eCryptfs: Use entire helper page during page crypto operations

When encrypting eCryptfs pages and decrypting pages from the lower
filesystem, utilize the entire helper page rather than only the first
4096 bytes.

This only affects architectures where PAGE_CACHE_SIZE is larger than
4096 bytes.

Signed-off-by: Tyler Hicks <tyhicks@canonical.com>

diff --git a/fs/ecryptfs/crypto.c b/fs/ecryptfs/crypto.c
index f71ec125290db7da87355f444f7308826ee1c034..e8976c004669eeac6a212996b0d651f35deb6e45 100644 (file)
--- a/fs/ecryptfs/crypto.c
+++ b/fs/ecryptfs/crypto.c
@@ -450,10 +450,11 @@ static int ecryptfs_encrypt_extent(struct page *enc_extent_page,
                        (unsigned long long)(extent_base + extent_offset), rc);
                goto out;
        }
-       rc = ecryptfs_encrypt_page_offset(crypt_stat, enc_extent_page, 0,
-                                         page, (extent_offset
-                                                * crypt_stat->extent_size),
-                                         crypt_stat->extent_size, extent_iv);
+       rc = ecryptfs_encrypt_page_offset(crypt_stat, enc_extent_page,
+                                       extent_offset * crypt_stat->extent_size,
+                                       page,
+                                       extent_offset * crypt_stat->extent_size,
+                                       crypt_stat->extent_size, extent_iv);
        if (rc < 0) {
                printk(KERN_ERR "%s: Error attempting to encrypt page with "
                       "page->index = [%ld], extent_offset = [%ld]; "
@@ -520,8 +521,9 @@ int ecryptfs_encrypt_page(struct page *page)
                                   * (PAGE_CACHE_SIZE
                                      / crypt_stat->extent_size))
                                  + extent_offset), crypt_stat);
-               rc = ecryptfs_write_lower(ecryptfs_inode, enc_extent_virt,
-                                         offset, crypt_stat->extent_size);
+               rc = ecryptfs_write_lower(ecryptfs_inode, (enc_extent_virt +
+                               extent_offset * crypt_stat->extent_size),
+                               offset, crypt_stat->extent_size);
                if (rc < 0) {
                        ecryptfs_printk(KERN_ERR, "Error attempting "
                                        "to write lower page; rc = [%d]"
@@ -558,10 +560,10 @@ static int ecryptfs_decrypt_extent(struct page *page,
                goto out;
        }
        rc = ecryptfs_decrypt_page_offset(crypt_stat, page,
-                                         (extent_offset
-                                          * crypt_stat->extent_size),
-                                         enc_extent_page, 0,
-                                         crypt_stat->extent_size, extent_iv);
+                                       extent_offset * crypt_stat->extent_size,
+                                       enc_extent_page,
+                                       extent_offset * crypt_stat->extent_size,
+                                       crypt_stat->extent_size, extent_iv);
        if (rc < 0) {
                printk(KERN_ERR "%s: Error attempting to decrypt to page with "
                       "page->index = [%ld], extent_offset = [%ld]; "
@@ -620,9 +622,10 @@ int ecryptfs_decrypt_page(struct page *page)
                        &offset, ((page->index * (PAGE_CACHE_SIZE
                                                  / crypt_stat->extent_size))
                                  + extent_offset), crypt_stat);
-               rc = ecryptfs_read_lower(enc_extent_virt, offset,
-                                        crypt_stat->extent_size,
-                                        ecryptfs_inode);
+               rc = ecryptfs_read_lower((enc_extent_virt +
+                               extent_offset * crypt_stat->extent_size),
+                               offset, crypt_stat->extent_size,
+                               ecryptfs_inode);
                if (rc < 0) {
                        ecryptfs_printk(KERN_ERR, "Error attempting "
                                        "to read lower page; rc = [%d]"