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 A6E5B2BEFE3; Tue, 26 Aug 2025 11:30:12 +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=1756207812; cv=none; b=e77CIUYtbITTz3GLX2wnWFRkUqEQ7JaCvHOWP7wa65oeIeLnaV2zEcw3kvmzPaAZih8jD+j/+dRUDGaBs6tXPGWZTuMOo2RMmyANO3AK/w+r6FXE+K9O5rTVG2UwiBFX6xgMDS/J7izGMXUVWLkH+1F9ZkC+il98mxnEUc+R+Cw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1756207812; c=relaxed/simple; bh=OTWKgj9hnP2mRnUON06KuAs849OTiJXBzh5dTLeRvwo=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=E+pcVOHHinvmDw92G2A+QiIgVJrVPvjsRbrxcS9gdazLN8Q+9lVMCa6n0+4q2lY4Z04thQfzp7rsYG48MUFv+RWTRNOsjMId70F3yXivuzcnrKZRMAJZiE1znRL5HdfsiTu+psV7g9C09ewMOdpPermsXBe8aQRR5Qx50PGT8QE= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=dk+wosTA; 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="dk+wosTA" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 3FF27C4CEF1; Tue, 26 Aug 2025 11:30:12 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1756207812; bh=OTWKgj9hnP2mRnUON06KuAs849OTiJXBzh5dTLeRvwo=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=dk+wosTAi58t4t46kVPRo4dvGvF05nvpoNsK0ZQjgsbyV61IWhP/NcTStaqjiuu0F bi1jme0nLTZVqAlfm/uGS9eRaDOgyuO0xMNgDKmZTnVXm+dMODWGKv6Q7vbLjrLt0T lLhaYlnQFRC24Cxly/zWZpeFIQEAkXq72NAmsIaM= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Pu Lehui , "Steven Rostedt (Google)" , Sasha Levin Subject: [PATCH 6.16 327/457] tracing: Limit access to parser->buffer when trace_get_user failed Date: Tue, 26 Aug 2025 13:10:11 +0200 Message-ID: <20250826110945.426909244@linuxfoundation.org> X-Mailer: git-send-email 2.50.1 In-Reply-To: <20250826110937.289866482@linuxfoundation.org> References: <20250826110937.289866482@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 6.16-stable review patch. If anyone has any objections, please let me know. ------------------ From: Pu Lehui [ Upstream commit 6a909ea83f226803ea0e718f6e88613df9234d58 ] When the length of the string written to set_ftrace_filter exceeds FTRACE_BUFF_MAX, the following KASAN alarm will be triggered: BUG: KASAN: slab-out-of-bounds in strsep+0x18c/0x1b0 Read of size 1 at addr ffff0000d00bd5ba by task ash/165 CPU: 1 UID: 0 PID: 165 Comm: ash Not tainted 6.16.0-g6bcdbd62bd56-dirty Hardware name: linux,dummy-virt (DT) Call trace: show_stack+0x34/0x50 (C) dump_stack_lvl+0xa0/0x158 print_address_description.constprop.0+0x88/0x398 print_report+0xb0/0x280 kasan_report+0xa4/0xf0 __asan_report_load1_noabort+0x20/0x30 strsep+0x18c/0x1b0 ftrace_process_regex.isra.0+0x100/0x2d8 ftrace_regex_release+0x484/0x618 __fput+0x364/0xa58 ____fput+0x28/0x40 task_work_run+0x154/0x278 do_notify_resume+0x1f0/0x220 el0_svc+0xec/0xf0 el0t_64_sync_handler+0xa0/0xe8 el0t_64_sync+0x1ac/0x1b0 The reason is that trace_get_user will fail when processing a string longer than FTRACE_BUFF_MAX, but not set the end of parser->buffer to 0. Then an OOB access will be triggered in ftrace_regex_release-> ftrace_process_regex->strsep->strpbrk. We can solve this problem by limiting access to parser->buffer when trace_get_user failed. Cc: stable@vger.kernel.org Link: https://lore.kernel.org/20250813040232.1344527-1-pulehui@huaweicloud.com Fixes: 8c9af478c06b ("ftrace: Handle commands when closing set_ftrace_filter file") Signed-off-by: Pu Lehui Signed-off-by: Steven Rostedt (Google) Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman --- kernel/trace/trace.c | 18 ++++++++++++------ kernel/trace/trace.h | 8 +++++++- 2 files changed, 19 insertions(+), 7 deletions(-) --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -1846,7 +1846,7 @@ int trace_get_user(struct trace_parser * ret = get_user(ch, ubuf++); if (ret) - return ret; + goto fail; read++; cnt--; @@ -1860,7 +1860,7 @@ int trace_get_user(struct trace_parser * while (cnt && isspace(ch)) { ret = get_user(ch, ubuf++); if (ret) - return ret; + goto fail; read++; cnt--; } @@ -1878,12 +1878,14 @@ int trace_get_user(struct trace_parser * while (cnt && !isspace(ch) && ch) { if (parser->idx < parser->size - 1) parser->buffer[parser->idx++] = ch; - else - return -EINVAL; + else { + ret = -EINVAL; + goto fail; + } ret = get_user(ch, ubuf++); if (ret) - return ret; + goto fail; read++; cnt--; } @@ -1898,11 +1900,15 @@ int trace_get_user(struct trace_parser * /* Make sure the parsed string always terminates with '\0'. */ parser->buffer[parser->idx] = 0; } else { - return -EINVAL; + ret = -EINVAL; + goto fail; } *ppos += read; return read; +fail: + trace_parser_fail(parser); + return ret; } /* TODO add a seq_buf_to_buffer() */ --- a/kernel/trace/trace.h +++ b/kernel/trace/trace.h @@ -1292,6 +1292,7 @@ bool ftrace_event_is_function(struct tra */ struct trace_parser { bool cont; + bool fail; char *buffer; unsigned idx; unsigned size; @@ -1299,7 +1300,7 @@ struct trace_parser { static inline bool trace_parser_loaded(struct trace_parser *parser) { - return (parser->idx != 0); + return !parser->fail && parser->idx != 0; } static inline bool trace_parser_cont(struct trace_parser *parser) @@ -1313,6 +1314,11 @@ static inline void trace_parser_clear(st parser->idx = 0; } +static inline void trace_parser_fail(struct trace_parser *parser) +{ + parser->fail = true; +} + extern int trace_parser_get_init(struct trace_parser *parser, int size); extern void trace_parser_put(struct trace_parser *parser); extern int trace_get_user(struct trace_parser *parser, const char __user *ubuf,