patch "test_firmware: Use correct snprintf() limit" added to char-misc-linus

[<gregkh@linuxfoundation.org>]

This is a note to let you know that I've just added the patch titled

    test_firmware: Use correct snprintf() limit

to my char-misc git tree which can be found at
    git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc.git
in the char-misc-linus branch.

The patch will show up in the next release of the linux-next tree
(usually sometime within the next 24 hours during the week.)

The patch will hopefully also be merged in Linus's tree for the
next -rc kernel release.

If you have any questions about this process, please let me know.


From bd17cc5a20ae9aaa3ed775f360b75ff93cd66a1d Mon Sep 17 00:00:00 2001
From: Dan Carpenter <dan.carpenter@oracle.com>
Date: Wed, 15 May 2019 12:33:22 +0300
Subject: test_firmware: Use correct snprintf() limit

The limit here is supposed to be how much of the page is left, but it's
just using PAGE_SIZE as the limit.

The other thing to remember is that snprintf() returns the number of
bytes which would have been copied if we had had enough room.  So that
means that if we run out of space then this code would end up passing a
negative value as the limit and the kernel would print an error message.
I have change the code to use scnprintf() which returns the number of
bytes that were successfully printed (not counting the NUL terminator).

Fixes: c92316bf8e94 ("test_firmware: add batched firmware tests")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 lib/test_firmware.c | 14 +++++++-------
 1 file changed, 7 insertions(+), 7 deletions(-)

diff --git a/lib/test_firmware.c b/lib/test_firmware.c
index 7222093ee00b..b5487ed829d7 100644
--- a/lib/test_firmware.c
+++ b/lib/test_firmware.c
@@ -223,30 +223,30 @@ static ssize_t config_show(struct device *dev,
 
 	mutex_lock(&test_fw_mutex);
 
-	len += snprintf(buf, PAGE_SIZE,
+	len += scnprintf(buf, PAGE_SIZE - len,
 			"Custom trigger configuration for: %s\n",
 			dev_name(dev));
 
 	if (test_fw_config->name)
-		len += snprintf(buf+len, PAGE_SIZE,
+		len += scnprintf(buf+len, PAGE_SIZE - len,
 				"name:\t%s\n",
 				test_fw_config->name);
 	else
-		len += snprintf(buf+len, PAGE_SIZE,
+		len += scnprintf(buf+len, PAGE_SIZE - len,
 				"name:\tEMTPY\n");
 
-	len += snprintf(buf+len, PAGE_SIZE,
+	len += scnprintf(buf+len, PAGE_SIZE - len,
 			"num_requests:\t%u\n", test_fw_config->num_requests);
 
-	len += snprintf(buf+len, PAGE_SIZE,
+	len += scnprintf(buf+len, PAGE_SIZE - len,
 			"send_uevent:\t\t%s\n",
 			test_fw_config->send_uevent ?
 			"FW_ACTION_HOTPLUG" :
 			"FW_ACTION_NOHOTPLUG");
-	len += snprintf(buf+len, PAGE_SIZE,
+	len += scnprintf(buf+len, PAGE_SIZE - len,
 			"sync_direct:\t\t%s\n",
 			test_fw_config->sync_direct ? "true" : "false");
-	len += snprintf(buf+len, PAGE_SIZE,
+	len += scnprintf(buf+len, PAGE_SIZE - len,
 			"read_fw_idx:\t%u\n", test_fw_config->read_fw_idx);
 
 	mutex_unlock(&test_fw_mutex);
-- 
2.21.0