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 2EE3C1C07C4; Tue, 15 Oct 2024 12:56:14 +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=1728996975; cv=none; b=f1nF4I1aWKYBLzz3a5pRwXEhx+l8Qu2Uws/Nx6Cs8as9sFjjXcC9/asiImnGhlmziInZEb/T4RxF5DVaJic4d0NwX7HfpjDjRdQuthggVs9lOX4ZIU3YdWEnw1otT92O54WWIHQWe7lLsAsrszwa2j8muqTx2z0DVsqZDLF8vSI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1728996975; c=relaxed/simple; bh=/y8hdch1bOMpq4Hp0cUZ28U1ANMobecvFn98aI3dsig=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=t3aOdU2LQ+fwQ7I0PaPyqqf2jEBUAh2bMOBJ3SX7aTAt1PYNNWx2i6PllKQCChT5dHLBp07fp23QBu4hBCFxh5iGKM6foxmNI7HEwQx/cEnAwL+b64dbW5/DwA/19xxTkq3rArAlH3y81pu8qdKY284ql6rulVQfIw2qN8kpsyA= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=A9/FBOF7; 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="A9/FBOF7" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 493A5C4CEC6; Tue, 15 Oct 2024 12:56:14 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1728996974; bh=/y8hdch1bOMpq4Hp0cUZ28U1ANMobecvFn98aI3dsig=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=A9/FBOF7/1pcOKiVBrs10gNKAzLnGFE/LFFKwXVr2e/gq6DeCodvegYWdtRVuxkte x7PKXgDBUW92LJMjoJ6KcXDGLaRA5vh1wVAqU8oXhmuecPQqAcpxt6Goqzv05DeD2E a7yY9q0uLT0Or50q4Mkn9vxj+pT+PW6YD+mW8ci4= 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 , Shivani Agarwal Subject: [PATCH 5.10 053/518] ftrace: Fix possible use-after-free issue in ftrace_location() Date: Tue, 15 Oct 2024 14:39:17 +0200 Message-ID: <20241015123919.059615048@linuxfoundation.org> X-Mailer: git-send-email 2.47.0 In-Reply-To: <20241015123916.821186887@linuxfoundation.org> References: <20241015123916.821186887@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: 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) [Shivani: Modified to apply on v5.10.y] Signed-off-by: Shivani Agarwal Signed-off-by: Greg Kroah-Hartman --- kernel/trace/ftrace.c | 39 +++++++++++++++++++++++---------------- 1 file changed, 23 insertions(+), 16 deletions(-) --- a/kernel/trace/ftrace.c +++ b/kernel/trace/ftrace.c @@ -1566,12 +1566,15 @@ static struct dyn_ftrace *lookup_rec(uns unsigned long ftrace_location_range(unsigned long start, unsigned long end) { struct dyn_ftrace *rec; + unsigned long ip = 0; + rcu_read_lock(); rec = lookup_rec(start, end); if (rec) - return rec->ip; + ip = rec->ip; + rcu_read_unlock(); - return 0; + return ip; } /** @@ -1584,25 +1587,22 @@ unsigned long ftrace_location_range(unsi */ 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; } /** @@ -6331,6 +6331,8 @@ 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; @@ -6513,6 +6515,9 @@ 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 */ @@ -6835,6 +6840,7 @@ 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; @@ -6878,12 +6884,8 @@ 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; @@ -6900,6 +6902,11 @@ 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)