546.6a51d359@gandalf.local.home/ - Slightly modify the commit message and comments. - Link: https://lore.kernel.org/all/20231213015138.281888-1-zhengyejian1@huawei.com/ v1: Link: https://lore.kernel.org/all/20231212113317.4159890-1-zhengyejian1@huawei.com/ diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index fbcd3bafb93e..fc1b2ada98a5 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -4964,6 +4964,12 @@ int tracing_release_file_tr(struct inode *inode, struct file *filp) return 0; } +int tracing_single_release_file_tr(struct inode *inode, struct file *filp) +{ + tracing_release_file_tr(inode, filp); + return single_release(inode, filp); +} + static int tracing_mark_open(struct inode *inode, struct file *filp) { stream_open(inode, filp); diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h index b7f4ea25a194..0489e72c8169 100644 --- a/kernel/trace/trace.h +++ b/kernel/trace/trace.h @@ -617,6 +617,7 @@ int tracing_open_generic(struct inode *inode, struct file *filp); int tracing_open_generic_tr(struct inode *inode, struct file *filp); int tracing_open_file_tr(struct inode *inode, struct file *filp); int tracing_release_file_tr(struct inode *inode, struct file *filp); +int tracing_single_release_file_tr(struct inode *inode, struct file *filp); bool tracing_is_disabled(void); bool tracer_tracing_is_on(struct trace_array *tr); void tracer_tracing_on(struct trace_array *tr); diff --git a/kernel/trace/trace_events_hist.c b/kernel/trace/trace_events_hist.c index 1abc07fba1b9..5ecf3c8bde20 100644 --- a/kernel/trace/trace_events_hist.c +++ b/kernel/trace/trace_events_hist.c @@ -5623,10 +5623,12 @@ static int event_hist_open(struct inode *inode, struct file *file) { int ret; - ret = security_locked_down(LOCKDOWN_TRACEFS); + ret = tracing_open_file_tr(inode, file); if (ret) return ret; + /* Clear private_data to avoid warning in single_open() */ + file->private_data = NULL; return single_open(file, hist_show, file); } @@ -5634,7 +5636,7 @@ const struct file_operations event_hist_fops = { .open = event_hist_open, .read = seq_read, .llseek = seq_lseek, - .release = single_release, + .release = tracing_single_release_file_tr, }; #ifdef CONFIG_HIST_TRIGGERS_DEBUG @@ -5900,10 +5902,12 @@ static int event_hist_debug_open(struct inode *inode, struct file *file) { int ret; - ret = security_locked_down(LOCKDOWN_TRACEFS); + ret = tracing_open_file_tr(inode, file); if (ret) return ret; + /* Clear private_data to avoid warning in single_open() */ + file->private_data = NULL; return single_open(file, hist_debug_show, file); } @@ -5911,7 +5915,7 @@ const struct file_operations event_hist_debug_fops = { .open = event_hist_debug_open, .read = seq_read, .llseek = seq_lseek, - .release = single_release, + .release = tracing_single_release_file_tr, }; #endif