linux-kernel - [PATCH] usb: atm: don't use snprintf() for sysfs attrs

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Date:   Mon, 24 Aug 2020 23:23:20 +0100
From:   Alex Dewar <alex.dewar90@...il.com>
To:     unlisted-recipients:; (no To-header on input)
Cc:     Alex Dewar <alex.dewar90@...il.com>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        "Gustavo A. R. Silva" <gustavoars@...nel.org>,
        accessrunner-general@...ts.sourceforge.net,
        linux-usb@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: [PATCH] usb: atm: don't use snprintf() for sysfs attrs

kernel/cpu.c: don't use snprintf() for sysfs attrs

As per the documentation (Documentation/filesystems/sysfs.rst),
snprintf() should not be used for formatting values returned by sysfs.

In all of these cases, sprintf() suffices as we know that the formatted
strings will be less than PAGE_SIZE in length.

Issue identified by Coccinelle.

Signed-off-by: Alex Dewar <alex.dewar90@...il.com>
---
 drivers/usb/atm/cxacru.c | 27 +++++++++++++--------------
 1 file changed, 13 insertions(+), 14 deletions(-)

diff --git a/drivers/usb/atm/cxacru.c b/drivers/usb/atm/cxacru.c
index ea66f8f385bae..e62a770a5d3bf 100644
--- a/drivers/usb/atm/cxacru.c
+++ b/drivers/usb/atm/cxacru.c
@@ -230,12 +230,12 @@ CXACRU__ATTR_INIT(_name)
 
 static ssize_t cxacru_sysfs_showattr_u32(u32 value, char *buf)
 {
-	return snprintf(buf, PAGE_SIZE, "%u\n", value);
+	return sprintf(buf, "%u\n", value);
 }
 
 static ssize_t cxacru_sysfs_showattr_s8(s8 value, char *buf)
 {
-	return snprintf(buf, PAGE_SIZE, "%d\n", value);
+	return sprintf(buf, "%d\n", value);
 }
 
 static ssize_t cxacru_sysfs_showattr_dB(s16 value, char *buf)
@@ -255,8 +255,8 @@ static ssize_t cxacru_sysfs_showattr_bool(u32 value, char *buf)
 	static char *str[] = { "no", "yes" };
 
 	if (unlikely(value >= ARRAY_SIZE(str)))
-		return snprintf(buf, PAGE_SIZE, "%u\n", value);
-	return snprintf(buf, PAGE_SIZE, "%s\n", str[value]);
+		return sprintf(buf, "%u\n", value);
+	return sprintf(buf, "%s\n", str[value]);
 }
 
 static ssize_t cxacru_sysfs_showattr_LINK(u32 value, char *buf)
@@ -264,8 +264,8 @@ static ssize_t cxacru_sysfs_showattr_LINK(u32 value, char *buf)
 	static char *str[] = { NULL, "not connected", "connected", "lost" };
 
 	if (unlikely(value >= ARRAY_SIZE(str) || str[value] == NULL))
-		return snprintf(buf, PAGE_SIZE, "%u\n", value);
-	return snprintf(buf, PAGE_SIZE, "%s\n", str[value]);
+		return sprintf(buf, "%u\n", value);
+	return sprintf(buf, "%s\n", str[value]);
 }
 
 static ssize_t cxacru_sysfs_showattr_LINE(u32 value, char *buf)
@@ -275,8 +275,8 @@ static ssize_t cxacru_sysfs_showattr_LINE(u32 value, char *buf)
 		"waiting", "initialising"
 	};
 	if (unlikely(value >= ARRAY_SIZE(str)))
-		return snprintf(buf, PAGE_SIZE, "%u\n", value);
-	return snprintf(buf, PAGE_SIZE, "%s\n", str[value]);
+		return sprintf(buf, "%u\n", value);
+	return sprintf(buf, "%s\n", str[value]);
 }
 
 static ssize_t cxacru_sysfs_showattr_MODU(u32 value, char *buf)
@@ -288,8 +288,8 @@ static ssize_t cxacru_sysfs_showattr_MODU(u32 value, char *buf)
 			"ITU-T G.992.2 (G.LITE)"
 	};
 	if (unlikely(value >= ARRAY_SIZE(str)))
-		return snprintf(buf, PAGE_SIZE, "%u\n", value);
-	return snprintf(buf, PAGE_SIZE, "%s\n", str[value]);
+		return sprintf(buf, "%u\n", value);
+	return sprintf(buf, "%s\n", str[value]);
 }
 
 /*
@@ -309,8 +309,7 @@ static ssize_t mac_address_show(struct device *dev,
 	if (instance == NULL || instance->usbatm->atm_dev == NULL)
 		return -ENODEV;
 
-	return snprintf(buf, PAGE_SIZE, "%pM\n",
-		instance->usbatm->atm_dev->esi);
+	return sprintf(buf, "%pM\n", instance->usbatm->atm_dev->esi);
 }
 
 static ssize_t adsl_state_show(struct device *dev,
@@ -326,8 +325,8 @@ static ssize_t adsl_state_show(struct device *dev,
 
 	value = instance->card_info[CXINF_LINE_STARTABLE];
 	if (unlikely(value >= ARRAY_SIZE(str)))
-		return snprintf(buf, PAGE_SIZE, "%u\n", value);
-	return snprintf(buf, PAGE_SIZE, "%s\n", str[value]);
+		return sprintf(buf, "%u\n", value);
+	return sprintf(buf, "%s\n", str[value]);
 }
 
 static ssize_t adsl_state_store(struct device *dev,
-- 
2.28.0