[PATCH] eCryptfs: Encrypted passthrough

[powerpc.git] / fs / ecryptfs / mmap.c

diff --git a/fs/ecryptfs/mmap.c b/fs/ecryptfs/mmap.c
index ba3650d..3386014 100644 (file)
--- a/fs/ecryptfs/mmap.c
+++ b/fs/ecryptfs/mmap.c
@@ -260,6 +260,33 @@ out:
                ClearPageUptodate(page);
        return rc;
 }
+/**
+ *   Header Extent:
+ *     Octets 0-7:        Unencrypted file size (big-endian)
+ *     Octets 8-15:       eCryptfs special marker
+ *     Octets 16-19:      Flags
+ *      Octet 16:         File format version number (between 0 and 255)
+ *      Octets 17-18:     Reserved
+ *      Octet 19:         Bit 1 (lsb): Reserved
+ *                        Bit 2: Encrypted?
+ *                        Bits 3-8: Reserved
+ *     Octets 20-23:      Header extent size (big-endian)
+ *     Octets 24-25:      Number of header extents at front of file
+ *                        (big-endian)
+ *     Octet  26:         Begin RFC 2440 authentication token packet set
+ */
+static void set_header_info(char *page_virt,
+                           struct ecryptfs_crypt_stat *crypt_stat)
+{
+       size_t written;
+       int save_num_header_extents_at_front =
+               crypt_stat->num_header_extents_at_front;
+
+       crypt_stat->num_header_extents_at_front = 1;
+       ecryptfs_write_header_metadata(page_virt + 20, crypt_stat, &written);
+       crypt_stat->num_header_extents_at_front =
+               save_num_header_extents_at_front;
+}
 
 /**
  * ecryptfs_readpage
@@ -289,10 +316,55 @@ static int ecryptfs_readpage(struct file *file, struct page *page)
                                        "[%d]\n", rc);
                        goto out;
                }
+       } else if (crypt_stat->flags & ECRYPTFS_VIEW_AS_ENCRYPTED) {
+               if (crypt_stat->flags & ECRYPTFS_METADATA_IN_XATTR) {
+                       int num_pages_in_header_region =
+                               (crypt_stat->header_extent_size
+                                / PAGE_CACHE_SIZE);
+
+                       if (page->index < num_pages_in_header_region) {
+                               char *page_virt;
+
+                               page_virt = (char *)kmap(page);
+                               if (!page_virt) {
+                                       rc = -ENOMEM;
+                                       printk(KERN_ERR "Error mapping page\n");
+                                       goto out;
+                               }
+                               memset(page_virt, 0, PAGE_CACHE_SIZE);
+                               if (page->index == 0) {
+                                       rc = ecryptfs_read_xattr_region(
+                                               page_virt, file->f_path.dentry);
+                                       set_header_info(page_virt, crypt_stat);
+                               }
+                               kunmap(page);
+                               if (rc) {
+                                       printk(KERN_ERR "Error reading xattr "
+                                              "region\n");
+                                       goto out;
+                               }
+                       } else {
+                               rc = ecryptfs_do_readpage(
+                                       file, page,
+                                       (page->index
+                                        - num_pages_in_header_region));
+                               if (rc) {
+                                       printk(KERN_ERR "Error reading page; "
+                                              "rc = [%d]\n", rc);
+                                       goto out;
+                               }
+                       }
+               } else {
+                       rc = ecryptfs_do_readpage(file, page, page->index);
+                       if (rc) {
+                               printk(KERN_ERR "Error reading page; rc = "
+                                      "[%d]\n", rc);
+                               goto out;
+                       }
+               }
        } else {
                rc = ecryptfs_decrypt_page(file, page);
                if (rc) {
-
                        ecryptfs_printk(KERN_ERR, "Error decrypting page; "
                                        "rc = [%d]\n", rc);
                        goto out;