[PATCH v1 2/4] lib/net_utils: Introduce mac_pton_from_user()

[Andy Shevchenko]

Some drivers are getting MAC from user space. Make a helper for them.

Signed-off-by: Andy Shevchenko <andriy.shevchenko at linux.intel.com>
---
 include/linux/kernel.h |  1 +
 lib/net_utils.c        | 12 ++++++++++++
 2 files changed, 13 insertions(+)

diff --git a/include/linux/kernel.h b/include/linux/kernel.h
index ce51455e2adf..e203b313608d 100644
--- a/include/linux/kernel.h
+++ b/include/linux/kernel.h
@@ -587,6 +587,7 @@ extern int __must_check hex2bin(u8 *dst, const char *src, size_t count);
 extern char *bin2hex(char *dst, const void *src, size_t count);
 
 bool mac_pton(const char *s, u8 *mac);
+int __must_check mac_pton_from_user(const char __user *s, size_t count, u8 *mac);
 
 /*
  * General tracing related utility functions - trace_printk(),
diff --git a/lib/net_utils.c b/lib/net_utils.c
index d32c6961fe0f..7be3483aece6 100644
--- a/lib/net_utils.c
+++ b/lib/net_utils.c
@@ -3,6 +3,7 @@
 #include <linux/if_ether.h>
 #include <linux/ctype.h>
 #include <linux/kernel.h>
+#include <linux/uaccess.h>
 
 #define MAC_PTON_MINLEN		(3 * ETH_ALEN - 1)
 
@@ -27,3 +28,14 @@ bool mac_pton(const char *s, u8 *mac)
 	return true;
 }
 EXPORT_SYMBOL(mac_pton);
+
+int mac_pton_from_user(const char __user *s, size_t count, u8 *mac)
+{
+	char buf[MAC_PTON_MINLEN];
+
+	count = min(count, sizeof(buf));
+	if (copy_from_user(buf, s, count))
+		return -EFAULT;
+	return mac_pton(buf, mac) ? 0 : -EINVAL;
+}
+EXPORT_SYMBOL(mac_pton_from_user);
-- 
2.15.1