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Merge branch 'overlayfs-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/vfs 

Pull overlayfs fixes from Miklos Szeredi:
 "This fixes a crash with SELinux and several other old and new bugs"

* 'overlayfs-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/vfs:
  ovl: check for bad and whiteout index on lookup
  ovl: do not cleanup directory and whiteout index entries
  ovl: fix xattr get and set with selinux
  ovl: remove unneeded check for IS_ERR()
  ovl: fix origin verification of index dir
  ovl: mark parent impure on ovl_link()
  ovl: fix random return value on mount
hifive-unleashed-5.1
Linus Torvalds 2017-07-21 16:24:22 -07:00
parent 0151ef0085 0e082555ce
commit 99313414dd
7 changed files with 88 additions and 42 deletions
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22
fs/overlayfs/dir.c
View File

@ -481,17 +481,30 @@ out_cleanup:
}
static int ovl_create_or_link(struct dentry *dentry, struct inode *inode,
struct cattr *attr, struct dentry *hardlink)
struct cattr *attr, struct dentry *hardlink,
bool origin)
{
int err;
const struct cred *old_cred;
struct cred *override_cred;
struct dentry *parent = dentry->d_parent;
err = ovl_copy_up(dentry->d_parent);
err = ovl_copy_up(parent);
if (err)
return err;
old_cred = ovl_override_creds(dentry->d_sb);
/*
* When linking a file with copy up origin into a new parent, mark the
* new parent dir "impure".
*/
if (origin) {
err = ovl_set_impure(parent, ovl_dentry_upper(parent));
if (err)
goto out_revert_creds;
}
err = -ENOMEM;
override_cred = prepare_creds();
if (override_cred) {
@ -550,7 +563,7 @@ static int ovl_create_object(struct dentry *dentry, int mode, dev_t rdev,
inode_init_owner(inode, dentry->d_parent->d_inode, mode);
attr.mode = inode->i_mode;
err = ovl_create_or_link(dentry, inode, &attr, NULL);
err = ovl_create_or_link(dentry, inode, &attr, NULL, false);
if (err)
iput(inode);
@ -609,7 +622,8 @@ static int ovl_link(struct dentry *old, struct inode *newdir,
inode = d_inode(old);
ihold(inode);
err = ovl_create_or_link(new, inode, NULL, ovl_dentry_upper(old));
err = ovl_create_or_link(new, inode, NULL, ovl_dentry_upper(old),
ovl_type_origin(old));
if (err)
iput(inode);

32
fs/overlayfs/inode.c
View File

@ -202,37 +202,38 @@ bool ovl_is_private_xattr(const char *name)
sizeof(OVL_XATTR_PREFIX) - 1) == 0;
}
int ovl_xattr_set(struct dentry *dentry, const char *name, const void *value,
size_t size, int flags)
int ovl_xattr_set(struct dentry *dentry, struct inode *inode, const char *name,
const void *value, size_t size, int flags)
{
int err;
struct path realpath;
enum ovl_path_type type = ovl_path_real(dentry, &realpath);
struct dentry *upperdentry = ovl_i_dentry_upper(inode);
struct dentry *realdentry = upperdentry ?: ovl_dentry_lower(dentry);
const struct cred *old_cred;
err = ovl_want_write(dentry);
if (err)
goto out;
if (!value && !OVL_TYPE_UPPER(type)) {
err = vfs_getxattr(realpath.dentry, name, NULL, 0);
if (!value && !upperdentry) {
err = vfs_getxattr(realdentry, name, NULL, 0);
if (err < 0)
goto out_drop_write;
}
err = ovl_copy_up(dentry);
if (err)
goto out_drop_write;
if (!upperdentry) {
err = ovl_copy_up(dentry);
if (err)
goto out_drop_write;
if (!OVL_TYPE_UPPER(type))
ovl_path_upper(dentry, &realpath);
realdentry = ovl_dentry_upper(dentry);
}
old_cred = ovl_override_creds(dentry->d_sb);
if (value)
err = vfs_setxattr(realpath.dentry, name, value, size, flags);
err = vfs_setxattr(realdentry, name, value, size, flags);
else {
WARN_ON(flags != XATTR_REPLACE);
err = vfs_removexattr(realpath.dentry, name);
err = vfs_removexattr(realdentry, name);
}
revert_creds(old_cred);
@ -242,12 +243,13 @@ out:
return err;
}
int ovl_xattr_get(struct dentry *dentry, const char *name,
int ovl_xattr_get(struct dentry *dentry, struct inode *inode, const char *name,
void *value, size_t size)
{
struct dentry *realdentry = ovl_dentry_real(dentry);
ssize_t res;
const struct cred *old_cred;
struct dentry *realdentry =
ovl_i_dentry_upper(inode) ?: ovl_dentry_lower(dentry);
old_cred = ovl_override_creds(dentry->d_sb);
res = vfs_getxattr(realdentry, name, value, size);

41
fs/overlayfs/namei.c
View File

@ -397,8 +397,19 @@ int ovl_verify_index(struct dentry *index, struct path *lowerstack,
if (!d_inode(index))
return 0;
err = -EISDIR;
if (d_is_dir(index))
/*
* Directory index entries are going to be used for looking up
* redirected upper dirs by lower dir fh when decoding an overlay
* file handle of a merge dir. Whiteout index entries are going to be
* used as an indication that an exported overlay file handle should
* be treated as stale (i.e. after unlink of the overlay inode).
* We don't know the verification rules for directory and whiteout
* index entries, because they have not been implemented yet, so return
* EROFS if those entries are found to avoid corrupting an index that
* was created by a newer kernel.
*/
err = -EROFS;
if (d_is_dir(index) || ovl_is_whiteout(index))
goto fail;
err = -EINVAL;
@ -436,8 +447,8 @@ out:
return err;
fail:
pr_warn_ratelimited("overlayfs: failed to verify index (%pd2, err=%i)\n",
index, err);
pr_warn_ratelimited("overlayfs: failed to verify index (%pd2, ftype=%x, err=%i)\n",
index, d_inode(index)->i_mode & S_IFMT, err);
goto out;
}
@ -502,6 +513,7 @@ static struct dentry *ovl_lookup_index(struct dentry *dentry,
goto out;
}
inode = d_inode(index);
if (d_is_negative(index)) {
if (upper && d_inode(origin)->i_nlink > 1) {
pr_warn_ratelimited("overlayfs: hard link with origin but no index (ino=%lu).\n",
@ -511,11 +523,22 @@ static struct dentry *ovl_lookup_index(struct dentry *dentry,
dput(index);
index = NULL;
} else if (upper && d_inode(index) != d_inode(upper)) {
inode = d_inode(index);
pr_warn_ratelimited("overlayfs: wrong index found (index ino: %lu, upper ino: %lu).\n",
d_inode(index)->i_ino,
d_inode(upper)->i_ino);
} else if (upper && d_inode(upper) != inode) {
pr_warn_ratelimited("overlayfs: wrong index found (index=%pd2, ino=%lu, upper ino=%lu).\n",
index, inode->i_ino, d_inode(upper)->i_ino);
goto fail;
} else if (ovl_dentry_weird(index) || ovl_is_whiteout(index) ||
((inode->i_mode ^ d_inode(origin)->i_mode) & S_IFMT)) {
/*
* Index should always be of the same file type as origin
* except for the case of a whiteout index. A whiteout
* index should only exist if all lower aliases have been
* unlinked, which means that finding a lower origin on lookup
* whose index is a whiteout should be treated as an error.
*/
pr_warn_ratelimited("overlayfs: bad index found (index=%pd2, ftype=%x, origin ftype=%x).\n",
index, d_inode(index)->i_mode & S_IFMT,
d_inode(origin)->i_mode & S_IFMT);
goto fail;
}

10
fs/overlayfs/overlayfs.h
View File

@ -47,7 +47,8 @@ enum ovl_flag {
/* Is the real inode encoded in fid an upper inode? */
#define OVL_FH_FLAG_PATH_UPPER (1 << 2)
#define OVL_FH_FLAG_ALL (OVL_FH_FLAG_BIG_ENDIAN | OVL_FH_FLAG_ANY_ENDIAN)
#define OVL_FH_FLAG_ALL (OVL_FH_FLAG_BIG_ENDIAN | OVL_FH_FLAG_ANY_ENDIAN | \
OVL_FH_FLAG_PATH_UPPER)
#if defined(__LITTLE_ENDIAN)
#define OVL_FH_FLAG_CPU_ENDIAN 0
@ -199,6 +200,7 @@ enum ovl_path_type ovl_path_real(struct dentry *dentry, struct path *path);
struct dentry *ovl_dentry_upper(struct dentry *dentry);
struct dentry *ovl_dentry_lower(struct dentry *dentry);
struct dentry *ovl_dentry_real(struct dentry *dentry);
struct dentry *ovl_i_dentry_upper(struct inode *inode);
struct inode *ovl_inode_upper(struct inode *inode);
struct inode *ovl_inode_lower(struct inode *inode);
struct inode *ovl_inode_real(struct inode *inode);
@ -270,9 +272,9 @@ int ovl_setattr(struct dentry *dentry, struct iattr *attr);
int ovl_getattr(const struct path *path, struct kstat *stat,
u32 request_mask, unsigned int flags);
int ovl_permission(struct inode *inode, int mask);
int ovl_xattr_set(struct dentry *dentry, const char *name, const void *value,
size_t size, int flags);
int ovl_xattr_get(struct dentry *dentry, const char *name,
int ovl_xattr_set(struct dentry *dentry, struct inode *inode, const char *name,
const void *value, size_t size, int flags);
int ovl_xattr_get(struct dentry *dentry, struct inode *inode, const char *name,
void *value, size_t size);
ssize_t ovl_listxattr(struct dentry *dentry, char *list, size_t size);
struct posix_acl *ovl_get_acl(struct inode *inode, int type);

5
fs/overlayfs/readdir.c
View File

@ -703,7 +703,10 @@ int ovl_indexdir_cleanup(struct dentry *dentry, struct vfsmount *mnt,
err = PTR_ERR(index);
break;
}
if (ovl_verify_index(index, lowerstack, numlower)) {
err = ovl_verify_index(index, lowerstack, numlower);
if (err) {
if (err == -EROFS)
break;
err = ovl_cleanup(dir, index);
if (err)
break;

13
fs/overlayfs/super.c
View File

@ -692,7 +692,7 @@ ovl_posix_acl_xattr_get(const struct xattr_handler *handler,
struct dentry *dentry, struct inode *inode,
const char *name, void *buffer, size_t size)
{
return ovl_xattr_get(dentry, handler->name, buffer, size);
return ovl_xattr_get(dentry, inode, handler->name, buffer, size);
}
static int __maybe_unused
@ -742,7 +742,7 @@ ovl_posix_acl_xattr_set(const struct xattr_handler *handler,
return err;
}
err = ovl_xattr_set(dentry, handler->name, value, size, flags);
err = ovl_xattr_set(dentry, inode, handler->name, value, size, flags);
if (!err)
ovl_copyattr(ovl_inode_real(inode), inode);
@ -772,7 +772,7 @@ static int ovl_other_xattr_get(const struct xattr_handler *handler,
struct dentry *dentry, struct inode *inode,
const char *name, void *buffer, size_t size)
{
return ovl_xattr_get(dentry, name, buffer, size);
return ovl_xattr_get(dentry, inode, name, buffer, size);
}
static int ovl_other_xattr_set(const struct xattr_handler *handler,
@ -780,7 +780,7 @@ static int ovl_other_xattr_set(const struct xattr_handler *handler,
const char *name, const void *value,
size_t size, int flags)
{
return ovl_xattr_set(dentry, name, value, size, flags);
return ovl_xattr_set(dentry, inode, name, value, size, flags);
}
static const struct xattr_handler __maybe_unused
@ -1058,10 +1058,6 @@ static int ovl_fill_super(struct super_block *sb, void *data, int silent)
ufs->indexdir = ovl_workdir_create(sb, ufs, workpath.dentry,
OVL_INDEXDIR_NAME, true);
err = PTR_ERR(ufs->indexdir);
if (IS_ERR(ufs->indexdir))
goto out_put_lower_mnt;
if (ufs->indexdir) {
/* Verify upper root is index dir origin */
err = ovl_verify_origin(ufs->indexdir, ufs->upper_mnt,
@ -1090,6 +1086,7 @@ static int ovl_fill_super(struct super_block *sb, void *data, int silent)
else
sb->s_d_op = &ovl_dentry_operations;
err = -ENOMEM;
ufs->creator_cred = cred = prepare_creds();
if (!cred)
goto out_put_indexdir;

7
fs/overlayfs/util.c
View File

@ -157,9 +157,14 @@ struct dentry *ovl_dentry_real(struct dentry *dentry)
return ovl_dentry_upper(dentry) ?: ovl_dentry_lower(dentry);
}
struct dentry *ovl_i_dentry_upper(struct inode *inode)
{
return ovl_upperdentry_dereference(OVL_I(inode));
}
struct inode *ovl_inode_upper(struct inode *inode)
{
struct dentry *upperdentry = ovl_upperdentry_dereference(OVL_I(inode));
struct dentry *upperdentry = ovl_i_dentry_upper(inode);
return upperdentry ? d_inode(upperdentry) : NULL;
}