Re: [PATCH 1/2] hfs: add error checking for hfs_find_init()

From: Vyacheslav Dubeyko
Date: Wed Apr 10 2013 - 02:40:34 EST

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On Tue, 2013-04-09 at 22:14 +0400, 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().
>

Looks good for me.

Reviewed-by: Vyacheslav Dubeyko <slava@xxxxxxxxxxx>

Tnanks,
Vyacheslav Dubeyko.

> Found by Linux Driver Verification project (linuxtesting.org).
>
> Signed-off-by: Alexey Khoroshilov <khoroshilov@xxxxxxxxx>
> ---
> 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;
> }
>
> -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;
> + }
>
> 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..0847471 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) {

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