[PATCH] orangefs: replace strncpy with strscpy

From: justinstitt
Date: Tue Jul 25 2023 - 17:31:01 EST


This patch aims to eliminate `strncpy` usage across the orangefs
tree.

`strncpy` is deprecated for use on NUL-terminated destination strings
[1].

A suitable replacement is `strscpy` [2].

Using the `strscpy` api over `strncpy` has a slight wrinkle in the use
cases presented within orangefs. There is frequent usage of `...LEN - 1`
which is no longer required since `strscpy` will guarantee
NUL-termination on its `dest` argument. As per `strscpy`s implementation
in `linux/lib/string.c`

| /* Hit buffer length without finding a NUL; force NUL-termination. */
| if (res)
| dest[res-1] = '\0';

There are some hopes that someday the `strncpy` api could be ripped out
due to the vast number of suitable replacements (strscpy, strscpy_pad,
strtomem, strtomem_pad, strlcpy) [1].

[1]: www.kernel.org/doc/html/latest/process/deprecated.html#strncpy-on-nul-terminated-strings
[2]: manpages.debian.org/testing/linux-manual-4.8/strscpy.9.en.html

---


Link: https://github.com/KSPP/linux/issues/90
Signed-off-by: Justin Stitt <justinstitt@xxxxxxxxxx>
---
fs/orangefs/dcache.c | 4 ++--
fs/orangefs/namei.c | 30 +++++++++++++++---------------
fs/orangefs/super.c | 14 +++++++-------
3 files changed, 24 insertions(+), 24 deletions(-)

diff --git a/fs/orangefs/dcache.c b/fs/orangefs/dcache.c
index 8bbe9486e3a6..96ed9900f7a9 100644
--- a/fs/orangefs/dcache.c
+++ b/fs/orangefs/dcache.c
@@ -33,9 +33,9 @@ static int orangefs_revalidate_lookup(struct dentry *dentry)

new_op->upcall.req.lookup.sym_follow = ORANGEFS_LOOKUP_LINK_NO_FOLLOW;
new_op->upcall.req.lookup.parent_refn = parent->refn;
- strncpy(new_op->upcall.req.lookup.d_name,
+ strscpy(new_op->upcall.req.lookup.d_name,
dentry->d_name.name,
- ORANGEFS_NAME_MAX - 1);
+ ORANGEFS_NAME_MAX);

gossip_debug(GOSSIP_DCACHE_DEBUG,
"%s:%s:%d interrupt flag [%d]\n",
diff --git a/fs/orangefs/namei.c b/fs/orangefs/namei.c
index 77518e248cf7..503d07769bb4 100644
--- a/fs/orangefs/namei.c
+++ b/fs/orangefs/namei.c
@@ -41,8 +41,8 @@ static int orangefs_create(struct mnt_idmap *idmap,
fill_default_sys_attrs(new_op->upcall.req.create.attributes,
ORANGEFS_TYPE_METAFILE, mode);

- strncpy(new_op->upcall.req.create.d_name,
- dentry->d_name.name, ORANGEFS_NAME_MAX - 1);
+ strscpy(new_op->upcall.req.create.d_name,
+ dentry->d_name.name, ORANGEFS_NAME_MAX);

ret = service_operation(new_op, __func__, get_interruptible_flag(dir));

@@ -137,8 +137,8 @@ static struct dentry *orangefs_lookup(struct inode *dir, struct dentry *dentry,
&parent->refn.khandle);
new_op->upcall.req.lookup.parent_refn = parent->refn;

- strncpy(new_op->upcall.req.lookup.d_name, dentry->d_name.name,
- ORANGEFS_NAME_MAX - 1);
+ strscpy(new_op->upcall.req.lookup.d_name, dentry->d_name.name,
+ ORANGEFS_NAME_MAX);

gossip_debug(GOSSIP_NAME_DEBUG,
"%s: doing lookup on %s under %pU,%d\n",
@@ -192,8 +192,8 @@ static int orangefs_unlink(struct inode *dir, struct dentry *dentry)
return -ENOMEM;

new_op->upcall.req.remove.parent_refn = parent->refn;
- strncpy(new_op->upcall.req.remove.d_name, dentry->d_name.name,
- ORANGEFS_NAME_MAX - 1);
+ strscpy(new_op->upcall.req.remove.d_name, dentry->d_name.name,
+ ORANGEFS_NAME_MAX);

ret = service_operation(new_op, "orangefs_unlink",
get_interruptible_flag(inode));
@@ -247,10 +247,10 @@ static int orangefs_symlink(struct mnt_idmap *idmap,
ORANGEFS_TYPE_SYMLINK,
mode);

- strncpy(new_op->upcall.req.sym.entry_name,
+ strscpy(new_op->upcall.req.sym.entry_name,
dentry->d_name.name,
- ORANGEFS_NAME_MAX - 1);
- strncpy(new_op->upcall.req.sym.target, symname, ORANGEFS_NAME_MAX - 1);
+ ORANGEFS_NAME_MAX);
+ strscpy(new_op->upcall.req.sym.target, symname, ORANGEFS_NAME_MAX);

ret = service_operation(new_op, __func__, get_interruptible_flag(dir));

@@ -324,8 +324,8 @@ static int orangefs_mkdir(struct mnt_idmap *idmap, struct inode *dir,
fill_default_sys_attrs(new_op->upcall.req.mkdir.attributes,
ORANGEFS_TYPE_DIRECTORY, mode);

- strncpy(new_op->upcall.req.mkdir.d_name,
- dentry->d_name.name, ORANGEFS_NAME_MAX - 1);
+ strscpy(new_op->upcall.req.mkdir.d_name,
+ dentry->d_name.name, ORANGEFS_NAME_MAX);

ret = service_operation(new_op, __func__, get_interruptible_flag(dir));

@@ -405,12 +405,12 @@ static int orangefs_rename(struct mnt_idmap *idmap,
new_op->upcall.req.rename.old_parent_refn = ORANGEFS_I(old_dir)->refn;
new_op->upcall.req.rename.new_parent_refn = ORANGEFS_I(new_dir)->refn;

- strncpy(new_op->upcall.req.rename.d_old_name,
+ strscpy(new_op->upcall.req.rename.d_old_name,
old_dentry->d_name.name,
- ORANGEFS_NAME_MAX - 1);
- strncpy(new_op->upcall.req.rename.d_new_name,
+ ORANGEFS_NAME_MAX);
+ strscpy(new_op->upcall.req.rename.d_new_name,
new_dentry->d_name.name,
- ORANGEFS_NAME_MAX - 1);
+ ORANGEFS_NAME_MAX);

ret = service_operation(new_op,
"orangefs_rename",
diff --git a/fs/orangefs/super.c b/fs/orangefs/super.c
index 5254256a224d..b4af98b5a216 100644
--- a/fs/orangefs/super.c
+++ b/fs/orangefs/super.c
@@ -253,7 +253,7 @@ int orangefs_remount(struct orangefs_sb_info_s *orangefs_sb)
new_op = op_alloc(ORANGEFS_VFS_OP_FS_MOUNT);
if (!new_op)
return -ENOMEM;
- strncpy(new_op->upcall.req.fs_mount.orangefs_config_server,
+ strscpy(new_op->upcall.req.fs_mount.orangefs_config_server,
orangefs_sb->devname,
ORANGEFS_MAX_SERVER_ADDR_LEN);

@@ -400,8 +400,8 @@ static int orangefs_unmount(int id, __s32 fs_id, const char *devname)
return -ENOMEM;
op->upcall.req.fs_umount.id = id;
op->upcall.req.fs_umount.fs_id = fs_id;
- strncpy(op->upcall.req.fs_umount.orangefs_config_server,
- devname, ORANGEFS_MAX_SERVER_ADDR_LEN - 1);
+ strscpy(op->upcall.req.fs_umount.orangefs_config_server,
+ devname, ORANGEFS_MAX_SERVER_ADDR_LEN);
r = service_operation(op, "orangefs_fs_umount", 0);
/* Not much to do about an error here. */
if (r)
@@ -494,9 +494,9 @@ struct dentry *orangefs_mount(struct file_system_type *fst,
if (!new_op)
return ERR_PTR(-ENOMEM);

- strncpy(new_op->upcall.req.fs_mount.orangefs_config_server,
+ strscpy(new_op->upcall.req.fs_mount.orangefs_config_server,
devname,
- ORANGEFS_MAX_SERVER_ADDR_LEN - 1);
+ ORANGEFS_MAX_SERVER_ADDR_LEN);

gossip_debug(GOSSIP_SUPER_DEBUG,
"Attempting ORANGEFS Mount via host %s\n",
@@ -543,9 +543,9 @@ struct dentry *orangefs_mount(struct file_system_type *fst,
* on successful mount, store the devname and data
* used
*/
- strncpy(ORANGEFS_SB(sb)->devname,
+ strscpy(ORANGEFS_SB(sb)->devname,
devname,
- ORANGEFS_MAX_SERVER_ADDR_LEN - 1);
+ ORANGEFS_MAX_SERVER_ADDR_LEN);

/* mount_pending must be cleared */
ORANGEFS_SB(sb)->mount_pending = 0;

---
base-commit: 0b5547c51827e053cc754db47d3ec3e6c2c451d2
change-id: 20230725-fs-orangefs-remove-deprecated-strncpy-ae0d40124620

Best regards,
--
Justin Stitt <justinstitt@xxxxxxxxxx>