eCryptfs: track header bytes rather than extents
Remove internal references to header extents; just keep track of header bytes instead. Headers can easily span multiple pages with the recent persistent file changes. Signed-off-by: Michael Halcrow <mhalcrow@us.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Michael Halcrow
Linus Torvalds
Родитель
7896b63182
Коммит
cc11beffdf
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@ -379,8 +379,7 @@ out:
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static void ecryptfs_lower_offset_for_extent(loff_t *offset, loff_t extent_num,
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struct ecryptfs_crypt_stat *crypt_stat)
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{
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(*offset) = ((crypt_stat->extent_size
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* crypt_stat->num_header_extents_at_front)
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(*offset) = (crypt_stat->num_header_bytes_at_front
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+ (crypt_stat->extent_size * extent_num));
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}
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@ -842,15 +841,13 @@ void ecryptfs_set_default_sizes(struct ecryptfs_crypt_stat *crypt_stat)
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set_extent_mask_and_shift(crypt_stat);
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crypt_stat->iv_bytes = ECRYPTFS_DEFAULT_IV_BYTES;
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if (crypt_stat->flags & ECRYPTFS_METADATA_IN_XATTR)
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crypt_stat->num_header_extents_at_front = 0;
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crypt_stat->num_header_bytes_at_front = 0;
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else {
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if (PAGE_CACHE_SIZE <= ECRYPTFS_MINIMUM_HEADER_EXTENT_SIZE)
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crypt_stat->num_header_extents_at_front =
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(ECRYPTFS_MINIMUM_HEADER_EXTENT_SIZE
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/ crypt_stat->extent_size);
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crypt_stat->num_header_bytes_at_front =
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ECRYPTFS_MINIMUM_HEADER_EXTENT_SIZE;
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else
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crypt_stat->num_header_extents_at_front =
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(PAGE_CACHE_SIZE / crypt_stat->extent_size);
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crypt_stat->num_header_bytes_at_front = PAGE_CACHE_SIZE;
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}
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}
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@ -1236,7 +1233,8 @@ ecryptfs_write_header_metadata(char *virt,
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header_extent_size = (u32)crypt_stat->extent_size;
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num_header_extents_at_front =
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(u16)crypt_stat->num_header_extents_at_front;
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(u16)(crypt_stat->num_header_bytes_at_front
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/ crypt_stat->extent_size);
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header_extent_size = cpu_to_be32(header_extent_size);
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memcpy(virt, &header_extent_size, 4);
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virt += 4;
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@ -1311,40 +1309,16 @@ static int ecryptfs_write_headers_virt(char *page_virt, size_t *size,
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static int
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ecryptfs_write_metadata_to_contents(struct ecryptfs_crypt_stat *crypt_stat,
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struct dentry *ecryptfs_dentry,
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char *page_virt)
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char *virt)
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{
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int current_header_page;
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int header_pages;
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int rc;
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rc = ecryptfs_write_lower(ecryptfs_dentry->d_inode, page_virt,
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0, PAGE_CACHE_SIZE);
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if (rc) {
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rc = ecryptfs_write_lower(ecryptfs_dentry->d_inode, virt,
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0, crypt_stat->num_header_bytes_at_front);
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if (rc)
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printk(KERN_ERR "%s: Error attempting to write header "
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"information to lower file; rc = [%d]\n", __FUNCTION__,
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rc);
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goto out;
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}
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header_pages = ((crypt_stat->extent_size
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* crypt_stat->num_header_extents_at_front)
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/ PAGE_CACHE_SIZE);
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memset(page_virt, 0, PAGE_CACHE_SIZE);
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current_header_page = 1;
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while (current_header_page < header_pages) {
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loff_t offset;
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offset = (((loff_t)current_header_page) << PAGE_CACHE_SHIFT);
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if ((rc = ecryptfs_write_lower(ecryptfs_dentry->d_inode,
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page_virt, offset,
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PAGE_CACHE_SIZE))) {
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printk(KERN_ERR "%s: Error attempting to write header "
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"information to lower file; rc = [%d]\n",
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__FUNCTION__, rc);
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goto out;
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}
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current_header_page++;
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}
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out:
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return rc;
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}
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@ -1370,15 +1344,13 @@ ecryptfs_write_metadata_to_xattr(struct dentry *ecryptfs_dentry,
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* retrieved via a prompt. Exactly what happens at this point should
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* be policy-dependent.
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*
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* TODO: Support header information spanning multiple pages
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*
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* Returns zero on success; non-zero on error
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*/
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int ecryptfs_write_metadata(struct dentry *ecryptfs_dentry)
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{
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struct ecryptfs_crypt_stat *crypt_stat =
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&ecryptfs_inode_to_private(ecryptfs_dentry->d_inode)->crypt_stat;
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char *page_virt;
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char *virt;
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size_t size = 0;
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int rc = 0;
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@ -1389,40 +1361,39 @@ int ecryptfs_write_metadata(struct dentry *ecryptfs_dentry)
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goto out;
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}
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} else {
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printk(KERN_WARNING "%s: Encrypted flag not set\n",
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__FUNCTION__);
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rc = -EINVAL;
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ecryptfs_printk(KERN_WARNING,
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"Called with crypt_stat->encrypted == 0\n");
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goto out;
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}
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/* Released in this function */
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page_virt = kmem_cache_zalloc(ecryptfs_header_cache_0, GFP_USER);
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if (!page_virt) {
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ecryptfs_printk(KERN_ERR, "Out of memory\n");
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virt = kzalloc(crypt_stat->num_header_bytes_at_front, GFP_KERNEL);
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if (!virt) {
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printk(KERN_ERR "%s: Out of memory\n", __FUNCTION__);
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rc = -ENOMEM;
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goto out;
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}
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rc = ecryptfs_write_headers_virt(page_virt, &size, crypt_stat,
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ecryptfs_dentry);
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rc = ecryptfs_write_headers_virt(virt, &size, crypt_stat,
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ecryptfs_dentry);
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if (unlikely(rc)) {
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ecryptfs_printk(KERN_ERR, "Error whilst writing headers\n");
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memset(page_virt, 0, PAGE_CACHE_SIZE);
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printk(KERN_ERR "%s: Error whilst writing headers; rc = [%d]\n",
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__FUNCTION__, rc);
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goto out_free;
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}
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if (crypt_stat->flags & ECRYPTFS_METADATA_IN_XATTR)
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rc = ecryptfs_write_metadata_to_xattr(ecryptfs_dentry,
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crypt_stat, page_virt,
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size);
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crypt_stat, virt, size);
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else
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rc = ecryptfs_write_metadata_to_contents(crypt_stat,
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ecryptfs_dentry,
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page_virt);
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ecryptfs_dentry, virt);
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if (rc) {
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printk(KERN_ERR "Error writing metadata out to lower file; "
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"rc = [%d]\n", rc);
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printk(KERN_ERR "%s: Error writing metadata out to lower file; "
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"rc = [%d]\n", __FUNCTION__, rc);
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goto out_free;
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}
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out_free:
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kmem_cache_free(ecryptfs_header_cache_0, page_virt);
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memset(virt, 0, crypt_stat->num_header_bytes_at_front);
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kfree(virt);
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out:
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return rc;
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}
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@ -1442,16 +1413,16 @@ static int parse_header_metadata(struct ecryptfs_crypt_stat *crypt_stat,
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virt += sizeof(u32);
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memcpy(&num_header_extents_at_front, virt, sizeof(u16));
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num_header_extents_at_front = be16_to_cpu(num_header_extents_at_front);
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crypt_stat->num_header_extents_at_front =
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(int)num_header_extents_at_front;
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crypt_stat->num_header_bytes_at_front =
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(((size_t)num_header_extents_at_front
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* (size_t)header_extent_size));
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(*bytes_read) = (sizeof(u32) + sizeof(u16));
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if ((validate_header_size == ECRYPTFS_VALIDATE_HEADER_SIZE)
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&& ((crypt_stat->extent_size
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* crypt_stat->num_header_extents_at_front)
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&& (crypt_stat->num_header_bytes_at_front
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< ECRYPTFS_MINIMUM_HEADER_EXTENT_SIZE)) {
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rc = -EINVAL;
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printk(KERN_WARNING "Invalid number of header extents: [%zd]\n",
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crypt_stat->num_header_extents_at_front);
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printk(KERN_WARNING "Invalid header size: [%zd]\n",
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crypt_stat->num_header_bytes_at_front);
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}
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return rc;
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}
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@ -1466,7 +1437,8 @@ static int parse_header_metadata(struct ecryptfs_crypt_stat *crypt_stat,
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*/
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static void set_default_header_data(struct ecryptfs_crypt_stat *crypt_stat)
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{
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crypt_stat->num_header_extents_at_front = 2;
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crypt_stat->num_header_bytes_at_front =
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ECRYPTFS_MINIMUM_HEADER_EXTENT_SIZE;
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}
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/**
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@ -237,7 +237,7 @@ struct ecryptfs_crypt_stat {
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u32 flags;
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unsigned int file_version;
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size_t iv_bytes;
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size_t num_header_extents_at_front;
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size_t num_header_bytes_at_front;
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size_t extent_size; /* Data extent size; default is 4096 */
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size_t key_size;
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size_t extent_shift;
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@ -518,7 +518,6 @@ extern struct kmem_cache *ecryptfs_file_info_cache;
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extern struct kmem_cache *ecryptfs_dentry_info_cache;
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extern struct kmem_cache *ecryptfs_inode_info_cache;
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extern struct kmem_cache *ecryptfs_sb_info_cache;
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extern struct kmem_cache *ecryptfs_header_cache_0;
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extern struct kmem_cache *ecryptfs_header_cache_1;
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extern struct kmem_cache *ecryptfs_header_cache_2;
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extern struct kmem_cache *ecryptfs_xattr_cache;
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@ -365,8 +365,7 @@ static struct dentry *ecryptfs_lookup(struct inode *dir, struct dentry *dentry,
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dentry->d_sb)->mount_crypt_stat;
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if (mount_crypt_stat->flags & ECRYPTFS_ENCRYPTED_VIEW_ENABLED) {
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if (crypt_stat->flags & ECRYPTFS_METADATA_IN_XATTR)
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file_size = ((crypt_stat->extent_size
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* crypt_stat->num_header_extents_at_front)
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file_size = (crypt_stat->num_header_bytes_at_front
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+ i_size_read(lower_dentry->d_inode));
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else
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file_size = i_size_read(lower_dentry->d_inode);
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@ -685,7 +684,7 @@ ecryptfs_put_link(struct dentry *dentry, struct nameidata *nd, void *ptr)
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* @crypt_stat: Crypt_stat associated with file
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* @upper_size: Size of the upper file
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*
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* Calculate the requried size of the lower file based on the
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* Calculate the required size of the lower file based on the
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* specified size of the upper file. This calculation is based on the
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* number of headers in the underlying file and the extent size.
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*
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@ -697,8 +696,7 @@ upper_size_to_lower_size(struct ecryptfs_crypt_stat *crypt_stat,
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{
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loff_t lower_size;
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lower_size = (crypt_stat->extent_size
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* crypt_stat->num_header_extents_at_front);
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lower_size = crypt_stat->num_header_bytes_at_front;
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if (upper_size != 0) {
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loff_t num_extents;
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@ -653,11 +653,6 @@ static struct ecryptfs_cache_info {
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.name = "ecryptfs_sb_cache",
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.size = sizeof(struct ecryptfs_sb_info),
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},
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{
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.cache = &ecryptfs_header_cache_0,
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.name = "ecryptfs_headers_0",
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.size = PAGE_CACHE_SIZE,
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},
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{
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.cache = &ecryptfs_header_cache_1,
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.name = "ecryptfs_headers_1",
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@ -100,13 +100,14 @@ static void set_header_info(char *page_virt,
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struct ecryptfs_crypt_stat *crypt_stat)
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{
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size_t written;
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int save_num_header_extents_at_front =
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crypt_stat->num_header_extents_at_front;
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size_t save_num_header_bytes_at_front =
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crypt_stat->num_header_bytes_at_front;
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crypt_stat->num_header_extents_at_front = 1;
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crypt_stat->num_header_bytes_at_front =
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ECRYPTFS_MINIMUM_HEADER_EXTENT_SIZE;
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ecryptfs_write_header_metadata(page_virt + 20, crypt_stat, &written);
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crypt_stat->num_header_extents_at_front =
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save_num_header_extents_at_front;
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crypt_stat->num_header_bytes_at_front =
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save_num_header_bytes_at_front;
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}
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/**
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@ -132,8 +133,11 @@ ecryptfs_copy_up_encrypted_with_header(struct page *page,
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loff_t view_extent_num = ((((loff_t)page->index)
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* num_extents_per_page)
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+ extent_num_in_page);
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size_t num_header_extents_at_front =
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(crypt_stat->num_header_bytes_at_front
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/ crypt_stat->extent_size);
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if (view_extent_num < crypt_stat->num_header_extents_at_front) {
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if (view_extent_num < num_header_extents_at_front) {
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/* This is a header extent */
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char *page_virt;
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@ -155,9 +159,8 @@ ecryptfs_copy_up_encrypted_with_header(struct page *page,
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} else {
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/* This is an encrypted data extent */
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loff_t lower_offset =
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((view_extent_num -
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crypt_stat->num_header_extents_at_front)
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* crypt_stat->extent_size);
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((view_extent_num * crypt_stat->extent_size)
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- crypt_stat->num_header_bytes_at_front);
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rc = ecryptfs_read_lower_page_segment(
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page, (lower_offset >> PAGE_CACHE_SHIFT),
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