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 36D3726988E; Tue, 8 Apr 2025 11:04:38 +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=1744110278; cv=none; b=ObMAHpL5PYOFKsjAo7jk6hSt2kfQ2NtEKjMyoec1v0NBf030XVjQWXUFs/KNIEt2+cpu37RZ8qK41UBGcVw/++xgbfZbZ5AYH5AljCQ8dSccHHapzUg6iH5OyAwuYl3wlgKAFvZAS80l2fw+EYs4nurf+HqGpfm4Ce4Ck3gUP7M= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1744110278; c=relaxed/simple; bh=V/oo2uwKf8sCNEb0uaUBY5qDW6enNH/jt/5ypBnxfzE=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=De2EjbXVxBlUP3u42mIcAPu/1/zT5h0WPvjnm8KQJTfmh/hEGcxJEOYxddYuyaOBDPBsqW73Nu7Xhvjy2EutKOxVit8m4jxPDTs9Dz3cT0CanquzgMDX17itqLeHxEFqGb3lp2mY56liC/F+8esHAbCcUGvta2lJXQ0IFCWOTBY= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=IbrEx/Dg; 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="IbrEx/Dg" Received: by smtp.kernel.org (Postfix) with ESMTPSA id B5C45C4CEE5; Tue, 8 Apr 2025 11:04:37 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1744110278; bh=V/oo2uwKf8sCNEb0uaUBY5qDW6enNH/jt/5ypBnxfzE=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=IbrEx/DgtdFtIHfOW2B6IK10x3Frbl2G4XRxfJtx+SVf1xhDPbz31wEoYB1NCJz3N ehwL4QhRJUK8JU8vUXfS6YtjLGqMPoOyC8EyIYwwMjaeAF5FwcPiIrdKsyDY00c5os osParWlJiEw2Lgzd8L/ONWmMhEccUWKFFg49m6Io= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Masami Hiramatsu , Mathieu Desnoyers , Zheng Yejian , Kairui Song , Tengda Wu , "Steven Rostedt (Google)" Subject: [PATCH 5.10 218/227] tracing: Fix use-after-free in print_graph_function_flags during tracer switching Date: Tue, 8 Apr 2025 12:49:56 +0200 Message-ID: <20250408104826.843968819@linuxfoundation.org> X-Mailer: git-send-email 2.49.0 In-Reply-To: <20250408104820.353768086@linuxfoundation.org> References: <20250408104820.353768086@linuxfoundation.org> User-Agent: quilt/0.68 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev 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: Tengda Wu commit 7f81f27b1093e4895e87b74143c59c055c3b1906 upstream. Kairui reported a UAF issue in print_graph_function_flags() during ftrace stress testing [1]. This issue can be reproduced if puting a 'mdelay(10)' after 'mutex_unlock(&trace_types_lock)' in s_start(), and executing the following script: $ echo function_graph > current_tracer $ cat trace > /dev/null & $ sleep 5 # Ensure the 'cat' reaches the 'mdelay(10)' point $ echo timerlat > current_tracer The root cause lies in the two calls to print_graph_function_flags within print_trace_line during each s_show(): * One through 'iter->trace->print_line()'; * Another through 'event->funcs->trace()', which is hidden in print_trace_fmt() before print_trace_line returns. Tracer switching only updates the former, while the latter continues to use the print_line function of the old tracer, which in the script above is print_graph_function_flags. Moreover, when switching from the 'function_graph' tracer to the 'timerlat' tracer, s_start only calls graph_trace_close of the 'function_graph' tracer to free 'iter->private', but does not set it to NULL. This provides an opportunity for 'event->funcs->trace()' to use an invalid 'iter->private'. To fix this issue, set 'iter->private' to NULL immediately after freeing it in graph_trace_close(), ensuring that an invalid pointer is not passed to other tracers. Additionally, clean up the unnecessary 'iter->private = NULL' during each 'cat trace' when using wakeup and irqsoff tracers. [1] https://lore.kernel.org/all/20231112150030.84609-1-ryncsn@gmail.com/ Cc: stable@vger.kernel.org Cc: Masami Hiramatsu Cc: Mathieu Desnoyers Cc: Zheng Yejian Link: https://lore.kernel.org/20250320122137.23635-1-wutengda@huaweicloud.com Fixes: eecb91b9f98d ("tracing: Fix memleak due to race between current_tracer and trace") Closes: https://lore.kernel.org/all/CAMgjq7BW79KDSCyp+tZHjShSzHsScSiJxn5ffskp-QzVM06fxw@mail.gmail.com/ Reported-by: Kairui Song Signed-off-by: Tengda Wu Signed-off-by: Steven Rostedt (Google) Signed-off-by: Greg Kroah-Hartman --- kernel/trace/trace_functions_graph.c | 1 + kernel/trace/trace_irqsoff.c | 2 -- kernel/trace/trace_sched_wakeup.c | 2 -- 3 files changed, 1 insertion(+), 4 deletions(-) --- a/kernel/trace/trace_functions_graph.c +++ b/kernel/trace/trace_functions_graph.c @@ -1246,6 +1246,7 @@ void graph_trace_close(struct trace_iter if (data) { free_percpu(data->cpu_data); kfree(data); + iter->private = NULL; } } --- a/kernel/trace/trace_irqsoff.c +++ b/kernel/trace/trace_irqsoff.c @@ -228,8 +228,6 @@ static void irqsoff_trace_open(struct tr { if (is_graph(iter->tr)) graph_trace_open(iter); - else - iter->private = NULL; } static void irqsoff_trace_close(struct trace_iterator *iter) --- a/kernel/trace/trace_sched_wakeup.c +++ b/kernel/trace/trace_sched_wakeup.c @@ -171,8 +171,6 @@ static void wakeup_trace_open(struct tra { if (is_graph(iter->tr)) graph_trace_open(iter); - else - iter->private = NULL; } static void wakeup_trace_close(struct trace_iterator *iter)