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Date: Wed, 8 Apr 2015 11:44:05 -0600
From: Andreas Dilger <adilger@...ger.ca>
To: Theodore Ts'o <tytso@....edu>
Cc: Ext4 Developers List <linux-ext4@...r.kernel.org>,
jaegeuk@...nel.org, mhalcrow@...gle.com,
Uday Savagaonkar <savagaon@...gle.com>,
Ildar Muslukhov <ildarm@...gle.com>
Subject: Re: [PATCH 17/22] ext4 crypto: partial update to namei.c for fname crypto
On Apr 2, 2015, at 4:10 PM, Theodore Ts'o <tytso@....edu> wrote:
>
> From: Michael Halcrow <mhalcrow@...gle.com>
>
> 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@...gle.com>
> Signed-off-by: Ildar Muslukhov <ildarm@...gle.com>
> Signed-off-by: Michael Halcrow <mhalcrow@...gle.com>
> Signed-off-by: Theodore Ts'o <tytso@....edu>
> ---
> 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++);
This is a bit strange, why not use "printk("%*.s", len, name)"?
> + ext4fs_dirhash(de->name,
> + de->name_len, &h);
> + printk(":(U)%x.%u ", h.hash,
> + (unsigned) ((char *) de
> + - base));
These two printk's could be combined into a single one.
> + } 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));
I guess this could be fixed similarly, or possibly restructured so that
the code is not duplicated?
> +#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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Cheers, Andreas
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