hfsplus: clean up delayed work if fill_super fails
Subsystems (2)
PATCH 1/2 hfsplus: clean up delayed work if fill_super fails
If no hidden directory exists, the hfsplus_fill_super() function will create it. A delayed work is then queued to sync the superblock, which is never canceled in case of failure. Fix this.
--- fs/hfsplus/super.c | 2 ++ 1 file changed, 2 insertions(+)
fs/hfsplus/super.c +2 -0
@@ -588,6 +588,8 @@ static int hfsplus_fill_super(struct super_block *sb, void *data, int silent)return 0 ; out_put_hidden_dir: +/* Creating an inode queues the sb for synchronization */ +cancel_delayed_work_sync (&sbi->sync_work);iput (sbi->hidden_dir); out_put_root:dput (sb->s_root);
Signature · 1 line
2.11.0
PATCH 2/2 hfsplus: always return error if fill_super fails
If the filesystem is corrupted in such a way that the HFS+ Private Data directory is not of type HFSPLUS_FOLDER, the mount will fail without throwing an error code. The vfs layer is then forced to dereference a NULL root dentry.
This bug was found by KASAN while running the reproducer provided by [email protected] for a separate issue.
--- fs/hfsplus/super.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-)
fs/hfsplus/super.c +3 -1
@@ -524,8 +524,10 @@ static int hfsplus_fill_super(struct super_block *sb, void *data, int silent) goto out_put_root;if (!hfs_brec_read (&fd, &entry,sizeof (entry))) {hfs_find_exit (&fd); -if (entry.type !=cpu_to_be16 (HFSPLUS_FOLDER )) +if (entry.type !=cpu_to_be16 (HFSPLUS_FOLDER )) { + err = -EINVAL ; goto out_put_root; + } inode =hfsplus_iget (sb,be32_to_cpu (entry.folder.id));if (IS_ERR (inode)) { err =PTR_ERR (inode);
Signature · 1 line
2.11.0
Al Viro
maintainerQuoted 3 lines · Ernesto A. Fern�ndez
If no hidden directory exists, the
hfsplus_fill_super()function will create it. A delayed work is then queued to sync the superblock, which is never canceled in case of failure. Fix this.
Wouldn't it be simpler to avoid all the crap with clearing ->s_root on failure, letting ->put_super() take care of everything? Or, better yet, take cleanups into ->kill_sb(), which is always called on superblock shutdown, ->s_root or no ->s_root...
Quoted 9 lines · Al Viro
Quoted 3 lines · Ernesto A. Fernández
If no hidden directory exists, the
hfsplus_fill_super()function will create it. A delayed work is then queued to sync the superblock, which is never canceled in case of failure. Fix this.Wouldn't it be simpler to avoid all the crap with clearing ->s_root on failure, letting ->put_super() take care of everything? Or, better yet, take cleanups into ->kill_sb(), which is always called on superblock shutdown, ->s_root or no ->s_root...
If you mean that I move all cleanups from fill_super() to ->kill_sb(), that sounds like a lot of trouble. Is this common in other filesystems?
As for letting ->put_super() do the cleanup, the problem is that it will flag the volume as consistent, even if the directory count was increased and the hidden dir was not added to the catalog. So we should correct that before returning from fill_super(). I wouldn't call this simpler, but I guess it's a bit better for consistency.
-- >8 --
Subject: [PATCH] hfsplus: fix cleanup for hfsplus_fill_super()
If no hidden directory exists, the hfsplus_fill_super() function will create it. A delayed work is then queued to sync the superblock, which is never canceled in case of failure.
Also, if the filesystem is corrupted in such a way that the hidden directory is not of type HFSPLUS_FOLDER, the mount will fail without throwing an error code. The vfs layer is then forced to dereference a NULL root dentry.
To fix these issues, return an error and allow ->put_super() to take care of most of the cleanup if failure occurs after sb->s_root has been set.
Before this patch the volume was simply flagged as inconsistent if the mount failed while creating the hidden directory. Since ->put_super() will now toggle those flags, be sure to correct the folder count before returning, with a call to hfsplus_delete_inode().
--- fs/hfsplus/super.c | 40 +++++++++++++++++++++------------------- 1 file changed, 21 insertions(+), 19 deletions(-)
fs/hfsplus/super.c +21 -19
@@ -514,22 +514,26 @@ static int hfsplus_fill_super(struct super_block *sb, void *data, int silent) goto out_put_alloc_file; } +/* From here on, most of the cleanup is handled by ->put_super */ + str.len =sizeof (HFSP_HIDDENDIR_NAME ) -1 ; str.name =HFSP_HIDDENDIR_NAME ; err =hfs_find_init (sbi->cat_tree, &fd);if (err) - goto out_put_root; + goto out; err =hfsplus_cat_build_key (sb, fd.search_key,HFSPLUS_ROOT_CNID , &str);if (unlikely (err <0 )) - goto out_put_root; + goto out;if (!hfs_brec_read (&fd, &entry,sizeof (entry))) {hfs_find_exit (&fd); -if (entry.type !=cpu_to_be16 (HFSPLUS_FOLDER )) - goto out_put_root; +if (entry.type !=cpu_to_be16 (HFSPLUS_FOLDER )) { + err = -EINVAL ; + goto out; + } inode =hfsplus_iget (sb,be32_to_cpu (entry.folder.id));if (IS_ERR (inode)) { err =PTR_ERR (inode); - goto out_put_root; + goto out; } sbi->hidden_dir = inode; }else
@@ -551,16 +555,13 @@ static int hfsplus_fill_super(struct super_block *sb, void *data, int silent)mutex_lock (&sbi->vh_mutex); sbi->hidden_dir =hfsplus_new_inode (sb, root,S_IFDIR );if (!sbi->hidden_dir) { -mutex_unlock (&sbi->vh_mutex); err = -ENOMEM ; - goto out_put_root; + goto out_unlock_vh_mutex; } err =hfsplus_create_cat (sbi->hidden_dir->i_ino, root, &str, sbi->hidden_dir); -if (err) { -mutex_unlock (&sbi->vh_mutex); - goto out_put_hidden_dir; - } +if (err) + goto out_delete_hidden_dir; err =hfsplus_init_inode_security (sbi->hidden_dir, root, &str);
@@ -573,8 +574,7 @@ static int hfsplus_fill_super(struct super_block *sb, void *data, int silent)*/ hfsplus_delete_cat (sbi->hidden_dir->i_ino, root, &str); -mutex_unlock (&sbi->vh_mutex); - goto out_put_hidden_dir; + goto out_delete_hidden_dir; }mutex_unlock (&sbi->vh_mutex);
@@ -587,11 +587,13 @@ static int hfsplus_fill_super(struct super_block *sb, void *data, int silent) sbi->nls = nls;return 0 ; -out_put_hidden_dir: -iput (sbi->hidden_dir); -out_put_root: -dput (sb->s_root); - sb->s_root =NULL ; +out_delete_hidden_dir: +clear_nlink (inode); +hfsplus_delete_inode (inode); +out_unlock_vh_mutex: +mutex_unlock (&sbi->vh_mutex); + goto out; + out_put_alloc_file:iput (sbi->alloc_file); out_close_attr_tree:
@@ -605,9 +607,9 @@ static int hfsplus_fill_super(struct super_block *sb, void *data, int silent)kfree (sbi->s_backup_vhdr_buf); out_unload_nls:unload_nls (sbi->nls); -unload_nls (nls);kfree (sbi); out: +unload_nls (nls);return err; }
Signature · 1 line
2.11.0
PATCH v3 1/1 hfsplus: fix cleanup for hfsplus_fill_super()
If no hidden directory exists, the hfsplus_fill_super() function will create it. A delayed work is then queued to sync the superblock, which is never canceled in case of failure.
Also, if the filesystem is corrupted in such a way that the hidden directory is not of type HFSPLUS_FOLDER, the mount will fail without throwing an error code. The vfs layer is then forced to dereference a NULL root dentry.
To fix these issues, return an error and allow ->put_super() to take care of most of the cleanup if failure occurs after sb->s_root has been set.
Before this patch the volume was simply flagged as inconsistent if the mount failed while creating the hidden directory. Since ->put_super() will now toggle those flags, we need to correct the folder count before returning, with a call to hfsplus_delete_inode(). Simplify this by using a new hfsplus_create_inode() function that can handle its own cleanup.
---
Changes in v3:
Move the code that creates the hidden dir into a separate function. I think this is more reasonable. The new function can also be called by hfsplus_mknod().
fs/hfsplus/dir.c | 28 +++----------------------- fs/hfsplus/hfsplus_fs.h | 2 ++ fs/hfsplus/inode.c | 32 +++++++++++++++++++++++++++++ fs/hfsplus/super.c | 53 +++++++++++++------------------------------------ 4 files changed, 51 insertions(+), 64 deletions(-)
fs/hfsplus/dir.c +3 -25
@@ -483,37 +483,15 @@ static int hfsplus_mknod(struct inode *dir, struct dentry *dentry, {struct hfsplus_sb_info *sbi =HFSPLUS_SB (dir->i_sb);struct inode *inode; -int res = -ENOMEM ; +int res;mutex_lock (&sbi->vh_mutex); - inode =hfsplus_new_inode (dir->i_sb, dir, mode); -if (!inode) - goto out; - -if (S_ISBLK (mode) ||S_ISCHR (mode) ||S_ISFIFO (mode) ||S_ISSOCK (mode)) -init_special_inode (inode, mode, rdev); - - res =hfsplus_create_cat (inode->i_ino, dir, &dentry->d_name, inode); + res =hfsplus_create_inode (dir, &dentry->d_name, mode, rdev, &inode);if (res) - goto failed_mknod; - - res =hfsplus_init_inode_security (inode, dir, &dentry->d_name); -if (res == -EOPNOTSUPP ) - res =0 ;/* Operation is not supported. */ -else if (res) { -/* Try to delete anyway without error analysis. */ -hfsplus_delete_cat (inode->i_ino, dir, &dentry->d_name); - goto failed_mknod; - } - + goto out;hfsplus_instantiate (dentry, inode, inode->i_ino);mark_inode_dirty (inode); - goto out; -failed_mknod: -clear_nlink (inode); -hfsplus_delete_inode (inode); -iput (inode); out:mutex_unlock (&sbi->vh_mutex);return res;
fs/hfsplus/hfsplus_fs.h +2 -0
@@ -480,6 +480,8 @@ extern const struct dentry_operations hfsplus_dentry_operations;struct inode *hfsplus_new_inode (struct super_block *sb,struct inode *dir,umode_t mode); +int hfsplus_create_inode (struct inode *dir,struct qstr *name,umode_t mode, +dev_t rdev,struct inode **inode);void hfsplus_delete_inode (struct inode *inode);void hfsplus_inode_read_fork (struct inode *inode,struct hfsplus_fork_raw *fork);
fs/hfsplus/inode.c +32 -0
@@ -413,6 +413,38 @@ struct inode *hfsplus_new_inode(struct super_block *sb, struct inode *dir,return inode; } +int hfsplus_create_inode (struct inode *dir,struct qstr *name,umode_t mode, +dev_t rdev,struct inode **inode) +{ +int res; + + *inode =hfsplus_new_inode (dir->i_sb, dir, mode); +if (!*inode) +return -ENOMEM ; + +if (S_ISBLK (mode) ||S_ISCHR (mode) ||S_ISFIFO (mode) ||S_ISSOCK (mode)) +init_special_inode (*inode, mode, rdev); + + res =hfsplus_create_cat ((*inode)->i_ino, dir, name, *inode); +if (res) + goto fail; + + res =hfsplus_init_inode_security (*inode, dir, name); +if (res && res != -EOPNOTSUPP ) { +/* Try to delete anyway without error analysis. */ +hfsplus_delete_cat ((*inode)->i_ino, dir, name); + goto fail; + } +return 0 ; + +fail: +clear_nlink (*inode); +hfsplus_delete_inode (*inode); +iput (*inode); + *inode =NULL ; +return res; +} +void hfsplus_delete_inode (struct inode *inode) {struct super_block *sb = inode->i_sb;
fs/hfsplus/super.c +14 -39
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Signature · 1 line
2.11.0