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Kernel v2.6.24 /fs/ecryptfs/crypto.c

Filename:/fs/ecryptfs/crypto.c
Lines Added:563
Lines Deleted:494
Also changed in: (Previous) 2.6.24-rc8  2.6.24-rc7  2.6.24-rc6-git12  2.6.24-rc6-git11  2.6.24-rc6-git10  2.6.24-rc6-git9 
(Following) 2.6.24-git16  2.6.24-git17  2.6.24-git18  2.6.24-git19  2.6.24-git20  2.6.24-git21 

Location
[  2.6.24
  [  fs
    [  ecryptfs
       o  crypto.c

Patch

diff --git a/fs/ecryptfs/crypto.c b/fs/ecryptfs/crypto.c
index 6ac6306..f8ef0af 100644
--- a/fs/ecryptfs/crypto.c
+++ b/fs/ecryptfs/crypto.c
@@ -115,17 +115,35 @@ static int ecryptfs_calculate_md5(char *dst,
       }
       crypt_stat->hash_tfm = desc.tfm;
    }
-   crypto_hash_init(&desc);
-   crypto_hash_update(&desc, &sg, len);
-   crypto_hash_final(&desc, dst);
-   mutex_unlock(&crypt_stat->cs_hash_tfm_mutex);
+   rc = crypto_hash_init(&desc);
+   if (rc) {
+      printk(KERN_ERR
+             "%s: Error initializing crypto hash; rc = [%d]\n",
+             __FUNCTION__, rc);
+      goto out;
+   }
+   rc = crypto_hash_update(&desc, &sg, len);
+   if (rc) {
+      printk(KERN_ERR
+             "%s: Error updating crypto hash; rc = [%d]\n",
+             __FUNCTION__, rc);
+      goto out;
+   }
+   rc = crypto_hash_final(&desc, dst);
+   if (rc) {
+      printk(KERN_ERR
+             "%s: Error finalizing crypto hash; rc = [%d]\n",
+             __FUNCTION__, rc);
+      goto out;
+   }
 out:
+   mutex_unlock(&crypt_stat->cs_hash_tfm_mutex);
    return rc;
 }
 
-int ecryptfs_crypto_api_algify_cipher_name(char **algified_name,
-                  char *cipher_name,
-                  char *chaining_modifier)
+static int ecryptfs_crypto_api_algify_cipher_name(char **algified_name,
+                    char *cipher_name,
+                    char *chaining_modifier)
 {
    int cipher_name_len = strlen(cipher_name);
    int chaining_modifier_len = strlen(chaining_modifier);
@@ -149,7 +167,7 @@ out:
  * ecryptfs_derive_iv
  * @iv: destination for the derived iv vale
  * @crypt_stat: Pointer to crypt_stat struct for the current inode
- * @offset: Offset of the page whose's iv we are to derive
+ * @offset: Offset of the extent whose IV we are to derive
  *
  * Generate the initialization vector from the given root IV and page
  * offset.
@@ -157,7 +175,7 @@ out:
  * Returns zero on success; non-zero on error.
  */
 static int ecryptfs_derive_iv(char *iv, struct ecryptfs_crypt_stat *crypt_stat,
-               pgoff_t offset)
+               loff_t offset)
 {
    int rc = 0;
    char dst[MD5_DIGEST_SIZE];
@@ -173,7 +191,7 @@ static int ecryptfs_derive_iv(char *iv, struct ecryptfs_crypt_stat *crypt_stat,
     * hashing business. -Halcrow */
    memcpy(src, crypt_stat->root_iv, crypt_stat->iv_bytes);
    memset((src + crypt_stat->iv_bytes), 0, 16);
-   snprintf((src + crypt_stat->iv_bytes), 16, "%ld", offset);
+   snprintf((src + crypt_stat->iv_bytes), 16, "%lld", offset);
    if (unlikely(ecryptfs_verbosity > 0)) {
       ecryptfs_printk(KERN_DEBUG, "source:\n");
       ecryptfs_dump_hex(src, (crypt_stat->iv_bytes + 16));
@@ -204,6 +222,8 @@ void
 ecryptfs_init_crypt_stat(struct ecryptfs_crypt_stat *crypt_stat)
 {
    memset((void *)crypt_stat, 0, sizeof(struct ecryptfs_crypt_stat));
+   INIT_LIST_HEAD(&crypt_stat->keysig_list);
+   mutex_init(&crypt_stat->keysig_list_mutex);
    mutex_init(&crypt_stat->cs_mutex);
    mutex_init(&crypt_stat->cs_tfm_mutex);
    mutex_init(&crypt_stat->cs_hash_tfm_mutex);
@@ -211,27 +231,48 @@ ecryptfs_init_crypt_stat(struct ecryptfs_crypt_stat *crypt_stat)
 }
 
 /**
- * ecryptfs_destruct_crypt_stat
+ * ecryptfs_destroy_crypt_stat
  * @crypt_stat: Pointer to the crypt_stat struct to initialize.
  *
  * Releases all memory associated with a crypt_stat struct.
  */
-void ecryptfs_destruct_crypt_stat(struct ecryptfs_crypt_stat *crypt_stat)
+void ecryptfs_destroy_crypt_stat(struct ecryptfs_crypt_stat *crypt_stat)
 {
+   struct ecryptfs_key_sig *key_sig, *key_sig_tmp;
+
    if (crypt_stat->tfm)
       crypto_free_blkcipher(crypt_stat->tfm);
    if (crypt_stat->hash_tfm)
       crypto_free_hash(crypt_stat->hash_tfm);
+   mutex_lock(&crypt_stat->keysig_list_mutex);
+   list_for_each_entry_safe(key_sig, key_sig_tmp,
+             &crypt_stat->keysig_list, crypt_stat_list) {
+      list_del(&key_sig->crypt_stat_list);
+      kmem_cache_free(ecryptfs_key_sig_cache, key_sig);
+   }
+   mutex_unlock(&crypt_stat->keysig_list_mutex);
    memset(crypt_stat, 0, sizeof(struct ecryptfs_crypt_stat));
 }
 
-void ecryptfs_destruct_mount_crypt_stat(
+void ecryptfs_destroy_mount_crypt_stat(
    struct ecryptfs_mount_crypt_stat *mount_crypt_stat)
 {
-   if (mount_crypt_stat->global_auth_tok_key)
-      key_put(mount_crypt_stat->global_auth_tok_key);
-   if (mount_crypt_stat->global_key_tfm)
-      crypto_free_blkcipher(mount_crypt_stat->global_key_tfm);
+   struct ecryptfs_global_auth_tok *auth_tok, *auth_tok_tmp;
+
+   if (!(mount_crypt_stat->flags & ECRYPTFS_MOUNT_CRYPT_STAT_INITIALIZED))
+      return;
+   mutex_lock(&mount_crypt_stat->global_auth_tok_list_mutex);
+   list_for_each_entry_safe(auth_tok, auth_tok_tmp,
+             &mount_crypt_stat->global_auth_tok_list,
+             mount_crypt_stat_list) {
+      list_del(&auth_tok->mount_crypt_stat_list);
+      mount_crypt_stat->num_global_auth_toks--;
+      if (auth_tok->global_auth_tok_key
+          && !(auth_tok->flags & ECRYPTFS_AUTH_TOK_INVALID))
+         key_put(auth_tok->global_auth_tok_key);
+      kmem_cache_free(ecryptfs_global_auth_tok_cache, auth_tok);
+   }
+   mutex_unlock(&mount_crypt_stat->global_auth_tok_list_mutex);
    memset(mount_crypt_stat, 0, sizeof(struct ecryptfs_mount_crypt_stat));
 }
 
@@ -256,13 +297,13 @@ int virt_to_scatterlist(const void *addr, int size, struct scatterlist *sg,
    int offset;
    int remainder_of_page;
 
+   sg_init_table(sg, sg_size);
+
    while (size > 0 && i < sg_size) {
       pg = virt_to_page(addr);
       offset = offset_in_page(addr);
-      if (sg) {
-         sg[i].page = pg;
-         sg[i].offset = offset;
-      }
+      if (sg)
+         sg_set_page(&sg[i], pg, 0, offset);
       remainder_of_page = PAGE_CACHE_SIZE - offset;
       if (size >= remainder_of_page) {
          if (sg)
@@ -330,114 +371,82 @@ out:
    return rc;
 }
 
-static void
-ecryptfs_extent_to_lwr_pg_idx_and_offset(unsigned long *lower_page_idx,
-                int *byte_offset,
-                struct ecryptfs_crypt_stat *crypt_stat,
-                unsigned long extent_num)
+/**
+ * ecryptfs_lower_offset_for_extent
+ *
+ * Convert an eCryptfs page index into a lower byte offset
+ */
+void ecryptfs_lower_offset_for_extent(loff_t *offset, loff_t extent_num,
+                  struct ecryptfs_crypt_stat *crypt_stat)
 {
-   unsigned long lower_extent_num;
-   int extents_occupied_by_headers_at_front;
-   int bytes_occupied_by_headers_at_front;
-   int extent_offset;
-   int extents_per_page;
-
-   bytes_occupied_by_headers_at_front =
-      ( crypt_stat->header_extent_size
-        * crypt_stat->num_header_extents_at_front );
-   extents_occupied_by_headers_at_front =
-      ( bytes_occupied_by_headers_at_front
-        / crypt_stat->extent_size );
-   lower_extent_num = extents_occupied_by_headers_at_front + extent_num;
-   extents_per_page = PAGE_CACHE_SIZE / crypt_stat->extent_size;
-   (*lower_page_idx) = lower_extent_num / extents_per_page;
-   extent_offset = lower_extent_num % extents_per_page;
-   (*byte_offset) = extent_offset * crypt_stat->extent_size;
-   ecryptfs_printk(KERN_DEBUG, " * crypt_stat->header_extent_size = "
-         "[%d]\n", crypt_stat->header_extent_size);
-   ecryptfs_printk(KERN_DEBUG, " * crypt_stat->"
-         "num_header_extents_at_front = [%d]\n",
-         crypt_stat->num_header_extents_at_front);
-   ecryptfs_printk(KERN_DEBUG, " * extents_occupied_by_headers_at_"
-         "front = [%d]\n", extents_occupied_by_headers_at_front);
-   ecryptfs_printk(KERN_DEBUG, " * lower_extent_num = [0x%.16x]\n",
-         lower_extent_num);
-   ecryptfs_printk(KERN_DEBUG, " * extents_per_page = [%d]\n",
-         extents_per_page);
-   ecryptfs_printk(KERN_DEBUG, " * (*lower_page_idx) = [0x%.16x]\n",
-         (*lower_page_idx));
-   ecryptfs_printk(KERN_DEBUG, " * extent_offset = [%d]\n",
-         extent_offset);
-   ecryptfs_printk(KERN_DEBUG, " * (*byte_offset) = [%d]\n",
-         (*byte_offset));
+   (*offset) = ((crypt_stat->extent_size
+            * crypt_stat->num_header_extents_at_front)
+           + (crypt_stat->extent_size * extent_num));
 }
 
-static int ecryptfs_write_out_page(struct ecryptfs_page_crypt_context *ctx,
-               struct page *lower_page,
-               struct inode *lower_inode,
-               int byte_offset_in_page, int bytes_to_write)
+/**
+ * ecryptfs_encrypt_extent
+ * @enc_extent_page: Allocated page into which to encrypt the data in
+ *                   @page
+ * @crypt_stat: crypt_stat containing cryptographic context for the
+ *              encryption operation
+ * @page: Page containing plaintext data extent to encrypt
+ * @extent_offset: Page extent offset for use in generating IV
+ *
+ * Encrypts one extent of data.
+ *
+ * Return zero on success; non-zero otherwise
+ */
+static int ecryptfs_encrypt_extent(struct page *enc_extent_page,
+               struct ecryptfs_crypt_stat *crypt_stat,
+               struct page *page,
+               unsigned long extent_offset)
 {
-   int rc = 0;
+   loff_t extent_base;
+   char extent_iv[ECRYPTFS_MAX_IV_BYTES];
+   int rc;
 
-   if (ctx->mode == ECRYPTFS_PREPARE_COMMIT_MODE) {
-      rc = ecryptfs_commit_lower_page(lower_page, lower_inode,
-                  ctx->param.lower_file,
-                  byte_offset_in_page,
-                  bytes_to_write);
-      if (rc) {
-         ecryptfs_printk(KERN_ERR, "Error calling lower "
-               "commit; rc = [%d]\n", rc);
-         goto out;
-      }
-   } else {
-      rc = ecryptfs_writepage_and_release_lower_page(lower_page,
-                            lower_inode,
-                            ctx->param.wbc);
-      if (rc) {
-         ecryptfs_printk(KERN_ERR, "Error calling lower "
-               "writepage(); rc = [%d]\n", rc);
-         goto out;
-      }
+   extent_base = (((loff_t)page->index)
+             * (PAGE_CACHE_SIZE / crypt_stat->extent_size));
+   rc = ecryptfs_derive_iv(extent_iv, crypt_stat,
+            (extent_base + extent_offset));
+   if (rc) {
+      ecryptfs_printk(KERN_ERR, "Error attempting to "
+            "derive IV for extent [0x%.16x]; "
+            "rc = [%d]\n", (extent_base + extent_offset),
+            rc);
+      goto out;
    }
-out:
-   return rc;
-}
-
-static int ecryptfs_read_in_page(struct ecryptfs_page_crypt_context *ctx,
-             struct page **lower_page,
-             struct inode *lower_inode,
-             unsigned long lower_page_idx,
-             int byte_offset_in_page)
-{
-   int rc = 0;
-
-   if (ctx->mode == ECRYPTFS_PREPARE_COMMIT_MODE) {
-      /* TODO: Limit this to only the data extents that are
-       * needed */
-      rc = ecryptfs_get_lower_page(lower_page, lower_inode,
-                    ctx->param.lower_file,
-                    lower_page_idx,
-                    byte_offset_in_page,
-                    (PAGE_CACHE_SIZE
-                     - byte_offset_in_page));
-      if (rc) {
-         ecryptfs_printk(
-            KERN_ERR, "Error attempting to grab, map, "
-            "and prepare_write lower page with index "
-            "[0x%.16x]; rc = [%d]\n", lower_page_idx, rc);
-         goto out;
-      }
-   } else {
-      *lower_page = grab_cache_page(lower_inode->i_mapping,
-                     lower_page_idx);
-      if (!(*lower_page)) {
-         rc = -EINVAL;
-         ecryptfs_printk(
-            KERN_ERR, "Error attempting to grab and map "
-            "lower page with index [0x%.16x]; rc = [%d]\n",
-            lower_page_idx, rc);
-         goto out;
-      }
+   if (unlikely(ecryptfs_verbosity > 0)) {
+      ecryptfs_printk(KERN_DEBUG, "Encrypting extent "
+            "with iv:\n");
+      ecryptfs_dump_hex(extent_iv, crypt_stat->iv_bytes);
+      ecryptfs_printk(KERN_DEBUG, "First 8 bytes before "
+            "encryption:\n");
+      ecryptfs_dump_hex((char *)
+              (page_address(page)
+               + (extent_offset * crypt_stat->extent_size)),
+              8);
+   }
+   rc = ecryptfs_encrypt_page_offset(crypt_stat, enc_extent_page, 0,
+                 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]; "
+             "rc = [%d]\n", __FUNCTION__, page->index, extent_offset,
+             rc);
+      goto out;
+   }
+   rc = 0;
+   if (unlikely(ecryptfs_verbosity > 0)) {
+      ecryptfs_printk(KERN_DEBUG, "Encrypt extent [0x%.16x]; "
+            "rc = [%d]\n", (extent_base + extent_offset),
+            rc);
+      ecryptfs_printk(KERN_DEBUG, "First 8 bytes after "
+            "encryption:\n");
+      ecryptfs_dump_hex((char *)(page_address(enc_extent_page)), 8);
    }
 out:
    return rc;
@@ -445,7 +454,9 @@ out:
 
 /**
  * ecryptfs_encrypt_page
- * @ctx: The context of the page
+ * @page: Page mapped from the eCryptfs inode for the file; contains
+ *        decrypted content that needs to be encrypted (to a temporary
+ *        page; not in place) and written out to the lower file
  *
  * Encrypt an eCryptfs page. This is done on a per-extent basis. Note
  * that eCryptfs pages may straddle the lower pages -- for instance,
@@ -455,128 +466,121 @@ out:
  * file, 24K of page 0 of the lower file will be read and decrypted,
  * and then 8K of page 1 of the lower file will be read and decrypted.
  *
- * The actual operations performed on each page depends on the
- * contents of the ecryptfs_page_crypt_context struct.
- *
  * Returns zero on success; negative on error
  */
-int ecryptfs_encrypt_page(struct ecryptfs_page_crypt_context *ctx)
+int ecryptfs_encrypt_page(struct page *page)
 {
-   char extent_iv[ECRYPTFS_MAX_IV_BYTES];
-   unsigned long base_extent;
-   unsigned long extent_offset = 0;
-   unsigned long lower_page_idx = 0;
-   unsigned long prior_lower_page_idx = 0;
-   struct page *lower_page;
-   struct inode *lower_inode;
-   struct ecryptfs_inode_info *inode_info;
+   struct inode *ecryptfs_inode;
    struct ecryptfs_crypt_stat *crypt_stat;
+   char *enc_extent_virt = NULL;
+   struct page *enc_extent_page;
+   loff_t extent_offset;
    int rc = 0;
-   int lower_byte_offset = 0;
-   int orig_byte_offset = 0;
-   int num_extents_per_page;
-#define ECRYPTFS_PAGE_STATE_UNREAD    0
-#define ECRYPTFS_PAGE_STATE_READ      1
-#define ECRYPTFS_PAGE_STATE_MODIFIED  2
-#define ECRYPTFS_PAGE_STATE_WRITTEN   3
-   int page_state;
-
-   lower_inode = ecryptfs_inode_to_lower(ctx->page->mapping->host);
-   inode_info = ecryptfs_inode_to_private(ctx->page->mapping->host);
-   crypt_stat = &inode_info->crypt_stat;
+
+   ecryptfs_inode = page->mapping->host;
+   crypt_stat =
+      &(ecryptfs_inode_to_private(ecryptfs_inode)->crypt_stat);
    if (!(crypt_stat->flags & ECRYPTFS_ENCRYPTED)) {
-      rc = ecryptfs_copy_page_to_lower(ctx->page, lower_inode,
-                   ctx->param.lower_file);
+      rc = ecryptfs_write_lower_page_segment(ecryptfs_inode, page,
+                         0, PAGE_CACHE_SIZE);
       if (rc)
-         ecryptfs_printk(KERN_ERR, "Error attempting to copy "
-               "page at index [0x%.16x]\n",
-               ctx->page->index);
+         printk(KERN_ERR "%s: Error attempting to copy "
+                "page at index [%ld]\n", __FUNCTION__,
+                page->index);
       goto out;
    }
-   num_extents_per_page = PAGE_CACHE_SIZE / crypt_stat->extent_size;
-   base_extent = (ctx->page->index * num_extents_per_page);
-   page_state = ECRYPTFS_PAGE_STATE_UNREAD;
-   while (extent_offset < num_extents_per_page) {
-      ecryptfs_extent_to_lwr_pg_idx_and_offset(
-         &lower_page_idx, &lower_byte_offset, crypt_stat,
-         (base_extent + extent_offset));
-      if (prior_lower_page_idx != lower_page_idx
-          && page_state == ECRYPTFS_PAGE_STATE_MODIFIED) {
-         rc = ecryptfs_write_out_page(ctx, lower_page,
-                       lower_inode,
-                       orig_byte_offset,
-                       (PAGE_CACHE_SIZE
-                        - orig_byte_offset));
-         if (rc) {
-            ecryptfs_printk(KERN_ERR, "Error attempting "
-                  "to write out page; rc = [%d]"
-                  "\n", rc);
-            goto out;
-         }
-         page_state = ECRYPTFS_PAGE_STATE_WRITTEN;
-      }
-      if (page_state == ECRYPTFS_PAGE_STATE_UNREAD
-          || page_state == ECRYPTFS_PAGE_STATE_WRITTEN) {
-         rc = ecryptfs_read_in_page(ctx, &lower_page,
-                     lower_inode, lower_page_idx,
-                     lower_byte_offset);
-         if (rc) {
-            ecryptfs_printk(KERN_ERR, "Error attempting "
-                  "to read in lower page with "
-                  "index [0x%.16x]; rc = [%d]\n",
-                  lower_page_idx, rc);
-            goto out;
-         }
-         orig_byte_offset = lower_byte_offset;
-         prior_lower_page_idx = lower_page_idx;
-         page_state = ECRYPTFS_PAGE_STATE_READ;
-      }
-      BUG_ON(!(page_state == ECRYPTFS_PAGE_STATE_MODIFIED
-          || page_state == ECRYPTFS_PAGE_STATE_READ));
-      rc = ecryptfs_derive_iv(extent_iv, crypt_stat,
-               (base_extent + extent_offset));
+   enc_extent_virt = kmalloc(PAGE_CACHE_SIZE, GFP_USER);
+   if (!enc_extent_virt) {
+      rc = -ENOMEM;
+      ecryptfs_printk(KERN_ERR, "Error allocating memory for "
+            "encrypted extent\n");
+      goto out;
+   }
+   enc_extent_page = virt_to_page(enc_extent_virt);
+   for (extent_offset = 0;
+        extent_offset < (PAGE_CACHE_SIZE / crypt_stat->extent_size);
+        extent_offset++) {
+      loff_t offset;
+
+      rc = ecryptfs_encrypt_extent(enc_extent_page, crypt_stat, page,
+                    extent_offset);
       if (rc) {
-         ecryptfs_printk(KERN_ERR, "Error attempting to "
-               "derive IV for extent [0x%.16x]; "
-               "rc = [%d]\n",
-               (base_extent + extent_offset), rc);
+         printk(KERN_ERR "%s: Error encrypting extent; "
+                "rc = [%d]\n", __FUNCTION__, rc);
          goto out;
       }
-      if (unlikely(ecryptfs_verbosity > 0)) {
-         ecryptfs_printk(KERN_DEBUG, "Encrypting extent "
-               "with iv:\n");
-         ecryptfs_dump_hex(extent_iv, crypt_stat->iv_bytes);
-         ecryptfs_printk(KERN_DEBUG, "First 8 bytes before "
-               "encryption:\n");
-         ecryptfs_dump_hex((char *)
-                 (page_address(ctx->page)
-                  + (extent_offset
-                     * crypt_stat->extent_size)), 8);
-      }
-      rc = ecryptfs_encrypt_page_offset(
-         crypt_stat, lower_page, lower_byte_offset, ctx->page,
-         (extent_offset * crypt_stat->extent_size),
-         crypt_stat->extent_size, extent_iv);
-      ecryptfs_printk(KERN_DEBUG, "Encrypt extent [0x%.16x]; "
-            "rc = [%d]\n",
-            (base_extent + extent_offset), rc);
-      if (unlikely(ecryptfs_verbosity > 0)) {
-         ecryptfs_printk(KERN_DEBUG, "First 8 bytes after "
-               "encryption:\n");
-         ecryptfs_dump_hex((char *)(page_address(lower_page)
-                     + lower_byte_offset), 8);
+      ecryptfs_lower_offset_for_extent(
+         &offset, ((((loff_t)page->index)
+               * (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);
+      if (rc) {
+         ecryptfs_printk(KERN_ERR, "Error attempting "
+               "to write lower page; rc = [%d]"
+               "\n", rc);
+         goto out;
       }
-      page_state = ECRYPTFS_PAGE_STATE_MODIFIED;
-      extent_offset++;
    }
-   BUG_ON(orig_byte_offset != 0);
-   rc = ecryptfs_write_out_page(ctx, lower_page, lower_inode, 0,
-                 (lower_byte_offset
-                  + crypt_stat->extent_size));
+out:
+   kfree(enc_extent_virt);
+   return rc;
+}
+
+static int ecryptfs_decrypt_extent(struct page *page,
+               struct ecryptfs_crypt_stat *crypt_stat,
+               struct page *enc_extent_page,
+               unsigned long extent_offset)
+{
+   loff_t extent_base;
+   char extent_iv[ECRYPTFS_MAX_IV_BYTES];
+   int rc;
+
+   extent_base = (((loff_t)page->index)
+             * (PAGE_CACHE_SIZE / crypt_stat->extent_size));
+   rc = ecryptfs_derive_iv(extent_iv, crypt_stat,
+            (extent_base + extent_offset));
    if (rc) {
-      ecryptfs_printk(KERN_ERR, "Error attempting to write out "
-            "page; rc = [%d]\n", rc);
-            goto out;
+      ecryptfs_printk(KERN_ERR, "Error attempting to "
+            "derive IV for extent [0x%.16x]; "
+            "rc = [%d]\n", (extent_base + extent_offset),
+            rc);
+      goto out;
+   }
+   if (unlikely(ecryptfs_verbosity > 0)) {
+      ecryptfs_printk(KERN_DEBUG, "Decrypting extent "
+            "with iv:\n");
+      ecryptfs_dump_hex(extent_iv, crypt_stat->iv_bytes);
+      ecryptfs_printk(KERN_DEBUG, "First 8 bytes before "
+            "decryption:\n");
+      ecryptfs_dump_hex((char *)
+              (page_address(enc_extent_page)
+               + (extent_offset * crypt_stat->extent_size)),
+              8);
+   }
+   rc = ecryptfs_decrypt_page_offset(crypt_stat, page,
+                 (extent_offset
+                  * crypt_stat->extent_size),
+                 enc_extent_page, 0,
+                 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]; "
+             "rc = [%d]\n", __FUNCTION__, page->index, extent_offset,
+             rc);
+      goto out;
+   }
+   rc = 0;
+   if (unlikely(ecryptfs_verbosity > 0)) {
+      ecryptfs_printk(KERN_DEBUG, "Decrypt extent [0x%.16x]; "
+            "rc = [%d]\n", (extent_base + extent_offset),
+            rc);
+      ecryptfs_printk(KERN_DEBUG, "First 8 bytes after "
+            "decryption:\n");
+      ecryptfs_dump_hex((char *)(page_address(page)
+                  + (extent_offset
+                     * crypt_stat->extent_size)), 8);
    }
 out:
    return rc;
@@ -584,8 +588,9 @@ out:
 
 /**
  * ecryptfs_decrypt_page
- * @file: The ecryptfs file
- * @page: The page in ecryptfs to decrypt
+ * @page: Page mapped from the eCryptfs inode for the file; data read
+ *        and decrypted from the lower file will be written into this
+ *        page
  *
  * Decrypt an eCryptfs page. This is done on a per-extent basis. Note
  * that eCryptfs pages may straddle the lower pages -- for instance,
@@ -597,108 +602,74 @@ out:
  *
  * Returns zero on success; negative on error
  */
-int ecryptfs_decrypt_page(struct file *file, struct page *page)
+int ecryptfs_decrypt_page(struct page *page)
 {
-   char extent_iv[ECRYPTFS_MAX_IV_BYTES];
-   unsigned long base_extent;
-   unsigned long extent_offset = 0;
-   unsigned long lower_page_idx = 0;
-   unsigned long prior_lower_page_idx = 0;
-   struct page *lower_page;
-   char *lower_page_virt = NULL;
-   struct inode *lower_inode;
+   struct inode *ecryptfs_inode;
    struct ecryptfs_crypt_stat *crypt_stat;
+   char *enc_extent_virt = NULL;
+   struct page *enc_extent_page;
+   unsigned long extent_offset;
    int rc = 0;
-   int byte_offset;
-   int num_extents_per_page;
-   int page_state;
 
-   crypt_stat = &(ecryptfs_inode_to_private(
-                page->mapping->host)->crypt_stat);
-   lower_inode = ecryptfs_inode_to_lower(page->mapping->host);
+   ecryptfs_inode = page->mapping->host;
+   crypt_stat =
+      &(ecryptfs_inode_to_private(ecryptfs_inode)->crypt_stat);
    if (!(crypt_stat->flags & ECRYPTFS_ENCRYPTED)) {
-      rc = ecryptfs_do_readpage(file, page, page->index);
+      rc = ecryptfs_read_lower_page_segment(page, page->index, 0,
+                        PAGE_CACHE_SIZE,
+                        ecryptfs_inode);
       if (rc)
-         ecryptfs_printk(KERN_ERR, "Error attempting to copy "
-               "page at index [0x%.16x]\n",
-               page->index);
+         printk(KERN_ERR "%s: Error attempting to copy "
+                "page at index [%ld]\n", __FUNCTION__,
+                page->index);
       goto out;
    }
-   num_extents_per_page = PAGE_CACHE_SIZE / crypt_stat->extent_size;
-   base_extent = (page->index * num_extents_per_page);
-   lower_page_virt = kmem_cache_alloc(ecryptfs_lower_page_cache,
-                  GFP_KERNEL);
-   if (!lower_page_virt) {
+   enc_extent_virt = kmalloc(PAGE_CACHE_SIZE, GFP_USER);
+   if (!enc_extent_virt) {
       rc = -ENOMEM;
-      ecryptfs_printk(KERN_ERR, "Error getting page for encrypted "
-            "lower page(s)\n");
+      ecryptfs_printk(KERN_ERR, "Error allocating memory for "
+            "encrypted extent\n");
       goto out;
    }
-   lower_page = virt_to_page(lower_page_virt);
-   page_state = ECRYPTFS_PAGE_STATE_UNREAD;
-   while (extent_offset < num_extents_per_page) {
-      ecryptfs_extent_to_lwr_pg_idx_and_offset(
-         &lower_page_idx, &byte_offset, crypt_stat,
-         (base_extent + extent_offset));
-      if (prior_lower_page_idx != lower_page_idx
-          || page_state == ECRYPTFS_PAGE_STATE_UNREAD) {
-         rc = ecryptfs_do_readpage(file, lower_page,
-                    lower_page_idx);
-         if (rc) {
-            ecryptfs_printk(KERN_ERR, "Error reading "
-                  "lower encrypted page; rc = "
-                  "[%d]\n", rc);
-            goto out;
-         }
-         prior_lower_page_idx = lower_page_idx;
-         page_state = ECRYPTFS_PAGE_STATE_READ;
-      }
-      rc = ecryptfs_derive_iv(extent_iv, crypt_stat,
-               (base_extent + extent_offset));
+   enc_extent_page = virt_to_page(enc_extent_virt);
+   for (extent_offset = 0;
+        extent_offset < (PAGE_CACHE_SIZE / crypt_stat->extent_size);
+        extent_offset++) {
+      loff_t offset;
+
+      ecryptfs_lower_offset_for_extent(
+         &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);
       if (rc) {
-         ecryptfs_printk(KERN_ERR, "Error attempting to "
-               "derive IV for extent [0x%.16x]; rc = "
-               "[%d]\n",
-               (base_extent + extent_offset), rc);
+         ecryptfs_printk(KERN_ERR, "Error attempting "
+               "to read lower page; rc = [%d]"
+               "\n", rc);
          goto out;
       }
-      if (unlikely(ecryptfs_verbosity > 0)) {
-         ecryptfs_printk(KERN_DEBUG, "Decrypting extent "
-               "with iv:\n");
-         ecryptfs_dump_hex(extent_iv, crypt_stat->iv_bytes);
-         ecryptfs_printk(KERN_DEBUG, "First 8 bytes before "
-               "decryption:\n");
-         ecryptfs_dump_hex((lower_page_virt + byte_offset), 8);
-      }
-      rc = ecryptfs_decrypt_page_offset(crypt_stat, page,
-                    (extent_offset
-                     * crypt_stat->extent_size),
-                    lower_page, byte_offset,
-                    crypt_stat->extent_size,
-                    extent_iv);
-      if (rc != crypt_stat->extent_size) {
-         ecryptfs_printk(KERN_ERR, "Error attempting to "
-               "decrypt extent [0x%.16x]\n",
-               (base_extent + extent_offset));
+      rc = ecryptfs_decrypt_extent(page, crypt_stat, enc_extent_page,
+                    extent_offset);
+      if (rc) {
+         printk(KERN_ERR "%s: Error encrypting extent; "
+                "rc = [%d]\n", __FUNCTION__, rc);
          goto out;
       }
-      rc = 0;
-      if (unlikely(ecryptfs_verbosity > 0)) {
-         ecryptfs_printk(KERN_DEBUG, "First 8 bytes after "
-               "decryption:\n");
-         ecryptfs_dump_hex((char *)(page_address(page)
-                     + byte_offset), 8);
-      }
-      extent_offset++;
    }
 out:
-   if (lower_page_virt)
-      kmem_cache_free(ecryptfs_lower_page_cache, lower_page_virt);
+   kfree(enc_extent_virt);
    return rc;
 }
 
 /**
  * decrypt_scatterlist
+ * @crypt_stat: Cryptographic context
+ * @dest_sg: The destination scatterlist to decrypt into
+ * @src_sg: The source scatterlist to decrypt from
+ * @size: The number of bytes to decrypt
+ * @iv: The initialization vector to use for the decryption
  *
  * Returns the number of bytes decrypted; negative value on error
  */
@@ -740,6 +711,13 @@ out:
 
 /**
  * ecryptfs_encrypt_page_offset
+ * @crypt_stat: The cryptographic context
+ * @dst_page: The page to encrypt into
+ * @dst_offset: The offset in the page to encrypt into
+ * @src_page: The page to encrypt from
+ * @src_offset: The offset in the page to encrypt from
+ * @size: The number of bytes to encrypt
+ * @iv: The initialization vector to use for the encryption
  *
  * Returns the number of bytes encrypted
  */
@@ -751,17 +729,23 @@ ecryptfs_encrypt_page_offset(struct ecryptfs_crypt_stat *crypt_stat,
 {
    struct scatterlist src_sg, dst_sg;
 
-   src_sg.page = src_page;
-   src_sg.offset = src_offset;
-   src_sg.length = size;
-   dst_sg.page = dst_page;
-   dst_sg.offset = dst_offset;
-   dst_sg.length = size;
+   sg_init_table(&src_sg, 1);
+   sg_init_table(&dst_sg, 1);
+
+   sg_set_page(&src_sg, src_page, size, src_offset);
+   sg_set_page(&dst_sg, dst_page, size, dst_offset);
    return encrypt_scatterlist(crypt_stat, &dst_sg, &src_sg, size, iv);
 }
 
 /**
  * ecryptfs_decrypt_page_offset
+ * @crypt_stat: The cryptographic context
+ * @dst_page: The page to decrypt into
+ * @dst_offset: The offset in the page to decrypt into
+ * @src_page: The page to decrypt from
+ * @src_offset: The offset in the page to decrypt from
+ * @size: The number of bytes to decrypt
+ * @iv: The initialization vector to use for the decryption
  *
  * Returns the number of bytes decrypted
  */
@@ -773,12 +757,12 @@ ecryptfs_decrypt_page_offset(struct ecryptfs_crypt_stat *crypt_stat,
 {
    struct scatterlist src_sg, dst_sg;
 
-   src_sg.page = src_page;
-   src_sg.offset = src_offset;
-   src_sg.length = size;
-   dst_sg.page = dst_page;
-   dst_sg.offset = dst_offset;
-   dst_sg.length = size;
+   sg_init_table(&src_sg, 1);
+   sg_set_page(&src_sg, src_page, size, src_offset);
+
+   sg_init_table(&dst_sg, 1);
+   sg_set_page(&dst_sg, dst_page, size, dst_offset);
+
    return decrypt_scatterlist(crypt_stat, &dst_sg, &src_sg, size, iv);
 }
 
@@ -815,7 +799,7 @@ int ecryptfs_init_crypt_ctx(struct ecryptfs_crypt_stat *crypt_stat)
    rc = ecryptfs_crypto_api_algify_cipher_name(&full_alg_name,
                       crypt_stat->cipher, "cbc");
    if (rc)
-      goto out;
+      goto out_unlock;
    crypt_stat->tfm = crypto_alloc_blkcipher(full_alg_name, 0,
                    CRYPTO_ALG_ASYNC);
    kfree(full_alg_name);
@@ -824,12 +808,12 @@ int ecryptfs_init_crypt_ctx(struct ecryptfs_crypt_stat *crypt_stat)
       ecryptfs_printk(KERN_ERR, "cryptfs: init_crypt_ctx(): "
             "Error initializing cipher [%s]\n",
             crypt_stat->cipher);
-      mutex_unlock(&crypt_stat->cs_tfm_mutex);
-      goto out;
+      goto out_unlock;
    }
    crypto_blkcipher_set_flags(crypt_stat->tfm, CRYPTO_TFM_REQ_WEAK_KEY);
-   mutex_unlock(&crypt_stat->cs_tfm_mutex);
    rc = 0;
+out_unlock:
+   mutex_unlock(&crypt_stat->cs_tfm_mutex);
 out:
    return rc;
 }
@@ -857,15 +841,17 @@ void ecryptfs_set_default_sizes(struct ecryptfs_crypt_stat *crypt_stat)
    crypt_stat->extent_size = ECRYPTFS_DEFAULT_EXTENT_SIZE;
    set_extent_mask_and_shift(crypt_stat);
    crypt_stat->iv_bytes = ECRYPTFS_DEFAULT_IV_BYTES;
-   if (PAGE_CACHE_SIZE <= ECRYPTFS_MINIMUM_HEADER_EXTENT_SIZE) {
-      crypt_stat->header_extent_size =
-         ECRYPTFS_MINIMUM_HEADER_EXTENT_SIZE;
-   } else
-      crypt_stat->header_extent_size = PAGE_CACHE_SIZE;
    if (crypt_stat->flags & ECRYPTFS_METADATA_IN_XATTR)
       crypt_stat->num_header_extents_at_front = 0;
-   else
-      crypt_stat->num_header_extents_at_front = 1;
+   else {
+      if (PAGE_CACHE_SIZE <= ECRYPTFS_MINIMUM_HEADER_EXTENT_SIZE)
+         crypt_stat->num_header_extents_at_front =
+            (ECRYPTFS_MINIMUM_HEADER_EXTENT_SIZE
+             / crypt_stat->extent_size);
+      else
+         crypt_stat->num_header_extents_at_front =
+            (PAGE_CACHE_SIZE / crypt_stat->extent_size);
+   }
 }
 
 /**
@@ -917,6 +903,8 @@ static void ecryptfs_generate_new_key(struct ecryptfs_crypt_stat *crypt_stat)
 
 /**
  * ecryptfs_copy_mount_wide_flags_to_inode_flags
+ * @crypt_stat: The inode's cryptographic context
+ * @mount_crypt_stat: The mount point's cryptographic context
  *
  * This function propagates the mount-wide flags to individual inode
  * flags.
@@ -931,9 +919,34 @@ static void ecryptfs_copy_mount_wide_flags_to_inode_flags(
       crypt_stat->flags |= ECRYPTFS_VIEW_AS_ENCRYPTED;
 }
 
+static int ecryptfs_copy_mount_wide_sigs_to_inode_sigs(
+   struct ecryptfs_crypt_stat *crypt_stat,
+   struct ecryptfs_mount_crypt_stat *mount_crypt_stat)
+{
+   struct ecryptfs_global_auth_tok *global_auth_tok;
+   int rc = 0;
+
+   mutex_lock(&mount_crypt_stat->global_auth_tok_list_mutex);
+   list_for_each_entry(global_auth_tok,
+             &mount_crypt_stat->global_auth_tok_list,
+             mount_crypt_stat_list) {
+      rc = ecryptfs_add_keysig(crypt_stat, global_auth_tok->sig);
+      if (rc) {
+         printk(KERN_ERR "Error adding keysig; rc = [%d]\n", rc);
+         mutex_unlock(
+            &mount_crypt_stat->global_auth_tok_list_mutex);
+         goto out;
+      }
+   }
+   mutex_unlock(&mount_crypt_stat->global_auth_tok_list_mutex);
+out:
+   return rc;
+}
+
 /**
  * ecryptfs_set_default_crypt_stat_vals
- * @crypt_stat
+ * @crypt_stat: The inode's cryptographic context
+ * @mount_crypt_stat: The mount point's cryptographic context
  *
  * Default values in the event that policy does not override them.
  */
@@ -953,7 +966,7 @@ static void ecryptfs_set_default_crypt_stat_vals(
 
 /**
  * ecryptfs_new_file_context
- * @ecryptfs_dentry
+ * @ecryptfs_dentry: The eCryptfs dentry
  *
  * If the crypto context for the file has not yet been established,
  * this is where we do that.  Establishing a new crypto context
@@ -970,49 +983,42 @@ static void ecryptfs_set_default_crypt_stat_vals(
  *
  * Returns zero on success; non-zero otherwise
  */
-/* Associate an authentication token(s) with the file */
 int ecryptfs_new_file_context(struct dentry *ecryptfs_dentry)
 {
-   int rc = 0;
    struct ecryptfs_crypt_stat *crypt_stat =
        &ecryptfs_inode_to_private(ecryptfs_dentry->d_inode)->crypt_stat;
    struct ecryptfs_mount_crypt_stat *mount_crypt_stat =
        &ecryptfs_superblock_to_private(
           ecryptfs_dentry->d_sb)->mount_crypt_stat;
    int cipher_name_len;
+   int rc = 0;
 
    ecryptfs_set_default_crypt_stat_vals(crypt_stat, mount_crypt_stat);
-   /* See if there are mount crypt options */
-   if (mount_crypt_stat->global_auth_tok) {
-      ecryptfs_printk(KERN_DEBUG, "Initializing context for new "
-            "file using mount_crypt_stat\n");
-      crypt_stat->flags |= ECRYPTFS_ENCRYPTED;
-      crypt_stat->flags |= ECRYPTFS_KEY_VALID;
-      ecryptfs_copy_mount_wide_flags_to_inode_flags(crypt_stat,
-                           mount_crypt_stat);
-      memcpy(crypt_stat->keysigs[crypt_stat->num_keysigs++],
-             mount_crypt_stat->global_auth_tok_sig,
-             ECRYPTFS_SIG_SIZE_HEX);
-      cipher_name_len =
-          strlen(mount_crypt_stat->global_default_cipher_name);
-      memcpy(crypt_stat->cipher,
-             mount_crypt_stat->global_default_cipher_name,
-             cipher_name_len);
-      crypt_stat->cipher[cipher_name_len] = '\0';
-      crypt_stat->key_size =
-         mount_crypt_stat->global_default_cipher_key_size;
-      ecryptfs_generate_new_key(crypt_stat);
-   } else
-      /* We should not encounter this scenario since we
-       * should detect lack of global_auth_tok at mount time
-       * TODO: Applies to 0.1 release only; remove in future
-       * release */
-      BUG();
+   crypt_stat->flags |= (ECRYPTFS_ENCRYPTED | ECRYPTFS_KEY_VALID);
+   ecryptfs_copy_mount_wide_flags_to_inode_flags(crypt_stat,
+                        mount_crypt_stat);
+   rc = ecryptfs_copy_mount_wide_sigs_to_inode_sigs(crypt_stat,
+                      mount_crypt_stat);
+   if (rc) {
+      printk(KERN_ERR "Error attempting to copy mount-wide key sigs "
+             "to the inode key sigs; rc = [%d]\n", rc);
+      goto out;
+   }
+   cipher_name_len =
+      strlen(mount_crypt_stat->global_default_cipher_name);
+   memcpy(crypt_stat->cipher,
+          mount_crypt_stat->global_default_cipher_name,
+          cipher_name_len);
+   crypt_stat->cipher[cipher_name_len] = '\0';
+   crypt_stat->key_size =
+      mount_crypt_stat->global_default_cipher_key_size;
+   ecryptfs_generate_new_key(crypt_stat);
    rc = ecryptfs_init_crypt_ctx(crypt_stat);
    if (rc)
       ecryptfs_printk(KERN_ERR, "Error initializing cryptographic "
             "context for cipher [%s]: rc = [%d]\n",
             crypt_stat->cipher, rc);
+out:
    return rc;
 }
 
@@ -1054,7 +1060,7 @@ static struct ecryptfs_flag_map_elem ecryptfs_flag_map[] = {
 
 /**
  * ecryptfs_process_flags
- * @crypt_stat
+ * @crypt_stat: The cryptographic context
  * @page_virt: Source data to be parsed
  * @bytes_read: Updated with the number of bytes read
  *
@@ -1142,7 +1148,7 @@ ecryptfs_cipher_code_str_map[] = {
 
 /**
  * ecryptfs_code_for_cipher_string
- * @str: The string representing the cipher name
+ * @crypt_stat: The cryptographic context
  *
  * Returns zero on no match, or the cipher code on match
  */
@@ -1198,59 +1204,28 @@ int ecryptfs_cipher_code_to_string(char *str, u16 cipher_code)
    return rc;
 }
 
-/**
- * ecryptfs_read_header_region
- * @data
- * @dentry
- * @nd
- *
- * Returns zero on success; non-zero otherwise
- */
-static int ecryptfs_read_header_region(char *data, struct dentry *dentry,
-                   struct vfsmount *mnt)
+int ecryptfs_read_and_validate_header_region(char *data,
+                    struct inode *ecryptfs_inode)
 {
-   struct file *lower_file;
-   mm_segment_t oldfs;
+   struct ecryptfs_crypt_stat *crypt_stat =
+      &(ecryptfs_inode_to_private(ecryptfs_inode)->crypt_stat);
    int rc;
 
-   if ((rc = ecryptfs_open_lower_file(&lower_file, dentry, mnt,
-                  O_RDONLY))) {
-      printk(KERN_ERR
-             "Error opening lower_file to read header region\n");
-      goto out;
-   }
-   lower_file->f_pos = 0;
-   oldfs = get_fs();
-   set_fs(get_ds());
-   /* For releases 0.1 and 0.2, all of the header information
-    * fits in the first data extent-sized region. */
-   rc = lower_file->f_op->read(lower_file, (char __user *)data,
-               ECRYPTFS_DEFAULT_EXTENT_SIZE, &lower_file->f_pos);
-   set_fs(oldfs);
-   if ((rc = ecryptfs_close_lower_file(lower_file))) {
-      printk(KERN_ERR "Error closing lower_file\n");
+   rc = ecryptfs_read_lower(data, 0, crypt_stat->extent_size,
+             ecryptfs_inode);
+   if (rc) {
+      printk(KERN_ERR "%s: Error reading header region; rc = [%d]\n",
+             __FUNCTION__, rc);
       goto out;
    }
-   rc = 0;
-out:
-   return rc;
-}
-
-int ecryptfs_read_and_validate_header_region(char *data, struct dentry *dentry,
-                    struct vfsmount *mnt)
-{
-   int rc;
-
-   rc = ecryptfs_read_header_region(data, dentry, mnt);
-   if (rc)
-      goto out;
-   if (!contains_ecryptfs_marker(data + ECRYPTFS_FILE_SIZE_BYTES))
+   if (!contains_ecryptfs_marker(data + ECRYPTFS_FILE_SIZE_BYTES)) {
       rc = -EINVAL;
+      ecryptfs_printk(KERN_DEBUG, "Valid marker not found\n");
+   }
 out:
    return rc;
 }
 
-
 void
 ecryptfs_write_header_metadata(char *virt,
                 struct ecryptfs_crypt_stat *crypt_stat,
@@ -1259,7 +1234,7 @@ ecryptfs_write_header_metadata(char *virt,
    u32 header_extent_size;
    u16 num_header_extents_at_front;
 
-   header_extent_size = (u32)crypt_stat->header_extent_size;
+   header_extent_size = (u32)crypt_stat->extent_size;
    num_header_extents_at_front =
       (u16)crypt_stat->num_header_extents_at_front;
    header_extent_size = cpu_to_be32(header_extent_size);
@@ -1276,9 +1251,10 @@ struct kmem_cache *ecryptfs_header_cache_2;
 
 /**
  * ecryptfs_write_headers_virt
- * @page_virt
- * @crypt_stat
- * @ecryptfs_dentry
+ * @page_virt: The virtual address to write the headers to
+ * @size: Set to the number of bytes written by this function
+ * @crypt_stat: The cryptographic context
+ * @ecryptfs_dentry: The eCryptfs dentry
  *
  * Format version: 1
  *
@@ -1332,53 +1308,50 @@ static int ecryptfs_write_headers_virt(char *page_virt, size_t *size,
    return rc;
 }
 
-static int ecryptfs_write_metadata_to_contents(struct ecryptfs_crypt_stat *crypt_stat,
-                      struct file *lower_file,
-                      char *page_virt)
+static int
+ecryptfs_write_metadata_to_contents(struct ecryptfs_crypt_stat *crypt_stat,
+                struct dentry *ecryptfs_dentry,
+                char *page_virt)
 {
-   mm_segment_t oldfs;
    int current_header_page;
    int header_pages;
-   ssize_t size;
-   int rc = 0;
+   int rc;
 
-   lower_file->f_pos = 0;
-   oldfs = get_fs();
-   set_fs(get_ds());
-   size = vfs_write(lower_file, (char __user *)page_virt, PAGE_CACHE_SIZE,
-          &lower_file->f_pos);
-   if (size < 0) {
-      rc = (int)size;
-      printk(KERN_ERR "Error attempting to write lower page; "
-             "rc = [%d]\n", rc);
-      set_fs(oldfs);
+   rc = ecryptfs_write_lower(ecryptfs_dentry->d_inode, page_virt,
+              0, PAGE_CACHE_SIZE);
+   if (rc) {
+      printk(KERN_ERR "%s: Error attempting to write header "
+             "information to lower file; rc = [%d]\n", __FUNCTION__,
+             rc);
       goto out;
    }
-   header_pages = ((crypt_stat->header_extent_size
+   header_pages = ((crypt_stat->extent_size
           * crypt_stat->num_header_extents_at_front)
          / PAGE_CACHE_SIZE);
    memset(page_virt, 0, PAGE_CACHE_SIZE);
    current_header_page = 1;
    while (current_header_page < header_pages) {
-      size = vfs_write(lower_file, (char __user *)page_virt,
-             PAGE_CACHE_SIZE, &lower_file->f_pos);
-      if (size < 0) {
-         rc = (int)size;
-         printk(KERN_ERR "Error attempting to write lower page; "
-                "rc = [%d]\n", rc);
-         set_fs(oldfs);
+      loff_t offset;
+
+      offset = (((loff_t)current_header_page) << PAGE_CACHE_SHIFT);
+      if ((rc = ecryptfs_write_lower(ecryptfs_dentry->d_inode,
+                      page_virt, offset,
+                      PAGE_CACHE_SIZE))) {
+         printk(KERN_ERR "%s: Error attempting to write header "
+                "information to lower file; rc = [%d]\n",
+                __FUNCTION__, rc);
          goto out;
       }
       current_header_page++;
    }
-   set_fs(oldfs);
 out:
    return rc;
 }
 
-static int ecryptfs_write_metadata_to_xattr(struct dentry *ecryptfs_dentry,
-                   struct ecryptfs_crypt_stat *crypt_stat,
-                   char *page_virt, size_t size)
+static int
+ecryptfs_write_metadata_to_xattr(struct dentry *ecryptfs_dentry,
+             struct ecryptfs_crypt_stat *crypt_stat,
+             char *page_virt, size_t size)
 {
    int rc;
 
@@ -1389,7 +1362,7 @@ static int ecryptfs_write_metadata_to_xattr(struct dentry *ecryptfs_dentry,
 
 /**
  * ecryptfs_write_metadata
- * @lower_file: The lower file struct, which was returned from dentry_open
+ * @ecryptfs_dentry: The eCryptfs dentry
  *
  * Write the file headers out.  This will likely involve a userspace
  * callout, in which the session key is encrypted with one or more
@@ -1397,22 +1370,21 @@ static int ecryptfs_write_metadata_to_xattr(struct dentry *ecryptfs_dentry,
  * retrieved via a prompt.  Exactly what happens at this point should
  * be policy-dependent.
  *
+ * TODO: Support header information spanning multiple pages
+ *
  * Returns zero on success; non-zero on error
  */
-int ecryptfs_write_metadata(struct dentry *ecryptfs_dentry,
-             struct file *lower_file)
+int ecryptfs_write_metadata(struct dentry *ecryptfs_dentry)
 {
-   struct ecryptfs_crypt_stat *crypt_stat;
+   struct ecryptfs_crypt_stat *crypt_stat =
+      &ecryptfs_inode_to_private(ecryptfs_dentry->d_inode)->crypt_stat;
    char *page_virt;
-   size_t size;
+   size_t size = 0;
    int rc = 0;
 
-   crypt_stat = &ecryptfs_inode_to_private(
-      ecryptfs_dentry->d_inode)->crypt_stat;
    if (likely(crypt_stat->flags & ECRYPTFS_ENCRYPTED)) {
       if (!(crypt_stat->flags & ECRYPTFS_KEY_VALID)) {
-         ecryptfs_printk(KERN_DEBUG, "Key is "
-               "invalid; bailing out\n");
+         printk(KERN_ERR "Key is invalid; bailing out\n");
          rc = -EINVAL;
          goto out;
       }
@@ -1441,7 +1413,8 @@ int ecryptfs_write_metadata(struct dentry *ecryptfs_dentry,
                         crypt_stat, page_virt,
                         size);
    else
-      rc = ecryptfs_write_metadata_to_contents(crypt_stat, lower_file,
+      rc = ecryptfs_write_metadata_to_contents(crypt_stat,
+                      ecryptfs_dentry,
                       page_virt);
    if (rc) {
       printk(KERN_ERR "Error writing metadata out to lower file; "
@@ -1464,28 +1437,28 @@ static int parse_header_metadata(struct ecryptfs_crypt_stat *crypt_stat,
    u32 header_extent_size;
    u16 num_header_extents_at_front;
 
-   memcpy(&header_extent_size, virt, 4);
+   memcpy(&header_extent_size, virt, sizeof(u32));
    header_extent_size = be32_to_cpu(header_extent_size);
-   virt += 4;
-   memcpy(&num_header_extents_at_front, virt, 2);
+   virt += sizeof(u32);
+   memcpy(&num_header_extents_at_front, virt, sizeof(u16));
    num_header_extents_at_front = be16_to_cpu(num_header_extents_at_front);
-   crypt_stat->header_extent_size = (int)header_extent_size;
    crypt_stat->num_header_extents_at_front =
       (int)num_header_extents_at_front;
-   (*bytes_read) = 6;
+   (*bytes_read) = (sizeof(u32) + sizeof(u16));
    if ((validate_header_size == ECRYPTFS_VALIDATE_HEADER_SIZE)
-       && ((crypt_stat->header_extent_size
+       && ((crypt_stat->extent_size
        * crypt_stat->num_header_extents_at_front)
       < ECRYPTFS_MINIMUM_HEADER_EXTENT_SIZE)) {
       rc = -EINVAL;
-      ecryptfs_printk(KERN_WARNING, "Invalid header extent size: "
-            "[%d]\n", crypt_stat->header_extent_size);
+      printk(KERN_WARNING "Invalid number of header extents: [%zd]\n",
+             crypt_stat->num_header_extents_at_front);
    }
    return rc;
 }
 
 /**
  * set_default_header_data
+ * @crypt_stat: The cryptographic context
  *
  * For version 0 file format; this function is only for backwards
  * compatibility for files created with the prior versions of
@@ -1493,12 +1466,15 @@ static int parse_header_metadata(struct ecryptfs_crypt_stat *crypt_stat,
  */
 static void set_default_header_data(struct ecryptfs_crypt_stat *crypt_stat)
 {
-   crypt_stat->header_extent_size = 4096;
-   crypt_stat->num_header_extents_at_front = 1;
+   crypt_stat->num_header_extents_at_front = 2;
 }
 
 /**
  * ecryptfs_read_headers_virt
+ * @page_virt: The virtual address into which to read the headers
+ * @crypt_stat: The cryptographic context
+ * @ecryptfs_dentry: The eCryptfs dentry
+ * @validate_header_size: Whether to validate the header size while reading
  *
  * Read/parse the header data. The header format is detailed in the
  * comment block for the ecryptfs_write_headers_virt() function.
@@ -1558,19 +1534,25 @@ out:
 
 /**
  * ecryptfs_read_xattr_region
+ * @page_virt: The vitual address into which to read the xattr data
+ * @ecryptfs_inode: The eCryptfs inode
  *
  * Attempts to read the crypto metadata from the extended attribute
  * region of the lower file.
+ *
+ * Returns zero on success; non-zero on error
  */
-int ecryptfs_read_xattr_region(char *page_virt, struct dentry *ecryptfs_dentry)
+int ecryptfs_read_xattr_region(char *page_virt, struct inode *ecryptfs_inode)
 {
+   struct dentry *lower_dentry =
+      ecryptfs_inode_to_private(ecryptfs_inode)->lower_file->f_dentry;
    ssize_t size;
    int rc = 0;
 
-   size = ecryptfs_getxattr(ecryptfs_dentry, ECRYPTFS_XATTR_NAME,
-             page_virt, ECRYPTFS_DEFAULT_EXTENT_SIZE);
+   size = ecryptfs_getxattr_lower(lower_dentry, ECRYPTFS_XATTR_NAME,
+                   page_virt, ECRYPTFS_DEFAULT_EXTENT_SIZE);
    if (size < 0) {
-      printk(KERN_DEBUG "Error attempting to read the [%s] "
+      printk(KERN_ERR "Error attempting to read the [%s] "
              "xattr from the lower file; return value = [%zd]\n",
              ECRYPTFS_XATTR_NAME, size);
       rc = -EINVAL;
@@ -1585,7 +1567,7 @@ int ecryptfs_read_and_validate_xattr_region(char *page_virt,
 {
    int rc;
 
-   rc = ecryptfs_read_xattr_region(page_virt, ecryptfs_dentry);
+   rc = ecryptfs_read_xattr_region(page_virt, ecryptfs_dentry->d_inode);
    if (rc)
       goto out;
    if (!contains_ecryptfs_marker(page_virt   + ECRYPTFS_FILE_SIZE_BYTES)) {
@@ -1609,15 +1591,13 @@ out:
  *
  * Returns zero if valid headers found and parsed; non-zero otherwise
  */
-int ecryptfs_read_metadata(struct dentry *ecryptfs_dentry,
-            struct file *lower_file)
+int ecryptfs_read_metadata(struct dentry *ecryptfs_dentry)
 {
    int rc = 0;
    char *page_virt = NULL;
-   mm_segment_t oldfs;
-   ssize_t bytes_read;
+   struct inode *ecryptfs_inode = ecryptfs_dentry->d_inode;
    struct ecryptfs_crypt_stat *crypt_stat =
-       &ecryptfs_inode_to_private(ecryptfs_dentry->d_inode)->crypt_stat;
+       &ecryptfs_inode_to_private(ecryptfs_inode)->crypt_stat;
    struct ecryptfs_mount_crypt_stat *mount_crypt_stat =
       &ecryptfs_superblock_to_private(
          ecryptfs_dentry->d_sb)->mount_crypt_stat;
@@ -1628,27 +1608,18 @@ int ecryptfs_read_metadata(struct dentry *ecryptfs_dentry,
    page_virt = kmem_cache_alloc(ecryptfs_header_cache_1, GFP_USER);
    if (!page_virt) {
       rc = -ENOMEM;
-      ecryptfs_printk(KERN_ERR, "Unable to allocate page_virt\n");
-      goto out;
-   }
-   lower_file->f_pos = 0;
-   oldfs = get_fs();
-   set_fs(get_ds());
-   bytes_read = lower_file->f_op->read(lower_file,
-                   (char __user *)page_virt,
-                   ECRYPTFS_DEFAULT_EXTENT_SIZE,
-                   &lower_file->f_pos);
-   set_fs(oldfs);
-   if (bytes_read != ECRYPTFS_DEFAULT_EXTENT_SIZE) {
-      rc = -EINVAL;
+      printk(KERN_ERR "%s: Unable to allocate page_virt\n",
+             __FUNCTION__);
       goto out;
    }
-   rc = ecryptfs_read_headers_virt(page_virt, crypt_stat,
-               ecryptfs_dentry,
-               ECRYPTFS_VALIDATE_HEADER_SIZE);
+   rc = ecryptfs_read_lower(page_virt, 0, crypt_stat->extent_size,
+             ecryptfs_inode);
+   if (!rc)
+      rc = ecryptfs_read_headers_virt(page_virt, crypt_stat,
+                  ecryptfs_dentry,
+                  ECRYPTFS_VALIDATE_HEADER_SIZE);
    if (rc) {
-      rc = ecryptfs_read_xattr_region(page_virt,
-                  ecryptfs_dentry);
+      rc = ecryptfs_read_xattr_region(page_virt, ecryptfs_inode);
       if (rc) {
          printk(KERN_DEBUG "Valid eCryptfs headers not found in "
                 "file header region or xattr region\n");
@@ -1776,7 +1747,7 @@ out:
 }
 
 /**
- * ecryptfs_process_cipher - Perform cipher initialization.
+ * ecryptfs_process_key_cipher - Perform key cipher initialization.
  * @key_tfm: Crypto context for key material, set by this function
  * @cipher_name: Name of the cipher
  * @key_size: Size of the key in bytes
@@ -1785,9 +1756,9 @@ out:
  * should be released by other functions, such as on a superblock put
  * event, regardless of whether this function succeeds for fails.
  */
-int
-ecryptfs_process_cipher(struct crypto_blkcipher **key_tfm, char *cipher_name,
-         size_t *key_size)
+static int
+ecryptfs_process_key_cipher(struct crypto_blkcipher **key_tfm,
+             char *cipher_name, size_t *key_size)
 {
    char dummy_key[ECRYPTFS_MAX_KEY_BYTES];
    char *full_alg_name;
@@ -1829,3 +1800,101 @@ ecryptfs_process_cipher(struct crypto_blkcipher **key_tfm, char *cipher_name,
 out:
    return rc;
 }
+
+struct kmem_cache *ecryptfs_key_tfm_cache;
+struct list_head key_tfm_list;
+struct mutex key_tfm_list_mutex;
+
+int ecryptfs_init_crypto(void)
+{
+   mutex_init(&key_tfm_list_mutex);
+   INIT_LIST_HEAD(&key_tfm_list);
+   return 0;
+}
+
+int ecryptfs_destroy_crypto(void)
+{
+   struct ecryptfs_key_tfm *key_tfm, *key_tfm_tmp;
+
+   mutex_lock(&key_tfm_list_mutex);
+   list_for_each_entry_safe(key_tfm, key_tfm_tmp, &key_tfm_list,
+             key_tfm_list) {
+      list_del(&key_tfm->key_tfm_list);
+      if (key_tfm->key_tfm)
+         crypto_free_blkcipher(key_tfm->key_tfm);
+      kmem_cache_free(ecryptfs_key_tfm_cache, key_tfm);
+   }
+   mutex_unlock(&key_tfm_list_mutex);
+   return 0;
+}
+
+int
+ecryptfs_add_new_key_tfm(struct ecryptfs_key_tfm **key_tfm, char *cipher_name,
+          size_t key_size)
+{
+   struct ecryptfs_key_tfm *tmp_tfm;
+   int rc = 0;
+
+   tmp_tfm = kmem_cache_alloc(ecryptfs_key_tfm_cache, GFP_KERNEL);
+   if (key_tfm != NULL)
+      (*key_tfm) = tmp_tfm;
+   if (!tmp_tfm) {
+      rc = -ENOMEM;
+      printk(KERN_ERR "Error attempting to allocate from "
+             "ecryptfs_key_tfm_cache\n");
+      goto out;
+   }
+   mutex_init(&tmp_tfm->key_tfm_mutex);
+   strncpy(tmp_tfm->cipher_name, cipher_name,
+      ECRYPTFS_MAX_CIPHER_NAME_SIZE);
+   tmp_tfm->cipher_name[ECRYPTFS_MAX_CIPHER_NAME_SIZE] = '\0';
+   tmp_tfm->key_size = key_size;
+   rc = ecryptfs_process_key_cipher(&tmp_tfm->key_tfm,
+                tmp_tfm->cipher_name,
+                &tmp_tfm->key_size);
+   if (rc) {
+      printk(KERN_ERR "Error attempting to initialize key TFM "
+             "cipher with name = [%s]; rc = [%d]\n",
+             tmp_tfm->cipher_name, rc);
+      kmem_cache_free(ecryptfs_key_tfm_cache, tmp_tfm);
+      if (key_tfm != NULL)
+         (*key_tfm) = NULL;
+      goto out;
+   }
+   mutex_lock(&key_tfm_list_mutex);
+   list_add(&tmp_tfm->key_tfm_list, &key_tfm_list);
+   mutex_unlock(&key_tfm_list_mutex);
+out:
+   return rc;
+}
+
+int ecryptfs_get_tfm_and_mutex_for_cipher_name(struct crypto_blkcipher **tfm,
+                      struct mutex **tfm_mutex,
+                      char *cipher_name)
+{
+   struct ecryptfs_key_tfm *key_tfm;
+   int rc = 0;
+
+   (*tfm) = NULL;
+   (*tfm_mutex) = NULL;
+   mutex_lock(&key_tfm_list_mutex);
+   list_for_each_entry(key_tfm, &key_tfm_list, key_tfm_list) {
+      if (strcmp(key_tfm->cipher_name, cipher_name) == 0) {
+         (*tfm) = key_tfm->key_tfm;
+         (*tfm_mutex) = &key_tfm->key_tfm_mutex;
+         mutex_unlock(&key_tfm_list_mutex);
+         goto out;
+      }
+   }
+   mutex_unlock(&key_tfm_list_mutex);
+   rc = ecryptfs_add_new_key_tfm(&key_tfm, cipher_name, 0);
+   if (rc) {
+      printk(KERN_ERR "Error adding new key_tfm to list; rc = [%d]\n",
+             rc);
+      goto out;
+   }
+   (*tfm) = key_tfm->key_tfm;
+   (*tfm_mutex) = &key_tfm->key_tfm_mutex;
+out:
+   return rc;
+}


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