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 C950F29A9; Fri, 15 Nov 2024 06:45:51 +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=1731653151; cv=none; b=h5GWEo/RTOzWddEgIFwc/V10c/gamoQnJCoanlq73WkBYbg/DkUqz1MtgXotQB16ioekMOtySYYb3MYypTRlbtm2FJVtJG5jnqhaX5Jf2W+qWwDQv84VG6mASmlcDaa2Riy0dpOKW4qHp8yYWmxBTxZw6ibebt7PXr2HHQMBAz0= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1731653151; c=relaxed/simple; bh=5XodOKaLVCr94qH/ZD89pJjco8QeVhdOHMQSP6+0MzY=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=rcuq2OHWFWdGuvNhs5XZcOAnJIFlY5M0wBz7SaxcYX6gHAgGi3bkOCKgU6jH0r6lvNvOcxFTzgs8QZKqQg57l7cuHW/t9aL7igYdP5jZ2eIsiI6bHX1RcgVLbqSNPIaTpS/pqB9zmS9Rx7rPpptcfWiQKjw/0T0oIJnazOrrdzU= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=oLe0i7WY; 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="oLe0i7WY" Received: by smtp.kernel.org (Postfix) with ESMTPSA id DF8F5C4CECF; Fri, 15 Nov 2024 06:45:50 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1731653151; bh=5XodOKaLVCr94qH/ZD89pJjco8QeVhdOHMQSP6+0MzY=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=oLe0i7WY6YM0fWORJSvYKrPjKzY4XGzCw0b0aHIsN+ZePor4i4l70eE0X1M/WBHky BSW9M0t9D4urx2gZb0zt+D30gMkwSLxqy9DPiTzLhIgGjKROtITkGjdqEyhelhHKqA bS6CXxK7ke4TF1gAL3CcV/lZZORFHiVSCrfr49Fs= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, mhiramat@kernel.org, mark.rutland@arm.com, mathieu.desnoyers@efficios.com, Steven Rostedt , Zheng Yejian , Hagar Hemdan Subject: [PATCH 5.4 50/66] ftrace: Fix possible use-after-free issue in ftrace_location() Date: Fri, 15 Nov 2024 07:37:59 +0100 Message-ID: <20241115063724.648039829@linuxfoundation.org> X-Mailer: git-send-email 2.47.0 In-Reply-To: <20241115063722.834793938@linuxfoundation.org> References: <20241115063722.834793938@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 5.4-stable review patch. If anyone has any objections, please let me know. ------------------ From: Zheng Yejian commit e60b613df8b6253def41215402f72986fee3fc8d upstream. 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+ [...] 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, in lookup_rec(), ftrace record of some address is being searched in ftrace pages of some module, but those ftrace pages at the same time is being freed in ftrace_release_mod() as the corresponding module is being deleted: CPU1 | CPU2 register_kprobes() { | delete_module() { check_kprobe_address_safe() { | arch_check_ftrace_location() { | ftrace_location() { | lookup_rec() // USE! | ftrace_release_mod() // Free! To fix this issue: 1. Hold rcu lock as accessing ftrace pages in ftrace_location_range(); 2. Use ftrace_location_range() instead of lookup_rec() in ftrace_location(); 3. Call synchronize_rcu() before freeing any ftrace pages both in ftrace_process_locs()/ftrace_release_mod()/ftrace_free_mem(). Link: https://lore.kernel.org/linux-trace-kernel/20240509192859.1273558-1-zhengyejian1@huawei.com Cc: stable@vger.kernel.org Cc: Cc: Cc: Fixes: ae6aa16fdc16 ("kprobes: introduce ftrace based optimization") Suggested-by: Steven Rostedt Signed-off-by: Zheng Yejian Signed-off-by: Steven Rostedt (Google) [Hagar: Modified to apply on v5.4.y] Signed-off-by: Hagar Hemdan Signed-off-by: Greg Kroah-Hartman --- kernel/trace/ftrace.c | 30 +++++++++++++++++++++--------- 1 file changed, 21 insertions(+), 9 deletions(-) --- a/kernel/trace/ftrace.c +++ b/kernel/trace/ftrace.c @@ -1552,7 +1552,9 @@ unsigned long ftrace_location_range(unsi struct ftrace_page *pg; struct dyn_ftrace *rec; struct dyn_ftrace key; + unsigned long ip = 0; + rcu_read_lock(); key.ip = start; key.flags = end; /* overload flags, as it is unsigned long */ @@ -1565,10 +1567,13 @@ unsigned long ftrace_location_range(unsi sizeof(struct dyn_ftrace), ftrace_cmp_recs); if (rec) - return rec->ip; + { + ip = rec->ip; + break; + } } - - return 0; + rcu_read_unlock(); + return ip; } /** @@ -5736,6 +5741,8 @@ static int ftrace_process_locs(struct mo /* We should have used all pages unless we skipped some */ if (pg_unuse) { WARN_ON(!skipped); + /* Need to synchronize with ftrace_location_range() */ + synchronize_rcu(); ftrace_free_pages(pg_unuse); } return ret; @@ -5889,6 +5896,9 @@ void ftrace_release_mod(struct module *m out_unlock: mutex_unlock(&ftrace_lock); + /* Need to synchronize with ftrace_location_range() */ + if (tmp_page) + synchronize_rcu(); for (pg = tmp_page; pg; pg = tmp_page) { /* Needs to be called outside of ftrace_lock */ @@ -6196,6 +6206,7 @@ void ftrace_free_mem(struct module *mod, unsigned long start = (unsigned long)(start_ptr); unsigned long end = (unsigned long)(end_ptr); struct ftrace_page **last_pg = &ftrace_pages_start; + struct ftrace_page *tmp_page = NULL; struct ftrace_page *pg; struct dyn_ftrace *rec; struct dyn_ftrace key; @@ -6239,12 +6250,8 @@ void ftrace_free_mem(struct module *mod, ftrace_update_tot_cnt--; if (!pg->index) { *last_pg = pg->next; - if (pg->records) { - free_pages((unsigned long)pg->records, pg->order); - ftrace_number_of_pages -= 1 << pg->order; - } - ftrace_number_of_groups--; - kfree(pg); + pg->next = tmp_page; + tmp_page = pg; pg = container_of(last_pg, struct ftrace_page, next); if (!(*last_pg)) ftrace_pages = pg; @@ -6261,6 +6268,11 @@ void ftrace_free_mem(struct module *mod, clear_func_from_hashes(func); kfree(func); } + /* Need to synchronize with ftrace_location_range() */ + if (tmp_page) { + synchronize_rcu(); + ftrace_free_pages(tmp_page); + } } void __init ftrace_free_init_mem(void)