linux-kernel - [patch] mfd: snprintf() returns largish values

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Message-ID: <20100812075009.GK645@bicker>
Date:	Thu, 12 Aug 2010 09:50:09 +0200
From:	Dan Carpenter <error27@...il.com>
To:	Feng Tang <feng.tang@...el.com>
Cc:	Greg Kroah-Hartman <gregkh@...e.de>,
	Alan Cox <alan@...ux.intel.com>, linux-kernel@...r.kernel.org,
	kernel-janitors@...r.kernel.org
Subject: [patch] mfd: snprintf() returns largish values

snprintf() returns the number of bytes which would have been written so
it can be larger than the size of the buffer.  In this case it's fine,
but people copy and paste this code so I've fixed it.

Signed-off-by: Dan Carpenter <error27@...il.com>

diff --git a/drivers/serial/mfd.c b/drivers/serial/mfd.c
index bc9af50..5aa25e5 100644
--- a/drivers/serial/mfd.c
+++ b/drivers/serial/mfd.c
@@ -171,6 +171,9 @@ static ssize_t port_show_regs(struct file *file, char __user *user_buf,
 	len += snprintf(buf + len, HSU_REGS_BUFSIZE - len,
 			"DIV: \t\t0x%08x\n", serial_in(up, UART_DIV));
 
+	if (len > HSU_REGS_BUFSIZE)
+		len = HSU_REGS_BUFSIZE;
+
 	ret =  simple_read_from_buffer(user_buf, count, ppos, buf, len);
 	kfree(buf);
 	return ret;
@@ -218,6 +221,9 @@ static ssize_t dma_show_regs(struct file *file, char __user *user_buf,
 	len += snprintf(buf + len, HSU_REGS_BUFSIZE - len,
 			"D0TSR: \t\t0x%08x\n", chan_readl(chan, HSU_CH_D3TSR));
 
+	if (len > HSU_REGS_BUFSIZE)
+		len = HSU_REGS_BUFSIZE;
+
 	ret =  simple_read_from_buffer(user_buf, count, ppos, buf, len);
 	kfree(buf);
 	return ret;
--
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