ext4 crypto: filename encryption modifications

Modifies htree_dirblock_to_tree, dx_make_map, ext4_match search_dir,
and ext4_find_dest_de to support fname crypto.  Filename encryption
feature is not yet enabled at this patch.

Signed-off-by: Uday Savagaonkar <savagaon@google.com>
Signed-off-by: Ildar Muslukhov <ildarm@google.com>
Signed-off-by: Michael Halcrow <mhalcrow@google.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>

1 files changed, 204 insertions, 44 deletions

diff --git a/fs/ext4/namei.c b/fs/ext4/namei.c
index 85add9a9e1cd..4c84db862891 100644
--- a/fs/ext4/namei.c
+++ b/fs/ext4/namei.c
@@ -253,8 +253,9 @@ static struct dx_frame *dx_probe(const struct qstr *d_name,
                                  struct dx_hash_info *hinfo,
                                  struct dx_frame *frame);
 static void dx_release(struct dx_frame *frames);
-static int dx_make_map(struct ext4_dir_entry_2 *de, unsigned blocksize,
-                       struct dx_hash_info *hinfo, struct dx_map_entry map[]);
+static int dx_make_map(struct inode *dir, struct ext4_dir_entry_2 *de,
+                       unsigned blocksize, struct dx_hash_info *hinfo,
+                       struct dx_map_entry map[]);
 static void dx_sort_map(struct dx_map_entry *map, unsigned count);
 static struct ext4_dir_entry_2 *dx_move_dirents(char *from, char *to,
                 struct dx_map_entry *offsets, int count, unsigned blocksize);
@@ -968,7 +969,8 @@ static int htree_dirblock_to_tree(struct file *dir_file,
         struct buffer_head *bh;
         struct ext4_dir_entry_2 *de, *top;
         int err = 0, count = 0;
-        struct ext4_str tmp_str;
+        struct ext4_fname_crypto_ctx *ctx = NULL;
+        struct ext4_str fname_crypto_str = {.name = NULL, .len = 0}, tmp_str;
 
         dxtrace(printk(KERN_INFO "In htree dirblock_to_tree: block %lu\n",
                                                         (unsigned long)block));
@@ -980,6 +982,24 @@ static int htree_dirblock_to_tree(struct file *dir_file,
         top = (struct ext4_dir_entry_2 *) ((char *) de +
                                            dir->i_sb->s_blocksize -
                                            EXT4_DIR_REC_LEN(0));
+#ifdef CONFIG_EXT4_FS_ENCRYPTION
+        /* Check if the directory is encrypted */
+        ctx = ext4_get_fname_crypto_ctx(dir, EXT4_NAME_LEN);
+        if (IS_ERR(ctx)) {
+                err = PTR_ERR(ctx);
+                brelse(bh);
+                return err;
+        }
+        if (ctx != NULL) {
+                err = ext4_fname_crypto_alloc_buffer(ctx, EXT4_NAME_LEN,
+                                                     &fname_crypto_str);
+                if (err < 0) {
+                        ext4_put_fname_crypto_ctx(&ctx);
+                        brelse(bh);
+                        return err;
+                }
+        }
+#endif
         for (; de < top; de = ext4_next_entry(de, dir->i_sb->s_blocksize)) {
                 if (ext4_check_dir_entry(dir, NULL, de, bh,
                                 bh->b_data, bh->b_size,
@@ -988,24 +1008,52 @@ static int htree_dirblock_to_tree(struct file *dir_file,
                         /* silently ignore the rest of the block */
                         break;
                 }
+#ifdef CONFIG_EXT4_FS_ENCRYPTION
+                err = ext4_fname_disk_to_hash(ctx, de, hinfo);
+                if (err < 0) {
+                        count = err;
+                        goto errout;
+                }
+#else
                 ext4fs_dirhash(de->name, de->name_len, hinfo);
+#endif
                 if ((hinfo->hash < start_hash) ||
                     ((hinfo->hash == start_hash) &&
                      (hinfo->minor_hash < start_minor_hash)))
                         continue;
                 if (de->inode == 0)
                         continue;
-                tmp_str.name = de->name;
-                tmp_str.len = de->name_len;
-                err = ext4_htree_store_dirent(dir_file,
-                           hinfo->hash, hinfo->minor_hash, de, &tmp_str);
+                if (ctx == NULL) {
+                        /* Directory is not encrypted */
+                        tmp_str.name = de->name;
+                        tmp_str.len = de->name_len;
+                        err = ext4_htree_store_dirent(dir_file,
+                                   hinfo->hash, hinfo->minor_hash, de,
+                                   &tmp_str);
+                } else {
+                        /* Directory is encrypted */
+                        err = ext4_fname_disk_to_usr(ctx, de,
+                                                     &fname_crypto_str);
+                        if (err < 0) {
+                                count = err;
+                                goto errout;
+                        }
+                        err = ext4_htree_store_dirent(dir_file,
+                                   hinfo->hash, hinfo->minor_hash, de,
+                                        &fname_crypto_str);
+                }
                 if (err != 0) {
-                        brelse(bh);
-                        return err;
+                        count = err;
+                        goto errout;
                 }
                 count++;
         }
+errout:
         brelse(bh);
+#ifdef CONFIG_EXT4_FS_ENCRYPTION
+        ext4_put_fname_crypto_ctx(&ctx);
+        ext4_fname_crypto_free_buffer(&fname_crypto_str);
+#endif
         return count;
 }
 
@@ -1138,17 +1186,33 @@ static inline int search_dirblock(struct buffer_head *bh,
  * Create map of hash values, offsets, and sizes, stored at end of block.
  * Returns number of entries mapped.
  */
-static int dx_make_map(struct ext4_dir_entry_2 *de, unsigned blocksize,
-                       struct dx_hash_info *hinfo,
+static int dx_make_map(struct inode *dir, struct ext4_dir_entry_2 *de,
+                       unsigned blocksize, struct dx_hash_info *hinfo,
                        struct dx_map_entry *map_tail)
 {
         int count = 0;
         char *base = (char *) de;
         struct dx_hash_info h = *hinfo;
+#ifdef CONFIG_EXT4_FS_ENCRYPTION
+        struct ext4_fname_crypto_ctx *ctx = NULL;
+        int err;
+
+        ctx = ext4_get_fname_crypto_ctx(dir, EXT4_NAME_LEN);
+        if (IS_ERR(ctx))
+                return PTR_ERR(ctx);
+#endif
 
         while ((char *) de < base + blocksize) {
                 if (de->name_len && de->inode) {
+#ifdef CONFIG_EXT4_FS_ENCRYPTION
+                        err = ext4_fname_disk_to_hash(ctx, de, &h);
+                        if (err < 0) {
+                                ext4_put_fname_crypto_ctx(&ctx);
+                                return err;
+                        }
+#else
                         ext4fs_dirhash(de->name, de->name_len, &h);
+#endif
                         map_tail--;
                         map_tail->hash = h.hash;
                         map_tail->offs = ((char *) de - base)>>2;
@@ -1159,6 +1223,9 @@ static int dx_make_map(struct ext4_dir_entry_2 *de, unsigned blocksize,
                 /* XXX: do we need to check rec_len == 0 case? -Chris */
                 de = ext4_next_entry(de, blocksize);
         }
+#ifdef CONFIG_EXT4_FS_ENCRYPTION
+        ext4_put_fname_crypto_ctx(&ctx);
+#endif
         return count;
 }
 
@@ -1209,57 +1276,107 @@ static void dx_insert_block(struct dx_frame *frame, u32 hash, ext4_lblk_t block)
  * `len <= EXT4_NAME_LEN' is guaranteed by caller.
  * `de != NULL' is guaranteed by caller.
  */
-static inline int ext4_match (int len, const char * const name,
-                              struct ext4_dir_entry_2 * de)
+static inline int ext4_match(struct ext4_fname_crypto_ctx *ctx,
+                             struct ext4_str *fname_crypto_str,
+                             int len, const char * const name,
+                             struct ext4_dir_entry_2 *de)
 {
-        if (len != de->name_len)
-                return 0;
+        int res;
+
         if (!de->inode)