[PATCH] net/mana: use %m for fscanf to read mac address

[longli@linuxonhyperv.com]

From: Long Li <longli@microsoft.com>

Use %m through fscanf to allocate mac dynamically is safer than using
mac[20], this guarantees there is no overflow on mac[].

Signed-off-by: Long Li <longli@microsoft.com>
---
 drivers/net/mana/mana.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/drivers/net/mana/mana.c b/drivers/net/mana/mana.c
index f1fdcf426a..28d8f5b23e 100644
--- a/drivers/net/mana/mana.c
+++ b/drivers/net/mana/mana.c
@@ -914,7 +914,6 @@ get_port_mac(struct ibv_device *device, unsigned int port,
 	DIR *dir;
 	struct dirent *dent;
 	unsigned int dev_port;
-	char mac[20];
 
 	MANA_MKSTR(path, "%s/device/net", device->ibdev_path);
 
@@ -924,6 +923,7 @@ get_port_mac(struct ibv_device *device, unsigned int port,
 
 	while ((dent = readdir(dir))) {
 		char *name = dent->d_name;
+		char *mac = NULL;
 
 		MANA_MKSTR(port_path, "%s/%s/dev_port", path, name);
 
@@ -951,7 +951,7 @@ get_port_mac(struct ibv_device *device, unsigned int port,
 			if (!file)
 				continue;
 
-			ret = fscanf(file, "%s", mac);
+			ret = fscanf(file, "%ms", &mac);
 			fclose(file);
 
 			if (ret < 0)
@@ -960,6 +960,8 @@ get_port_mac(struct ibv_device *device, unsigned int port,
 			ret = rte_ether_unformat_addr(mac, addr);
 			if (ret)
 				DRV_LOG(ERR, "unrecognized mac addr %s", mac);
+
+			free(mac);
 			break;
 		}
 	}
-- 
2.34.1