orangefs: cleanup uses of strncpy

strncpy() is deprecated for use on NUL-terminated destination strings
[1] and as such we should prefer more robust and less ambiguous string
interfaces.

There is some care taken to ensure these destination buffers are
NUL-terminated by bounding the strncpy()'s by ORANGEFS_NAME_MAX - 1 or
ORANGEFS_MAX_SERVER_ADDR_LEN - 1. Instead, we can use the new 2-argument
version of strscpy() to guarantee NUL-termination on the destination
buffers while simplifying the code.

Based on usage with printf-likes, we can see these buffers are expected
to be NUL-terminated:
|	gossip_debug(GOSSIP_NAME_DEBUG,
|			"%s: doing lookup on %s under %pU,%d\n",
|			__func__,
|			new_op->upcall.req.lookup.d_name,
|			&new_op->upcall.req.lookup.parent_refn.khandle,
|			new_op->upcall.req.lookup.parent_refn.fs_id);
...
|	gossip_debug(GOSSIP_SUPER_DEBUG,
|			"Attempting ORANGEFS Remount via host %s\n",
|			new_op->upcall.req.fs_mount.orangefs_config_server);

NUL-padding isn't required for any of these destination buffers as
they've all been zero-allocated with op_alloc() or kzalloc().

Link: https://www.kernel.org/doc/html/latest/process/deprecated.html#strncpy-on-nul-terminated-strings
Link: https://manpages.debian.org/testing/linux-manual-4.8/strscpy.9.en.html
Link: https://github.com/KSPP/linux/issues/90
Cc: linux-hardening@vger.kernel.org
Signed-off-by: Justin Stitt <justinstitt@google.com>
Link: https://lore.kernel.org/r/20240322-strncpy-fs-orangefs-dcache-c-v1-1-15d12debbf38@google.com
Reviewed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Christian Brauner <brauner@kernel.org>

diff --git a/fs/orangefs/dcache.c b/fs/orangefs/dcache.c
index 8bbe9486e3a6228c40c46971d23c305127e2007b..395a00ed8ac75f64b6a4c122ff843689b42f6cac 100644 (file)
--- a/fs/orangefs/dcache.c
+++ b/fs/orangefs/dcache.c
@@ -33,9 +33,7 @@ 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,
-               dentry->d_name.name,
-               ORANGEFS_NAME_MAX - 1);
+       strscpy(new_op->upcall.req.lookup.d_name, dentry->d_name.name);
 
        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 c9dfd5c6a0970c1d9de8e917f26da4b5b4d50dde..200558ec72f086c36ab53567b0fc7ea93f2e9675 100644 (file)
--- a/fs/orangefs/namei.c
+++ b/fs/orangefs/namei.c
@@ -41,8 +41,7 @@ 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);
 
        ret = service_operation(new_op, __func__, get_interruptible_flag(dir));
 
@@ -137,8 +136,7 @@ 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);
 
        gossip_debug(GOSSIP_NAME_DEBUG,
                     "%s: doing lookup on %s under %pU,%d\n",
@@ -192,8 +190,7 @@ 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);
 
        ret = service_operation(new_op, "orangefs_unlink",
                                get_interruptible_flag(inode));
@@ -247,10 +244,8 @@ static int orangefs_symlink(struct mnt_idmap *idmap,
                               ORANGEFS_TYPE_SYMLINK,
                               mode);
 
-       strncpy(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);
+       strscpy(new_op->upcall.req.sym.entry_name, dentry->d_name.name);
+       strscpy(new_op->upcall.req.sym.target, symname);
 
        ret = service_operation(new_op, __func__, get_interruptible_flag(dir));
 
@@ -324,8 +319,7 @@ 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);
 
        ret = service_operation(new_op, __func__, get_interruptible_flag(dir));
 
@@ -405,12 +399,8 @@ 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,
-               old_dentry->d_name.name,
-               ORANGEFS_NAME_MAX - 1);
-       strncpy(new_op->upcall.req.rename.d_new_name,
-               new_dentry->d_name.name,
-               ORANGEFS_NAME_MAX - 1);
+       strscpy(new_op->upcall.req.rename.d_old_name, old_dentry->d_name.name);
+       strscpy(new_op->upcall.req.rename.d_new_name, new_dentry->d_name.name);
 
        ret = service_operation(new_op,
                                "orangefs_rename",

diff --git a/fs/orangefs/super.c b/fs/orangefs/super.c
index 34849b4a3243ca5a2d27114d8a6f5f0a6074d329..fb4d09c2f531f0e668daf135323484bfa6023e80 100644 (file)
--- a/fs/orangefs/super.c
+++ b/fs/orangefs/super.c
@@ -253,9 +253,8 @@ 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,
-               orangefs_sb->devname,
-               ORANGEFS_MAX_SERVER_ADDR_LEN);
+       strscpy(new_op->upcall.req.fs_mount.orangefs_config_server,
+               orangefs_sb->devname);
 
        gossip_debug(GOSSIP_SUPER_DEBUG,
                     "Attempting ORANGEFS Remount via host %s\n",
@@ -400,8 +399,7 @@ 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);
        r = service_operation(op, "orangefs_fs_umount", 0);
        /* Not much to do about an error here. */
        if (r)
@@ -494,9 +492,7 @@ 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,
-               devname,
-               ORANGEFS_MAX_SERVER_ADDR_LEN - 1);
+       strscpy(new_op->upcall.req.fs_mount.orangefs_config_server, devname);
 
        gossip_debug(GOSSIP_SUPER_DEBUG,
                     "Attempting ORANGEFS Mount via host %s\n",
@@ -543,9 +539,8 @@ struct dentry *orangefs_mount(struct file_system_type *fst,
         * on successful mount, store the devname and data
         * used
         */
-       strncpy(ORANGEFS_SB(sb)->devname,
-               devname,
-               ORANGEFS_MAX_SERVER_ADDR_LEN - 1);
+       strscpy(ORANGEFS_SB(sb)->devname, devname);
+
 
        /* mount_pending must be cleared */
        ORANGEFS_SB(sb)->mount_pending = 0;