net: use scnprintf() to avoid potential buffer overflow

strlcpy() returns the total length of the string they tried to create, so
we should not use its return value without any check. scnprintf() returns
the number of characters written into @buf not including the trailing '\0',
so use it instead here.

Signed-off-by: Changli Gao <xiaosuo@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Changli Gao 2010-08-24 13:32:58 +00:00 committed by David S. Miller
parent 145ce502e4
commit 53f91dc1f7

View File

@ -367,7 +367,7 @@ struct net_device *alloc_etherdev_mq(int sizeof_priv, unsigned int queue_count)
EXPORT_SYMBOL(alloc_etherdev_mq);
static size_t _format_mac_addr(char *buf, int buflen,
const unsigned char *addr, int len)
const unsigned char *addr, int len)
{
int i;
char *cp = buf;
@ -376,7 +376,7 @@ static size_t _format_mac_addr(char *buf, int buflen,
cp += scnprintf(cp, buflen - (cp - buf), "%02x", addr[i]);
if (i == len - 1)
break;
cp += strlcpy(cp, ":", buflen - (cp - buf));
cp += scnprintf(cp, buflen - (cp - buf), ":");
}
return cp - buf;
}
@ -386,7 +386,7 @@ ssize_t sysfs_format_mac(char *buf, const unsigned char *addr, int len)
size_t l;
l = _format_mac_addr(buf, PAGE_SIZE, addr, len);
l += strlcpy(buf + l, "\n", PAGE_SIZE - l);
l += scnprintf(buf + l, PAGE_SIZE - l, "\n");
return ((ssize_t) l);
}
EXPORT_SYMBOL(sysfs_format_mac);