void *prompt_passphrase(stegdisk_t *sctx)
{
void *hash = steg_malloc(KEY_BYTES);
if(get_key_hash(hash)) {
steg_free(hash);
return NULL;
}
return hash;
}
/**
* main_enc_dec
* @f: pointer to struct which contains information about input,temporary and output files
* @user_args: pointer to struct user_args_t which contains arguments given by user in user-space
*
* Initiates basic validation checks to be performed before starting encryption/decryption. Gets the required file handles. Post encryption
* or decryption, renames and unlinks the file as required.
*
* Returns 0 on success;non-zero otherwise
*/
int main_enc_dec(struct file_struct *f, struct user_args_t *user_args)
{
int err, tmp_err;
char *key_hash;
struct dentry *lower_old_dentry;
struct dentry *lower_new_dentry;
struct dentry *lower_old_dir_dentry;
struct dentry *lower_new_dir_dentry;
struct dentry *trap = NULL;
err = validate_in_out_file(f);
f->filp_in = f->filp_out = f->filp_temp = NULL;
if (err) {
printk(KERN_ALERT"error in validate in out");
goto ERR;
}
key_hash = get_key_hash(user_args->enc_key);
if (IS_ERR(key_hash)) {
err = PTR_ERR(key_hash);
goto ERR;
}
err = get_file_handle(&(f->filp_in), f->in_file->name, O_RDONLY, 0);
if (err)
goto ERR_KEY;
if (!(f->filp_in->f_op->read)) {
printk(KERN_ALERT"read operation not supported\n");
err = -EPERM;
goto ERR_IN;
}
printk(KERN_ALERT"read file permission\n");
if (f->create_out_file == 'y') {
printk(KERN_ALERT"file with default permission\n");
err = get_file_handle(&(f->filp_temp), "/tmp/my_temp_file", O_WRONLY|O_CREAT|O_TRUNC, 0666-current_umask());
} else {
printk(KERN_ALERT"creating file with outfile mode\n");
err = get_file_handle(&(f->filp_temp), "/tmp/my_temp_file", O_WRONLY|O_CREAT|O_TRUNC, f->out_file_mode);
}
if (err)
goto ERR_IN;
printk(KERN_ALERT"file permission for temp file=\n");
printk(KERN_ALERT"\n");
if (user_args->flags == 1)
err = encrypt(f, &key_hash[0], user_args);
else
err = decrypt(f, &key_hash[0], user_args);
if (err) {
tmp_err = err;
err = vfs_unlink(d_inode(f->filp_temp->f_path.dentry->d_parent), f->filp_temp->f_path.dentry, NULL);
if (err)
printk(KERN_ALERT"Error in unlink\n");
err = tmp_err;
goto ERR_IN;
}
printk(KERN_ALERT"enc/dec done so now doing a rename\n");
if (f->create_out_file == 'y')
err = get_file_handle(&(f->filp_out), f->out_file->name, O_WRONLY|O_CREAT|O_TRUNC, 0666-current_umask());
else
err = get_file_handle(&(f->filp_out), f->out_file->name, O_WRONLY, 0);
if (err)
goto ERR_OUT;
if (!(f->filp_out->f_op->write)) {
printk(KERN_ALERT"write operation not supported\n");
err = -EPERM;
goto ERR;
}
lower_old_dentry = f->filp_temp->f_path.dentry;
lower_old_dir_dentry = dget_parent(lower_old_dentry);
lower_new_dentry = f->filp_out->f_path.dentry;
lower_new_dir_dentry = dget_parent(lower_new_dentry);
trap = lock_rename(lower_old_dir_dentry, lower_new_dir_dentry);
err = vfs_rename(d_inode(lower_old_dir_dentry), lower_old_dentry,
d_inode(lower_new_dir_dentry), lower_new_dentry,
NULL, 0);
if (err) {
printk(KERN_ALERT"error in rename\n");
tmp_err = err;
err = vfs_unlink(d_inode(f->filp_temp->f_path.dentry->d_parent), f->filp_temp->f_path.dentry, NULL);
if (err)
printk(KERN_ALERT"Error in unlink\n");
if (f->create_out_file == 'y') {
err = vfs_unlink(d_inode(f->filp_temp->f_path.dentry->d_parent), f->filp_temp->f_path.dentry, NULL);
if (err)
printk(KERN_ALERT"Error in unlink\n");
}
err = tmp_err;
}
printk(KERN_ALERT"rename done!\n");
unlock_rename(lower_old_dir_dentry, lower_new_dir_dentry);
if (f->filp_temp)
filp_close(f->filp_temp, NULL);
ERR_OUT:
if (f->filp_out)
filp_close(f->filp_out, NULL);
ERR_IN:
if (f->filp_in)
filp_close(f->filp_in, NULL);
ERR_KEY:
kfree(key_hash);
ERR:
return err;
}
