eCryptfs: Improve statfs reporting (4a26620d) · Commits · 戴 / test

fs/ecryptfs/crypto.c

+61 −7

Original line number	Diff line number	Diff line
		@@ -1990,6 +1990,17 @@ out:
		return;
		}

		static size_t ecryptfs_max_decoded_size(size_t encoded_size)
		{
		/* Not exact; conservatively long. Every block of 4
		* encoded characters decodes into a block of 3
		* decoded characters. This segment of code provides
		* the caller with the maximum amount of allocated
		* space that @dst will need to point to in a
		* subsequent call. */
		return ((encoded_size + 1) * 3) / 4;
		}

		/**
		* ecryptfs_decode_from_filename
		* @dst: If NULL, this function only sets @dst_size and returns. If
		@@ -2008,13 +2019,7 @@ ecryptfs_decode_from_filename(unsigned char dst, size_t dst_size,
		size_t dst_byte_offset = 0;

		if (dst == NULL) {
		/* Not exact; conservatively long. Every block of 4
		* encoded characters decodes into a block of 3
		* decoded characters. This segment of code provides
		* the caller with the maximum amount of allocated
		* space that @dst will need to point to in a
		* subsequent call. */
		(dst_size) = (((src_size + 1) 3) / 4);
		(*dst_size) = ecryptfs_max_decoded_size(src_size);
		goto out;
		}
		while (src_byte_offset < src_size) {
		@@ -2239,3 +2244,52 @@ out_free:
		out:
		return rc;
		}

		#define ENC_NAME_MAX_BLOCKLEN_8_OR_16 143

		int ecryptfs_set_f_namelen(long *namelen, long lower_namelen,
		struct ecryptfs_mount_crypt_stat *mount_crypt_stat)
		{
		struct blkcipher_desc desc;
		struct mutex *tfm_mutex;
		size_t cipher_blocksize;
		int rc;

		if (!(mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES)) {
		(*namelen) = lower_namelen;
		return 0;
		}

		rc = ecryptfs_get_tfm_and_mutex_for_cipher_name(&desc.tfm, &tfm_mutex,
		mount_crypt_stat->global_default_fn_cipher_name);
		if (unlikely(rc)) {
		(*namelen) = 0;
		return rc;
		}

		mutex_lock(tfm_mutex);
		cipher_blocksize = crypto_blkcipher_blocksize(desc.tfm);
		mutex_unlock(tfm_mutex);

		/* Return an exact amount for the common cases */
		if (lower_namelen == NAME_MAX
		&& (cipher_blocksize == 8 \|\| cipher_blocksize == 16)) {
		(*namelen) = ENC_NAME_MAX_BLOCKLEN_8_OR_16;
		return 0;
		}

		/* Return a safe estimate for the uncommon cases */
		(*namelen) = lower_namelen;
		(*namelen) -= ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE;
		/* Since this is the max decoded size, subtract 1 "decoded block" len */
		(namelen) = ecryptfs_max_decoded_size(namelen) - 3;
		(*namelen) -= ECRYPTFS_TAG_70_MAX_METADATA_SIZE;
		(*namelen) -= ECRYPTFS_FILENAME_MIN_RANDOM_PREPEND_BYTES;
		/* Worst case is that the filename is padded nearly a full block size */
		(*namelen) -= cipher_blocksize - 1;

		if ((*namelen) < 0)
		(*namelen) = 0;

		return 0;
		}

fs/ecryptfs/ecryptfs_kernel.h

+6 −0

Original line number	Diff line number	Diff line
		@@ -162,6 +162,10 @@ ecryptfs_get_key_payload_data(struct key *key)
		#define ECRYPTFS_NON_NULL 0x42 /* A reasonable substitute for NULL */
		#define MD5_DIGEST_SIZE 16
		#define ECRYPTFS_TAG_70_DIGEST_SIZE MD5_DIGEST_SIZE
		#define ECRYPTFS_TAG_70_MIN_METADATA_SIZE (1 + ECRYPTFS_MIN_PKT_LEN_SIZE \
		+ ECRYPTFS_SIG_SIZE + 1 + 1)
		#define ECRYPTFS_TAG_70_MAX_METADATA_SIZE (1 + ECRYPTFS_MAX_PKT_LEN_SIZE \
		+ ECRYPTFS_SIG_SIZE + 1 + 1)
		#define ECRYPTFS_FEK_ENCRYPTED_FILENAME_PREFIX "ECRYPTFS_FEK_ENCRYPTED."
		#define ECRYPTFS_FEK_ENCRYPTED_FILENAME_PREFIX_SIZE 23
		#define ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX "ECRYPTFS_FNEK_ENCRYPTED."
		@@ -701,6 +705,8 @@ ecryptfs_parse_tag_70_packet(char *filename, size_t filename_size,
		size_t *packet_size,
		struct ecryptfs_mount_crypt_stat *mount_crypt_stat,
		char *data, size_t max_packet_size);
		int ecryptfs_set_f_namelen(long *namelen, long lower_namelen,
		struct ecryptfs_mount_crypt_stat *mount_crypt_stat);
		int ecryptfs_derive_iv(char iv, struct ecryptfs_crypt_stat crypt_stat,
		loff_t offset);

fs/ecryptfs/keystore.c

+3 −6

Original line number	Diff line number	Diff line
		@@ -679,10 +679,7 @@ ecryptfs_write_tag_70_packet(char dest, size_t remaining_bytes,
		* Octets N3-N4: Block-aligned encrypted filename
		* - Consists of a minimum number of random characters, a \0
		* separator, and then the filename */
		s->max_packet_size = (1 /* Tag 70 identifier */
		+ 3 /* Max Tag 70 packet size */
		+ ECRYPTFS_SIG_SIZE /* FNEK sig */
		+ 1 /* Cipher identifier */
		s->max_packet_size = (ECRYPTFS_TAG_70_MAX_METADATA_SIZE
		+ s->block_aligned_filename_size);
		if (dest == NULL) {
		(*packet_size) = s->max_packet_size;
		@@ -934,10 +931,10 @@ ecryptfs_parse_tag_70_packet(char *filename, size_t filename_size,
		goto out;
		}
		s->desc.flags = CRYPTO_TFM_REQ_MAY_SLEEP;
		if (max_packet_size < (1 + 1 + ECRYPTFS_SIG_SIZE + 1 + 1)) {
		if (max_packet_size < ECRYPTFS_TAG_70_MIN_METADATA_SIZE) {
		printk(KERN_WARNING "%s: max_packet_size is [%zd]; it must be "
		"at least [%d]\n", __func__, max_packet_size,
		(1 + 1 + ECRYPTFS_SIG_SIZE + 1 + 1));
		ECRYPTFS_TAG_70_MIN_METADATA_SIZE);
		rc = -EINVAL;
		goto out;
		}

fs/ecryptfs/super.c

+13 −1

Original line number	Diff line number	Diff line
		@@ -30,6 +30,8 @@
		#include <linux/seq_file.h>
		#include <linux/file.h>
		#include <linux/crypto.h>
		#include <linux/statfs.h>
		#include <linux/magic.h>
		#include "ecryptfs_kernel.h"

		struct kmem_cache *ecryptfs_inode_info_cache;
		@@ -102,10 +104,20 @@ static void ecryptfs_destroy_inode(struct inode *inode)
		static int ecryptfs_statfs(struct dentry dentry, struct kstatfs buf)
		{
		struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry);
		int rc;

		if (!lower_dentry->d_sb->s_op->statfs)
		return -ENOSYS;
		return lower_dentry->d_sb->s_op->statfs(lower_dentry, buf);

		rc = lower_dentry->d_sb->s_op->statfs(lower_dentry, buf);
		if (rc)
		return rc;

		buf->f_type = ECRYPTFS_SUPER_MAGIC;
		rc = ecryptfs_set_f_namelen(&buf->f_namelen, buf->f_namelen,
		&ecryptfs_superblock_to_private(dentry->d_sb)->mount_crypt_stat);

		return rc;
		}

		/**

Admin message