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Message-Id: <20170209212837.14197-2-richard@nod.at>
Date: Thu, 9 Feb 2017 22:28:35 +0100
From: Richard Weinberger <richard@....at>
To: linux-mtd@...ts.infradead.org
Cc: linux-kernel@...r.kernel.org, dedekind1@...il.com,
david.oberhollenzer@...ma-star.at,
Richard Weinberger <richard@....at>
Subject: [PATCH 2/4] ubifs: Fix unlink code wrt. double hash lookups
When removing an encrypted file with a long anem and without having
the key we have to be able to locate and remove the directory entry
via a double hash. This corner case was simply forgotten.
Reported-by: David Oberhollenzer <david.oberhollenzer@...ma-star.at>
Signed-off-by: Richard Weinberger <richard@....at>
---
fs/ubifs/journal.c | 10 ++++-
fs/ubifs/tnc.c | 129 ++++++++++++++++++++++++++++++++++++++++++++---------
fs/ubifs/ubifs.h | 2 +
3 files changed, 117 insertions(+), 24 deletions(-)
diff --git a/fs/ubifs/journal.c b/fs/ubifs/journal.c
index f3b620cbdda4..7aef413ea2a9 100644
--- a/fs/ubifs/journal.c
+++ b/fs/ubifs/journal.c
@@ -585,7 +585,10 @@ int ubifs_jnl_update(struct ubifs_info *c, const struct inode *dir,
if (!xent) {
dent->ch.node_type = UBIFS_DENT_NODE;
- dent_key_init(c, &dent_key, dir->i_ino, nm);
+ if (nm->hash)
+ dent_key_init_hash(c, &dent_key, dir->i_ino, nm->hash);
+ else
+ dent_key_init(c, &dent_key, dir->i_ino, nm);
} else {
dent->ch.node_type = UBIFS_XENT_NODE;
xent_key_init(c, &dent_key, dir->i_ino, nm);
@@ -629,7 +632,10 @@ int ubifs_jnl_update(struct ubifs_info *c, const struct inode *dir,
kfree(dent);
if (deletion) {
- err = ubifs_tnc_remove_nm(c, &dent_key, nm);
+ if (nm->hash)
+ err = ubifs_tnc_remove_dh(c, &dent_key, nm->minor_hash);
+ else
+ err = ubifs_tnc_remove_nm(c, &dent_key, nm);
if (err)
goto out_ro;
err = ubifs_add_dirt(c, lnum, dlen);
diff --git a/fs/ubifs/tnc.c b/fs/ubifs/tnc.c
index 709aa098dd46..d84f4ba467a3 100644
--- a/fs/ubifs/tnc.c
+++ b/fs/ubifs/tnc.c
@@ -1880,48 +1880,65 @@ int ubifs_tnc_lookup_nm(struct ubifs_info *c, const union ubifs_key *key,
return do_lookup_nm(c, key, node, nm);
}
-static int do_lookup_dh(struct ubifs_info *c, const union ubifs_key *key,
- struct ubifs_dent_node *dent, uint32_t cookie)
+static int search_dh_cookie(struct ubifs_info *c, const union ubifs_key *key,
+ struct ubifs_dent_node *dent, uint32_t cookie,
+ struct ubifs_znode **zn, int *n)
{
- int n, err, type = key_type(c, key);
- struct ubifs_znode *znode;
+ int err;
+ struct ubifs_znode *znode = *zn;
struct ubifs_zbranch *zbr;
- union ubifs_key *dkey, start_key;
-
- ubifs_assert(is_hash_key(c, key));
-
- lowest_dent_key(c, &start_key, key_inum(c, key));
-
- mutex_lock(&c->tnc_mutex);
- err = ubifs_lookup_level0(c, &start_key, &znode, &n);
- if (unlikely(err < 0))
- goto out_unlock;
+ union ubifs_key *dkey;
for (;;) {
if (!err) {
- err = tnc_next(c, &znode, &n);
+ err = tnc_next(c, &znode, n);
if (err)
- goto out_unlock;
+ goto out;
}
- zbr = &znode->zbranch[n];
+ zbr = &znode->zbranch[*n];
dkey = &zbr->key;
if (key_inum(c, dkey) != key_inum(c, key) ||
- key_type(c, dkey) != type) {
+ key_type(c, dkey) != key_type(c, key)) {
err = -ENOENT;
- goto out_unlock;
+ goto out;
}
err = tnc_read_hashed_node(c, zbr, dent);
if (err)
- goto out_unlock;
+ goto out;
if (key_hash(c, key) == key_hash(c, dkey) &&
- le32_to_cpu(dent->cookie) == cookie)
- goto out_unlock;
+ le32_to_cpu(dent->cookie) == cookie) {
+ *zn = znode;
+ goto out;
+ }
}
+out:
+
+ return err;
+}
+
+static int do_lookup_dh(struct ubifs_info *c, const union ubifs_key *key,
+ struct ubifs_dent_node *dent, uint32_t cookie)
+{
+ int n, err;
+ struct ubifs_znode *znode;
+ union ubifs_key start_key;
+
+ ubifs_assert(is_hash_key(c, key));
+
+ lowest_dent_key(c, &start_key, key_inum(c, key));
+
+ mutex_lock(&c->tnc_mutex);
+ err = ubifs_lookup_level0(c, &start_key, &znode, &n);
+ if (unlikely(err < 0))
+ goto out_unlock;
+
+ err = search_dh_cookie(c, key, dent, cookie, &znode, &n);
+
out_unlock:
mutex_unlock(&c->tnc_mutex);
return err;
@@ -2663,6 +2680,74 @@ int ubifs_tnc_remove_nm(struct ubifs_info *c, const union ubifs_key *key,
}
/**
+ * ubifs_tnc_remove_dh - remove an index entry for a "double hashed" node.
+ * @c: UBIFS file-system description object
+ * @key: key of node
+ * @cookie: node cookie for collision resolution
+ *
+ * Returns %0 on success or negative error code on failure.
+ */
+int ubifs_tnc_remove_dh(struct ubifs_info *c, const union ubifs_key *key,
+ uint32_t cookie)
+{
+ int n, err;
+ struct ubifs_znode *znode;
+ struct ubifs_dent_node *dent;
+ struct ubifs_zbranch *zbr;
+
+ if (!c->double_hash)
+ return -EOPNOTSUPP;
+
+ mutex_lock(&c->tnc_mutex);
+ err = lookup_level0_dirty(c, key, &znode, &n);
+ if (err <= 0)
+ goto out_unlock;
+
+ zbr = &znode->zbranch[n];
+ dent = kmalloc(UBIFS_MAX_DENT_NODE_SZ, GFP_NOFS);
+ if (!dent) {
+ err = -ENOMEM;
+ goto out_unlock;
+ }
+
+ err = tnc_read_hashed_node(c, zbr, dent);
+ if (err)
+ goto out_free;
+
+ /* If the cookie does not match, we're facing a hash collision. */
+ if (le32_to_cpu(dent->cookie) != cookie) {
+ union ubifs_key start_key;
+
+ lowest_dent_key(c, &start_key, key_inum(c, key));
+
+ err = ubifs_lookup_level0(c, &start_key, &znode, &n);
+ if (unlikely(err < 0))
+ goto out_unlock;
+
+ err = search_dh_cookie(c, key, dent, cookie, &znode, &n);
+ if (err)
+ goto out_free;
+ }
+
+ if (znode->cnext || !ubifs_zn_dirty(znode)) {
+ znode = dirty_cow_bottom_up(c, znode);
+ if (IS_ERR(znode)) {
+ err = PTR_ERR(znode);
+ goto out_unlock;
+ }
+ }
+ err = tnc_delete(c, znode, n);
+
+out_free:
+ kfree(dent);
+out_unlock:
+ if (!err)
+ err = dbg_check_tnc(c, 0);
+ mutex_unlock(&c->tnc_mutex);
+ return err;
+}
+
+/**
* key_in_range - determine if a key falls within a range of keys.
* @c: UBIFS file-system description object
* @key: key to check
diff --git a/fs/ubifs/ubifs.h b/fs/ubifs/ubifs.h
index ca72382ce6cc..36df4613b803 100644
--- a/fs/ubifs/ubifs.h
+++ b/fs/ubifs/ubifs.h
@@ -1589,6 +1589,8 @@ int ubifs_tnc_add_nm(struct ubifs_info *c, const union ubifs_key *key,
int ubifs_tnc_remove(struct ubifs_info *c, const union ubifs_key *key);
int ubifs_tnc_remove_nm(struct ubifs_info *c, const union ubifs_key *key,
const struct fscrypt_name *nm);
+int ubifs_tnc_remove_dh(struct ubifs_info *c, const union ubifs_key *key,
+ uint32_t cookie);
int ubifs_tnc_remove_range(struct ubifs_info *c, union ubifs_key *from_key,
union ubifs_key *to_key);
int ubifs_tnc_remove_ino(struct ubifs_info *c, ino_t inum);
--
2.10.2
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