linux-kernel - [PATCH v1] ipmi: use %*ph to print small buffer

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Date:   Fri, 11 Oct 2019 17:52:13 +0300
From:   Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
To:     Corey Minyard <minyard@....org>,
        openipmi-developer@...ts.sourceforge.net,
        linux-kernel@...r.kernel.org
Cc:     Andy Shevchenko <andy.shevchenko@...il.com>,
        Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
Subject: [PATCH v1] ipmi: use %*ph to print small buffer

From: Andy Shevchenko <andy.shevchenko@...il.com>

Use %*ph format to print small buffer as hex string.

The change is safe since the specifier can handle up to 64 bytes and taking
into account the buffer size of 100 bytes on stack the function has never been
used to dump more than 32 bytes. Note, this also avoids potential buffer
overflow if the length of the input buffer is bigger.

Signed-off-by: Andy Shevchenko <andy.shevchenko@...il.com>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
---
 drivers/char/ipmi/ipmi_msghandler.c | 9 +--------
 1 file changed, 1 insertion(+), 8 deletions(-)

diff --git a/drivers/char/ipmi/ipmi_msghandler.c b/drivers/char/ipmi/ipmi_msghandler.c
index 2aab80e19ae0..d0cefd95fa57 100644
--- a/drivers/char/ipmi/ipmi_msghandler.c
+++ b/drivers/char/ipmi/ipmi_msghandler.c
@@ -48,14 +48,7 @@ static int handle_one_recv_msg(struct ipmi_smi *intf,
 static void ipmi_debug_msg(const char *title, unsigned char *data,
 			   unsigned int len)
 {
-	int i, pos;
-	char buf[100];
-
-	pos = snprintf(buf, sizeof(buf), "%s: ", title);
-	for (i = 0; i < len; i++)
-		pos += snprintf(buf + pos, sizeof(buf) - pos,
-				" %2.2x", data[i]);
-	pr_debug("%s\n", buf);
+	pr_debug("%s: %*ph\n", title, len, buf);
 }
 #else
 static void ipmi_debug_msg(const char *title, unsigned char *data,
-- 
2.23.0