[PATCH 17/22] ext4 crypto: partial update to namei.c for fname crypto

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From: Michael Halcrow <mhalcrow@xxxxxxxxxx>

Modifies dx_show_leaf and dx_probe to support fname encryption.
Filename encryption not yet enabled.

Change-Id: I2058ea5cf6c3920a05c75e42acb2baab631fa1e8
Signed-off-by: Uday Savagaonkar <savagaon@xxxxxxxxxx>
Signed-off-by: Ildar Muslukhov <ildarm@xxxxxxxxxx>
Signed-off-by: Michael Halcrow <mhalcrow@xxxxxxxxxx>
Signed-off-by: Theodore Ts'o <tytso@xxxxxxx>
---
 fs/ext4/namei.c | 161 ++++++++++++++++++++++++++++++++++++++++++--------------
 1 file changed, 122 insertions(+), 39 deletions(-)

diff --git a/fs/ext4/namei.c b/fs/ext4/namei.c
index cbedeb0..4fccb76 100644
--- a/fs/ext4/namei.c
+++ b/fs/ext4/namei.c
@@ -588,8 +588,10 @@ struct stats
 	unsigned bcount;
 };
 
-static struct stats dx_show_leaf(struct dx_hash_info *hinfo, struct ext4_dir_entry_2 *de,
-				 int size, int show_names)
+static struct stats dx_show_leaf(struct inode *dir,
+				struct dx_hash_info *hinfo,
+				struct ext4_dir_entry_2 *de,
+				int size, int show_names)
 {
 	unsigned names = 0, space = 0;
 	char *base = (char *) de;
@@ -602,12 +604,85 @@ static struct stats dx_show_leaf(struct dx_hash_info *hinfo, struct ext4_dir_ent
 		{
 			if (show_names)
 			{
+#ifdef CONFIG_EXT4_FS_ENCRYPTION
+				int len;
+				char *name;
+				struct ext4_str fname_crypto_str
+					= {.name = NULL, .len = 0};
+				struct ext4_fname_crypto_ctx *ctx = NULL;
+				int res;
+
+				name  = de->name;
+				len = de->name_len;
+				ctx = ext4_get_fname_crypto_ctx(dir,
+								EXT4_NAME_LEN);
+				if (IS_ERR(ctx)) {
+					printk(KERN_WARNING "Error acquiring"
+					" crypto ctxt--skipping crypto\n");
+					ctx = NULL;
+				}
+				if (ctx == NULL) {
+					/* Directory is not encrypted */
+					while (len--)
+						printk("%c", *name++);
+					ext4fs_dirhash(de->name,
+						de->name_len, &h);
+					printk(":(U)%x.%u ", h.hash,
+						(unsigned) ((char *) de
+							- base));
+				} else {
+					/* Directory is encrypted */
+					res = ext4_fname_crypto_alloc_buffer(
+						ctx, &fname_crypto_str.name,
+						&fname_crypto_str.len,
+						de->name_len);
+					if (res < 0) {
+						printk(KERN_WARNING "Error "
+							"allocating crypto "
+							"buffer--skipping "
+							"crypto\n");
+						ext4_put_fname_crypto_ctx(&ctx);
+						ctx = NULL;
+					}
+					res = ext4_fname_disk_to_usr(ctx, de,
+							&fname_crypto_str);
+					if (res < 0) {
+						printk(KERN_WARNING "Error "
+							"converting filename "
+							"from disk to usr"
+							"\n");
+						name = "??";
+						len = 2;
+					} else {
+						name = fname_crypto_str.name;
+						len = fname_crypto_str.len;
+					}
+					while (len--)
+						printk("%c", *name++);
+					res = ext4_fname_disk_to_hash(ctx, de,
+								      &h);
+					if (res < 0) {
+						printk(KERN_WARNING "Error "
+							"converting filename "
+							"from disk to htree"
+							"\n");
+						h.hash = 0xDEADBEEF;
+					}
+					printk(":(E)%x.%u ", h.hash,
+						(unsigned) ((char *) de
+						- base));
+					ext4_put_fname_crypto_ctx(&ctx);
+					ext4_fname_crypto_free_buffer(
+						(void **)&fname_crypto_str.name);
+				}
+#else
 				int len = de->name_len;
 				char *name = de->name;
 				while (len--) printk("%c", *name++);
 				ext4fs_dirhash(de->name, de->name_len, &h);
 				printk(":%x.%u ", h.hash,
 				       (unsigned) ((char *) de - base));
+#endif
 			}
 			space += EXT4_DIR_REC_LEN(de->name_len);
 			names++;
@@ -639,7 +714,8 @@ struct stats dx_show_entries(struct dx_hash_info *hinfo, struct inode *dir,
 			continue;
 		stats = levels?
 		   dx_show_entries(hinfo, dir, ((struct dx_node *) bh->b_data)->entries, levels - 1):
-		   dx_show_leaf(hinfo, (struct ext4_dir_entry_2 *) bh->b_data, blocksize, 0);
+		   dx_show_leaf(dir, hinfo, (struct ext4_dir_entry_2 *)
+			bh->b_data, blocksize, 0);
 		names += stats.names;
 		space += stats.space;
 		bcount += stats.bcount;
@@ -672,6 +748,10 @@ dx_probe(const struct qstr *d_name, struct inode *dir,
 	struct dx_frame *frame = frame_in;
 	struct dx_frame *ret_err = ERR_PTR(ERR_BAD_DX_DIR);
 	u32 hash;
+#ifdef CONFIG_EXT4_FS_ENCRYPTION
+	struct ext4_fname_crypto_ctx *ctx = NULL;
+	int res;
+#endif
 
 	frame->bh = ext4_read_dirblock(dir, 0, INDEX);
 	if (IS_ERR(frame->bh))
@@ -689,8 +769,25 @@ dx_probe(const struct qstr *d_name, struct inode *dir,
 	if (hinfo->hash_version <= DX_HASH_TEA)
 		hinfo->hash_version += EXT4_SB(dir->i_sb)->s_hash_unsigned;
 	hinfo->seed = EXT4_SB(dir->i_sb)->s_hash_seed;
+#ifdef CONFIG_EXT4_FS_ENCRYPTION
+	if (d_name) {
+		/* Check if the directory is encrypted */
+		ctx = ext4_get_fname_crypto_ctx(dir, EXT4_NAME_LEN);
+		if (IS_ERR(ctx)) {
+			ret_err = ERR_PTR(PTR_ERR(ctx));
+			goto fail;
+		}
+		res = ext4_fname_usr_to_hash(ctx, d_name, hinfo);
+		if (res < 0) {
+			ret_err = ERR_PTR(res);
+			goto fail;
+		}
+	}
+#else
 	if (d_name)
 		ext4fs_dirhash(d_name->name, d_name->len, hinfo);
+#endif
+
 	hash = hinfo->hash;
 
 	if (root->info.unused_flags & 1) {
@@ -775,6 +872,11 @@ fail:
 		brelse(frame->bh);
 		frame--;
 	}
+#ifdef CONFIG_EXT4_FS_ENCRYPTION
+	/* Free up the memory allocated for EXT4 crypto */
+	ext4_put_fname_crypto_ctx(&ctx);
+#endif
+
 	if (ret_err == ERR_PTR(ERR_BAD_DX_DIR))
 		ext4_warning(dir->i_sb,
 			     "Corrupt dir inode %lu, running e2fsck is "
@@ -1602,8 +1704,10 @@ static struct ext4_dir_entry_2 *do_split(handle_t *handle, struct inode *dir,
 		initialize_dirent_tail(t, blocksize);
 	}
 
-	dxtrace(dx_show_leaf (hinfo, (struct ext4_dir_entry_2 *) data1, blocksize, 1));
-	dxtrace(dx_show_leaf (hinfo, (struct ext4_dir_entry_2 *) data2, blocksize, 1));
+	dxtrace(dx_show_leaf(dir, hinfo, (struct ext4_dir_entry_2 *) data1,
+			blocksize, 1));
+	dxtrace(dx_show_leaf(dir, hinfo, (struct ext4_dir_entry_2 *) data2,
+			blocksize, 1));
 
 	/* Which block gets the new entry? */
 	if (hinfo->hash >= hash2) {
@@ -1796,8 +1900,13 @@ static int make_indexed_dir(handle_t *handle, struct dentry *dentry,
 			    struct inode *inode, struct buffer_head *bh)
 {
 	struct inode	*dir = dentry->d_parent->d_inode;
+#ifdef CONFIG_EXT4_FS_ENCRYPTION
+	struct ext4_fname_crypto_ctx *ctx = NULL;
+	int res;
+#else
 	const char	*name = dentry->d_name.name;
 	int		namelen = dentry->d_name.len;
+#endif
 	struct buffer_head *bh2;
 	struct dx_root	*root;
 	struct dx_frame	frames[2], *frame;
@@ -1812,24 +1921,11 @@ static int make_indexed_dir(handle_t *handle, struct dentry *dentry,
 	ext4_lblk_t  block;
 	struct fake_dirent *fde;
 	int csum_size = 0;
-#ifdef CONFIG_EXT4_FS_ENCRYPTION
-	struct ext4_fname_crypto_ctx *ctx = NULL;
-	struct ext4_str fname_crypto_str = {.name = NULL, .len = 0};
-	int res;
 
+#ifdef CONFIG_EXT4_FS_ENCRYPTION
 	ctx = ext4_get_fname_crypto_ctx(dir, EXT4_NAME_LEN);
 	if (IS_ERR(ctx))
-		return -1;
-	if (ctx != NULL) {
-		/* Allocate buffer to hold maximum name length */
-		res = ext4_fname_crypto_alloc_buffer(ctx,
-			&fname_crypto_str.name, &fname_crypto_str.len,
-			EXT4_NAME_LEN);
-		if (res < 0) {
-			ext4_put_fname_crypto_ctx(&ctx);
-			return -1;
-		}
-	}
+		return PTR_ERR(ctx);
 #endif
 
 	if (ext4_has_metadata_csum(inode->i_sb))
@@ -1898,27 +1994,14 @@ static int make_indexed_dir(handle_t *handle, struct dentry *dentry,
 		hinfo.hash_version += EXT4_SB(dir->i_sb)->s_hash_unsigned;
 	hinfo.seed = EXT4_SB(dir->i_sb)->s_hash_seed;
 #ifdef CONFIG_EXT4_FS_ENCRYPTION
-	if (ctx == NULL) {
-		/* Directory is not encrypted */
-		ext4fs_dirhash(name, namelen, &hinfo);
-	} else {
-		/* Directory is encrypted */
-		res = ext4_fname_usr_to_htree(ctx, &dentry->d_name,
-					      &fname_crypto_str);
-		if (res < 0) {
-			ext4_put_fname_crypto_ctx(&ctx);
-			ext4_fname_crypto_free_buffer(
-			    (void **)&fname_crypto_str.name);
-			ext4_mark_inode_dirty(handle, dir);
-			brelse(bh);
-			return res;
-		}
-		ext4fs_dirhash(fname_crypto_str.name,
-			       fname_crypto_str.len,
-			       &hinfo);
+	res = ext4_fname_usr_to_hash(ctx, &dentry->d_name, &hinfo);
+	if (res < 0) {
 		ext4_put_fname_crypto_ctx(&ctx);
-		ext4_fname_crypto_free_buffer((void **)&fname_crypto_str.name);
+		ext4_mark_inode_dirty(handle, dir);
+		brelse(bh);
+		return res;
 	}
+	ext4_put_fname_crypto_ctx(&ctx);
 #else
 	ext4fs_dirhash(name, namelen, &hinfo);
 #endif
-- 
2.3.0

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