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https://github.com/Fishwaldo/Star64_linux.git
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[PATCH] eCryptfs: Generalize metadata read/write
Generalize the metadata reading and writing mechanisms, with two targets for now: metadata in file header and metadata in the user.ecryptfs xattr of the lower file. [akpm@osdl.org: printk warning fix] [bunk@stusta.de: make some needlessly global code static] 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
parent
17398957aa
commit
dd2a3b7ad9
7 changed files with 348 additions and 146 deletions
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@ -3,7 +3,7 @@
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*
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* Copyright (C) 1997-2004 Erez Zadok
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* Copyright (C) 2001-2004 Stony Brook University
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* Copyright (C) 2004-2006 International Business Machines Corp.
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* Copyright (C) 2004-2007 International Business Machines Corp.
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* Author(s): Michael A. Halcrow <mahalcro@us.ibm.com>
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* Michael C. Thompson <mcthomps@us.ibm.com>
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*
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@ -863,7 +863,10 @@ void ecryptfs_set_default_sizes(struct ecryptfs_crypt_stat *crypt_stat)
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ECRYPTFS_MINIMUM_HEADER_EXTENT_SIZE;
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} else
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crypt_stat->header_extent_size = PAGE_CACHE_SIZE;
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crypt_stat->num_header_extents_at_front = 1;
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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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else
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crypt_stat->num_header_extents_at_front = 1;
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}
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/**
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@ -1021,7 +1024,7 @@ int ecryptfs_new_file_context(struct dentry *ecryptfs_dentry)
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*
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* Returns one if marker found; zero if not found
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*/
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int contains_ecryptfs_marker(char *data)
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static int contains_ecryptfs_marker(char *data)
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{
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u32 m_1, m_2;
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@ -1047,7 +1050,8 @@ struct ecryptfs_flag_map_elem {
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/* Add support for additional flags by adding elements here. */
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static struct ecryptfs_flag_map_elem ecryptfs_flag_map[] = {
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{0x00000001, ECRYPTFS_ENABLE_HMAC},
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{0x00000002, ECRYPTFS_ENCRYPTED}
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{0x00000002, ECRYPTFS_ENCRYPTED},
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{0x00000004, ECRYPTFS_METADATA_IN_XATTR}
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};
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/**
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@ -1207,8 +1211,8 @@ int ecryptfs_cipher_code_to_string(char *str, u16 cipher_code)
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*
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* Returns zero on success; non-zero otherwise
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*/
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int ecryptfs_read_header_region(char *data, struct dentry *dentry,
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struct vfsmount *mnt)
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static int ecryptfs_read_header_region(char *data, struct dentry *dentry,
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struct vfsmount *mnt)
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{
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struct file *lower_file;
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mm_segment_t oldfs;
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@ -1237,6 +1241,21 @@ out:
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return rc;
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}
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int ecryptfs_read_and_validate_header_region(char *data, struct dentry *dentry,
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struct vfsmount *mnt)
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{
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int rc;
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rc = ecryptfs_read_header_region(data, dentry, mnt);
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if (rc)
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goto out;
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if (!contains_ecryptfs_marker(data + ECRYPTFS_FILE_SIZE_BYTES))
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rc = -EINVAL;
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out:
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return rc;
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}
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static void
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write_header_metadata(char *virt, struct ecryptfs_crypt_stat *crypt_stat,
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size_t *written)
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@ -1288,9 +1307,9 @@ struct kmem_cache *ecryptfs_header_cache_2;
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*
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* Returns zero on success
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*/
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int ecryptfs_write_headers_virt(char *page_virt,
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struct ecryptfs_crypt_stat *crypt_stat,
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struct dentry *ecryptfs_dentry)
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static int ecryptfs_write_headers_virt(char *page_virt, size_t *size,
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struct ecryptfs_crypt_stat *crypt_stat,
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struct dentry *ecryptfs_dentry)
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{
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int rc;
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size_t written;
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@ -1309,11 +1328,53 @@ int ecryptfs_write_headers_virt(char *page_virt,
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if (rc)
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ecryptfs_printk(KERN_WARNING, "Error generating key packet "
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"set; rc = [%d]\n", rc);
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if (size) {
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offset += written;
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*size = offset;
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}
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return rc;
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}
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static int ecryptfs_write_metadata_to_contents(struct ecryptfs_crypt_stat *crypt_stat,
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struct file *lower_file,
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char *page_virt)
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{
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mm_segment_t oldfs;
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int current_header_page;
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int header_pages;
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lower_file->f_pos = 0;
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oldfs = get_fs();
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set_fs(get_ds());
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lower_file->f_op->write(lower_file, (char __user *)page_virt,
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PAGE_CACHE_SIZE, &lower_file->f_pos);
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header_pages = ((crypt_stat->header_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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lower_file->f_op->write(lower_file, (char __user *)page_virt,
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PAGE_CACHE_SIZE, &lower_file->f_pos);
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current_header_page++;
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}
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set_fs(oldfs);
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return 0;
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}
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static int ecryptfs_write_metadata_to_xattr(struct dentry *ecryptfs_dentry,
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struct ecryptfs_crypt_stat *crypt_stat,
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char *page_virt, size_t size)
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{
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int rc;
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rc = ecryptfs_setxattr(ecryptfs_dentry, ECRYPTFS_XATTR_NAME, page_virt,
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size, 0);
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return rc;
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}
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/**
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* ecryptfs_write_headers
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* ecryptfs_write_metadata
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* @lower_file: The lower file struct, which was returned from dentry_open
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*
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* Write the file headers out. This will likely involve a userspace
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@ -1324,14 +1385,12 @@ int ecryptfs_write_headers_virt(char *page_virt,
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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_headers(struct dentry *ecryptfs_dentry,
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struct file *lower_file)
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int ecryptfs_write_metadata(struct dentry *ecryptfs_dentry,
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struct file *lower_file)
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{
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mm_segment_t oldfs;
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struct ecryptfs_crypt_stat *crypt_stat;
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char *page_virt;
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int current_header_page;
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int header_pages;
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size_t size;
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int rc = 0;
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crypt_stat = &ecryptfs_inode_to_private(
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@ -1358,48 +1417,36 @@ int ecryptfs_write_headers(struct dentry *ecryptfs_dentry,
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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, crypt_stat,
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ecryptfs_dentry);
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rc = ecryptfs_write_headers_virt(page_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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goto out_free;
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}
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ecryptfs_printk(KERN_DEBUG,
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"Writing key packet set to underlying file\n");
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lower_file->f_pos = 0;
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oldfs = get_fs();
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set_fs(get_ds());
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ecryptfs_printk(KERN_DEBUG, "Calling lower_file->f_op->"
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"write() w/ header page; lower_file->f_pos = "
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"[0x%.16x]\n", lower_file->f_pos);
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lower_file->f_op->write(lower_file, (char __user *)page_virt,
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PAGE_CACHE_SIZE, &lower_file->f_pos);
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header_pages = ((crypt_stat->header_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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ecryptfs_printk(KERN_DEBUG, "Calling lower_file->f_op->"
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"write() w/ zero'd page; lower_file->f_pos = "
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"[0x%.16x]\n", lower_file->f_pos);
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lower_file->f_op->write(lower_file, (char __user *)page_virt,
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PAGE_CACHE_SIZE, &lower_file->f_pos);
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current_header_page++;
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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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else
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rc = ecryptfs_write_metadata_to_contents(crypt_stat, lower_file,
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page_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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goto out_free;
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}
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set_fs(oldfs);
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ecryptfs_printk(KERN_DEBUG,
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"Done writing key packet set to underlying file.\n");
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out_free:
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kmem_cache_free(ecryptfs_header_cache_0, page_virt);
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out:
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return rc;
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}
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#define ECRYPTFS_DONT_VALIDATE_HEADER_SIZE 0
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#define ECRYPTFS_VALIDATE_HEADER_SIZE 1
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static int parse_header_metadata(struct ecryptfs_crypt_stat *crypt_stat,
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char *virt, int *bytes_read)
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char *virt, int *bytes_read,
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int validate_header_size)
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{
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int rc = 0;
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u32 header_extent_size;
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@ -1414,9 +1461,10 @@ static int parse_header_metadata(struct ecryptfs_crypt_stat *crypt_stat,
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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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(*bytes_read) = 6;
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if ((crypt_stat->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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if ((validate_header_size == ECRYPTFS_VALIDATE_HEADER_SIZE)
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&& ((crypt_stat->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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rc = -EINVAL;
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ecryptfs_printk(KERN_WARNING, "Invalid header extent size: "
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"[%d]\n", crypt_stat->header_extent_size);
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@ -1447,7 +1495,8 @@ static void set_default_header_data(struct ecryptfs_crypt_stat *crypt_stat)
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*/
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static int ecryptfs_read_headers_virt(char *page_virt,
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struct ecryptfs_crypt_stat *crypt_stat,
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struct dentry *ecryptfs_dentry)
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struct dentry *ecryptfs_dentry,
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int validate_header_size)
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{
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int rc = 0;
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int offset;
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@ -1481,7 +1530,7 @@ static int ecryptfs_read_headers_virt(char *page_virt,
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offset += bytes_read;
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if (crypt_stat->file_version >= 1) {
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rc = parse_header_metadata(crypt_stat, (page_virt + offset),
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&bytes_read);
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&bytes_read, validate_header_size);
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if (rc) {
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ecryptfs_printk(KERN_WARNING, "Error reading header "
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"metadata; rc = [%d]\n", rc);
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@ -1496,12 +1545,60 @@ out:
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}
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/**
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* ecryptfs_read_headers
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* ecryptfs_read_xattr_region
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*
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* Attempts to read the crypto metadata from the extended attribute
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* region of the lower file.
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*/
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int ecryptfs_read_xattr_region(char *page_virt, struct dentry *ecryptfs_dentry)
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{
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ssize_t size;
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int rc = 0;
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size = ecryptfs_getxattr(ecryptfs_dentry, ECRYPTFS_XATTR_NAME,
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page_virt, ECRYPTFS_DEFAULT_EXTENT_SIZE);
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if (size < 0) {
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printk(KERN_DEBUG "Error attempting to read the [%s] "
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"xattr from the lower file; return value = [%zd]\n",
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ECRYPTFS_XATTR_NAME, size);
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rc = -EINVAL;
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goto out;
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}
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out:
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return rc;
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}
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int ecryptfs_read_and_validate_xattr_region(char *page_virt,
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struct dentry *ecryptfs_dentry)
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{
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int rc;
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rc = ecryptfs_read_xattr_region(page_virt, ecryptfs_dentry);
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if (rc)
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goto out;
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if (!contains_ecryptfs_marker(page_virt + ECRYPTFS_FILE_SIZE_BYTES)) {
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printk(KERN_WARNING "Valid data found in [%s] xattr, but "
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"the marker is invalid\n", ECRYPTFS_XATTR_NAME);
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rc = -EINVAL;
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}
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out:
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return rc;
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}
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/**
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* ecryptfs_read_metadata
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*
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* Common entry point for reading file metadata. From here, we could
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* retrieve the header information from the header region of the file,
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* the xattr region of the file, or some other repostory that is
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* stored separately from the file itself. The current implementation
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* supports retrieving the metadata information from the file contents
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* and from the xattr region.
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*
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* Returns zero if valid headers found and parsed; non-zero otherwise
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*/
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int ecryptfs_read_headers(struct dentry *ecryptfs_dentry,
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struct file *lower_file)
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int ecryptfs_read_metadata(struct dentry *ecryptfs_dentry,
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struct file *lower_file)
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{
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int rc = 0;
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char *page_virt = NULL;
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@ -1530,11 +1627,36 @@ int ecryptfs_read_headers(struct dentry *ecryptfs_dentry,
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goto out;
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}
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rc = ecryptfs_read_headers_virt(page_virt, crypt_stat,
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ecryptfs_dentry);
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ecryptfs_dentry,
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ECRYPTFS_VALIDATE_HEADER_SIZE);
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if (rc) {
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ecryptfs_printk(KERN_DEBUG, "Valid eCryptfs headers not "
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"found\n");
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rc = -EINVAL;
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rc = ecryptfs_read_xattr_region(page_virt,
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ecryptfs_dentry);
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if (rc) {
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printk(KERN_DEBUG "Valid eCryptfs headers not found in "
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"file header region or xattr region\n");
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rc = -EINVAL;
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goto out;
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}
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rc = ecryptfs_read_headers_virt(page_virt, crypt_stat,
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ecryptfs_dentry,
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ECRYPTFS_DONT_VALIDATE_HEADER_SIZE);
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if (rc) {
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printk(KERN_DEBUG "Valid eCryptfs headers not found in "
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"file xattr region either\n");
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rc = -EINVAL;
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}
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if (crypt_stat->mount_crypt_stat->flags
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& ECRYPTFS_XATTR_METADATA_ENABLED) {
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crypt_stat->flags |= ECRYPTFS_METADATA_IN_XATTR;
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} else {
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printk(KERN_WARNING "Attempt to access file with "
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"crypto metadata only in the extended attribute "
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"region, but eCryptfs was mounted without "
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"xattr support enabled. eCryptfs will not treat "
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"this like an encrypted file.\n");
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rc = -EINVAL;
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}
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}
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out:
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if (page_virt) {
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