linux-kernel - [PATCH] blktrace: fix a bug in blk_msg

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-next>] [day] [month] [year] [list]

Message-ID: <49D5BB56.7000807@cn.fujitsu.com>
Date:	Fri, 03 Apr 2009 15:31:34 +0800
From:	Li Zefan <lizf@...fujitsu.com>
To:	Ingo Molnar <mingo@...e.hu>, Jens Axboe <jens.axboe@...cle.com>
CC:	Arnaldo Carvalho de Melo <acme@...hat.com>,
	"Alan D. Brunelle" <alan.brunelle@...com>,
	LKML <linux-kernel@...r.kernel.org>
Subject: [PATCH] blktrace: fix a bug in blk_msg_write()

This is another long-standing bug.


================


 (console 1)
 # echo -n 'a' > /sys/kernel/debug/block/sda/msg
 (console 2)
 # blktrace -d /dev/sda -a pc -o - | blkparse -i -
  8,0    0        0     0.000000000     0  m   N a������@��

We should terminate the msg buffer with '\0'.

Signed-off-by: Li Zefan <lizf@...fujitsu.com>
---
 kernel/trace/blktrace.c |    5 +++--
 1 files changed, 3 insertions(+), 2 deletions(-)

diff --git a/kernel/trace/blktrace.c b/kernel/trace/blktrace.c
index c0ef70d..2bf341f 100644
--- a/kernel/trace/blktrace.c
+++ b/kernel/trace/blktrace.c
@@ -327,10 +327,10 @@ static ssize_t blk_msg_write(struct file *filp, const char __user *buffer,
 	char *msg;
 	struct blk_trace *bt;
 
-	if (count > BLK_TN_MAX_MSG)
+	if (count >= BLK_TN_MAX_MSG)
 		return -EINVAL;
 
-	msg = kmalloc(count, GFP_KERNEL);
+	msg = kmalloc(count + 1, GFP_KERNEL);
 	if (msg == NULL)
 		return -ENOMEM;
 
@@ -338,6 +338,7 @@ static ssize_t blk_msg_write(struct file *filp, const char __user *buffer,
 		kfree(msg);
 		return -EFAULT;
 	}
+	msg[count] = '\0';
 
 	bt = filp->private_data;
 	__trace_note_message(bt, "%s", msg);
-- 
1.5.4.rc3


--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/