Merge commit 'v2.6.30' into for-2.6.31
[safe/jmp/linux-2.6] / fs / ecryptfs / inode.c
index 5e78fc1..2f0945d 100644 (file)
@@ -52,8 +52,7 @@ static void unlock_dir(struct dentry *dir)
 /**
  * ecryptfs_create_underlying_file
  * @lower_dir_inode: inode of the parent in the lower fs of the new file
- * @lower_dentry: New file's dentry in the lower fs
- * @ecryptfs_dentry: New file's dentry in ecryptfs
+ * @dentry: New file's dentry
  * @mode: The mode of the new file
  * @nd: nameidata of ecryptfs' parent's dentry & vfsmount
  *
@@ -228,8 +227,7 @@ ecryptfs_create(struct inode *directory_inode, struct dentry *ecryptfs_dentry,
 {
        int rc;
 
-       /* ecryptfs_do_create() calls ecryptfs_interpose(), which opens
-        * the crypt_stat->lower_file (persistent file) */
+       /* ecryptfs_do_create() calls ecryptfs_interpose() */
        rc = ecryptfs_do_create(directory_inode, ecryptfs_dentry, mode, nd);
        if (unlikely(rc)) {
                ecryptfs_printk(KERN_WARNING, "Failed to create file in"
@@ -244,141 +242,96 @@ out:
 }
 
 /**
- * ecryptfs_lookup
- * @dir: inode
- * @dentry: The dentry
- * @nd: nameidata, may be NULL
- *
- * Find a file on disk. If the file does not exist, then we'll add it to the
- * dentry cache and continue on to read it from the disk.
+ * ecryptfs_lookup_and_interpose_lower - Perform a lookup
  */
-static struct dentry *ecryptfs_lookup(struct inode *dir, struct dentry *dentry,
-                                     struct nameidata *nd)
+int ecryptfs_lookup_and_interpose_lower(struct dentry *ecryptfs_dentry,
+                                       struct dentry *lower_dentry,
+                                       struct inode *ecryptfs_dir_inode,
+                                       struct nameidata *ecryptfs_nd)
 {
-       int rc = 0;
        struct dentry *lower_dir_dentry;
-       struct dentry *lower_dentry;
        struct vfsmount *lower_mnt;
-       char *encoded_name;
-       int encoded_namelen;
-       struct ecryptfs_crypt_stat *crypt_stat = NULL;
+       struct inode *lower_inode;
        struct ecryptfs_mount_crypt_stat *mount_crypt_stat;
+       struct ecryptfs_crypt_stat *crypt_stat;
        char *page_virt = NULL;
-       struct inode *lower_inode;
        u64 file_size;
+       int rc = 0;
 
-       lower_dir_dentry = ecryptfs_dentry_to_lower(dentry->d_parent);
-       dentry->d_op = &ecryptfs_dops;
-       if ((dentry->d_name.len == 1 && !strcmp(dentry->d_name.name, "."))
-           || (dentry->d_name.len == 2
-               && !strcmp(dentry->d_name.name, ".."))) {
-               d_drop(dentry);
-               goto out;
-       }
-       encoded_namelen = ecryptfs_encode_filename(crypt_stat,
-                                                  dentry->d_name.name,
-                                                  dentry->d_name.len,
-                                                  &encoded_name);
-       if (encoded_namelen < 0) {
-               rc = encoded_namelen;
-               d_drop(dentry);
-               goto out;
-       }
-       ecryptfs_printk(KERN_DEBUG, "encoded_name = [%s]; encoded_namelen "
-                       "= [%d]\n", encoded_name, encoded_namelen);
-       lower_dentry = lookup_one_len(encoded_name, lower_dir_dentry,
-                                     encoded_namelen - 1);
-       kfree(encoded_name);
-       if (IS_ERR(lower_dentry)) {
-               ecryptfs_printk(KERN_ERR, "ERR from lower_dentry\n");
-               rc = PTR_ERR(lower_dentry);
-               d_drop(dentry);
-               goto out;
-       }
-       lower_mnt = mntget(ecryptfs_dentry_to_lower_mnt(dentry->d_parent));
-       ecryptfs_printk(KERN_DEBUG, "lower_dentry = [%p]; lower_dentry->"
-                       "d_name.name = [%s]\n", lower_dentry,
-               lower_dentry->d_name.name);
+       lower_dir_dentry = lower_dentry->d_parent;
+       lower_mnt = mntget(ecryptfs_dentry_to_lower_mnt(
+                                  ecryptfs_dentry->d_parent));
        lower_inode = lower_dentry->d_inode;
-       fsstack_copy_attr_atime(dir, lower_dir_dentry->d_inode);
+       fsstack_copy_attr_atime(ecryptfs_dir_inode, lower_dir_dentry->d_inode);
        BUG_ON(!atomic_read(&lower_dentry->d_count));
-       ecryptfs_set_dentry_private(dentry,
+       ecryptfs_set_dentry_private(ecryptfs_dentry,
                                    kmem_cache_alloc(ecryptfs_dentry_info_cache,
                                                     GFP_KERNEL));
-       if (!ecryptfs_dentry_to_private(dentry)) {
+       if (!ecryptfs_dentry_to_private(ecryptfs_dentry)) {
                rc = -ENOMEM;
-               ecryptfs_printk(KERN_ERR, "Out of memory whilst attempting "
-                               "to allocate ecryptfs_dentry_info struct\n");
+               printk(KERN_ERR "%s: Out of memory whilst attempting "
+                      "to allocate ecryptfs_dentry_info struct\n",
+                       __func__);
                goto out_dput;
        }
-       ecryptfs_set_dentry_lower(dentry, lower_dentry);
-       ecryptfs_set_dentry_lower_mnt(dentry, lower_mnt);
+       ecryptfs_set_dentry_lower(ecryptfs_dentry, lower_dentry);
+       ecryptfs_set_dentry_lower_mnt(ecryptfs_dentry, lower_mnt);
        if (!lower_dentry->d_inode) {
                /* We want to add because we couldn't find in lower */
-               d_add(dentry, NULL);
+               d_add(ecryptfs_dentry, NULL);
                goto out;
        }
-       rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb,
-                               ECRYPTFS_INTERPOSE_FLAG_D_ADD);
+       rc = ecryptfs_interpose(lower_dentry, ecryptfs_dentry,
+                               ecryptfs_dir_inode->i_sb, 1);
        if (rc) {
-               ecryptfs_printk(KERN_ERR, "Error interposing\n");
+               printk(KERN_ERR "%s: Error interposing; rc = [%d]\n",
+                      __func__, rc);
                goto out;
        }
-       if (S_ISDIR(lower_inode->i_mode)) {
-               ecryptfs_printk(KERN_DEBUG, "Is a directory; returning\n");
+       if (S_ISDIR(lower_inode->i_mode))
                goto out;
-       }
-       if (S_ISLNK(lower_inode->i_mode)) {
-               ecryptfs_printk(KERN_DEBUG, "Is a symlink; returning\n");
+       if (S_ISLNK(lower_inode->i_mode))
                goto out;
-       }
-       if (special_file(lower_inode->i_mode)) {
-               ecryptfs_printk(KERN_DEBUG, "Is a special file; returning\n");
+       if (special_file(lower_inode->i_mode))
                goto out;
-       }
-       if (!nd) {
-               ecryptfs_printk(KERN_DEBUG, "We have a NULL nd, just leave"
-                               "as we *think* we are about to unlink\n");
+       if (!ecryptfs_nd)
                goto out;
-       }
        /* Released in this function */
-       page_virt = kmem_cache_zalloc(ecryptfs_header_cache_2,
-                                     GFP_USER);
+       page_virt = kmem_cache_zalloc(ecryptfs_header_cache_2, GFP_USER);
        if (!page_virt) {
+               printk(KERN_ERR "%s: Cannot kmem_cache_zalloc() a page\n",
+                      __func__);
                rc = -ENOMEM;
-               ecryptfs_printk(KERN_ERR,
-                               "Cannot ecryptfs_kmalloc a page\n");
                goto out;
        }
-       crypt_stat = &ecryptfs_inode_to_private(dentry->d_inode)->crypt_stat;
-       if (!(crypt_stat->flags & ECRYPTFS_POLICY_APPLIED))
-               ecryptfs_set_default_sizes(crypt_stat);
-       if (!ecryptfs_inode_to_private(dentry->d_inode)->lower_file) {
-               rc = ecryptfs_init_persistent_file(dentry);
+       if (!ecryptfs_inode_to_private(ecryptfs_dentry->d_inode)->lower_file) {
+               rc = ecryptfs_init_persistent_file(ecryptfs_dentry);
                if (rc) {
                        printk(KERN_ERR "%s: Error attempting to initialize "
                               "the persistent file for the dentry with name "
                               "[%s]; rc = [%d]\n", __func__,
-                              dentry->d_name.name, rc);
-                       goto out;
+                              ecryptfs_dentry->d_name.name, rc);
+                       goto out_free_kmem;
                }
        }
+       crypt_stat = &ecryptfs_inode_to_private(
+                                       ecryptfs_dentry->d_inode)->crypt_stat;
+       /* TODO: lock for crypt_stat comparison */
+       if (!(crypt_stat->flags & ECRYPTFS_POLICY_APPLIED))
+                       ecryptfs_set_default_sizes(crypt_stat);
        rc = ecryptfs_read_and_validate_header_region(page_virt,
-                                                     dentry->d_inode);
+                                                     ecryptfs_dentry->d_inode);
        if (rc) {
-               rc = ecryptfs_read_and_validate_xattr_region(page_virt, dentry);
+               rc = ecryptfs_read_and_validate_xattr_region(page_virt,
+                                                            ecryptfs_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;
+                       goto out_free_kmem;
                }
                crypt_stat->flags |= ECRYPTFS_METADATA_IN_XATTR;
        }
        mount_crypt_stat = &ecryptfs_superblock_to_private(
-               dentry->d_sb)->mount_crypt_stat;
+               ecryptfs_dentry->d_sb)->mount_crypt_stat;
        if (mount_crypt_stat->flags & ECRYPTFS_ENCRYPTED_VIEW_ENABLED) {
                if (crypt_stat->flags & ECRYPTFS_METADATA_IN_XATTR)
                        file_size = (crypt_stat->num_header_bytes_at_front
@@ -388,14 +341,94 @@ static struct dentry *ecryptfs_lookup(struct inode *dir, struct dentry *dentry,
        } else {
                file_size = get_unaligned_be64(page_virt);
        }
-       i_size_write(dentry->d_inode, (loff_t)file_size);
+       i_size_write(ecryptfs_dentry->d_inode, (loff_t)file_size);
+out_free_kmem:
        kmem_cache_free(ecryptfs_header_cache_2, page_virt);
        goto out;
-
 out_dput:
        dput(lower_dentry);
-       d_drop(dentry);
+       d_drop(ecryptfs_dentry);
 out:
+       return rc;
+}
+
+/**
+ * ecryptfs_lookup
+ * @ecryptfs_dir_inode: The eCryptfs directory inode
+ * @ecryptfs_dentry: The eCryptfs dentry that we are looking up
+ * @ecryptfs_nd: nameidata; may be NULL
+ *
+ * Find a file on disk. If the file does not exist, then we'll add it to the
+ * dentry cache and continue on to read it from the disk.
+ */
+static struct dentry *ecryptfs_lookup(struct inode *ecryptfs_dir_inode,
+                                     struct dentry *ecryptfs_dentry,
+                                     struct nameidata *ecryptfs_nd)
+{
+       char *encrypted_and_encoded_name = NULL;
+       size_t encrypted_and_encoded_name_size;
+       struct ecryptfs_mount_crypt_stat *mount_crypt_stat = NULL;
+       struct dentry *lower_dir_dentry, *lower_dentry;
+       int rc = 0;
+
+       ecryptfs_dentry->d_op = &ecryptfs_dops;
+       if ((ecryptfs_dentry->d_name.len == 1
+            && !strcmp(ecryptfs_dentry->d_name.name, "."))
+           || (ecryptfs_dentry->d_name.len == 2
+               && !strcmp(ecryptfs_dentry->d_name.name, ".."))) {
+               goto out_d_drop;
+       }
+       lower_dir_dentry = ecryptfs_dentry_to_lower(ecryptfs_dentry->d_parent);
+       mutex_lock(&lower_dir_dentry->d_inode->i_mutex);
+       lower_dentry = lookup_one_len(ecryptfs_dentry->d_name.name,
+                                     lower_dir_dentry,
+                                     ecryptfs_dentry->d_name.len);
+       mutex_unlock(&lower_dir_dentry->d_inode->i_mutex);
+       if (IS_ERR(lower_dentry)) {
+               rc = PTR_ERR(lower_dentry);
+               printk(KERN_ERR "%s: lookup_one_len() returned [%d] on "
+                      "lower_dentry = [%s]\n", __func__, rc,
+                      ecryptfs_dentry->d_name.name);
+               goto out_d_drop;
+       }
+       if (lower_dentry->d_inode)
+               goto lookup_and_interpose;
+       mount_crypt_stat = &ecryptfs_superblock_to_private(
+                               ecryptfs_dentry->d_sb)->mount_crypt_stat;
+       if (!(mount_crypt_stat
+           && (mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES)))
+               goto lookup_and_interpose;
+       dput(lower_dentry);
+       rc = ecryptfs_encrypt_and_encode_filename(
+               &encrypted_and_encoded_name, &encrypted_and_encoded_name_size,
+               NULL, mount_crypt_stat, ecryptfs_dentry->d_name.name,
+               ecryptfs_dentry->d_name.len);
+       if (rc) {
+               printk(KERN_ERR "%s: Error attempting to encrypt and encode "
+                      "filename; rc = [%d]\n", __func__, rc);
+               goto out_d_drop;
+       }
+       mutex_lock(&lower_dir_dentry->d_inode->i_mutex);
+       lower_dentry = lookup_one_len(encrypted_and_encoded_name,
+                                     lower_dir_dentry,
+                                     encrypted_and_encoded_name_size - 1);
+       mutex_unlock(&lower_dir_dentry->d_inode->i_mutex);
+       if (IS_ERR(lower_dentry)) {
+               rc = PTR_ERR(lower_dentry);
+               printk(KERN_ERR "%s: lookup_one_len() returned [%d] on "
+                      "lower_dentry = [%s]\n", __func__, rc,
+                      encrypted_and_encoded_name);
+               goto out_d_drop;
+       }
+lookup_and_interpose:
+       rc = ecryptfs_lookup_and_interpose_lower(ecryptfs_dentry, lower_dentry,
+                                                ecryptfs_dir_inode,
+                                                ecryptfs_nd);
+       goto out;
+out_d_drop:
+       d_drop(ecryptfs_dentry);
+out:
+       kfree(encrypted_and_encoded_name);
        return ERR_PTR(rc);
 }
 
@@ -466,19 +499,21 @@ static int ecryptfs_symlink(struct inode *dir, struct dentry *dentry,
        struct dentry *lower_dentry;
        struct dentry *lower_dir_dentry;
        char *encoded_symname;
-       int encoded_symlen;
-       struct ecryptfs_crypt_stat *crypt_stat = NULL;
+       size_t encoded_symlen;
+       struct ecryptfs_mount_crypt_stat *mount_crypt_stat = NULL;
 
        lower_dentry = ecryptfs_dentry_to_lower(dentry);
        dget(lower_dentry);
        lower_dir_dentry = lock_parent(lower_dentry);
-       encoded_symlen = ecryptfs_encode_filename(crypt_stat, symname,
-                                                 strlen(symname),
-                                                 &encoded_symname);
-       if (encoded_symlen < 0) {
-               rc = encoded_symlen;
+       mount_crypt_stat = &ecryptfs_superblock_to_private(
+               dir->i_sb)->mount_crypt_stat;
+       rc = ecryptfs_encrypt_and_encode_filename(&encoded_symname,
+                                                 &encoded_symlen,
+                                                 NULL,
+                                                 mount_crypt_stat, symname,
+                                                 strlen(symname));
+       if (rc)
                goto out_lock;
-       }
        rc = vfs_symlink(lower_dir_dentry->d_inode, lower_dentry,
                         encoded_symname);
        kfree(encoded_symname);
@@ -602,53 +637,66 @@ out_lock:
 }
 
 static int
-ecryptfs_readlink(struct dentry *dentry, char __user * buf, int bufsiz)
+ecryptfs_readlink(struct dentry *dentry, char __user *buf, int bufsiz)
 {
-       int rc;
-       struct dentry *lower_dentry;
-       char *decoded_name;
        char *lower_buf;
+       size_t lower_bufsiz;
+       struct dentry *lower_dentry;
+       struct ecryptfs_mount_crypt_stat *mount_crypt_stat;
+       char *plaintext_name;
+       size_t plaintext_name_size;
        mm_segment_t old_fs;
-       struct ecryptfs_crypt_stat *crypt_stat;
+       int rc;
 
        lower_dentry = ecryptfs_dentry_to_lower(dentry);
-       if (!lower_dentry->d_inode->i_op ||
-           !lower_dentry->d_inode->i_op->readlink) {
+       if (!lower_dentry->d_inode->i_op->readlink) {
                rc = -EINVAL;
                goto out;
        }
+       mount_crypt_stat = &ecryptfs_superblock_to_private(
+                                               dentry->d_sb)->mount_crypt_stat;
+       /*
+        * If the lower filename is encrypted, it will result in a significantly
+        * longer name.  If needed, truncate the name after decode and decrypt.
+        */
+       if (mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES)
+               lower_bufsiz = PATH_MAX;
+       else
+               lower_bufsiz = bufsiz;
        /* Released in this function */
-       lower_buf = kmalloc(bufsiz, GFP_KERNEL);
+       lower_buf = kmalloc(lower_bufsiz, GFP_KERNEL);
        if (lower_buf == NULL) {
-               ecryptfs_printk(KERN_ERR, "Out of memory\n");
+               printk(KERN_ERR "%s: Out of memory whilst attempting to "
+                      "kmalloc [%zd] bytes\n", __func__, lower_bufsiz);
                rc = -ENOMEM;
                goto out;
        }
        old_fs = get_fs();
        set_fs(get_ds());
-       ecryptfs_printk(KERN_DEBUG, "Calling readlink w/ "
-                       "lower_dentry->d_name.name = [%s]\n",
-                       lower_dentry->d_name.name);
        rc = lower_dentry->d_inode->i_op->readlink(lower_dentry,
                                                   (char __user *)lower_buf,
-                                                  bufsiz);
+                                                  lower_bufsiz);
        set_fs(old_fs);
        if (rc >= 0) {
-               crypt_stat = NULL;
-               rc = ecryptfs_decode_filename(crypt_stat, lower_buf, rc,
-                                             &decoded_name);
-               if (rc == -ENOMEM)
+               rc = ecryptfs_decode_and_decrypt_filename(&plaintext_name,
+                                                         &plaintext_name_size,
+                                                         dentry, lower_buf,
+                                                         rc);
+               if (rc) {
+                       printk(KERN_ERR "%s: Error attempting to decode and "
+                              "decrypt filename; rc = [%d]\n", __func__,
+                               rc);
                        goto out_free_lower_buf;
-               if (rc > 0) {
-                       ecryptfs_printk(KERN_DEBUG, "Copying [%d] bytes "
-                                       "to userspace: [%*s]\n", rc,
-                                       decoded_name);
-                       if (copy_to_user(buf, decoded_name, rc))
-                               rc = -EFAULT;
                }
-               kfree(decoded_name);
-               fsstack_copy_attr_atime(dentry->d_inode,
-                                       lower_dentry->d_inode);
+               /* Check for bufsiz <= 0 done in sys_readlinkat() */
+               rc = copy_to_user(buf, plaintext_name,
+                                 min((size_t) bufsiz, plaintext_name_size));
+               if (rc)
+                       rc = -EFAULT;
+               else
+                       rc = plaintext_name_size;
+               kfree(plaintext_name);
+               fsstack_copy_attr_atime(dentry->d_inode, lower_dentry->d_inode);
        }
 out_free_lower_buf:
        kfree(lower_buf);
@@ -670,8 +718,6 @@ static void *ecryptfs_follow_link(struct dentry *dentry, struct nameidata *nd)
        }
        old_fs = get_fs();
        set_fs(get_ds());
-       ecryptfs_printk(KERN_DEBUG, "Calling readlink w/ "
-                       "dentry->d_name.name = [%s]\n", dentry->d_name.name);
        rc = dentry->d_inode->i_op->readlink(dentry, (char __user *)buf, len);
        set_fs(old_fs);
        if (rc < 0)
@@ -784,6 +830,13 @@ int ecryptfs_truncate(struct dentry *dentry, loff_t new_length)
                size_t num_zeros = (PAGE_CACHE_SIZE
                                    - (new_length & ~PAGE_CACHE_MASK));
 
+               if (!(crypt_stat->flags & ECRYPTFS_ENCRYPTED)) {
+                       rc = vmtruncate(inode, new_length);
+                       if (rc)
+                               goto out_free;
+                       rc = vmtruncate(lower_dentry->d_inode, new_length);
+                       goto out_free;
+               }
                if (num_zeros) {
                        char *zeros_virt;
 
@@ -885,8 +938,6 @@ static int ecryptfs_setattr(struct dentry *dentry, struct iattr *ia)
                        }
                        rc = 0;
                        crypt_stat->flags &= ~(ECRYPTFS_ENCRYPTED);
-                       mutex_unlock(&crypt_stat->cs_mutex);
-                       goto out;
                }
        }
        mutex_unlock(&crypt_stat->cs_mutex);