From patchwork Mon Apr 1 12:55:43 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Zheng Yejian X-Patchwork-Id: 13612747 Received: from szxga02-in.huawei.com (szxga02-in.huawei.com [45.249.212.188]) (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 63D2F2940D; Mon, 1 Apr 2024 12:55:16 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=45.249.212.188 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1711976119; cv=none; b=uCRXJZe4fgOin1c7V2/ApqyWEZ9NoaRhU3TGxdwFEEfT8PkFr5weuEWziH1SbfTcMyBTzZUE2ayg+7Ta37rW1Me88zbzjytPR4TLAXClrqp8olgkVezDbfjR6bFzS0HIhSvWUBCEw7cHU4JT/FvxZNFU1aYZgfAWIChEcjvI8kY= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1711976119; c=relaxed/simple; bh=9+vzMVeUAI2Mzq8O0Xp2MRVfQENYZAVm0EKdXfmvQxc=; h=From:To:CC:Subject:Date:Message-ID:MIME-Version:Content-Type; b=cgdO1EBLc6o1cdK6/pkS95iXaQvHxuHJpLR08Z8XCU+GT1xJBOYUlikfYI97vM1NecFi0qgb7o73ugAha7CzO4tqeDbC+Ok2cUl6AAdN59L/rfjIQdg2hbluzU6jt9R+gG+Xbedp9vi2a8J/Q1skqRS/V/jh+dsZ8GI9F6BLzTI= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=huawei.com; spf=pass smtp.mailfrom=huawei.com; arc=none smtp.client-ip=45.249.212.188 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=huawei.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=huawei.com Received: from mail.maildlp.com (unknown [172.19.163.174]) by szxga02-in.huawei.com (SkyGuard) with ESMTP id 4V7WDW1N6Vzbf3g; Mon, 1 Apr 2024 20:54:19 +0800 (CST) Received: from dggpeml500012.china.huawei.com (unknown [7.185.36.15]) by mail.maildlp.com (Postfix) with ESMTPS id 52C541400D1; Mon, 1 Apr 2024 20:55:13 +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_256_GCM_SHA384) id 15.1.2507.35; Mon, 1 Apr 2024 20:55:13 +0800 From: Zheng Yejian To: , , , CC: , , Subject: [PATCH] ftrace: Fix use-after-free issue in ftrace_location() Date: Mon, 1 Apr 2024 20:55:43 +0800 Message-ID: <20240401125543.1282845-1-zhengyejian1@huawei.com> X-Mailer: git-send-email 2.25.1 Precedence: bulk X-Mailing-List: linux-trace-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-ClientProxiedBy: dggems701-chm.china.huawei.com (10.3.19.178) To dggpeml500012.china.huawei.com (7.185.36.15) KASAN reports a bug: BUG: KASAN: use-after-free in ftrace_location+0x90/0x120 Read of size 8 at addr ffff888141d40010 by task insmod/424 CPU: 8 PID: 424 Comm: insmod Tainted: G W 6.9.0-rc2+ #213 [...] Call Trace: dump_stack_lvl+0x68/0xa0 print_report+0xcf/0x610 kasan_report+0xb5/0xe0 ftrace_location+0x90/0x120 register_kprobe+0x14b/0xa40 kprobe_init+0x2d/0xff0 [kprobe_example] do_one_initcall+0x8f/0x2d0 do_init_module+0x13a/0x3c0 load_module+0x3082/0x33d0 init_module_from_file+0xd2/0x130 __x64_sys_finit_module+0x306/0x440 do_syscall_64+0x68/0x140 entry_SYSCALL_64_after_hwframe+0x71/0x79 The root cause is that when lookup_rec() is lookuping ftrace record of an address in some module, and at the same time in ftrace_release_mod(), the memory that saving ftrace records has been freed as that module is being deleted. register_kprobes() { check_kprobe_address_safe() { arch_check_ftrace_location() { ftrace_location() { lookup_rec() // access memory that has been freed by // ftrace_release_mod() !!! It seems that the ftrace_lock is required when lookuping records in ftrace_location(), so is ftrace_location_range(). Fixes: ae6aa16fdc16 ("kprobes: introduce ftrace based optimization") Signed-off-by: Zheng Yejian --- kernel/trace/ftrace.c | 28 ++++++++++++++++++---------- 1 file changed, 18 insertions(+), 10 deletions(-) diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c index da1710499698..838d175709c1 100644 --- a/kernel/trace/ftrace.c +++ b/kernel/trace/ftrace.c @@ -1581,7 +1581,7 @@ static struct dyn_ftrace *lookup_rec(unsigned long start, unsigned long end) } /** - * ftrace_location_range - return the first address of a traced location + * ftrace_location_range_locked - return the first address of a traced location * if it touches the given ip range * @start: start of range to search. * @end: end of range to search (inclusive). @end points to the last byte @@ -1592,7 +1592,7 @@ static struct dyn_ftrace *lookup_rec(unsigned long start, unsigned long end) * that is either a NOP or call to the function tracer. It checks the ftrace * internal tables to determine if the address belongs or not. */ -unsigned long ftrace_location_range(unsigned long start, unsigned long end) +static unsigned long ftrace_location_range_locked(unsigned long start, unsigned long end) { struct dyn_ftrace *rec; @@ -1603,6 +1603,17 @@ unsigned long ftrace_location_range(unsigned long start, unsigned long end) return 0; } +unsigned long ftrace_location_range(unsigned long start, unsigned long end) +{ + unsigned long loc; + + mutex_lock(&ftrace_lock); + loc = ftrace_location_range_locked(start, end); + mutex_unlock(&ftrace_lock); + + return loc; +} + /** * ftrace_location - return the ftrace location * @ip: the instruction pointer to check @@ -1614,25 +1625,22 @@ unsigned long ftrace_location_range(unsigned long start, unsigned long end) */ unsigned long ftrace_location(unsigned long ip) { - struct dyn_ftrace *rec; + unsigned long loc; unsigned long offset; unsigned long size; - rec = lookup_rec(ip, ip); - if (!rec) { + loc = ftrace_location_range(ip, ip); + if (!loc) { if (!kallsyms_lookup_size_offset(ip, &size, &offset)) goto out; /* map sym+0 to __fentry__ */ if (!offset) - rec = lookup_rec(ip, ip + size - 1); + loc = ftrace_location_range(ip, ip + size - 1); } - if (rec) - return rec->ip; - out: - return 0; + return loc; } /**