From: Eric Sandeen <sandeen@redhat.com>
Date: Tue, 18 Dec 2007 12:18:43 -0600
Subject: [fs] ecryptfs: upstream fixes
Message-id: 47680F03.4020302@redhat.com
O-Subject: [RHEL 5.2 PATCH] 15/15: eCryptfs: upstream fixes from -mm
Bugzilla: 228341

5 patches I submitted to -mm, they address errors found while testing,
descriptions are below.

All but last (which was just sent today) are in -mm, all are acked by
upstream author. (on IRC if not formally in the patch...)

 crypto.c     |    1 +
 keystore.c   |    2 +-
 main.c       |    1 +
 mmap.c       |   31 ++++++++++++++++++++-----------
 read_write.c |   27 +++++++++++++++++++++------
 super.c      |   52 +++++++++++++++++++++++++++++++---------------------
 6 files changed, 75 insertions(+), 39 deletions(-)

diff --git a/fs/ecryptfs/crypto.c b/fs/ecryptfs/crypto.c
index bfc45b5..ce98068 100644
--- a/fs/ecryptfs/crypto.c
+++ b/fs/ecryptfs/crypto.c
@@ -1778,6 +1778,7 @@ ecryptfs_add_new_key_tfm(struct ecryptfs_key_tfm **key_tfm, char *cipher_name,
 	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,
diff --git a/fs/ecryptfs/keystore.c b/fs/ecryptfs/keystore.c
index 6ebbc26..5993724 100644
--- a/fs/ecryptfs/keystore.c
+++ b/fs/ecryptfs/keystore.c
@@ -1851,7 +1851,7 @@ ecryptfs_add_global_auth_tok(struct ecryptfs_mount_crypt_stat *mount_crypt_stat,
 	struct ecryptfs_global_auth_tok *new_auth_tok;
 	int rc = 0;
 
-	new_auth_tok = kmem_cache_alloc(ecryptfs_global_auth_tok_cache,
+	new_auth_tok = kmem_cache_zalloc(ecryptfs_global_auth_tok_cache,
 					GFP_KERNEL);
 	if (!new_auth_tok) {
 		rc = -ENOMEM;
diff --git a/fs/ecryptfs/main.c b/fs/ecryptfs/main.c
index 74db5b9..7ed9eee 100644
--- a/fs/ecryptfs/main.c
+++ b/fs/ecryptfs/main.c
@@ -523,6 +523,7 @@ static int ecryptfs_read_super(struct super_block *sb, const char *dev_name)
 	lower_mnt = nd.mnt;
 	ecryptfs_set_superblock_lower(sb, lower_root->d_sb);
 	sb->s_maxbytes = lower_root->d_sb->s_maxbytes;
+	sb->s_blocksize = lower_root->d_sb->s_blocksize;
 	ecryptfs_set_dentry_lower(sb->s_root, lower_root);
 	ecryptfs_set_dentry_lower_mnt(sb->s_root, lower_mnt);
 	rc = ecryptfs_interpose(lower_root, sb->s_root, sb, 0);
diff --git a/fs/ecryptfs/mmap.c b/fs/ecryptfs/mmap.c
index dbfb805..f02cb00 100644
--- a/fs/ecryptfs/mmap.c
+++ b/fs/ecryptfs/mmap.c
@@ -263,14 +263,13 @@ out:
 	return 0;
 }
 
+/* This function must zero any hole we create */
 static int ecryptfs_prepare_write(struct file *file, struct page *page,
 				  unsigned from, unsigned to)
 {
 	int rc = 0;
+	loff_t prev_page_end_size;
 
-	if (from == 0 && to == PAGE_CACHE_SIZE)
-		goto out;	/* If we are writing a full page, it will be
-				   up to date. */
 	if (!PageUptodate(page)) {
 		rc = ecryptfs_read_lower_page_segment(page, page->index, 0,
 						      PAGE_CACHE_SIZE,
@@ -283,22 +282,32 @@ static int ecryptfs_prepare_write(struct file *file, struct page *page,
 		} else
 			SetPageUptodate(page);
 	}
-	if (page->index != 0) {
-		loff_t end_of_prev_pg_pos =
-			(((loff_t)page->index << PAGE_CACHE_SHIFT) - 1);
 
-		if (end_of_prev_pg_pos > i_size_read(page->mapping->host)) {
+	prev_page_end_size = ((loff_t)page->index << PAGE_CACHE_SHIFT);
+
+	/*
+	 * If creating a page or more of holes, zero them out via truncate.
+	 * Note, this will increase i_size.
+	 */
+	if (page->index != 0) {
+		if (prev_page_end_size > i_size_read(page->mapping->host)) {
 			rc = ecryptfs_truncate(file->f_dentry,
-					       end_of_prev_pg_pos);
+					       prev_page_end_size);
 			if (rc) {
 				printk(KERN_ERR "Error on attempt to "
 				       "truncate to (higher) offset [%lld];"
-				       " rc = [%d]\n", end_of_prev_pg_pos, rc);
+				       " rc = [%d]\n", prev_page_end_size, rc);
 				goto out;
 			}
 		}
-		if (end_of_prev_pg_pos + 1 > i_size_read(page->mapping->host))
-			memclear_highpage_flush(page, 0, PAGE_CACHE_SIZE);
+	}
+	/*
+	 * Writing to a new page, and creating a small hole from start of page?
+	 * Zero it out.
+	 */
+	if ((i_size_read(page->mapping->host) == prev_page_end_size) &&
+	    (from != 0)) {
+		memclear_highpage_flush(page, 0, PAGE_CACHE_SIZE);
 	}
 out:
 	return rc;
diff --git a/fs/ecryptfs/read_write.c b/fs/ecryptfs/read_write.c
index 6b7474a..948f576 100644
--- a/fs/ecryptfs/read_write.c
+++ b/fs/ecryptfs/read_write.c
@@ -124,6 +124,10 @@ int ecryptfs_write(struct file *ecryptfs_file, char *data, loff_t offset,
 	loff_t pos;
 	int rc = 0;
 
+	/*
+	 * if we are writing beyond current size, then start pos
+	 * at the current size - we'll fill in zeros from there.
+	 */
 	if (offset > ecryptfs_file_size)
 		pos = ecryptfs_file_size;
 	else
@@ -137,6 +141,7 @@ int ecryptfs_write(struct file *ecryptfs_file, char *data, loff_t offset,
 		if (num_bytes > total_remaining_bytes)
 			num_bytes = total_remaining_bytes;
 		if (pos < offset) {
+			/* remaining zeros to write, up to destination offset */
 			size_t total_remaining_zeros = (offset - pos);
 
 			if (num_bytes > total_remaining_zeros)
@@ -167,17 +172,27 @@ int ecryptfs_write(struct file *ecryptfs_file, char *data, loff_t offset,
 			}
 		}
 		ecryptfs_page_virt = kmap_atomic(ecryptfs_page, KM_USER0);
+
+		/*
+		 * pos: where we're now writing, offset: where the request was
+		 * If current pos is before request, we are filling zeros
+		 * If we are at or beyond request, we are writing the *data*
+		 * If we're in a fresh page beyond eof, zero it in either case
+		 */
+		if (pos < offset || !start_offset_in_page) {
+			/* We are extending past the previous end of the file.
+			 * Fill in zero values to the end of the page */
+			memset(((char *)ecryptfs_page_virt
+				+ start_offset_in_page), 0,
+				PAGE_CACHE_SIZE - start_offset_in_page);
+		}
+
+		/* pos >= offset, we are now writing the data request */
 		if (pos >= offset) {
 			memcpy(((char *)ecryptfs_page_virt
 				+ start_offset_in_page),
 			       (data + data_offset), num_bytes);
 			data_offset += num_bytes;
-		} else {
-			/* We are extending past the previous end of the file.
-			 * Fill in zero values up to the start of where we
-			 * will be writing data. */
-			memset(((char *)ecryptfs_page_virt
-				+ start_offset_in_page), 0, num_bytes);
 		}
 		kunmap_atomic(ecryptfs_page_virt, KM_USER0);
 		flush_dcache_page(ecryptfs_page);
diff --git a/fs/ecryptfs/super.c b/fs/ecryptfs/super.c
index b3202a5..f074a67 100644
--- a/fs/ecryptfs/super.c
+++ b/fs/ecryptfs/super.c
@@ -157,32 +157,42 @@ static void ecryptfs_clear_inode(struct inode *inode)
 /**
  * ecryptfs_show_options
  *
- * Prints the directory we are currently mounted over.
- * Returns zero on success; non-zero otherwise
+ * Prints the mount options for a given superblock.
+ * Returns zero; does not fail.
  */
 static int ecryptfs_show_options(struct seq_file *m, struct vfsmount *mnt)
 {
 	struct super_block *sb = mnt->mnt_sb;
-	struct dentry *lower_root_dentry = ecryptfs_dentry_to_lower(sb->s_root);
-	struct vfsmount *lower_mnt = ecryptfs_dentry_to_lower_mnt(sb->s_root);
-	char *tmp_page;
-	char *path;
-	int rc = 0;
-
-	tmp_page = (char *)__get_free_page(GFP_KERNEL);
-	if (!tmp_page) {
-		rc = -ENOMEM;
-		goto out;
-	}
-	path = d_path(lower_root_dentry, lower_mnt, tmp_page, PAGE_SIZE);
-	if (IS_ERR(path)) {
-		rc = PTR_ERR(path);
-		goto out;
+	struct ecryptfs_mount_crypt_stat *mount_crypt_stat =
+		&ecryptfs_superblock_to_private(sb)->mount_crypt_stat;
+	struct ecryptfs_global_auth_tok *walker;
+
+	mutex_lock(&mount_crypt_stat->global_auth_tok_list_mutex);
+	list_for_each_entry(walker,
+			    &mount_crypt_stat->global_auth_tok_list,
+			    mount_crypt_stat_list) {
+		seq_printf(m, ",ecryptfs_sig=%s", walker->sig);
 	}
-	seq_printf(m, ",dir=%s", path);
-	free_page((unsigned long)tmp_page);
-out:
-	return rc;
+	mutex_unlock(&mount_crypt_stat->global_auth_tok_list_mutex);
+
+	/* Note this is global and probably shouldn't be a mount option */
+	if (ecryptfs_verbosity)
+		seq_printf(m, ",ecryptfs_debug=%d\n", ecryptfs_verbosity);
+
+	seq_printf(m, ",ecryptfs_cipher=%s",
+		mount_crypt_stat->global_default_cipher_name);
+
+	if (mount_crypt_stat->global_default_cipher_key_size)
+		seq_printf(m, ",ecryptfs_key_bytes=%zd",
+			   mount_crypt_stat->global_default_cipher_key_size);
+	if (mount_crypt_stat->flags & ECRYPTFS_PLAINTEXT_PASSTHROUGH_ENABLED)
+		seq_printf(m, ",ecryptfs_passthrough");
+	if (mount_crypt_stat->flags & ECRYPTFS_XATTR_METADATA_ENABLED)
+		seq_printf(m, ",ecryptfs_xattr_metadata");
+	if (mount_crypt_stat->flags & ECRYPTFS_ENCRYPTED_VIEW_ENABLED)
+		seq_printf(m, ",ecryptfs_encrypted_view");
+
+	return 0;
 }
 
 struct super_operations ecryptfs_sops = {