[PATCH v2 21/25] ovl: use vfs_{get,set}_fscaps() for copy-up

Seth Forshee (DigitalOcean)
2024-02-21T21:25:07Z

Using vfs_{get,set}xattr() for fscaps will be blocked in a future
commit, so convert ovl to use the new interfaces. Also remove the now
unused ovl_getxattr_value().

Reviewed-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Seth Forshee (DigitalOcean) <sforshee@kernel.org>
---
fs/overlayfs/copy_up.c | 72 ++++++++++++++++++++++++++------------------------
1 file changed, 37 insertions(+), 35 deletions(-)

diff --git a/fs/overlayfs/copy_up.c b/fs/overlayfs/copy_up.c
index b8e25ca51016..d7c8d76e2394 100644
--- a/fs/overlayfs/copy_up.c
+++ b/fs/overlayfs/copy_up.c
@@ -73,6 +73,23 @@ static int ovl_copy_acl(struct ovl_fs *ofs, const struct path *path,
return err;
}

+static int ovl_copy_fscaps(struct ovl_fs *ofs, const struct path *oldpath,
+ struct dentry *new)
+{
+ struct vfs_caps capability;
+ int err;
+
+ err = vfs_get_fscaps(mnt_idmap(oldpath->mnt), oldpath->dentry,
+ &capability);
+ if (err) {
+ if (err == -ENODATA || err == -EOPNOTSUPP)
+ return 0;
+ return err;
+ }
+
+ return vfs_set_fscaps(ovl_upper_mnt_idmap(ofs), new, &capability, 0);
+}
+
int ovl_copy_xattr(struct super_block *sb, const struct path *oldpath, struct dentry *new)
{
struct dentry *old = oldpath->dentry;
@@ -130,6 +147,14 @@ int ovl_copy_xattr(struct super_block *sb, const struct path *oldpath, struct de
break;
}

+ if (is_fscaps_xattr(name)) {
+ error = ovl_copy_fscaps(OVL_FS(sb), oldpath, new);
+ if (!error)
+ continue;
+ /* fs capabilities must be copied */
+ break;
+ }
+
retry:
size = ovl_do_getxattr(oldpath, name, value, value_size);
if (size == -ERANGE)
@@ -1039,61 +1064,40 @@ static bool ovl_need_meta_copy_up(struct dentry *dentry, umode_t mode,
return true;
}

-static ssize_t ovl_getxattr_value(const struct path *path, char *name, char **value)
-{
- ssize_t res;
- char *buf;
-
- res = ovl_do_getxattr(path, name, NULL, 0);
- if (res == -ENODATA || res == -EOPNOTSUPP)
- res = 0;
-
- if (res > 0) {
- buf = kzalloc(res, GFP_KERNEL);
- if (!buf)
- return -ENOMEM;
-
- res = ovl_do_getxattr(path, name, buf, res);
- if (res < 0)
- kfree(buf);
- else
- *value = buf;
- }
- return res;
-}
-
/* Copy up data of an inode which was copied up metadata only in the past. */
static int ovl_copy_up_meta_inode_data(struct ovl_copy_up_ctx *c)
{
struct ovl_fs *ofs = OVL_FS(c->dentry->d_sb);
struct path upperpath;
int err;
- char *capability = NULL;
- ssize_t cap_size;
+ struct vfs_caps capability;
+ bool has_capability = false;

ovl_path_upper(c->dentry, &upperpath);
if (WARN_ON(upperpath.dentry == NULL))
return -EIO;

if (c->stat.size) {
- err = cap_size = ovl_getxattr_value(&upperpath, XATTR_NAME_CAPS,
- &capability);
- if (cap_size < 0)
+ err = vfs_get_fscaps(mnt_idmap(upperpath.mnt), upperpath.dentry,
+ &capability);
+ if (!err)
+ has_capability = 1;
+ else if (err != -ENODATA && err != EOPNOTSUPP)
goto out;
}

err = ovl_copy_up_data(c, &upperpath);
if (err)
- goto out_free;
+ goto out;

/*
* Writing to upper file will clear security.capability xattr. We
* don't want that to happen for normal copy-up operation.
*/
ovl_start_write(c->dentry);
- if (capability) {
- err = ovl_do_setxattr(ofs, upperpath.dentry, XATTR_NAME_CAPS,
- capability, cap_size, 0);
+ if (has_capability) {
+ err = vfs_set_fscaps(mnt_idmap(upperpath.mnt), upperpath.dentry,
+ &capability, 0);
}
if (!err) {
err = ovl_removexattr(ofs, upperpath.dentry,
@@ -1101,13 +1105,11 @@ static int ovl_copy_up_meta_inode_data(struct ovl_copy_up_ctx *c)
}
ovl_end_write(c->dentry);
if (err)
- goto out_free;
+ goto out;

ovl_clear_flag(OVL_HAS_DIGEST, d_inode(c->dentry));
ovl_clear_flag(OVL_VERIFIED_DIGEST, d_inode(c->dentry));
ovl_set_upperdata(d_inode(c->dentry));
-out_free:
- kfree(capability);
out:
return err;
}

--
2.43.0