From: Artem Chernyshev <artem.chernyshev@red-soft.ru>
Date: Sat, 19 Nov 2022 08:13:29 +0000 (+0300)
Subject: btrfs: replace strncpy() with strscpy()
X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=63d5429f68a3d4c4aa27e65a05196c17f86c41d6;p=linux.git

btrfs: replace strncpy() with strscpy()

Using strncpy() on NUL-terminated strings are deprecated.  To avoid
possible forming of non-terminated string strscpy() should be used.

Found by Linux Verification Center (linuxtesting.org) with SVACE.

CC: stable@vger.kernel.org # 4.9+
Signed-off-by: Artem Chernyshev <artem.chernyshev@red-soft.ru>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
---

diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
index bed74a3ff5744..4fd6b61b06a46 100644
--- a/fs/btrfs/ioctl.c
+++ b/fs/btrfs/ioctl.c
@@ -2859,13 +2859,10 @@ static long btrfs_ioctl_dev_info(struct btrfs_fs_info *fs_info,
 	di_args->bytes_used = btrfs_device_get_bytes_used(dev);
 	di_args->total_bytes = btrfs_device_get_total_bytes(dev);
 	memcpy(di_args->uuid, dev->uuid, sizeof(di_args->uuid));
-	if (dev->name) {
-		strncpy(di_args->path, btrfs_dev_name(dev),
-				sizeof(di_args->path) - 1);
-		di_args->path[sizeof(di_args->path) - 1] = 0;
-	} else {
+	if (dev->name)
+		strscpy(di_args->path, btrfs_dev_name(dev), sizeof(di_args->path));
+	else
 		di_args->path[0] = '\0';
-	}
 
 out:
 	rcu_read_unlock();
diff --git a/fs/btrfs/rcu-string.h b/fs/btrfs/rcu-string.h
index 5c1a617eb25de..5c2b66d155ef7 100644
--- a/fs/btrfs/rcu-string.h
+++ b/fs/btrfs/rcu-string.h
@@ -18,7 +18,11 @@ static inline struct rcu_string *rcu_string_strdup(const char *src, gfp_t mask)
 					 (len * sizeof(char)), mask);
 	if (!ret)
 		return ret;
-	strncpy(ret->str, src, len);
+	/* Warn if the source got unexpectedly truncated. */
+	if (WARN_ON(strscpy(ret->str, src, len) < 0)) {
+		kfree(ret);
+		return NULL;
+	}
 	return ret;
 }