linux-kernel - [PATCH AUTOSEL 5.15 10/10] net: hns3: fix strncpy() not using dest-buf length as length issue

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Message-Id: <20230709151528.513775-10-sashal@kernel.org>
Date:   Sun,  9 Jul 2023 11:15:28 -0400
From:   Sasha Levin <sashal@...nel.org>
To:     linux-kernel@...r.kernel.org, stable@...r.kernel.org
Cc:     Hao Chen <chenhao418@...wei.com>,
        kernel test robot <lkp@...el.com>,
        Hao Lan <lanhao@...wei.com>, Paolo Abeni <pabeni@...hat.com>,
        Sasha Levin <sashal@...nel.org>, yisen.zhuang@...wei.com,
        salil.mehta@...wei.com, davem@...emloft.net, edumazet@...gle.com,
        kuba@...nel.org, guoren@...nel.org, huangguangbin2@...wei.com,
        netdev@...r.kernel.org, linux-csky@...r.kernel.org
Subject: [PATCH AUTOSEL 5.15 10/10] net: hns3: fix strncpy() not using dest-buf length as length issue

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

[ Upstream commit 1cf3d5567f273a8746d1bade00633a93204f80f0 ]

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>
Signed-off-by: Paolo Abeni <pabeni@...hat.com>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
 .../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 3158c08a3aa9c..ff931b8ef569e 100644
--- a/drivers/net/ethernet/hisilicon/hns3/hns3_debugfs.c
+++ b/drivers/net/ethernet/hisilicon/hns3/hns3_debugfs.c
@@ -388,19 +388,36 @@ 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 9cda8b3562b89..9d064efdfd59f 100644
--- a/drivers/net/ethernet/hisilicon/hns3/hns3pf/hclge_debugfs.c
+++ b/drivers/net/ethernet/hisilicon/hns3/hns3pf/hclge_debugfs.c
@@ -81,16 +81,35 @@ 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';
-- 
2.39.2