On Tue, 2016-01-26 at 12:26 +0300, Dan Carpenter wrote:
> I was looking through static analysis warnings and we seem to be copying
> garbage into &rd->key. This goes back to before the start of git...
>
> Signed-off-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx>
> ---
> Not tested. Please review carefully.
>
> diff --git a/fs/hfs/dir.c b/fs/hfs/dir.c
> index 70788e0..66485d7 100644
> --- a/fs/hfs/dir.c
> +++ b/fs/hfs/dir.c
> @@ -163,7 +163,7 @@ static int hfs_readdir(struct file *file, struct dir_context *ctx)
> rd->file = file;
> list_add(&rd->list, &HFS_I(inode)->open_dir_list);
> }
> - memcpy(&rd->key, &fd.key, sizeof(struct hfs_cat_key));
> + memcpy(&rd->key, &fd.key->cat, sizeof(struct hfs_cat_key));
The field "key" is union:
164 typedef union hfs_btree_key {
165 u8 key_len; /* number of bytes in the key */
166 struct hfs_cat_key cat;
167 struct hfs_ext_key ext;
168 } hfs_btree_key;
The struct hfs_cat_key is the biggest item. So, size of this structure
is dominating in the union:
157 struct hfs_ext_key {
158 u8 key_len; /* number of bytes in the key */
159 u8 FkType; /* HFS_FK_{DATA,RSRC} */
160 __be32 FNum; /* The File ID of the file */
161 __be16 FABN; /* allocation blocks number*/
162 } __packed;
149 struct hfs_cat_key {
150 u8 key_len; /* number of bytes in the key */
151 u8 reserved; /* padding */
152 __be32 ParID; /* CNID of the parent dir */
153 struct hfs_name CName; /* The filename of the entry */
154 } __packed;
because:
27 #define HFS_NAMELEN 31 /* maximum length of an HFS filename */
87 struct hfs_name {
88 u8 len;
89 u8 name[HFS_NAMELEN];
90 } __packed;
If we are using sizeof(struct hfs_cat_key) then it looks like that we
could potentially miss one byte of the union during catalog key copying.
But if we will copy struct hfs_ext_key then we will copy some amount of
"garbage" anyway. So, I don't think that it's good fix of the issue.
What do you think?
Another worry could be the "search_key" field of the struct
hfs_find_data.
Thanks,
Vyacheslav Dubeyko.
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