From: Amir Goldstein <amir73il@gmail.com>
To: Miklos Szeredi <miklos@szeredi.hu>
Cc: linux-unionfs@vger.kernel.org
Subject: [PATCH v4 06/25] ovl: verify upper root dir matches lower root dir
Date: Wed, 21 Jun 2017 15:28:37 +0300 [thread overview]
Message-ID: <1498048136-28218-7-git-send-email-amir73il@gmail.com> (raw)
In-Reply-To: <1498048136-28218-1-git-send-email-amir73il@gmail.com>
When inodes index feature is enabled, verify that the file handle stored
in upper root dir matches the lower root dir or fail to mount.
If upper root dir has no stored file handle, encode and store the lower
root dir file handle in overlay.origin xattr.
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
---
fs/overlayfs/copy_up.c | 2 +-
fs/overlayfs/namei.c | 103 ++++++++++++++++++++++++++++++++++++++++-------
fs/overlayfs/overlayfs.h | 3 ++
fs/overlayfs/super.c | 8 ++++
4 files changed, 101 insertions(+), 15 deletions(-)
diff --git a/fs/overlayfs/copy_up.c b/fs/overlayfs/copy_up.c
index d3047fdc0377..ee0b894e1d99 100644
--- a/fs/overlayfs/copy_up.c
+++ b/fs/overlayfs/copy_up.c
@@ -233,7 +233,7 @@ int ovl_set_attr(struct dentry *upperdentry, struct kstat *stat)
return err;
}
-static struct ovl_fh *ovl_encode_fh(struct dentry *lower)
+struct ovl_fh *ovl_encode_fh(struct dentry *lower)
{
struct ovl_fh *fh;
int fh_type, fh_len, dwords;
diff --git a/fs/overlayfs/namei.c b/fs/overlayfs/namei.c
index 4ca6061f7bfa..c08e334c879c 100644
--- a/fs/overlayfs/namei.c
+++ b/fs/overlayfs/namei.c
@@ -88,13 +88,10 @@ static int ovl_acceptable(void *ctx, struct dentry *dentry)
return 1;
}
-static struct dentry *ovl_get_origin(struct dentry *dentry,
- struct vfsmount *mnt)
+static struct ovl_fh *ovl_get_origin_fh(struct dentry *dentry)
{
int res;
struct ovl_fh *fh = NULL;
- struct dentry *origin = NULL;
- int bytes;
res = vfs_getxattr(dentry, OVL_XATTR_ORIGIN, NULL, 0);
if (res < 0) {
@@ -106,7 +103,7 @@ static struct dentry *ovl_get_origin(struct dentry *dentry,
if (res == 0)
return NULL;
- fh = kzalloc(res, GFP_TEMPORARY);
+ fh = kzalloc(res, GFP_TEMPORARY);
if (!fh)
return ERR_PTR(-ENOMEM);
@@ -129,7 +126,29 @@ static struct dentry *ovl_get_origin(struct dentry *dentry,
(fh->flags & OVL_FH_FLAG_BIG_ENDIAN) != OVL_FH_FLAG_CPU_ENDIAN)
goto out;
- bytes = (fh->len - offsetof(struct ovl_fh, fid));
+ return fh;
+
+out:
+ kfree(fh);
+ return NULL;
+
+fail:
+ pr_warn_ratelimited("overlayfs: failed to get origin (%i)\n", res);
+ goto out;
+invalid:
+ pr_warn_ratelimited("overlayfs: invalid origin (%*phN)\n", res, fh);
+ goto out;
+}
+
+static struct dentry *ovl_get_origin(struct dentry *dentry,
+ struct vfsmount *mnt)
+{
+ struct dentry *origin = NULL;
+ struct ovl_fh *fh = ovl_get_origin_fh(dentry);
+ int bytes;
+
+ if (IS_ERR_OR_NULL(fh))
+ return (struct dentry *)fh;
/*
* Make sure that the stored uuid matches the uuid of the lower
@@ -138,6 +157,7 @@ static struct dentry *ovl_get_origin(struct dentry *dentry,
if (uuid_be_cmp(fh->uuid, *(uuid_be *) &mnt->mnt_sb->s_uuid))
goto out;
+ bytes = (fh->len - offsetof(struct ovl_fh, fid));
origin = exportfs_decode_fh(mnt, (struct fid *)fh->fid,
bytes >> 2, (int)fh->type,
ovl_acceptable, NULL);
@@ -149,21 +169,17 @@ static struct dentry *ovl_get_origin(struct dentry *dentry,
}
if (ovl_dentry_weird(origin) ||
- ((d_inode(origin)->i_mode ^ d_inode(dentry)->i_mode) & S_IFMT)) {
- dput(origin);
- origin = NULL;
+ ((d_inode(origin)->i_mode ^ d_inode(dentry)->i_mode) & S_IFMT))
goto invalid;
- }
out:
kfree(fh);
return origin;
-fail:
- pr_warn_ratelimited("overlayfs: failed to get origin (%i)\n", res);
- goto out;
invalid:
- pr_warn_ratelimited("overlayfs: invalid origin (%*phN)\n", res, fh);
+ pr_warn_ratelimited("overlayfs: invalid origin (%pd2)\n", origin);
+ dput(origin);
+ origin = NULL;
goto out;
}
@@ -305,6 +321,65 @@ static int ovl_check_origin(struct dentry *dentry, struct dentry *upperdentry,
}
/*
+ * Verify that @fh matches the origin file handle stored in OVL_XATTR_ORIGIN.
+ * Return 0 on match, -ESTALE on mismatch, < 0 on error.
+ */
+static int ovl_verify_origin_fh(struct dentry *dentry, struct ovl_fh *fh)
+{
+ struct ovl_fh *ofh = ovl_get_origin_fh(dentry);
+ int err = 0;
+
+ if (!ofh)
+ return -ENODATA;
+
+ if (IS_ERR(ofh))
+ return PTR_ERR(ofh);
+
+ if (fh->len != ofh->len || memcmp(fh, ofh, fh->len))
+ err = -ESTALE;
+
+ kfree(ofh);
+ return err;
+}
+
+/*
+ * Verify that an inode matches the origin file handle stored in upper inode.
+ *
+ * If @set is true and there is no stored file handle, encode and store origin
+ * file handle in OVL_XATTR_ORIGIN.
+ *
+ * Return 0 on match, -ESTALE on mismatch, < 0 on error.
+ */
+int ovl_verify_origin(struct dentry *dentry, struct vfsmount *mnt,
+ struct dentry *origin, bool set)
+{
+ struct inode *inode = NULL;
+ struct ovl_fh *fh = NULL;
+ int err;
+
+ fh = ovl_encode_fh(origin);
+ err = PTR_ERR(fh);
+ if (IS_ERR(fh))
+ goto fail;
+
+ err = ovl_verify_origin_fh(dentry, fh);
+ if (set && err == -ENODATA)
+ err = ovl_do_setxattr(dentry, OVL_XATTR_ORIGIN, fh, fh->len, 0);
+ if (err)
+ goto fail;
+
+out:
+ kfree(fh);
+ return err;
+
+fail:
+ inode = d_inode(origin);
+ pr_warn_ratelimited("overlayfs: failed to verify origin (%pd2, ino=%lu, err=%i)\n",
+ origin, inode ? inode->i_ino : 0, err);
+ goto out;
+}
+
+/*
* Returns next layer in stack starting from top.
* Returns -1 if this is the last layer.
*/
diff --git a/fs/overlayfs/overlayfs.h b/fs/overlayfs/overlayfs.h
index 9ec93063c3a8..12d96a77c217 100644
--- a/fs/overlayfs/overlayfs.h
+++ b/fs/overlayfs/overlayfs.h
@@ -235,6 +235,8 @@ static inline bool ovl_is_impuredir(struct dentry *dentry)
/* namei.c */
+int ovl_verify_origin(struct dentry *dentry, struct vfsmount *mnt,
+ struct dentry *origin, bool set);
int ovl_path_next(int idx, struct dentry *dentry, struct path *path, int *idxp);
struct dentry *ovl_lookup(struct inode *dir, struct dentry *dentry, unsigned int flags);
bool ovl_lower_positive(struct dentry *dentry);
@@ -293,3 +295,4 @@ int ovl_copy_up(struct dentry *dentry);
int ovl_copy_up_flags(struct dentry *dentry, int flags);
int ovl_copy_xattr(struct dentry *old, struct dentry *new);
int ovl_set_attr(struct dentry *upper, struct kstat *stat);
+struct ovl_fh *ovl_encode_fh(struct dentry *lower);
diff --git a/fs/overlayfs/super.c b/fs/overlayfs/super.c
index d92c7486bdf2..7c621bb265db 100644
--- a/fs/overlayfs/super.c
+++ b/fs/overlayfs/super.c
@@ -1030,6 +1030,14 @@ static int ovl_fill_super(struct super_block *sb, void *data, int silent)
ufs->same_sb = NULL;
if (!(ovl_force_readonly(ufs)) && ufs->config.index) {
+ /* Verify lower root is upper root origin */
+ err = ovl_verify_origin(upperpath.dentry, ufs->lower_mnt[0],
+ stack[0].dentry, true);
+ if (err) {
+ pr_err("overlayfs: failed to verify upper root origin\n");
+ goto out_put_lower_mnt;
+ }
+
ufs->indexdir = ovl_workdir_create(sb, ufs, workpath.dentry,
OVL_INDEXDIR_NAME, true);
err = PTR_ERR(ufs->indexdir);
--
2.7.4
next prev parent reply other threads:[~2017-06-21 12:28 UTC|newest]
Thread overview: 31+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-06-21 12:28 [PATCH v4 00/25] Overlayfs inodes index Amir Goldstein
2017-06-21 12:28 ` [PATCH v4 01/25] vfs: introduce inode 'inuse' lock Amir Goldstein
2017-06-21 12:28 ` [PATCH v4 02/25] ovl: get exclusive ownership on upper/work dirs Amir Goldstein
2017-06-21 12:28 ` [PATCH v4 03/25] ovl: relax same fs constrain for ovl_check_origin() Amir Goldstein
2017-06-21 12:28 ` [PATCH v4 04/25] ovl: generalize ovl_create_workdir() Amir Goldstein
2017-06-21 12:28 ` [PATCH v4 05/25] ovl: introduce the inodes index dir feature Amir Goldstein
2017-06-21 12:28 ` Amir Goldstein [this message]
2017-06-21 12:28 ` [PATCH v4 07/25] ovl: verify index dir matches upper dir Amir Goldstein
2017-06-21 12:28 ` [PATCH v4 08/25] ovl: store path type in dentry Amir Goldstein
2017-06-21 12:28 ` [PATCH v4 09/25] ovl: cram dentry state booleans into type flags Amir Goldstein
2017-06-21 12:28 ` [PATCH v4 10/25] ovl: lookup index entry for copy up origin Amir Goldstein
2017-06-21 12:28 ` [PATCH v4 11/25] ovl: cleanup bad and stale index entries on mount Amir Goldstein
2017-06-21 12:28 ` [PATCH v4 12/25] ovl: allocate an ovl_inode struct Amir Goldstein
2017-06-21 12:28 ` [PATCH v4 13/25] ovl: store upper/lower real inode in ovl_inode_info Amir Goldstein
2017-06-21 12:28 ` [PATCH v4 14/25] ovl: use ovl_inode_init() for initializing new inode Amir Goldstein
2017-06-21 12:28 ` [PATCH v4 15/25] ovl: hash overlay non-dir inodes by copy up origin inode Amir Goldstein
2017-06-21 12:28 ` [PATCH v4 16/25] ovl: defer upper dir lock to tempfile link Amir Goldstein
2017-06-21 12:28 ` [PATCH v4 17/25] ovl: factor out ovl_copy_up_inode() helper Amir Goldstein
2017-06-21 12:28 ` [PATCH v4 18/25] ovl: generalize ovl_copy_up_locked() using actors Amir Goldstein
2017-06-21 12:28 ` [PATCH v4 19/25] ovl: generalize ovl_copy_up_one() " Amir Goldstein
2017-06-21 12:28 ` [PATCH v4 20/25] ovl: use ovl_inode mutex to synchronize concurrent copy up Amir Goldstein
2017-06-21 12:28 ` [PATCH v4 21/25] ovl: implement index dir copy up method Amir Goldstein
2017-06-21 12:28 ` [PATCH v4 22/25] ovl: link up indexed lower hardlink on lookup Amir Goldstein
2017-06-21 12:28 ` [PATCH v4 23/25] ovl: fix nlink leak in ovl_rename() Amir Goldstein
2017-06-21 12:28 ` [PATCH v4 24/25] ovl: persistent overlay inode nlink for indexed inodes Amir Goldstein
2017-06-23 11:34 ` Amir Goldstein
2017-06-21 12:28 ` [PATCH v4 25/25] ovl: cleanup orphan index entries Amir Goldstein
2017-06-21 16:45 ` Amir Goldstein
2017-06-21 17:02 ` [PATCH v4 00/25] Overlayfs inodes index Amir Goldstein
2017-06-21 20:03 ` Amir Goldstein
2017-06-22 10:18 ` [PATCH v4 26/25] ovl: document copying layers restrictions with " Amir Goldstein
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