leandrof/linux
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

cifsd: re-implement ksmbd_vfs_kern_path

Browse Source 
re-implement ksmbd_vfs_kern_path() to change
recursion to iteration.

Signed-off-by: Hyunchul Lee <hyc.lee@gmail.com>
Signed-off-by: Namjae Jeon <namjae.jeon@samsung.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
This commit is contained in:
Hyunchul Lee 2021-04-13 13:22:31 +09:00 committed by Steve French
parent 7c3d3e99ca
commit 3c20378325
1 changed files with 61 additions and 42 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

103
fs/cifsd/vfs.c
View File

@ -50,14 +50,6 @@ static char *extract_last_component(char *path)
return p;
}
static void rollback_path_modification(char *filename)
{
if (filename) {
filename--;
*filename = '/';
}
}
static void ksmbd_vfs_inherit_owner(struct ksmbd_work *work,
struct inode *parent_inode, struct inode *inode)
{
@ -1231,44 +1223,32 @@ static int __caseless_lookup(struct dir_context *ctx, const char *name,
/**
* ksmbd_vfs_lookup_in_dir() - lookup a file in a directory
* @dirname: directory name
* @filename: filename to lookup
* @dir: path info
* @name: filename to lookup
* @namelen: filename length
*
* Return: 0 on success, otherwise error
*/
static int ksmbd_vfs_lookup_in_dir(char *dirname, char *filename)
static int ksmbd_vfs_lookup_in_dir(struct path *dir, char *name, size_t namelen)
{
struct path dir_path;
int ret;
struct file *dfilp;
int flags = O_RDONLY | O_LARGEFILE;
int dirnamelen = strlen(dirname);
struct ksmbd_readdir_data readdir_data = {
.ctx.actor = __caseless_lookup,
.private = filename,
.used = strlen(filename),
.private = name,
.used = namelen,
.dirent_count = 0,
};
ret = ksmbd_vfs_kern_path(dirname, 0, &dir_path, true);
if (ret)
goto error;
dfilp = dentry_open(&dir_path, flags, current_cred());
if (IS_ERR(dfilp)) {
path_put(&dir_path);
ksmbd_err("cannot open directory %s\n", dirname);
ret = -EINVAL;
goto error;
}
dfilp = dentry_open(dir, flags, current_cred());
if (IS_ERR(dfilp))
return PTR_ERR(dfilp);
ret = ksmbd_vfs_readdir(dfilp, &readdir_data);
if (readdir_data.dirent_count > 0)
ret = 0;
fput(dfilp);
path_put(&dir_path);
error:
dirname[dirnamelen] = '/';
return ret;
}
@ -1284,30 +1264,69 @@ error:
int ksmbd_vfs_kern_path(char *name, unsigned int flags, struct path *path,
bool caseless)
{
char *filename = NULL;
int err;
if (name[0] != '/')
return -EINVAL;
err = kern_path(name, flags, path);
if (!err)
return err;
return 0;
if (caseless) {
filename = extract_last_component(name);
if (!filename)
goto out;
char *filepath;
struct path parent;
size_t path_len, remain_len;
/* root reached */
if (strlen(name) == 0)
goto out;
filepath = kstrdup(name, GFP_KERNEL);
if (!filepath)
return -ENOMEM;
err = ksmbd_vfs_lookup_in_dir(name, filename);
path_len = strlen(filepath);
remain_len = path_len - 1;
err = kern_path("/", flags, &parent);
if (err)
goto out;
err = kern_path(name, flags, path);
}
while (d_can_lookup(parent.dentry)) {
char *filename = filepath + path_len - remain_len;
char *next = strchrnul(filename, '/');
size_t filename_len = next - filename;
bool is_last = !next[0];
if (filename_len == 0)
break;
err = ksmbd_vfs_lookup_in_dir(&parent, filename,
filename_len);
if (err) {
path_put(&parent);
goto out;
}
path_put(&parent);
next[0] = '\0';
err = kern_path(filepath, flags, &parent);
if (err)
goto out;
if (is_last) {
path->mnt = parent.mnt;
path->dentry = parent.dentry;
goto out;
}
next[0] = '/';
remain_len -= filename_len + 1;
}
path_put(&parent);
err = -EINVAL;
out:
rollback_path_modification(filename);
kfree(filepath);
}
return err;
}