[PATCH] eCryptfs: Generalize metadata read/write
Michael Halcrow [Mon, 12 Feb 2007 08:53:46 +0000 (00:53 -0800)]
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>

fs/ecryptfs/crypto.c
fs/ecryptfs/ecryptfs_kernel.h
fs/ecryptfs/file.c
fs/ecryptfs/inode.c
fs/ecryptfs/main.c
fs/ecryptfs/messaging.c
fs/ecryptfs/mmap.c

index 6d85aab..96fa40a 100644 (file)
@@ -3,7 +3,7 @@
  *
  * Copyright (C) 1997-2004 Erez Zadok
  * Copyright (C) 2001-2004 Stony Brook University
- * Copyright (C) 2004-2006 International Business Machines Corp.
+ * Copyright (C) 2004-2007 International Business Machines Corp.
  *   Author(s): Michael A. Halcrow <mahalcro@us.ibm.com>
  *             Michael C. Thompson <mcthomps@us.ibm.com>
  *
@@ -863,7 +863,10 @@ void ecryptfs_set_default_sizes(struct ecryptfs_crypt_stat *crypt_stat)
                        ECRYPTFS_MINIMUM_HEADER_EXTENT_SIZE;
        } else
                crypt_stat->header_extent_size = PAGE_CACHE_SIZE;
-       crypt_stat->num_header_extents_at_front = 1;
+       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;
 }
 
 /**
@@ -1021,7 +1024,7 @@ int ecryptfs_new_file_context(struct dentry *ecryptfs_dentry)
  *
  * Returns one if marker found; zero if not found
  */
-int contains_ecryptfs_marker(char *data)
+static int contains_ecryptfs_marker(char *data)
 {
        u32 m_1, m_2;
 
@@ -1047,7 +1050,8 @@ struct ecryptfs_flag_map_elem {
 /* Add support for additional flags by adding elements here. */
 static struct ecryptfs_flag_map_elem ecryptfs_flag_map[] = {
        {0x00000001, ECRYPTFS_ENABLE_HMAC},
-       {0x00000002, ECRYPTFS_ENCRYPTED}
+       {0x00000002, ECRYPTFS_ENCRYPTED},
+       {0x00000004, ECRYPTFS_METADATA_IN_XATTR}
 };
 
 /**
@@ -1207,8 +1211,8 @@ int ecryptfs_cipher_code_to_string(char *str, u16 cipher_code)
  *
  * Returns zero on success; non-zero otherwise
  */
-int ecryptfs_read_header_region(char *data, struct dentry *dentry,
-                               struct vfsmount *mnt)
+static int ecryptfs_read_header_region(char *data, struct dentry *dentry,
+                                      struct vfsmount *mnt)
 {
        struct file *lower_file;
        mm_segment_t oldfs;
@@ -1237,6 +1241,21 @@ 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))
+               rc = -EINVAL;
+out:
+       return rc;
+}
+
+
 static void
 write_header_metadata(char *virt, struct ecryptfs_crypt_stat *crypt_stat,
                      size_t *written)
@@ -1288,9 +1307,9 @@ struct kmem_cache *ecryptfs_header_cache_2;
  *
  * Returns zero on success
  */
-int ecryptfs_write_headers_virt(char *page_virt,
-                               struct ecryptfs_crypt_stat *crypt_stat,
-                               struct dentry *ecryptfs_dentry)
+static int ecryptfs_write_headers_virt(char *page_virt, size_t *size,
+                                      struct ecryptfs_crypt_stat *crypt_stat,
+                                      struct dentry *ecryptfs_dentry)
 {
        int rc;
        size_t written;
@@ -1309,11 +1328,53 @@ int ecryptfs_write_headers_virt(char *page_virt,
        if (rc)
                ecryptfs_printk(KERN_WARNING, "Error generating key packet "
                                "set; rc = [%d]\n", rc);
+       if (size) {
+               offset += written;
+               *size = offset;
+       }
+       return rc;
+}
+
+static int ecryptfs_write_metadata_to_contents(struct ecryptfs_crypt_stat *crypt_stat,
+                                              struct file *lower_file,
+                                              char *page_virt)
+{
+       mm_segment_t oldfs;
+       int current_header_page;
+       int header_pages;
+
+       lower_file->f_pos = 0;
+       oldfs = get_fs();
+       set_fs(get_ds());
+       lower_file->f_op->write(lower_file, (char __user *)page_virt,
+                               PAGE_CACHE_SIZE, &lower_file->f_pos);
+       header_pages = ((crypt_stat->header_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) {
+               lower_file->f_op->write(lower_file, (char __user *)page_virt,
+                                       PAGE_CACHE_SIZE, &lower_file->f_pos);
+               current_header_page++;
+       }
+       set_fs(oldfs);
+       return 0;
+}
+
+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;
+
+       rc = ecryptfs_setxattr(ecryptfs_dentry, ECRYPTFS_XATTR_NAME, page_virt,
+                              size, 0);
        return rc;
 }
 
 /**
- * ecryptfs_write_headers
+ * ecryptfs_write_metadata
  * @lower_file: The lower file struct, which was returned from dentry_open
  *
  * Write the file headers out.  This will likely involve a userspace
@@ -1324,14 +1385,12 @@ int ecryptfs_write_headers_virt(char *page_virt,
  *
  * Returns zero on success; non-zero on error
  */
-int ecryptfs_write_headers(struct dentry *ecryptfs_dentry,
-                          struct file *lower_file)
+int ecryptfs_write_metadata(struct dentry *ecryptfs_dentry,
+                           struct file *lower_file)
 {
-       mm_segment_t oldfs;
        struct ecryptfs_crypt_stat *crypt_stat;
        char *page_virt;
-       int current_header_page;
-       int header_pages;
+       size_t size;
        int rc = 0;
 
        crypt_stat = &ecryptfs_inode_to_private(
@@ -1358,48 +1417,36 @@ int ecryptfs_write_headers(struct dentry *ecryptfs_dentry,
                rc = -ENOMEM;
                goto out;
        }
-
-       rc = ecryptfs_write_headers_virt(page_virt, crypt_stat,
-                                        ecryptfs_dentry);
+       rc = ecryptfs_write_headers_virt(page_virt, &size, crypt_stat,
+                                        ecryptfs_dentry);
        if (unlikely(rc)) {
                ecryptfs_printk(KERN_ERR, "Error whilst writing headers\n");
                memset(page_virt, 0, PAGE_CACHE_SIZE);
                goto out_free;
        }
-       ecryptfs_printk(KERN_DEBUG,
-                       "Writing key packet set to underlying file\n");
-       lower_file->f_pos = 0;
-       oldfs = get_fs();
-       set_fs(get_ds());
-       ecryptfs_printk(KERN_DEBUG, "Calling lower_file->f_op->"
-                       "write() w/ header page; lower_file->f_pos = "
-                       "[0x%.16x]\n", lower_file->f_pos);
-       lower_file->f_op->write(lower_file, (char __user *)page_virt,
-                               PAGE_CACHE_SIZE, &lower_file->f_pos);
-       header_pages = ((crypt_stat->header_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) {
-               ecryptfs_printk(KERN_DEBUG, "Calling lower_file->f_op->"
-                               "write() w/ zero'd page; lower_file->f_pos = "
-                               "[0x%.16x]\n", lower_file->f_pos);
-               lower_file->f_op->write(lower_file, (char __user *)page_virt,
-                                       PAGE_CACHE_SIZE, &lower_file->f_pos);
-               current_header_page++;
+       if (crypt_stat->flags & ECRYPTFS_METADATA_IN_XATTR)
+               rc = ecryptfs_write_metadata_to_xattr(ecryptfs_dentry,
+                                                     crypt_stat, page_virt,
+                                                     size);
+       else
+               rc = ecryptfs_write_metadata_to_contents(crypt_stat, lower_file,
+                                                        page_virt);
+       if (rc) {
+               printk(KERN_ERR "Error writing metadata out to lower file; "
+                      "rc = [%d]\n", rc);
+               goto out_free;
        }
-       set_fs(oldfs);
-       ecryptfs_printk(KERN_DEBUG,
-                       "Done writing key packet set to underlying file.\n");
 out_free:
        kmem_cache_free(ecryptfs_header_cache_0, page_virt);
 out:
        return rc;
 }
 
+#define ECRYPTFS_DONT_VALIDATE_HEADER_SIZE 0
+#define ECRYPTFS_VALIDATE_HEADER_SIZE 1
 static int parse_header_metadata(struct ecryptfs_crypt_stat *crypt_stat,
-                                char *virt, int *bytes_read)
+                                char *virt, int *bytes_read,
+                                int validate_header_size)
 {
        int rc = 0;
        u32 header_extent_size;
@@ -1414,9 +1461,10 @@ static int parse_header_metadata(struct ecryptfs_crypt_stat *crypt_stat,
        crypt_stat->num_header_extents_at_front =
                (int)num_header_extents_at_front;
        (*bytes_read) = 6;
-       if ((crypt_stat->header_extent_size
-            * crypt_stat->num_header_extents_at_front)
-           < ECRYPTFS_MINIMUM_HEADER_EXTENT_SIZE) {
+       if ((validate_header_size == ECRYPTFS_VALIDATE_HEADER_SIZE)
+           && ((crypt_stat->header_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);
@@ -1447,7 +1495,8 @@ static void set_default_header_data(struct ecryptfs_crypt_stat *crypt_stat)
  */
 static int ecryptfs_read_headers_virt(char *page_virt,
                                      struct ecryptfs_crypt_stat *crypt_stat,
-                                     struct dentry *ecryptfs_dentry)
+                                     struct dentry *ecryptfs_dentry,
+                                     int validate_header_size)
 {
        int rc = 0;
        int offset;
@@ -1481,7 +1530,7 @@ static int ecryptfs_read_headers_virt(char *page_virt,
        offset += bytes_read;
        if (crypt_stat->file_version >= 1) {
                rc = parse_header_metadata(crypt_stat, (page_virt + offset),
-                                          &bytes_read);
+                                          &bytes_read, validate_header_size);
                if (rc) {
                        ecryptfs_printk(KERN_WARNING, "Error reading header "
                                        "metadata; rc = [%d]\n", rc);
@@ -1496,12 +1545,60 @@ out:
 }
 
 /**
- * ecryptfs_read_headers
+ * ecryptfs_read_xattr_region
+ *
+ * Attempts to read the crypto metadata from the extended attribute
+ * region of the lower file.
+ */
+int ecryptfs_read_xattr_region(char *page_virt, struct dentry *ecryptfs_dentry)
+{
+       ssize_t size;
+       int rc = 0;
+
+       size = ecryptfs_getxattr(ecryptfs_dentry, ECRYPTFS_XATTR_NAME,
+                                page_virt, ECRYPTFS_DEFAULT_EXTENT_SIZE);
+       if (size < 0) {
+               printk(KERN_DEBUG "Error attempting to read the [%s] "
+                      "xattr from the lower file; return value = [%zd]\n",
+                      ECRYPTFS_XATTR_NAME, size);
+               rc = -EINVAL;
+               goto out;
+       }
+out:
+       return rc;
+}
+
+int ecryptfs_read_and_validate_xattr_region(char *page_virt,
+                                           struct dentry *ecryptfs_dentry)
+{
+       int rc;
+
+       rc = ecryptfs_read_xattr_region(page_virt, ecryptfs_dentry);
+       if (rc)
+               goto out;
+       if (!contains_ecryptfs_marker(page_virt + ECRYPTFS_FILE_SIZE_BYTES)) {
+               printk(KERN_WARNING "Valid data found in [%s] xattr, but "
+                       "the marker is invalid\n", ECRYPTFS_XATTR_NAME);
+               rc = -EINVAL;
+       }
+out:
+       return rc;
+}
+
+/**
+ * ecryptfs_read_metadata
+ *
+ * Common entry point for reading file metadata. From here, we could
+ * retrieve the header information from the header region of the file,
+ * the xattr region of the file, or some other repostory that is
+ * stored separately from the file itself. The current implementation
+ * supports retrieving the metadata information from the file contents
+ * and from the xattr region.
  *
  * Returns zero if valid headers found and parsed; non-zero otherwise
  */
-int ecryptfs_read_headers(struct dentry *ecryptfs_dentry,
-                         struct file *lower_file)
+int ecryptfs_read_metadata(struct dentry *ecryptfs_dentry,
+                          struct file *lower_file)
 {
        int rc = 0;
        char *page_virt = NULL;
@@ -1530,11 +1627,36 @@ int ecryptfs_read_headers(struct dentry *ecryptfs_dentry,
                goto out;
        }
        rc = ecryptfs_read_headers_virt(page_virt, crypt_stat,
-                                       ecryptfs_dentry);
+                                       ecryptfs_dentry,
+                                       ECRYPTFS_VALIDATE_HEADER_SIZE);
        if (rc) {
-               ecryptfs_printk(KERN_DEBUG, "Valid eCryptfs headers not "
-                               "found\n");
-               rc = -EINVAL;
+               rc = ecryptfs_read_xattr_region(page_virt,
+                                               ecryptfs_dentry);
+               if (rc) {
+                       printk(KERN_DEBUG "Valid eCryptfs headers not found in "
+                              "file header region or xattr region\n");
+                       rc = -EINVAL;
+                       goto out;
+               }
+               rc = ecryptfs_read_headers_virt(page_virt, crypt_stat,
+                                               ecryptfs_dentry,
+                                               ECRYPTFS_DONT_VALIDATE_HEADER_SIZE);
+               if (rc) {
+                       printk(KERN_DEBUG "Valid eCryptfs headers not found in "
+                              "file xattr region either\n");
+                       rc = -EINVAL;
+               }
+               if (crypt_stat->mount_crypt_stat->flags
+                   & ECRYPTFS_XATTR_METADATA_ENABLED) {
+                       crypt_stat->flags |= ECRYPTFS_METADATA_IN_XATTR;
+               } else {
+                       printk(KERN_WARNING "Attempt to access file with "
+                              "crypto metadata only in the extended attribute "
+                              "region, but eCryptfs was mounted without "
+                              "xattr support enabled. eCryptfs will not treat "
+                              "this like an encrypted file.\n");
+                       rc = -EINVAL;
+               }
        }
 out:
        if (page_virt) {
index 7bbd6e6..020abcd 100644 (file)
@@ -4,7 +4,7 @@
  *
  * Copyright (C) 1997-2003 Erez Zadok
  * Copyright (C) 2001-2003 Stony Brook University
- * Copyright (C) 2004-2006 International Business Machines Corp.
+ * Copyright (C) 2004-2007 International Business Machines Corp.
  *   Author(s): Michael A. Halcrow <mahalcro@us.ibm.com>
  *              Trevor S. Highland <trevor.highland@gmail.com>
  *              Tyler Hicks <tyhicks@ou.edu>
@@ -50,8 +50,8 @@
 #define ECRYPTFS_VERSIONING_XATTR                 0x00000010
 #define ECRYPTFS_VERSIONING_MASK (ECRYPTFS_VERSIONING_PASSPHRASE \
                                  | ECRYPTFS_VERSIONING_PLAINTEXT_PASSTHROUGH \
-                                 | ECRYPTFS_VERSIONING_PUBKEY)
-
+                                 | ECRYPTFS_VERSIONING_PUBKEY \
+                                 | ECRYPTFS_VERSIONING_XATTR)
 #define ECRYPTFS_MAX_PASSWORD_LENGTH 64
 #define ECRYPTFS_MAX_PASSPHRASE_BYTES ECRYPTFS_MAX_PASSWORD_LENGTH
 #define ECRYPTFS_SALT_SIZE 8
@@ -83,6 +83,7 @@
 #define ECRYPTFS_TRANSPORT_CONNECTOR 1
 #define ECRYPTFS_TRANSPORT_RELAYFS 2
 #define ECRYPTFS_DEFAULT_TRANSPORT ECRYPTFS_TRANSPORT_NETLINK
+#define ECRYPTFS_XATTR_NAME "user.ecryptfs"
 
 #define RFC2440_CIPHER_DES3_EDE 0x02
 #define RFC2440_CIPHER_CAST_5 0x03
@@ -327,18 +328,6 @@ struct ecryptfs_msg_ctx {
        struct mutex mux;
 };
 
-extern struct list_head ecryptfs_msg_ctx_free_list;
-extern struct list_head ecryptfs_msg_ctx_alloc_list;
-extern struct mutex ecryptfs_msg_ctx_lists_mux;
-
-#define ecryptfs_uid_hash(uid) \
-        hash_long((unsigned long)uid, ecryptfs_hash_buckets)
-extern struct hlist_head *ecryptfs_daemon_id_hash;
-extern struct mutex ecryptfs_daemon_id_hash_mux;
-extern int ecryptfs_hash_buckets;
-
-extern unsigned int ecryptfs_msg_counter;
-extern struct ecryptfs_msg_ctx *ecryptfs_msg_ctx_arr;
 extern unsigned int ecryptfs_transport;
 
 struct ecryptfs_daemon_id {
@@ -479,6 +468,7 @@ extern struct kmem_cache *ecryptfs_sb_info_cache;
 extern struct kmem_cache *ecryptfs_header_cache_0;
 extern struct kmem_cache *ecryptfs_header_cache_1;
 extern struct kmem_cache *ecryptfs_header_cache_2;
+extern struct kmem_cache *ecryptfs_xattr_cache;
 extern struct kmem_cache *ecryptfs_lower_page_cache;
 
 int ecryptfs_interpose(struct dentry *hidden_dentry,
@@ -505,9 +495,13 @@ int ecryptfs_init_crypt_ctx(struct ecryptfs_crypt_stat *crypt_stat);
 int ecryptfs_crypto_api_algify_cipher_name(char **algified_name,
                                           char *cipher_name,
                                           char *chaining_modifier);
-int ecryptfs_write_inode_size_to_header(struct file *lower_file,
-                                       struct inode *lower_inode,
-                                       struct inode *inode);
+#define ECRYPTFS_LOWER_I_MUTEX_NOT_HELD 0
+#define ECRYPTFS_LOWER_I_MUTEX_HELD 1
+int ecryptfs_write_inode_size_to_metadata(struct file *lower_file,
+                                         struct inode *lower_inode,
+                                         struct inode *inode,
+                                         struct dentry *ecryptfs_dentry,
+                                         int lower_i_mutex_held);
 int ecryptfs_get_lower_page(struct page **lower_page, struct inode *lower_inode,
                            struct file *lower_file,
                            unsigned long lower_page_index, int byte_offset,
@@ -529,17 +523,15 @@ int ecryptfs_writepage_and_release_lower_page(struct page *lower_page,
                                              struct writeback_control *wbc);
 int ecryptfs_encrypt_page(struct ecryptfs_page_crypt_context *ctx);
 int ecryptfs_decrypt_page(struct file *file, struct page *page);
-int ecryptfs_write_headers(struct dentry *ecryptfs_dentry,
+int ecryptfs_write_metadata(struct dentry *ecryptfs_dentry,
+                           struct file *lower_file);
+int ecryptfs_read_metadata(struct dentry *ecryptfs_dentry,
                           struct file *lower_file);
-int ecryptfs_write_headers_virt(char *page_virt,
-                               struct ecryptfs_crypt_stat *crypt_stat,
-                               struct dentry *ecryptfs_dentry);
-int ecryptfs_read_headers(struct dentry *ecryptfs_dentry,
-                         struct file *lower_file);
 int ecryptfs_new_file_context(struct dentry *ecryptfs_dentry);
-int contains_ecryptfs_marker(char *data);
-int ecryptfs_read_header_region(char *data, struct dentry *dentry,
-                               struct vfsmount *mnt);
+int ecryptfs_read_and_validate_header_region(char *data, struct dentry *dentry,
+                                            struct vfsmount *mnt);
+int ecryptfs_read_and_validate_xattr_region(char *page_virt,
+                                           struct dentry *ecryptfs_dentry);
 u16 ecryptfs_code_for_cipher_string(struct ecryptfs_crypt_stat *crypt_stat);
 int ecryptfs_cipher_code_to_string(char *str, u16 cipher_code);
 void ecryptfs_set_default_sizes(struct ecryptfs_crypt_stat *crypt_stat);
@@ -562,6 +554,11 @@ int ecryptfs_open_lower_file(struct file **lower_file,
                             struct dentry *lower_dentry,
                             struct vfsmount *lower_mnt, int flags);
 int ecryptfs_close_lower_file(struct file *lower_file);
+ssize_t ecryptfs_getxattr(struct dentry *dentry, const char *name, void *value,
+                         size_t size);
+int
+ecryptfs_setxattr(struct dentry *dentry, const char *name, const void *value,
+                 size_t size, int flags);
 
 int ecryptfs_process_helo(unsigned int transport, uid_t uid, pid_t pid);
 int ecryptfs_process_quit(uid_t uid, pid_t pid);
index 779c347..f22c3a7 100644 (file)
@@ -3,7 +3,7 @@
  *
  * Copyright (C) 1997-2004 Erez Zadok
  * Copyright (C) 2001-2004 Stony Brook University
- * Copyright (C) 2004-2006 International Business Machines Corp.
+ * Copyright (C) 2004-2007 International Business Machines Corp.
  *   Author(s): Michael A. Halcrow <mhalcrow@us.ibm.com>
  *             Michael C. Thompson <mcthomps@us.ibm.com>
  *
@@ -293,26 +293,11 @@ static int ecryptfs_open(struct inode *inode, struct file *file)
                goto out;
        }
        mutex_lock(&crypt_stat->cs_mutex);
-       if (i_size_read(lower_inode) < ECRYPTFS_MINIMUM_HEADER_EXTENT_SIZE) {
-               if (!(mount_crypt_stat->flags
-                     & ECRYPTFS_PLAINTEXT_PASSTHROUGH_ENABLED)) {
-                       rc = -EIO;
-                       printk(KERN_WARNING "Attempt to read file that is "
-                              "not in a valid eCryptfs format, and plaintext "
-                              "passthrough mode is not enabled; returning "
-                              "-EIO\n");
-                       mutex_unlock(&crypt_stat->cs_mutex);
-                       goto out_puts;
-               }
-               crypt_stat->flags &= ~(ECRYPTFS_ENCRYPTED);
-               rc = 0;
-               mutex_unlock(&crypt_stat->cs_mutex);
-               goto out;
-       } else if (!ECRYPTFS_CHECK_FLAG(crypt_stat->flags,
-                                       ECRYPTFS_POLICY_APPLIED)
-                  || !ECRYPTFS_CHECK_FLAG(crypt_stat->flags,
-                                          ECRYPTFS_KEY_VALID)) {
-               rc = ecryptfs_read_headers(ecryptfs_dentry, lower_file);
+       if (!ECRYPTFS_CHECK_FLAG(crypt_stat->flags,
+                                ECRYPTFS_POLICY_APPLIED)
+           || !ECRYPTFS_CHECK_FLAG(crypt_stat->flags,
+                                   ECRYPTFS_KEY_VALID)) {
+               rc = ecryptfs_read_metadata(ecryptfs_dentry, lower_file);
                if (rc) {
                        ecryptfs_printk(KERN_DEBUG,
                                        "Valid headers not found\n");
index d4f02f3..6b45b29 100644 (file)
@@ -3,7 +3,7 @@
  *
  * Copyright (C) 1997-2004 Erez Zadok
  * Copyright (C) 2001-2004 Stony Brook University
- * Copyright (C) 2004-2006 International Business Machines Corp.
+ * Copyright (C) 2004-2007 International Business Machines Corp.
  *   Author(s): Michael A. Halcrow <mahalcro@us.ibm.com>
  *              Michael C. Thompsion <mcthomps@us.ibm.com>
  *
@@ -169,7 +169,9 @@ static int grow_file(struct dentry *ecryptfs_dentry, struct file *lower_file,
                goto out;
        }
        i_size_write(inode, 0);
-       ecryptfs_write_inode_size_to_header(lower_file, lower_inode, inode);
+       ecryptfs_write_inode_size_to_metadata(lower_file, lower_inode, inode,
+                                             ecryptfs_dentry,
+                                             ECRYPTFS_LOWER_I_MUTEX_NOT_HELD);
        ECRYPTFS_SET_FLAG(ecryptfs_inode_to_private(inode)->crypt_stat.flags,
                          ECRYPTFS_NEW_FILE);
 out:
@@ -225,7 +227,7 @@ static int ecryptfs_initialize_file(struct dentry *ecryptfs_dentry)
                                "context\n");
                goto out_fput;
        }
-       rc = ecryptfs_write_headers(ecryptfs_dentry, lower_file);
+       rc = ecryptfs_write_metadata(ecryptfs_dentry, lower_file);
        if (rc) {
                ecryptfs_printk(KERN_DEBUG, "Error writing headers\n");
                goto out_fput;
@@ -362,32 +364,33 @@ static struct dentry *ecryptfs_lookup(struct inode *dir, struct dentry *dentry,
        }
        /* Released in this function */
        page_virt = kmem_cache_zalloc(ecryptfs_header_cache_2,
-                                    GFP_USER);
+                                     GFP_USER);
        if (!page_virt) {
                rc = -ENOMEM;
                ecryptfs_printk(KERN_ERR,
                                "Cannot ecryptfs_kmalloc a page\n");
                goto out_dput;
        }
-
-       rc = ecryptfs_read_header_region(page_virt, lower_dentry, nd->mnt);
        crypt_stat = &ecryptfs_inode_to_private(dentry->d_inode)->crypt_stat;
        if (!ECRYPTFS_CHECK_FLAG(crypt_stat->flags, ECRYPTFS_POLICY_APPLIED))
                ecryptfs_set_default_sizes(crypt_stat);
+       rc = ecryptfs_read_and_validate_header_region(page_virt, lower_dentry,
+                                                     nd->mnt);
        if (rc) {
-               rc = 0;
-               ecryptfs_printk(KERN_WARNING, "Error reading header region;"
-                               " assuming unencrypted\n");
-       } else {
-               if (!contains_ecryptfs_marker(page_virt
-                                             + ECRYPTFS_FILE_SIZE_BYTES)) {
+               rc = ecryptfs_read_and_validate_xattr_region(page_virt, dentry);
+               if (rc) {
+                       printk(KERN_DEBUG "Valid metadata not found in header "
+                              "region or xattr region; treating file as "
+                              "unencrypted\n");
+                       rc = 0;
                        kmem_cache_free(ecryptfs_header_cache_2, page_virt);
                        goto out;
                }
-               memcpy(&file_size, page_virt, sizeof(file_size));
-               file_size = be64_to_cpu(file_size);
-               i_size_write(dentry->d_inode, (loff_t)file_size);
+               crypt_stat->flags |= ECRYPTFS_METADATA_IN_XATTR;
        }
+       memcpy(&file_size, page_virt, sizeof(file_size));
+       file_size = be64_to_cpu(file_size);
+       i_size_write(dentry->d_inode, (loff_t)file_size);
        kmem_cache_free(ecryptfs_header_cache_2, page_virt);
        goto out;
 
@@ -781,20 +784,26 @@ int ecryptfs_truncate(struct dentry *dentry, loff_t new_length)
                        goto out_fput;
                }
                i_size_write(inode, new_length);
-               rc = ecryptfs_write_inode_size_to_header(lower_file,
-                                                        lower_dentry->d_inode,
-                                                        inode);
+               rc = ecryptfs_write_inode_size_to_metadata(
+                       lower_file, lower_dentry->d_inode, inode, dentry,
+                       ECRYPTFS_LOWER_I_MUTEX_NOT_HELD);
                if (rc) {
-                       ecryptfs_printk(KERN_ERR,
-                                       "Problem with ecryptfs_write"
-                                       "_inode_size\n");
+                       printk(KERN_ERR "Problem with "
+                              "ecryptfs_write_inode_size_to_metadata; "
+                              "rc = [%d]\n", rc);
                        goto out_fput;
                }
        } else { /* new_length < i_size_read(inode) */
                vmtruncate(inode, new_length);
-               ecryptfs_write_inode_size_to_header(lower_file,
-                                                   lower_dentry->d_inode,
-                                                   inode);
+               rc = ecryptfs_write_inode_size_to_metadata(
+                       lower_file, lower_dentry->d_inode, inode, dentry,
+                       ECRYPTFS_LOWER_I_MUTEX_NOT_HELD);
+               if (rc) {
+                       printk(KERN_ERR "Problem with "
+                              "ecryptfs_write_inode_size_to_metadata; "
+                              "rc = [%d]\n", rc);
+                       goto out_fput;
+               }
                /* We are reducing the size of the ecryptfs file, and need to
                 * know if we need to reduce the size of the lower file. */
                lower_size_before_truncate =
@@ -881,7 +890,7 @@ out:
        return rc;
 }
 
-static int
+int
 ecryptfs_setxattr(struct dentry *dentry, const char *name, const void *value,
                  size_t size, int flags)
 {
@@ -901,7 +910,7 @@ out:
        return rc;
 }
 
-static ssize_t
+ssize_t
 ecryptfs_getxattr(struct dentry *dentry, const char *name, void *value,
                  size_t size)
 {
index a3efdcc..26fe405 100644 (file)
@@ -3,7 +3,7 @@
  *
  * Copyright (C) 1997-2003 Erez Zadok
  * Copyright (C) 2001-2003 Stony Brook University
- * Copyright (C) 2004-2006 International Business Machines Corp.
+ * Copyright (C) 2004-2007 International Business Machines Corp.
  *   Author(s): Michael A. Halcrow <mahalcro@us.ibm.com>
  *              Michael C. Thompson <mcthomps@us.ibm.com>
  *              Tyler Hicks <tyhicks@ou.edu>
@@ -642,6 +642,11 @@ static struct ecryptfs_cache_info {
                .size = PAGE_CACHE_SIZE,
        },
        {
+               .cache = &ecryptfs_xattr_cache,
+               .name = "ecryptfs_xattr_cache",
+               .size = PAGE_CACHE_SIZE,
+       },
+       {
                .cache = &ecryptfs_lower_page_cache,
                .name = "ecryptfs_lower_page_cache",
                .size = PAGE_CACHE_SIZE,
index e8ba627..47d7e7b 100644 (file)
 
 #include "ecryptfs_kernel.h"
 
-LIST_HEAD(ecryptfs_msg_ctx_free_list);
-LIST_HEAD(ecryptfs_msg_ctx_alloc_list);
-struct mutex ecryptfs_msg_ctx_lists_mux;
+static LIST_HEAD(ecryptfs_msg_ctx_free_list);
+static LIST_HEAD(ecryptfs_msg_ctx_alloc_list);
+static struct mutex ecryptfs_msg_ctx_lists_mux;
 
-struct hlist_head *ecryptfs_daemon_id_hash;
-struct mutex ecryptfs_daemon_id_hash_mux;
-int ecryptfs_hash_buckets;
+static struct hlist_head *ecryptfs_daemon_id_hash;
+static struct mutex ecryptfs_daemon_id_hash_mux;
+static int ecryptfs_hash_buckets;
+#define ecryptfs_uid_hash(uid) \
+        hash_long((unsigned long)uid, ecryptfs_hash_buckets)
 
-unsigned int ecryptfs_msg_counter;
-struct ecryptfs_msg_ctx *ecryptfs_msg_ctx_arr;
+static unsigned int ecryptfs_msg_counter;
+static struct ecryptfs_msg_ctx *ecryptfs_msg_ctx_arr;
 
 /**
  * ecryptfs_acquire_free_msg_ctx
index 0af3aa3..ba3650d 100644 (file)
@@ -6,7 +6,7 @@
  *
  * Copyright (C) 1997-2003 Erez Zadok
  * Copyright (C) 2001-2003 Stony Brook University
- * Copyright (C) 2004-2006 International Business Machines Corp.
+ * Copyright (C) 2004-2007 International Business Machines Corp.
  *   Author(s): Michael A. Halcrow <mahalcro@us.ibm.com>
  *
  * This program is free software; you can redistribute it and/or
@@ -308,6 +308,9 @@ out:
        return rc;
 }
 
+/**
+ * Called with lower inode mutex held.
+ */
 static int fill_zeros_to_end_of_page(struct page *page, unsigned int to)
 {
        struct inode *inode = page->mapping->host;
@@ -407,10 +410,9 @@ static void ecryptfs_unmap_and_release_lower_page(struct page *lower_page)
  *
  * Returns zero on success; non-zero on error.
  */
-int
-ecryptfs_write_inode_size_to_header(struct file *lower_file,
-                                   struct inode *lower_inode,
-                                   struct inode *inode)
+static int ecryptfs_write_inode_size_to_header(struct file *lower_file,
+                                              struct inode *lower_inode,
+                                              struct inode *inode)
 {
        int rc = 0;
        struct page *header_page;
@@ -442,6 +444,80 @@ out:
        return rc;
 }
 
+static int ecryptfs_write_inode_size_to_xattr(struct inode *lower_inode,
+                                             struct inode *inode,
+                                             struct dentry *ecryptfs_dentry,
+                                             int lower_i_mutex_held)
+{
+       ssize_t size;
+       void *xattr_virt;
+       struct dentry *lower_dentry;
+       u64 file_size;
+       int rc;
+
+       xattr_virt = kmem_cache_alloc(ecryptfs_xattr_cache, GFP_KERNEL);
+       if (!xattr_virt) {
+               printk(KERN_ERR "Out of memory whilst attempting to write "
+                      "inode size to xattr\n");
+               rc = -ENOMEM;
+               goto out;
+       }
+       lower_dentry = ecryptfs_dentry_to_lower(ecryptfs_dentry);
+       if (!lower_dentry->d_inode->i_op->getxattr) {
+               printk(KERN_WARNING
+                      "No support for setting xattr in lower filesystem\n");
+               rc = -ENOSYS;
+               kmem_cache_free(ecryptfs_xattr_cache, xattr_virt);
+               goto out;
+       }
+       if (!lower_i_mutex_held)
+               mutex_lock(&lower_dentry->d_inode->i_mutex);
+       size = lower_dentry->d_inode->i_op->getxattr(lower_dentry,
+                                                    ECRYPTFS_XATTR_NAME,
+                                                    xattr_virt,
+                                                    PAGE_CACHE_SIZE);
+       if (!lower_i_mutex_held)
+               mutex_unlock(&lower_dentry->d_inode->i_mutex);
+       if (size < 0)
+               size = 8;
+       file_size = (u64)i_size_read(inode);
+       file_size = cpu_to_be64(file_size);
+       memcpy(xattr_virt, &file_size, sizeof(u64));
+       if (!lower_i_mutex_held)
+               mutex_lock(&lower_dentry->d_inode->i_mutex);
+       rc = lower_dentry->d_inode->i_op->setxattr(lower_dentry,
+                                                  ECRYPTFS_XATTR_NAME,
+                                                  xattr_virt, size, 0);
+       if (!lower_i_mutex_held)
+               mutex_unlock(&lower_dentry->d_inode->i_mutex);
+       if (rc)
+               printk(KERN_ERR "Error whilst attempting to write inode size "
+                      "to lower file xattr; rc = [%d]\n", rc);
+       kmem_cache_free(ecryptfs_xattr_cache, xattr_virt);
+out:
+       return rc;
+}
+
+int
+ecryptfs_write_inode_size_to_metadata(struct file *lower_file,
+                                     struct inode *lower_inode,
+                                     struct inode *inode,
+                                     struct dentry *ecryptfs_dentry,
+                                     int lower_i_mutex_held)
+{
+       struct ecryptfs_crypt_stat *crypt_stat;
+
+       crypt_stat = &ecryptfs_inode_to_private(inode)->crypt_stat;
+       if (crypt_stat->flags & ECRYPTFS_METADATA_IN_XATTR)
+               return ecryptfs_write_inode_size_to_xattr(lower_inode, inode,
+                                                         ecryptfs_dentry,
+                                                         lower_i_mutex_held);
+       else
+               return ecryptfs_write_inode_size_to_header(lower_file,
+                                                          lower_inode,
+                                                          inode);
+}
+
 int ecryptfs_get_lower_page(struct page **lower_page, struct inode *lower_inode,
                            struct file *lower_file,
                            unsigned long lower_page_index, int byte_offset,
@@ -528,6 +604,8 @@ out:
        return rc;
 }
 
+struct kmem_cache *ecryptfs_xattr_cache;
+
 /**
  * ecryptfs_commit_write
  * @file: The eCryptfs file object
@@ -581,7 +659,6 @@ static int ecryptfs_commit_write(struct file *file, struct page *page,
                                "index [0x%.16x])\n", page->index);
                goto out;
        }
-       rc = 0;
        inode->i_blocks = lower_inode->i_blocks;
        pos = (page->index << PAGE_CACHE_SHIFT) + to;
        if (pos > i_size_read(inode)) {
@@ -589,7 +666,12 @@ static int ecryptfs_commit_write(struct file *file, struct page *page,
                ecryptfs_printk(KERN_DEBUG, "Expanded file size to "
                                "[0x%.16x]\n", i_size_read(inode));
        }
-       ecryptfs_write_inode_size_to_header(lower_file, lower_inode, inode);
+       rc = ecryptfs_write_inode_size_to_metadata(lower_file, lower_inode,
+                                                  inode, file->f_dentry,
+                                                  ECRYPTFS_LOWER_I_MUTEX_HELD);
+       if (rc)
+               printk(KERN_ERR "Error writing inode size to metadata; "
+                      "rc = [%d]\n", rc);
        lower_inode->i_mtime = lower_inode->i_ctime = CURRENT_TIME;
        mark_inode_dirty_sync(inode);
 out: