linux-kernel - [PATCH] tracing: Fix strncpy warning in trace_events

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [day] [month] [year] [list]

Message-ID: <77deca8cbfd226981b3f1eab203967381e9b5bd9.camel@kernel.org>
Date:   Thu, 10 Mar 2022 11:17:07 -0600
From:   Tom Zanussi <zanussi@...nel.org>
To:     Steven Rostedt <rostedt@...dmis.org>
Cc:     kernel test robot <lkp@...el.com>, kbuild-all@...ts.01.org,
        Linux Memory Management List <linux-mm@...ck.org>,
        linux-kernel@...r.kernel.org
Subject: [PATCH] tracing: Fix strncpy warning in trace_events_synth.c

0-day reported the strncpy error below:

../kernel/trace/trace_events_synth.c: In function 'last_cmd_set':
../kernel/trace/trace_events_synth.c:65:9: warning: 'strncpy' specified bound depends on the length o\
f the source argument [-Wstringop-truncation]
   65 |         strncpy(last_cmd, str, strlen(str) + 1);
      |         ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
../kernel/trace/trace_events_synth.c:65:32: note: length computed here
   65 |         strncpy(last_cmd, str, strlen(str) + 1);
      |                                ^~~~~~~~~~~

There's no reason to use strncpy here, in fact there's no reason to do
anything but a simple kstrdup() (note we don't even need to check for
failure since last_cmod is expected to be either the last cmd string
or NULL, and the containing function is a void return).

Fixes: 27c888da9867 ("tracing: Remove size restriction on synthetic event cmd error logging")

Reported-by: kernel test robot <lkp@...el.com>
Signed-off-by: Tom Zanussi <zanussi@...nel.org>
---
 kernel/trace/trace_events_synth.c | 5 +----
 1 file changed, 1 insertion(+), 4 deletions(-)

diff --git a/kernel/trace/trace_events_synth.c b/kernel/trace/trace_events_synth.c
index fdd79e07e2fc..5e8c07aef071 100644
--- a/kernel/trace/trace_events_synth.c
+++ b/kernel/trace/trace_events_synth.c
@@ -58,11 +58,8 @@ static void last_cmd_set(const char *str)
 		return;
 
 	kfree(last_cmd);
-	last_cmd = kzalloc(strlen(str) + 1, GFP_KERNEL);
-	if (!last_cmd)
-		return;
 
-	strncpy(last_cmd, str, strlen(str) + 1);
+	last_cmd = kstrdup(str, GFP_KERNEL);
 }
 
 static void synth_err(u8 err_type, u16 err_pos)
-- 
2.17.1