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overlayfs update for 5.1

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Merge tag 'ovl-update-5.1' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/vfs

Pull overlayfs updates from Miklos Szeredi:
 "Fix copy up of security related xattrs"

* tag 'ovl-update-5.1' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/vfs:
  ovl: Do not lose security.capability xattr over metadata file copy-up
  ovl: During copy up, first copy up data and then xattrs
This commit is contained in:
Linus Torvalds 2019-03-12 14:48:52 -07:00
commit f88c5942cf
3 changed files with 85 additions and 39 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

59
fs/overlayfs/copy_up.c
View File

@ -443,6 +443,24 @@ static int ovl_copy_up_inode(struct ovl_copy_up_ctx *c, struct dentry *temp)
{
int err;
/*
* Copy up data first and then xattrs. Writing data after
* xattrs will remove security.capability xattr automatically.
*/
if (S_ISREG(c->stat.mode) && !c->metacopy) {
struct path upperpath, datapath;
ovl_path_upper(c->dentry, &upperpath);
if (WARN_ON(upperpath.dentry != NULL))
return -EIO;
upperpath.dentry = temp;
ovl_path_lowerdata(c->dentry, &datapath);
err = ovl_copy_up_data(&datapath, &upperpath, c->stat.size);
if (err)
return err;
}
err = ovl_copy_xattr(c->lowerpath.dentry, temp);
if (err)
return err;
@ -460,19 +478,6 @@ static int ovl_copy_up_inode(struct ovl_copy_up_ctx *c, struct dentry *temp)
return err;
}
if (S_ISREG(c->stat.mode) && !c->metacopy) {
struct path upperpath, datapath;
ovl_path_upper(c->dentry, &upperpath);
BUG_ON(upperpath.dentry != NULL);
upperpath.dentry = temp;
ovl_path_lowerdata(c->dentry, &datapath);
err = ovl_copy_up_data(&datapath, &upperpath, c->stat.size);
if (err)
return err;
}
if (c->metacopy) {
err = ovl_check_setxattr(c->dentry, temp, OVL_XATTR_METACOPY,
NULL, 0, -EOPNOTSUPP);
@ -737,6 +742,8 @@ static int ovl_copy_up_meta_inode_data(struct ovl_copy_up_ctx *c)
{
struct path upperpath, datapath;
int err;
char *capability = NULL;
ssize_t uninitialized_var(cap_size);
ovl_path_upper(c->dentry, &upperpath);
if (WARN_ON(upperpath.dentry == NULL))
@ -746,15 +753,37 @@ static int ovl_copy_up_meta_inode_data(struct ovl_copy_up_ctx *c)
if (WARN_ON(datapath.dentry == NULL))
return -EIO;
if (c->stat.size) {
err = cap_size = ovl_getxattr(upperpath.dentry, XATTR_NAME_CAPS,
&capability, 0);
if (err < 0 && err != -ENODATA)
goto out;
}
err = ovl_copy_up_data(&datapath, &upperpath, c->stat.size);
if (err)
return err;
goto out_free;
/*
* Writing to upper file will clear security.capability xattr. We
* don't want that to happen for normal copy-up operation.
*/
if (capability) {
err = ovl_do_setxattr(upperpath.dentry, XATTR_NAME_CAPS,
capability, cap_size, 0);
if (err)
goto out_free;
}
err = vfs_removexattr(upperpath.dentry, OVL_XATTR_METACOPY);
if (err)
return err;
goto out_free;
ovl_set_upperdata(d_inode(c->dentry));
out_free:
kfree(capability);
out:
return err;
}

2
fs/overlayfs/overlayfs.h
View File

@ -277,6 +277,8 @@ int ovl_lock_rename_workdir(struct dentry *workdir, struct dentry *upperdir);
int ovl_check_metacopy_xattr(struct dentry *dentry);
bool ovl_is_metacopy_dentry(struct dentry *dentry);
char *ovl_get_redirect_xattr(struct dentry *dentry, int padding);
ssize_t ovl_getxattr(struct dentry *dentry, char *name, char **value,
size_t padding);
static inline bool ovl_is_impuredir(struct dentry *dentry)
{

61
fs/overlayfs/util.c
View File

@ -863,28 +863,49 @@ bool ovl_is_metacopy_dentry(struct dentry *dentry)
return (oe->numlower > 1);
}
ssize_t ovl_getxattr(struct dentry *dentry, char *name, char **value,
size_t padding)
{
ssize_t res;
char *buf = NULL;
res = vfs_getxattr(dentry, name, NULL, 0);
if (res < 0) {
if (res == -ENODATA || res == -EOPNOTSUPP)
return -ENODATA;
goto fail;
}
if (res != 0) {
buf = kzalloc(res + padding, GFP_KERNEL);
if (!buf)
return -ENOMEM;
res = vfs_getxattr(dentry, name, buf, res);
if (res < 0)
goto fail;
}
*value = buf;
return res;
fail:
pr_warn_ratelimited("overlayfs: failed to get xattr %s: err=%zi)\n",
name, res);
kfree(buf);
return res;
}
char *ovl_get_redirect_xattr(struct dentry *dentry, int padding)
{
int res;
char *s, *next, *buf = NULL;
res = vfs_getxattr(dentry, OVL_XATTR_REDIRECT, NULL, 0);
if (res < 0) {
if (res == -ENODATA || res == -EOPNOTSUPP)
res = ovl_getxattr(dentry, OVL_XATTR_REDIRECT, &buf, padding + 1);
if (res == -ENODATA)
return NULL;
goto fail;
}
buf = kzalloc(res + padding + 1, GFP_KERNEL);
if (!buf)
return ERR_PTR(-ENOMEM);
if (res == 0)
goto invalid;
res = vfs_getxattr(dentry, OVL_XATTR_REDIRECT, buf, res);
if (res < 0)
goto fail;
return ERR_PTR(res);
if (res == 0)
goto invalid;
@ -900,15 +921,9 @@ char *ovl_get_redirect_xattr(struct dentry *dentry, int padding)
}
return buf;
err_free:
kfree(buf);
return ERR_PTR(res);
fail:
pr_warn_ratelimited("overlayfs: failed to get redirect (%i)\n", res);
goto err_free;
invalid:
pr_warn_ratelimited("overlayfs: invalid redirect (%s)\n", buf);
res = -EINVAL;
goto err_free;
kfree(buf);
return ERR_PTR(res);
}