eCryptfs: update metadata read/write functions

Update the metadata read/write functions and grow_file() to use the
read_write.c routines.  Do not open another lower file; use the persistent
lower file instead.  Provide a separate function for
crypto.c::ecryptfs_read_xattr_region() to get to the lower xattr without
having to go through the eCryptfs getxattr.

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>

5 files changed, 114 insertions, 133 deletions

diff --git a/fs/ecryptfs/crypto.c b/fs/ecryptfs/crypto.c
index 7f788ea5da2..55110ffe9eb 100644
--- a/fs/ecryptfs/crypto.c
+++ b/fs/ecryptfs/crypto.c
@@ -1342,21 +1342,28 @@ out:
         return rc;
 }
 
-int ecryptfs_read_and_validate_header_region(char *data, struct dentry *dentry,
-                                             struct vfsmount *mnt)
+int ecryptfs_read_and_validate_header_region(char *data,
+                                             struct inode *ecryptfs_inode)
 {
+        struct ecryptfs_crypt_stat *crypt_stat =
+                &(ecryptfs_inode_to_private(ecryptfs_inode)->crypt_stat);
         int rc;
 
-        rc = ecryptfs_read_header_region(data, dentry, mnt);
-        if (rc)
+        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;
-        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,
@@ -1441,24 +1448,19 @@ static int ecryptfs_write_headers_virt(char *page_virt, size_t *size,
 
 static int
 ecryptfs_write_metadata_to_contents(struct ecryptfs_crypt_stat *crypt_stat,
-                                    struct file *lower_file, char *page_virt)
+                                    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->extent_size
@@ -1467,18 +1469,19 @@ ecryptfs_write_metadata_to_contents(struct ecryptfs_crypt_stat *crypt_stat,
         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 = (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;
 }
@@ -1498,7 +1501,6 @@ ecryptfs_write_metadata_to_xattr(struct dentry *ecryptfs_dentry,
 /**
  * ecryptfs_write_metadata
  * @ecryptfs_dentry: The eCryptfs dentry
- * @lower_file: The lower file struct, which was returned from dentry_open
  *
  * Write the file headers out.  This will likely involve a userspace
  * callout, in which the session key is encrypted with one or more
@@ -1506,22 +1508,21 @@ 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;
                 }
@@ -1550,7 +1551,8 @@ 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; "
@@ -1678,15 +1680,17 @@ out:
  *
  * 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;
@@ -1701,7 +1705,7 @@ 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)) {
@@ -1715,8 +1719,6 @@ out:
 
 /**
  * ecryptfs_read_metadata
- * @ecryptfs_dentry: The eCryptfs dentry
- * @lower_file: The lower file from which to read the metadata
  *
  * Common entry point for reading file metadata. From here, we could
  * retrieve the header information from the header region of the file,
@@ -1727,15 +1729,13 @@ 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;
@@ -1746,27 +1746,18 @@ 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");
+                printk(KERN_ERR "%s: Unable to allocate page_virt\n",
+                       __FUNCTION__);
                 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;
-                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");
diff --git a/fs/ecryptfs/ecryptfs_kernel.h b/fs/ecryptfs/ecryptfs_kernel.h
index 65f7ddfd4d4..3e52b42fba0 100644
--- a/fs/ecryptfs/ecryptfs_kernel.h
+++ b/fs/ecryptfs/ecryptfs_kernel.h
@@ -570,13 +570,11 @@ int ecryptfs_writepage_and_release_lower_page(struct page *lower_page,
                                               struct writeback_control *wbc);
 int ecryptfs_encrypt_page(struct page *page);
 int ecryptfs_decrypt_page(struct page *page);
-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_metadata(struct dentry *ecryptfs_dentry);
+int ecryptfs_read_metadata(struct dentry *ecryptfs_dentry);
 int ecryptfs_new_file_context(struct dentry *ecryptfs_dentry);
-int ecryptfs_read_and_validate_header_region(char *data, struct dentry *dentry,
-                                             struct vfsmount *mnt);
+int ecryptfs_read_and_validate_header_region(char *data,
+                                             struct inode *ecryptfs_inode);
 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);
@@ -599,10 +597,13 @@ int ecryptfs_open_lower_file(struct file **lower_file,
 int ecryptfs_close_lower_file(struct file *lower_file);
 ssize_t ecryptfs_getxattr(struct dentry *dentry, const char *name, void *value,
                           size_t size);
+ssize_t
+ecryptfs_getxattr_lower(struct dentry *lower_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_read_xattr_region(char *page_virt, struct dentry *ecryptfs_dentry);
+int ecryptfs_read_xattr_region(char *page_virt, struct inode *ecryptfs_inode);
 int ecryptfs_process_helo(unsigned int transport, uid_t uid, pid_t pid);
 int ecryptfs_process_quit(uid_t uid, pid_t pid);
 int ecryptfs_process_response(struct ecryptfs_message *msg, uid_t uid,
diff --git a/fs/ecryptfs/file.c b/fs/ecryptfs/file.c
index 59c846d29a8..df70bfa176d 100644
--- a/fs/ecryptfs/file.c
+++ b/fs/ecryptfs/file.c
@@ -248,7 +248,7 @@ static int ecryptfs_open(struct inode *inode, struct file *file)
         mutex_lock(&crypt_stat->cs_mutex);
         if (!(crypt_stat->flags & ECRYPTFS_POLICY_APPLIED)
             || !(crypt_stat->flags & ECRYPTFS_KEY_VALID)) {
-                rc = ecryptfs_read_metadata(ecryptfs_dentry, lower_file);
+                rc = ecryptfs_read_metadata(ecryptfs_dentry);
                 if (rc) {
                         ecryptfs_printk(KERN_DEBUG,
                                         "Valid headers not found\n");
diff --git a/fs/ecryptfs/inode.c b/fs/ecryptfs/inode.c
index c746b5d8a33..a29dc31965f 100644
--- a/fs/ecryptfs/inode.c
+++ b/fs/ecryptfs/inode.c
@@ -153,37 +153,30 @@ out:
 
 /**
  * grow_file
- * @ecryptfs_dentry: the ecryptfs dentry
- * @lower_file: The lower file
- * @inode: The ecryptfs inode
- * @lower_inode: The lower inode
+ * @ecryptfs_dentry: the eCryptfs dentry
  *
  * This is the code which will grow the file to its correct size.
  */
-static int grow_file(struct dentry *ecryptfs_dentry, struct file *lower_file,
-                     struct inode *inode, struct inode *lower_inode)
+static int grow_file(struct dentry *ecryptfs_dentry)
 {
-        int rc = 0;
+        struct inode *ecryptfs_inode = ecryptfs_dentry->d_inode;
         struct file fake_file;
         struct ecryptfs_file_info tmp_file_info;
+        char zero_virt[] = { 0x00 };
+        int rc = 0;
 
         memset(&fake_file, 0, sizeof(fake_file));
         fake_file.f_path.dentry = ecryptfs_dentry;
         memset(&tmp_file_info, 0, sizeof(tmp_file_info));
         ecryptfs_set_file_private(&fake_file, &tmp_file_info);
-        ecryptfs_set_file_lower(&fake_file, lower_file);
-        rc = ecryptfs_fill_zeros(&fake_file, 1);
-        if (rc) {
-                ecryptfs_inode_to_private(inode)->crypt_stat.flags |=
-                        ECRYPTFS_SECURITY_WARNING;
-                ecryptfs_printk(KERN_WARNING, "Error attempting to fill zeros "
-                                "in file; rc = [%d]\n", rc);
-                goto out;
-        }
-        i_size_write(inode, 0);
-        rc = ecryptfs_write_inode_size_to_metadata(inode);
-        ecryptfs_inode_to_private(inode)->crypt_stat.flags |= ECRYPTFS_NEW_FILE;
-out:
+        ecryptfs_set_file_lower(
+                &fake_file,
+                ecryptfs_inode_to_private(ecryptfs_inode)->lower_file);
+        rc = ecryptfs_write(&fake_file, zero_virt, 0, 1);
+        i_size_write(ecryptfs_inode, 0);
+        rc = ecryptfs_write_inode_size_to_metadata(ecryptfs_inode);
+        ecryptfs_inode_to_private(ecryptfs_inode)->crypt_stat.flags |=
+                ECRYPTFS_NEW_FILE;
         return rc;
 }
 
@@ -197,53 +190,31 @@ out:
  */
 static int ecryptfs_initialize_file(struct dentry *ecryptfs_dentry)
 {
+        struct ecryptfs_crypt_stat *crypt_stat =
+                &ecryptfs_inode_to_private(ecryptfs_dentry->d_inode)->crypt_stat;
         int rc = 0;
-        int lower_flags;
-        struct ecryptfs_crypt_stat *crypt_stat;
-        struct dentry *lower_dentry;
-        struct file *lower_file;
-        struct inode *inode, *lower_inode;
-        struct vfsmount *lower_mnt;
 
-        lower_dentry = ecryptfs_dentry_to_lower(ecryptfs_dentry);
-        ecryptfs_printk(KERN_DEBUG, "lower_dentry->d_name.name = [%s]\n",
-                        lower_dentry->d_name.name);
-        inode = ecryptfs_dentry->d_inode;
-        crypt_stat = &ecryptfs_inode_to_private(inode)->crypt_stat;
-        lower_flags = ((O_CREAT | O_TRUNC) & O_ACCMODE) | O_RDWR;
-        lower_mnt = ecryptfs_dentry_to_lower_mnt(ecryptfs_dentry);
-        /* Corresponding fput() at end of this function */
-        rc = ecryptfs_open_lower_file(&lower_file, lower_dentry, lower_mnt,
-                                      lower_flags);
-        if (rc) {
-                ecryptfs_printk(KERN_ERR,
-                                "Error opening dentry; rc = [%i]\n", rc);
-                goto out;
-        }
-        lower_inode = lower_dentry->d_inode;
         if (S_ISDIR(ecryptfs_dentry->d_inode->i_mode)) {
                 ecryptfs_printk(KERN_DEBUG, "This is a directory\n");
                 crypt_stat->flags &= ~(ECRYPTFS_ENCRYPTED);
-                goto out_fput;
+                goto out;
         }
         crypt_stat->flags |= ECRYPTFS_NEW_FILE;
         ecryptfs_printk(KERN_DEBUG, "Initializing crypto context\n");
         rc = ecryptfs_new_file_context(ecryptfs_dentry);
         if (rc) {
-                ecryptfs_printk(KERN_DEBUG, "Error creating new file "
-                                "context\n");
-                goto out_fput;
+                ecryptfs_printk(KERN_ERR, "Error creating new file "
+                                "context; rc = [%d]\n", rc);
+                goto out;
         }
-        rc = ecryptfs_write_metadata(ecryptfs_dentry, lower_file);
+        rc = ecryptfs_write_metadata(ecryptfs_dentry);
         if (rc) {
-                ecryptfs_printk(KERN_DEBUG, "Error writing headers\n");
-                goto out_fput;
+                printk(KERN_ERR "Error writing headers; rc = [%d]\n", rc);
+                goto out;
         }
-        rc = grow_file(ecryptfs_dentry, lower_file, inode, lower_inode);
-out_fput:
-        rc = ecryptfs_close_lower_file(lower_file);
+        rc = grow_file(ecryptfs_dentry);
         if (rc)
-                printk(KERN_ERR "Error closing lower_file\n");
+                printk(KERN_ERR "Error growing file; rc = [%d]\n", rc);
 out:
         return rc;
 }
@@ -389,8 +360,8 @@ static struct dentry *ecryptfs_lookup(struct inode *dir, struct dentry *dentry,
         crypt_stat = &ecryptfs_inode_to_private(dentry->d_inode)->crypt_stat;
         if (!(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);
+        rc = ecryptfs_read_and_validate_header_region(page_virt,
+                                                      dentry->d_inode);
         if (rc) {
                 rc = ecryptfs_read_and_validate_xattr_region(page_virt, dentry);
                 if (rc) {
@@ -941,7 +912,7 @@ static int ecryptfs_setattr(struct dentry *dentry, struct iattr *ia)
                 }
                 mount_crypt_stat = &ecryptfs_superblock_to_private(
                         dentry->d_sb)->mount_crypt_stat;
-                rc = ecryptfs_read_metadata(dentry, lower_file);
+                rc = ecryptfs_read_metadata(dentry);
                 if (rc) {
                         if (!(mount_crypt_stat->flags
                               & ECRYPTFS_PLAINTEXT_PASSTHROUGH_ENABLED)) {
@@ -1003,6 +974,24 @@ out:
 }
 
 ssize_t
+ecryptfs_getxattr_lower(struct dentry *lower_dentry, const char *name,
+                        void *value, size_t size)
+{
+        int rc = 0;
+
+        if (!lower_dentry->d_inode->i_op->getxattr) {
+                rc = -ENOSYS;
+                goto out;
+        }
+        mutex_lock(&lower_dentry->d_inode->i_mutex);
+        rc = lower_dentry->d_inode->i_op->getxattr(lower_dentry, name, value,
+                                                   size);
+        mutex_unlock(&lower_dentry->d_inode->i_mutex);
+out:
+        return rc;
+}
+
+ssize_t
 ecryptfs_getxattr(struct dentry *dentry, const char *name, void *value,
                   size_t size)
 {
diff --git a/fs/ecryptfs/mmap.c b/fs/ecryptfs/mmap.c
index 9b621108d5c..60e635eddc7 100644
--- a/fs/ecryptfs/mmap.c
+++ b/fs/ecryptfs/mmap.c
@@ -307,7 +307,7 @@ static int ecryptfs_readpage(struct file *file, struct page *page)
                                 memset(page_virt, 0, PAGE_CACHE_SIZE);
                                 if (page->index == 0) {
                                         rc = ecryptfs_read_xattr_region(
-                                                page_virt, file->f_path.dentry);
+                                                page_virt, page->mapping->host);
                                         set_header_info(page_virt, crypt_stat);
                                 }
                                 kunmap_atomic(page_virt, KM_USER0);