netdev - [PATCH net-next v3 2/3] net: hns3: fix strncpy() not using dest-buf length as length issue

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Message-ID: <20230621123309.34381-3-lanhao@huawei.com>
Date: Wed, 21 Jun 2023 20:33:08 +0800
From: Hao Lan <lanhao@...wei.com>
To: <netdev@...r.kernel.org>
CC: <yisen.zhuang@...wei.com>, <salil.mehta@...wei.com>,
	<davem@...emloft.net>, <edumazet@...gle.com>, <kuba@...nel.org>,
	<pabeni@...hat.com>, <richardcochran@...il.com>, <lanhao@...wei.com>,
	<wangpeiyang1@...wei.com>, <shenjian15@...wei.com>, <chenhao418@...wei.com>,
	<simon.horman@...igine.com>, <wangjie125@...wei.com>, <yuanjilin@...rlc.com>,
	<cai.huoqing@...ux.dev>, <xiujianfeng@...wei.com>
Subject: [PATCH net-next v3 2/3] net: hns3: fix strncpy() not using dest-buf length as length issue

From: Hao Chen <chenhao418@...wei.com>

Now, strncpy() in hns3_dbg_fill_content() use src-length as copy-length,
it may result in dest-buf overflow.

This patch is to fix intel compile warning for csky-linux-gcc (GCC) 12.1.0
compiler.

The warning reports as below:

hclge_debugfs.c:92:25: warning: 'strncpy' specified bound depends on
the length of the source argument [-Wstringop-truncation]

strncpy(pos, items[i].name, strlen(items[i].name));

hclge_debugfs.c:90:25: warning: 'strncpy' output truncated before
terminating nul copying as many bytes from a string as its length
[-Wstringop-truncation]

strncpy(pos, result[i], strlen(result[i]));

strncpy() use src-length as copy-length, it may result in
dest-buf overflow.

So,this patch add some values check to avoid this issue.

Signed-off-by: Hao Chen <chenhao418@...wei.com>
Reported-by: kernel test robot <lkp@...el.com>
Closes: https://lore.kernel.org/lkml/202207170606.7WtHs9yS-lkp@intel.com/T/
Signed-off-by: Hao Lan <lanhao@...wei.com>
---
ChangeLog:
v2-v3:
Use strscpy instead of strncpy
suggested by Paolo Abeni.
v1->v2:
Use strcpy substitutes for memcpy
suggested by Simon Horman.
---
 .../ethernet/hisilicon/hns3/hns3_debugfs.c    | 31 ++++++++++++++-----
 .../hisilicon/hns3/hns3pf/hclge_debugfs.c     | 29 ++++++++++++++---
 2 files changed, 48 insertions(+), 12 deletions(-)

diff --git a/drivers/net/ethernet/hisilicon/hns3/hns3_debugfs.c b/drivers/net/ethernet/hisilicon/hns3/hns3_debugfs.c
index d385ffc21876..32bb14303473 100644
--- a/drivers/net/ethernet/hisilicon/hns3/hns3_debugfs.c
+++ b/drivers/net/ethernet/hisilicon/hns3/hns3_debugfs.c
@@ -438,19 +438,36 @@ static void hns3_dbg_fill_content(char *content, u16 len,
 				  const struct hns3_dbg_item *items,
 				  const char **result, u16 size)
 {
+#define HNS3_DBG_LINE_END_LEN	2
 	char *pos = content;
+	u16 item_len;
 	u16 i;
 
+	if (!len) {
+		return;
+	} else if (len <= HNS3_DBG_LINE_END_LEN) {
+		*pos++ = '\0';
+		return;
+	}
+
 	memset(content, ' ', len);
-	for (i = 0; i < size; i++) {
-		if (result)
-			strncpy(pos, result[i], strlen(result[i]));
-		else
-			strncpy(pos, items[i].name, strlen(items[i].name));
+	len -= HNS3_DBG_LINE_END_LEN;
 
-		pos += strlen(items[i].name) + items[i].interval;
+	for (i = 0; i < size; i++) {
+		item_len = strlen(items[i].name) + items[i].interval;
+		if (len < item_len)
+			break;
+
+		if (result) {
+			if (item_len < strlen(result[i]))
+				break;
+			strscpy(pos, result[i], strlen(result[i]));
+		} else {
+			strscpy(pos, items[i].name, strlen(items[i].name));
+		}
+		pos += item_len;
+		len -= item_len;
 	}
-
 	*pos++ = '\n';
 	*pos++ = '\0';
 }
diff --git a/drivers/net/ethernet/hisilicon/hns3/hns3pf/hclge_debugfs.c b/drivers/net/ethernet/hisilicon/hns3/hns3pf/hclge_debugfs.c
index a0b46e7d863e..233c132dc513 100644
--- a/drivers/net/ethernet/hisilicon/hns3/hns3pf/hclge_debugfs.c
+++ b/drivers/net/ethernet/hisilicon/hns3/hns3pf/hclge_debugfs.c
@@ -88,16 +88,35 @@ static void hclge_dbg_fill_content(char *content, u16 len,
 				   const struct hclge_dbg_item *items,
 				   const char **result, u16 size)
 {
+#define HCLGE_DBG_LINE_END_LEN	2
 	char *pos = content;
+	u16 item_len;
 	u16 i;
 
+	if (!len) {
+		return;
+	} else if (len <= HCLGE_DBG_LINE_END_LEN) {
+		*pos++ = '\0';
+		return;
+	}
+
 	memset(content, ' ', len);
+	len -= HCLGE_DBG_LINE_END_LEN;
+
 	for (i = 0; i < size; i++) {
-		if (result)
-			strncpy(pos, result[i], strlen(result[i]));
-		else
-			strncpy(pos, items[i].name, strlen(items[i].name));
-		pos += strlen(items[i].name) + items[i].interval;
+		item_len = strlen(items[i].name) + items[i].interval;
+		if (len < item_len)
+			break;
+
+		if (result) {
+			if (item_len < strlen(result[i]))
+				break;
+			strscpy(pos, result[i], strlen(result[i]));
+		} else {
+			strscpy(pos, items[i].name, strlen(items[i].name));
+		}
+		pos += item_len;
+		len -= item_len;
 	}
 	*pos++ = '\n';
 	*pos++ = '\0';
-- 
2.30.0