From mboxrd@z Thu Jan 1 00:00:00 1970 From: Dan Carpenter Date: Tue, 30 Mar 2010 09:43:42 +0000 Subject: [patch] s390: potential buffer overflow Message-Id: <20100330094342.GJ5069@bicker> List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: Martin Schwidefsky Cc: Heiko Carstens , linux390@de.ibm.com, Hans-Joachim Picht , "Eric W. Biederman" , Sebastian Ott , linux-s390@vger.kernel.org, linux-kernel@vger.kernel.org, kernel-janitors@vger.kernel.org "len" hasn't been properly range checked so we shouldn't use it as an array offset. This can only be written to by root but it would still be annoying to accidentally write more than 3 characters and corrupt your memory. Signed-off-by: Dan Carpenter --- I don't have a cross compile environment to compile this. Sorry. :/ diff --git a/drivers/s390/char/sclp_async.c b/drivers/s390/char/sclp_async.c index f449c69..72c2e90 100644 --- a/drivers/s390/char/sclp_async.c +++ b/drivers/s390/char/sclp_async.c @@ -84,7 +84,7 @@ static int proc_handler_callhome(struct ctl_table *ctl, int write, rc = copy_from_user(buf, buffer, sizeof(buf)); if (rc != 0) return -EFAULT; - buf[len - 1] = '\0'; + buf[sizeof(buf) - 1] = '\0'; if (strict_strtoul(buf, 0, &val) != 0) return -EINVAL; if (val != 0 && val != 1) @@ -99,6 +99,7 @@ static int proc_handler_callhome(struct ctl_table *ctl, int write, static struct ctl_table callhome_table[] = { { .procname = "callhome", + .maxlen = 3, .mode = 0644, .proc_handler = proc_handler_callhome, },