From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from relay.hostedemail.com (smtprelay0017.hostedemail.com [216.40.44.17]) (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 3F8172FE580; Tue, 12 Aug 2025 18:37:29 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=216.40.44.17 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1755023853; cv=none; b=e7wZFjwt/MiBfOemXG6SXOz48k65430VhBUF612L9cSYWhKNZA5iSIdRvQ/0h9gExpo47qa6pOB5Y8gvMxwynsFAYOiY+77gkPADKDcNMZbd0AshuKrybP/2KDV0+ZaP6nES1whw20NCGe2kWbM8Y0uNEuwdcTmgh8Lv8jrODxM= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1755023853; c=relaxed/simple; bh=xdyl3wNJUL9EHqqJro185lpBfTTfmDjVvZZoTQKXqtI=; h=Date:From:To:Cc:Subject:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=tv420E5XnKCdg/hmzUbvxg3wSruqM3ZSu4Fm1ukOwTq8gGL3NiU3jZyQ6b5DQwaD08r34pHx8Sj6TyjFFCOvjcwofofVrUrT1CLcPf0xtMSEKshJH0aUG5jiiM0XITBlIX4jks0tsNlwopcgDHVpUSHG+RMz3LBdNBcVJ6QHkfw= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=goodmis.org; spf=pass smtp.mailfrom=goodmis.org; arc=none smtp.client-ip=216.40.44.17 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=goodmis.org Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=goodmis.org Received: from omf06.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay10.hostedemail.com (Postfix) with ESMTP id E0AA1C0162; Tue, 12 Aug 2025 18:37:28 +0000 (UTC) Received: from [HIDDEN] (Authenticated sender: rostedt@goodmis.org) by omf06.hostedemail.com (Postfix) with ESMTPA id 1B4A82000E; Tue, 12 Aug 2025 18:37:27 +0000 (UTC) Date: Tue, 12 Aug 2025 14:38:12 -0400 From: Steven Rostedt To: Pu Lehui Cc: mhiramat@kernel.org, mathieu.desnoyers@efficios.com, linux-kernel@vger.kernel.org, linux-trace-kernel@vger.kernel.org, pulehui@huawei.com Subject: Re: [PATCH v2] tracing: Limit access to parser->buffer when trace_get_user failed Message-ID: <20250812143812.3df42a3c@gandalf.local.home> In-Reply-To: <20250806070109.1320165-1-pulehui@huaweicloud.com> References: <20250806070109.1320165-1-pulehui@huaweicloud.com> X-Mailer: Claws Mail 3.20.0git84 (GTK+ 2.24.33; x86_64-pc-linux-gnu) Precedence: bulk X-Mailing-List: linux-trace-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-Stat-Signature: 5a185amd6tbuffwtnkh7ciux83yz84x3 X-Rspamd-Server: rspamout01 X-Rspamd-Queue-Id: 1B4A82000E X-Session-Marker: 726F737465647440676F6F646D69732E6F7267 X-Session-ID: U2FsdGVkX18gcOGu3+FY9SK9Wp/5BgUn63hPXMMlCoQ= X-HE-Tag: 1755023847-742556 X-HE-Meta: U2FsdGVkX18vGft3o/UTStQhqbdctPJOfkt53+XA2AoFDMHSNw23K2lfAkeTyB5Q7I22VVi49E9cKnZP5TImEQ567G1V/qx3WIjQ1fE0oD4O4DpSMT6VnHNG55qe1mvT/GwO+wTemynh7DKcKPkKNbvQtEV7c/mWxNQH5IqqdQkpCJV2gjNnrpOu81K/nNEXGMLuZ7OKtJyAsivzk62pxGwAVGVp7YS/8fB222T0FqFi9NVSJ8XmEtHUING/k3aA/S7283Kjw3KvPc3ylfYzPTQ/6ZVixjQjsUfkAbO0AN/n4YecKlkxqy+iEYU9sVHqy92w4YXUd3SMwZzLIH19KVziwM3df7IH On Wed, 6 Aug 2025 07:01:09 +0000 Pu Lehui wrote: > diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c > index 4283ed4e8f59..138212f4ecde 100644 > --- a/kernel/trace/trace.c > +++ b/kernel/trace/trace.c > @@ -1814,9 +1814,11 @@ int trace_get_user(struct trace_parser *parser, const char __user *ubuf, > if (!*ppos) > trace_parser_clear(parser); > > + parser->fail = false; This should be set when the parser is initialized. > + > ret = get_user(ch, ubuf++); > if (ret) > - return ret; > + goto fail; > > read++; > cnt--; > @@ -1830,7 +1832,7 @@ int trace_get_user(struct trace_parser *parser, const char __user *ubuf, > while (cnt && isspace(ch)) { > ret = get_user(ch, ubuf++); > if (ret) > - return ret; > + goto fail; > read++; > cnt--; > } > @@ -1848,12 +1850,14 @@ int trace_get_user(struct trace_parser *parser, const char __user *ubuf, > 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--; > } > @@ -1868,11 +1872,15 @@ int trace_get_user(struct trace_parser *parser, const char __user *ubuf, > /* 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: > + parser->fail = true; Should have a helper function called: trace_parser_fail(parser) and use that. -- Steve > + return ret; > } > > /* TODO add a seq_buf_to_buffer() */ > diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h > index 1dbf1d3cf2f1..5072bb25a860 100644 > --- a/kernel/trace/trace.h > +++ b/kernel/trace/trace.h > @@ -1292,6 +1292,7 @@ bool ftrace_event_is_function(struct trace_event_call *call); > */ > 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)