linux-kernel - [PATCH 2/2] tracing: Use strncpy instead of memcpy when copying comm in trace.c

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

Message-Id: <1d6ebac26570c2a29ce9fb575379f17ef5c8b81b.1551802084.git.tom.zanussi@linux.intel.com>
Date:   Tue,  5 Mar 2019 10:12:00 -0600
From:   Tom Zanussi <zanussi@...nel.org>
To:     rostedt@...dmis.org
Cc:     linux-kernel@...r.kernel.org
Subject: [PATCH 2/2] tracing: Use strncpy instead of memcpy when copying comm in trace.c

From: Tom Zanussi <tom.zanussi@...ux.intel.com>

Because there may be random garbage beyond a string's null terminator,
code that might use the entire comm array e.g. histogram keys, can
give unexpected results if that garbage is copied in too, so avoid
that possibility by using strncpy instead of memcpy.

Signed-off-by: Tom Zanussi <tom.zanussi@...ux.intel.com>
Suggested-by: Steven Rostedt (VMware) <rostedt@...dmis.org>
---
 kernel/trace/trace.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index 3835f7ed3293..e9cc47e59d25 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -1497,7 +1497,7 @@ __update_max_tr(struct trace_array *tr, struct task_struct *tsk, int cpu)
 	max_data->critical_start = data->critical_start;
 	max_data->critical_end = data->critical_end;
 
-	memcpy(max_data->comm, tsk->comm, TASK_COMM_LEN);
+	strncpy(max_data->comm, tsk->comm, TASK_COMM_LEN);
 	max_data->pid = tsk->pid;
 	/*
 	 * If tsk == current, then use current_uid(), as that does not use
@@ -1923,7 +1923,7 @@ static inline char *get_saved_cmdlines(int idx)
 
 static inline void set_cmdline(int idx, const char *cmdline)
 {
-	memcpy(get_saved_cmdlines(idx), cmdline, TASK_COMM_LEN);
+	strncpy(get_saved_cmdlines(idx), cmdline, TASK_COMM_LEN);
 }
 
 static int allocate_cmdlines_buffer(unsigned int val,
-- 
2.14.1