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Commit 1530be50 authored by Paul Lawrence's avatar Paul Lawrence
Browse files

ANDROID: Incremental fs: Add INCFS_IOC_PERMIT_FILL 



Provide a securable way to open a file for filling

Test: incfs_test passes
Bug: 138149732
Signed-off-by: default avatarPaul Lawrence <paullawrence@google.com>
Change-Id: Ib4b6fd839ad30ce08e31121d19e2c0d7066d302f
parent 73e7d656

fs/incfs/vfs.c

+60 −2
Original line number Diff line number Diff line
@@ -132,6 +132,11 @@ static const struct file_operations incfs_file_ops = { 
	.compat_ioctl = dispatch_ioctl

};



enum FILL_PERMISSION {

	CANT_FILL = 0,

	CAN_FILL = 1,

};



static const struct file_operations incfs_pending_read_file_ops = {

	.read = pending_reads_read,

	.poll = pending_reads_poll,
@@ -1281,6 +1286,9 @@ static long ioctl_fill_blocks(struct file *f, void __user *arg) 
	if (!df)

		return -EBADF;



	if ((uintptr_t)f->private_data != CAN_FILL)

		return -EPERM;



	if (copy_from_user(&fill_blocks, usr_fill_blocks, sizeof(fill_blocks)))

		return -EFAULT;
@@ -1333,6 +1341,53 @@ static long ioctl_fill_blocks(struct file *f, void __user *arg) 
	return i;

}



static long ioctl_permit_fill(struct file *f, void __user *arg)

{

	struct incfs_permit_fill __user *usr_permit_fill = arg;

	struct incfs_permit_fill permit_fill;

	long error = 0;

	struct file *file = 0;



	if (f->f_op != &incfs_pending_read_file_ops)

		return -EPERM;



	if (copy_from_user(&permit_fill, usr_permit_fill, sizeof(permit_fill)))

		return -EFAULT;



	file = fget(permit_fill.file_descriptor);

	if (IS_ERR(file))

		return PTR_ERR(file);



	if (file->f_op != &incfs_file_ops) {

		error = -EPERM;

		goto out;

	}



	if (file->f_inode->i_sb != f->f_inode->i_sb) {

		error = -EPERM;

		goto out;

	}



	switch ((uintptr_t)file->private_data) {

	case CANT_FILL:

		file->private_data = (void *)CAN_FILL;

		break;



	case CAN_FILL:

		pr_debug("CAN_FILL already set");

		break;



	default:

		pr_warn("Invalid file private data");

		error = -EFAULT;

		goto out;

	}



out:

	fput(file);

	return error;

}



static long ioctl_read_file_signature(struct file *f, void __user *arg)

{

	struct incfs_get_file_sig_args __user *args_usr_ptr = arg;
@@ -1390,6 +1445,8 @@ static long dispatch_ioctl(struct file *f, unsigned int req, unsigned long arg) 
		return ioctl_create_file(mi, (void __user *)arg);

	case INCFS_IOC_FILL_BLOCKS:

		return ioctl_fill_blocks(f, (void __user *)arg);

	case INCFS_IOC_PERMIT_FILL:

		return ioctl_permit_fill(f, (void __user *)arg);

	case INCFS_IOC_READ_FILE_SIGNATURE:

		return ioctl_read_file_signature(f, (void __user *)arg);

	default:
@@ -1820,9 +1877,10 @@ static int file_open(struct inode *inode, struct file *file) 
		goto out;

	}



	if (S_ISREG(inode->i_mode))

	if (S_ISREG(inode->i_mode)) {

		err = make_inode_ready_for_data_ops(mi, inode, backing_file);

	else if (S_ISDIR(inode->i_mode)) {

		file->private_data = (void *)CANT_FILL;

	} else if (S_ISDIR(inode->i_mode)) {

		struct dir_file *dir = NULL;



		dir = incfs_open_dir_file(mi, backing_file);

include/uapi/linux/incrementalfs.h

+22 −1
Original line number Diff line number Diff line
@@ -51,13 +51,23 @@ 
	_IOR(INCFS_IOCTL_BASE_CODE, 31, struct incfs_get_file_sig_args)



/*

 * Fill in one or more data block

 * Fill in one or more data block. This may only be called on a handle

 * passed as a parameter to INCFS_IOC_PERMIT_FILLING

 *

 * Returns number of blocks filled in, or error if none were

 */

#define INCFS_IOC_FILL_BLOCKS                                                  \

	_IOR(INCFS_IOCTL_BASE_CODE, 32, struct incfs_fill_blocks)



/*

 * Permit INCFS_IOC_FILL_BLOCKS on the given file descriptor

 * May only be called on .pending_reads file

 *

 * Returns 0 on success or error

 */

#define INCFS_IOC_PERMIT_FILL                                                  \

	_IOW(INCFS_IOCTL_BASE_CODE, 33, struct incfs_permit_fill)



enum incfs_compression_alg {

	COMPRESSION_NONE = 0,

	COMPRESSION_LZ4 = 1
@@ -136,6 +146,17 @@ struct incfs_fill_blocks { 
	__aligned_u64 fill_blocks;

};



/*

 * Permit INCFS_IOC_FILL_BLOCKS on the given file descriptor

 * May only be called on .pending_reads file

 *

 * Argument for INCFS_IOC_PERMIT_FILL

 */

struct incfs_permit_fill {

	/* File to permit fills on */

	__u32 file_descriptor;

};



enum incfs_hash_tree_algorithm {

	INCFS_HASH_TREE_NONE = 0,

	INCFS_HASH_TREE_SHA256 = 1

tools/testing/selftests/filesystems/incfs/incfs_test.c

+61 −12
Original line number Diff line number Diff line
@@ -204,15 +204,43 @@ static char *get_index_filename(const char *mnt_dir, incfs_uuid_t id) 
	return strdup(path);

}



int open_file_by_id(char *mnt_dir, incfs_uuid_t id)

int open_file_by_id(const char *mnt_dir, incfs_uuid_t id, bool use_ioctl)

{

	char *path = get_index_filename(mnt_dir, id);

	int cmd_fd = open_commands_file(mnt_dir);

	int fd = open(path, O_RDWR);

	struct incfs_permit_fill permit_fill = {

		.file_descriptor = fd,

	};

	int error = 0;



	free(path);

	if (fd < 0) {

		print_error("Can't open file by id.");

		error = -errno;

		goto out;

	}



	if (use_ioctl && ioctl(cmd_fd, INCFS_IOC_PERMIT_FILL, &permit_fill)) {

		print_error("Failed to call PERMIT_FILL");

		error = -errno;

		goto out;

	}



	if (ioctl(fd, INCFS_IOC_PERMIT_FILL, &permit_fill) != -1 ||

	    errno != EPERM) {

		print_error(

			"Successfully called PERMIT_FILL on non pending_read file");

		return -errno;

		goto out;

	}



out:

	free(path);

	close(cmd_fd);



	if (error) {

		close(fd);

		return error;

	}



	return fd;
@@ -258,12 +286,6 @@ static int emit_test_blocks(char *mnt_dir, struct test_file *file, 
	int i = 0;

	int blocks_written = 0;



	fd = open_file_by_id(mnt_dir, file->id);

	if (fd <= 0) {

		error = -errno;

		goto out;

	}



	for (i = 0; i < block_count; i++) {

		int block_index = blocks[i];

		bool compress = (file->index + block_index) % 2 == 0;
@@ -315,6 +337,24 @@ static int emit_test_blocks(char *mnt_dir, struct test_file *file, 
	}



	if (!error) {

		fd = open_file_by_id(mnt_dir, file->id, false);

		if (fd < 0) {

			error = -errno;

			goto out;

		}

		write_res = ioctl(fd, INCFS_IOC_FILL_BLOCKS, &fill_blocks);

		if (write_res >= 0) {

			ksft_print_msg("Wrote to file via normal fd error\n");

			error = -EPERM;

			goto out;

		}



		close(fd);

		fd = open_file_by_id(mnt_dir, file->id, true);

		if (fd < 0) {

			error = -errno;

			goto out;

		}

		write_res = ioctl(fd, INCFS_IOC_FILL_BLOCKS, &fill_blocks);

		if (write_res < 0)

			error = -errno;
@@ -706,7 +746,6 @@ static int load_hash_tree(const char *mount_dir, struct test_file *file) 
	int err;

	int i;

	int fd;

	char *file_path;

	struct incfs_fill_blocks fill_blocks = {

		.count = file->mtree_block_count,

	};
@@ -729,9 +768,7 @@ static int load_hash_tree(const char *mount_dir, struct test_file *file) 
		};

	}



	file_path  = concat_file_name(mount_dir, file->name);

	fd = open(file_path, O_RDWR);

	free(file_path);

	fd = open_file_by_id(mount_dir, file->id, false);

	if (fd < 0) {

		err = errno;

		goto failure;
@@ -739,7 +776,19 @@ static int load_hash_tree(const char *mount_dir, struct test_file *file) 


	err = ioctl(fd, INCFS_IOC_FILL_BLOCKS, &fill_blocks);

	close(fd);

	if (err >= 0) {

		err = -EPERM;

		goto failure;

	}



	fd = open_file_by_id(mount_dir, file->id, true);

	if (fd < 0) {

		err = errno;

		goto failure;

	}



	err = ioctl(fd, INCFS_IOC_FILL_BLOCKS, &fill_blocks);

	close(fd);

	if (err < fill_blocks.count)

		err = errno;

	else {