Re: [PATCH] hfs: add error checking for hfs_find_init()

[Hin-Tak Leung <htl10@users.sourceforge.net>]

--- On Sat, 30/3/13, Vyacheslav Dubeyko <slava@dubeyko.com> wrote:

> From: Vyacheslav Dubeyko <slava@dubeyko.com>
> Subject: Re: [PATCH] hfs: add error checking for hfs_find_init()
> To: "Alexey Khoroshilov" <khoroshilov@ispras.ru>
> Cc: "Al Viro" <viro@zeniv.linux.org.uk>, "Artem Bityutskiy" <artem.bityutskiy@linux.intel.com>, "Christoph Hellwig" <hch@lst.de>, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, ldv-project@linuxtesting.org, "Hin-Tak Leung" <htl10@users.sourceforge.net>
> Date: Saturday, 30 March, 2013, 11:35
> Hi Alexey,
> 
> On Mar 30, 2013, at 12:44 AM, Alexey Khoroshilov wrote:
> 
> > hfs_find_init() may fail with ENOMEM, but there are
> places,
> > where the returned value is not checked. The
> consequences can be
> > very unpleasant, e.g. kfree uninitialized pointer and
> > inappropriate mutex unlocking.
> > 
> > The patch adds checks for errors in hfs_find_init().
> > 
> 
> Thank you for your efforts. I have several remarks. Please,
> see below.

Argh, interesting. I wonder if that is related to how I can get the hfsplus driver all confused just running 'du' on one large directory in one of my disks repeatedly. I'll be interested to trying the hfsplus version out. Perhaps I would suggest/add a few dprint/printk's so that there is a sign in dmesg when the error condition is triggered.

Hin-Tak
 
> > Found by Linux Driver Verification project
> (linuxtesting.org).
> > 
> > Signed-off-by: Alexey Khoroshilov <khoroshilov@ispras.ru>
> > ---
> > fs/hfs/catalog.c |   12 +++++++++---
> > fs/hfs/dir.c     |    8
> ++++++--
> > fs/hfs/extent.c  |   48
> +++++++++++++++++++++++++++++++++---------------
> > fs/hfs/hfs_fs.h  |    2 +-
> > fs/hfs/inode.c   |   11
> +++++++++--
> > fs/hfs/super.c   |    4 +++-
> > 6 files changed, 61 insertions(+), 24 deletions(-)
> > 
> > diff --git a/fs/hfs/catalog.c b/fs/hfs/catalog.c
> > index 424b033..9569b39 100644
> > --- a/fs/hfs/catalog.c
> > +++ b/fs/hfs/catalog.c
> > @@ -92,7 +92,9 @@ int hfs_cat_create(u32 cnid, struct
> inode *dir, struct qstr *str, struct inode *
> >         return -ENOSPC;
> > 
> >     sb = dir->i_sb;
> > -   
> hfs_find_init(HFS_SB(sb)->cat_tree, &fd);
> > +    err =
> hfs_find_init(HFS_SB(sb)->cat_tree, &fd);
> > +    if (err)
> > +        return err;
> > 
> >     hfs_cat_build_key(sb, fd.search_key,
> cnid, NULL);
> >     entry_size =
> hfs_cat_build_thread(sb, &entry,
> S_ISDIR(inode->i_mode) ?
> > @@ -214,7 +216,9 @@ int hfs_cat_delete(u32 cnid, struct
> inode *dir, struct qstr *str)
> > 
> >     dprint(DBG_CAT_MOD, "delete_cat:
> %s,%u\n", str ? str->name : NULL, cnid);
> >     sb = dir->i_sb;
> > -   
> hfs_find_init(HFS_SB(sb)->cat_tree, &fd);
> > +    res =
> hfs_find_init(HFS_SB(sb)->cat_tree, &fd);
> > +    if (res)
> > +        return res;
> > 
> >     hfs_cat_build_key(sb, fd.search_key,
> dir->i_ino, str);
> >     res = hfs_brec_find(&fd);
> > @@ -281,7 +285,9 @@ int hfs_cat_move(u32 cnid, struct
> inode *src_dir, struct qstr *src_name,
> >     dprint(DBG_CAT_MOD, "rename_cat: %u
> - %lu,%s - %lu,%s\n", cnid, src_dir->i_ino,
> src_name->name,
> >        
> dst_dir->i_ino, dst_name->name);
> >     sb = src_dir->i_sb;
> > -   
> hfs_find_init(HFS_SB(sb)->cat_tree, &src_fd);
> > +    err =
> hfs_find_init(HFS_SB(sb)->cat_tree, &src_fd);
> > +    if (err)
> > +        return err;
> >     dst_fd = src_fd;
> > 
> >     /* find the old dir entry and read
> the data */
> > diff --git a/fs/hfs/dir.c b/fs/hfs/dir.c
> > index 5f7f1ab..e1c8048 100644
> > --- a/fs/hfs/dir.c
> > +++ b/fs/hfs/dir.c
> > @@ -25,7 +25,9 @@ static struct dentry
> *hfs_lookup(struct inode *dir, struct dentry *dentry,
> >     struct inode *inode = NULL;
> >     int res;
> > 
> > -   
> hfs_find_init(HFS_SB(dir->i_sb)->cat_tree, &fd);
> > +    res =
> hfs_find_init(HFS_SB(dir->i_sb)->cat_tree, &fd);
> > +    if (res)
> > +        return
> ERR_PTR(res);
> >     hfs_cat_build_key(dir->i_sb,
> fd.search_key, dir->i_ino, &dentry->d_name);
> >     res = hfs_brec_read(&fd,
> &rec, sizeof(rec));
> >     if (res) {
> > @@ -63,7 +65,9 @@ static int hfs_readdir(struct file
> *filp, void *dirent, filldir_t filldir)
> >     if (filp->f_pos >=
> inode->i_size)
> >         return 0;
> > 
> > -   
> hfs_find_init(HFS_SB(sb)->cat_tree, &fd);
> > +    err =
> hfs_find_init(HFS_SB(sb)->cat_tree, &fd);
> > +    if (err)
> > +        return err;
> >     hfs_cat_build_key(sb, fd.search_key,
> inode->i_ino, NULL);
> >     err = hfs_brec_find(&fd);
> >     if (err)
> > diff --git a/fs/hfs/extent.c b/fs/hfs/extent.c
> > index a67955a..813447b 100644
> > --- a/fs/hfs/extent.c
> > +++ b/fs/hfs/extent.c
> > @@ -107,7 +107,7 @@ static u16 hfs_ext_lastblock(struct
> hfs_extent *ext)
> >     return be16_to_cpu(ext->block) +
> be16_to_cpu(ext->count);
> > }
> > 
> > -static void __hfs_ext_write_extent(struct inode
> *inode, struct hfs_find_data *fd)
> > +static int __hfs_ext_write_extent(struct inode *inode,
> struct hfs_find_data *fd)
> > {
> >     int res;
> > 
> > @@ -116,26 +116,31 @@ static void
> __hfs_ext_write_extent(struct inode *inode, struct
> hfs_find_data *fd
> >     res = hfs_brec_find(fd);
> >     if (HFS_I(inode)->flags &
> HFS_FLG_EXT_NEW) {
> >         if (res !=
> -ENOENT)
> > -       
>     return;
> > +       
>     return res;
> >        
> hfs_brec_insert(fd, HFS_I(inode)->cached_extents,
> sizeof(hfs_extent_rec));
> >        
> HFS_I(inode)->flags &=
> ~(HFS_FLG_EXT_DIRTY|HFS_FLG_EXT_NEW);
> >     } else {
> >         if (res)
> > -       
>     return;
> > +       
>     return res;
> >        
> hfs_bnode_write(fd->bnode,
> HFS_I(inode)->cached_extents, fd->entryoffset,
> fd->entrylength);
> >        
> HFS_I(inode)->flags &= ~HFS_FLG_EXT_DIRTY;
> >     }
> > +    return 0;
> > }
> > 
> 
> As I see, this fix makes sense and for hfsplus also. Please,
> make it and for hfsplus.
> 
> > -void hfs_ext_write_extent(struct inode *inode)
> > +int hfs_ext_write_extent(struct inode *inode)
> > {
> >     struct hfs_find_data fd;
> > +    int res = 0;
> > 
> >     if (HFS_I(inode)->flags &
> HFS_FLG_EXT_DIRTY) {
> > -       
> hfs_find_init(HFS_SB(inode->i_sb)->ext_tree,
> &fd);
> > -       
> __hfs_ext_write_extent(inode, &fd);
> > +        res =
> hfs_find_init(HFS_SB(inode->i_sb)->ext_tree,
> &fd);
> > +        if (res)
> > +       
>     return res;
> > +        res =
> __hfs_ext_write_extent(inode, &fd);
> >        
> hfs_find_exit(&fd);
> >     }
> > +    return res;
> > }
> > 
> > static inline int __hfs_ext_read_extent(struct
> hfs_find_data *fd, struct hfs_extent *extent,
> > @@ -161,8 +166,11 @@ static inline int
> __hfs_ext_cache_extent(struct hfs_find_data *fd, struct
> inode
> > {
> >     int res;
> > 
> > -    if (HFS_I(inode)->flags &
> HFS_FLG_EXT_DIRTY)
> > -       
> __hfs_ext_write_extent(inode, fd);
> > +    if (HFS_I(inode)->flags &
> HFS_FLG_EXT_DIRTY) {
> > +        res =
> __hfs_ext_write_extent(inode, fd);
> > +        if (res)
> > +       
>     return res;
> > +    }
> > 
> 
> Ditto for hfsplus.
> 
> Thanks,
> Vyacheslav Dubeyko.
> 
> >     res = __hfs_ext_read_extent(fd,
> HFS_I(inode)->cached_extents, inode->i_ino,
> >        
>             block,
> HFS_IS_RSRC(inode) ? HFS_FK_RSRC : HFS_FK_DATA);
> > @@ -185,9 +193,11 @@ static int
> hfs_ext_read_extent(struct inode *inode, u16 block)
> >         block <
> HFS_I(inode)->cached_start +
> HFS_I(inode)->cached_blocks)
> >         return 0;
> > 
> > -   
> hfs_find_init(HFS_SB(inode->i_sb)->ext_tree,
> &fd);
> > -    res =
> __hfs_ext_cache_extent(&fd, inode, block);
> > -    hfs_find_exit(&fd);
> > +    res =
> hfs_find_init(HFS_SB(inode->i_sb)->ext_tree,
> &fd);
> > +    if (!res) {
> > +        res =
> __hfs_ext_cache_extent(&fd, inode, block);
> > +       
> hfs_find_exit(&fd);
> > +    }
> >     return res;
> > }
> > 
> > @@ -298,7 +308,9 @@ int hfs_free_fork(struct
> super_block *sb, struct hfs_cat_file *file, int type)
> >     if (total_blocks == blocks)
> >         return 0;
> > 
> > -   
> hfs_find_init(HFS_SB(sb)->ext_tree, &fd);
> > +    res =
> hfs_find_init(HFS_SB(sb)->ext_tree, &fd);
> > +    if (res)
> > +        return res;
> >     do {
> >         res =
> __hfs_ext_read_extent(&fd, extent, cnid, total_blocks,
> type);
> >         if (res)
> > @@ -438,7 +450,9 @@ out:
> > 
> > insert_extent:
> >     dprint(DBG_EXTENT, "insert new
> extent\n");
> > -    hfs_ext_write_extent(inode);
> > +    res = hfs_ext_write_extent(inode);
> > +    if (res)
> > +        goto out;
> > 
> >    
> memset(HFS_I(inode)->cached_extents, 0,
> sizeof(hfs_extent_rec));
> >    
> HFS_I(inode)->cached_extents[0].block =
> cpu_to_be16(start);
> > @@ -466,7 +480,6 @@ void hfs_file_truncate(struct inode
> *inode)
> >         struct
> address_space *mapping = inode->i_mapping;
> >         void *fsdata;
> >         struct page
> *page;
> > -        int res;
> > 
> >         /* XXX: Can use
> generic_cont_expand? */
> >         size =
> inode->i_size - 1;
> > @@ -488,7 +501,12 @@ void hfs_file_truncate(struct
> inode *inode)
> >         goto out;
> > 
> >    
> mutex_lock(&HFS_I(inode)->extents_lock);
> > -   
> hfs_find_init(HFS_SB(sb)->ext_tree, &fd);
> > +    res =
> hfs_find_init(HFS_SB(sb)->ext_tree, &fd);
> > +    if (res) {
> > +       
> mutex_unlock(&HFS_I(inode)->extents_lock);
> > +        /* XXX: We lack
> error handling of hfs_file_truncate() */
> > +        return;
> > +    }
> >     while (1) {
> >         if (alloc_cnt ==
> HFS_I(inode)->first_blocks) {
> >        
>     hfs_free_extents(sb,
> HFS_I(inode)->first_extents,
> > diff --git a/fs/hfs/hfs_fs.h b/fs/hfs/hfs_fs.h
> > index 693df9f..67817af 100644
> > --- a/fs/hfs/hfs_fs.h
> > +++ b/fs/hfs/hfs_fs.h
> > @@ -174,7 +174,7 @@ extern const struct
> inode_operations hfs_dir_inode_operations;
> > /* extent.c */
> > extern int hfs_ext_keycmp(const btree_key *, const
> btree_key *);
> > extern int hfs_free_fork(struct super_block *, struct
> hfs_cat_file *, int);
> > -extern void hfs_ext_write_extent(struct inode *);
> > +extern int hfs_ext_write_extent(struct inode *);
> > extern int hfs_extend_file(struct inode *);
> > extern void hfs_file_truncate(struct inode *);
> > 
> > diff --git a/fs/hfs/inode.c b/fs/hfs/inode.c
> > index 3031dfd..8ff4b5a 100644
> > --- a/fs/hfs/inode.c
> > +++ b/fs/hfs/inode.c
> > @@ -416,9 +416,12 @@ int hfs_write_inode(struct inode
> *inode, struct writeback_control *wbc)
> >     struct inode *main_inode = inode;
> >     struct hfs_find_data fd;
> >     hfs_cat_rec rec;
> > +    int res;
> > 
> >     dprint(DBG_INODE, "hfs_write_inode:
> %lu\n", inode->i_ino);
> > -    hfs_ext_write_extent(inode);
> > +    res = hfs_ext_write_extent(inode);
> > +    if (res)
> > +        return res;
> > 
> >     if (inode->i_ino <
> HFS_FIRSTUSER_CNID) {
> >         switch
> (inode->i_ino) {
> > @@ -515,7 +518,11 @@ static struct dentry
> *hfs_file_lookup(struct inode *dir, struct dentry *dentry,
> >     if (!inode)
> >         return
> ERR_PTR(-ENOMEM);
> > 
> > -   
> hfs_find_init(HFS_SB(dir->i_sb)->cat_tree, &fd);
> > +    res =
> hfs_find_init(HFS_SB(dir->i_sb)->cat_tree, &fd);
> > +    if (res) {
> > +        iput(inode);
> > +        return
> ERR_PTR(res);
> > +    }
> >     fd.search_key->cat =
> HFS_I(dir)->cat_key;
> >     res = hfs_brec_read(&fd,
> &rec, sizeof(rec));
> >     if (!res) {
> > diff --git a/fs/hfs/super.c b/fs/hfs/super.c
> > index bbaaa8a..719760b 100644
> > --- a/fs/hfs/super.c
> > +++ b/fs/hfs/super.c
> > @@ -418,7 +418,9 @@ static int hfs_fill_super(struct
> super_block *sb, void *data, int silent)
> >     }
> > 
> >     /* try to get the root inode */
> > -   
> hfs_find_init(HFS_SB(sb)->cat_tree, &fd);
> > +    res =
> hfs_find_init(HFS_SB(sb)->cat_tree, &fd);
> > +    if (res)
> > +        goto
> bail_no_root;
> >     res = hfs_cat_find_brec(sb,
> HFS_ROOT_CNID, &fd);
> >     if (!res) {
> >         if
> (fd.entrylength > sizeof(rec) || fd.entrylength < 0)
> {
> > -- 
> > 1.7.9.5
> > 
> > --
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