linux-kernel - [PATCH v4] btrfs: replace deprecated strcpy with strscpy

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [day] [month] [year] [list]

Message-ID: <20250620164957.14922-1-listout@listout.xyz>
Date: Fri, 20 Jun 2025 22:19:57 +0530
From: Brahmajit Das <listout@...tout.xyz>
To: linux-hardening@...r.kernel.org,
	linux-kernel@...r.kernel.org,
	linux-btrfs@...r.kernel.org
Cc: clm@...com,
	josef@...icpanda.com,
	dsterba@...e.com,
	kees@...nel.org,
	ailiop@...e.com,
	mark@...mstone.com,
	David Sterba <dsterba@...e.cz>,
	Brahmajit Das <bdas@...e.de>
Subject: [PATCH v4] btrfs: replace deprecated strcpy with strscpy

strcpy is deprecated due to lack of bounds checking. This patch replaces
strcpy with strscpy, the recommended alternative for null terminated
strings, to follow best practices.

There are instances where strscpy cannot be used such as where both the
source and destination are character pointers. In that instance we can
use sysfs_emit.

Link: https://github.com/KSPP/linux/issues/88
Suggested-by: Anthony Iliopoulos <ailiop@...e.com>
Suggested-by: David Sterba <dsterba@...e.cz>
Signed-off-by: Brahmajit Das <bdas@...e.de>
---

Changes in v2: using sysfs_emit instead of scnprintf.
Changes in v3: Removed string.h in xattr, since we are not using any.
fucntions from string.h and fixed length in memcpy in volumes.c
Changes in v4: As suggested by David, moving "NONE" as initial value of
buf in describe_relocation() and removed copying of "NONE" to bp in
btrfs_describe_block_groups().
---
 fs/btrfs/ioctl.c      | 2 +-
 fs/btrfs/relocation.c | 2 +-
 fs/btrfs/send.c       | 2 +-
 fs/btrfs/volumes.c    | 1 -
 fs/btrfs/xattr.c      | 3 +--
 5 files changed, 4 insertions(+), 6 deletions(-)

diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
index 913acef3f0a9..203f309f00b1 100644
--- a/fs/btrfs/ioctl.c
+++ b/fs/btrfs/ioctl.c
@@ -4200,7 +4200,7 @@ static int btrfs_ioctl_set_fslabel(struct file *file, void __user *arg)
 	}
 
 	spin_lock(&fs_info->super_lock);
-	strcpy(super_block->label, label);
+	strscpy(super_block->label, label);
 	spin_unlock(&fs_info->super_lock);
 	ret = btrfs_commit_transaction(trans);
 
diff --git a/fs/btrfs/relocation.c b/fs/btrfs/relocation.c
index 02086191630d..c136552e129c 100644
--- a/fs/btrfs/relocation.c
+++ b/fs/btrfs/relocation.c
@@ -3880,7 +3880,7 @@ static void free_reloc_control(struct reloc_control *rc)
  */
 static void describe_relocation(struct btrfs_block_group *block_group)
 {
-	char buf[128] = {'\0'};
+	char buf[128] = "NONE";
 
 	btrfs_describe_block_groups(block_group->flags, buf, sizeof(buf));
 
diff --git a/fs/btrfs/send.c b/fs/btrfs/send.c
index 2891ec4056c6..66ee9e1b1e96 100644
--- a/fs/btrfs/send.c
+++ b/fs/btrfs/send.c
@@ -758,7 +758,7 @@ static int send_header(struct send_ctx *sctx)
 {
 	struct btrfs_stream_header hdr;
 
-	strcpy(hdr.magic, BTRFS_SEND_STREAM_MAGIC);
+	strscpy(hdr.magic, BTRFS_SEND_STREAM_MAGIC);
 	hdr.version = cpu_to_le32(sctx->proto);
 	return write_buf(sctx->send_filp, &hdr, sizeof(hdr),
 					&sctx->send_off);
diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index 89835071cfea..8280474ec3d1 100644
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -215,7 +215,6 @@ void btrfs_describe_block_groups(u64 bg_flags, char *buf, u32 size_buf)
 	u32 size_bp = size_buf;
 
 	if (!flags) {
-		strcpy(bp, "NONE");
 		return;
 	}
 
diff --git a/fs/btrfs/xattr.c b/fs/btrfs/xattr.c
index 3e0edbcf73e1..49fd8a49584a 100644
--- a/fs/btrfs/xattr.c
+++ b/fs/btrfs/xattr.c
@@ -516,8 +516,7 @@ static int btrfs_initxattrs(struct inode *inode,
 			ret = -ENOMEM;
 			break;
 		}
-		strcpy(name, XATTR_SECURITY_PREFIX);
-		strcpy(name + XATTR_SECURITY_PREFIX_LEN, xattr->name);
+		sysfs_emit(name, "%s%s", XATTR_SECURITY_PREFIX, xattr->name);
 
 		if (strcmp(name, XATTR_NAME_CAPS) == 0)
 			clear_bit(BTRFS_INODE_NO_CAP_XATTR, &BTRFS_I(inode)->runtime_flags);
-- 
2.50.0