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    SubjectRe: [PATCH 15/26] ubifs: Implement encrypt/decrypt for all IO
    On Fri, Oct 21, 2016 at 02:48:30PM +0200, Richard Weinberger wrote:
    > Signed-off-by: Richard Weinberger <richard@nod.at>
    > ---
    > fs/ubifs/file.c | 36 ++++++++++++++++++
    > fs/ubifs/journal.c | 105 +++++++++++++++++++++++++++++++++++++++++++----------
    > fs/ubifs/super.c | 6 ++-
    > fs/ubifs/ubifs.h | 6 +++
    > 4 files changed, 131 insertions(+), 22 deletions(-)
    >
    > diff --git a/fs/ubifs/file.c b/fs/ubifs/file.c
    > index bd0049788e24..60e089d50c82 100644
    > --- a/fs/ubifs/file.c
    > +++ b/fs/ubifs/file.c
    > @@ -78,6 +78,24 @@ static int read_block(struct inode *inode, void *addr, unsigned int block,
    > goto dump;
    >
    > dlen = le32_to_cpu(dn->ch.len) - UBIFS_DATA_NODE_SZ;
    > +
    > + if (ubifs_crypt_is_encrypted(inode)) {
    > + int clen = le16_to_cpu(dn->compr_size);
    > +
    > + if (clen <= 0 || clen > UBIFS_BLOCK_SIZE || clen > dlen)
    > + goto dump;
    > +
    > + ubifs_assert(dlen <= UBIFS_BLOCK_SIZE);
    > + err = fscrypt_decrypt_buffer(inode, &dn->data, &dn->data, dlen, block, GFP_NOFS);
    > + if (err) {
    > + ubifs_err(c, "fscrypt_decrypt_buffer failed: %i", err);
    > + return err;
    > + }
    > +
    > + ubifs_assert(clen <= dlen);
    > + dlen = clen;
    > + }
    > +
    > out_len = UBIFS_BLOCK_SIZE;
    > err = ubifs_decompress(c, &dn->data, dlen, addr, &out_len,
    > le16_to_cpu(dn->compr_type));
    > @@ -650,6 +668,24 @@ static int populate_page(struct ubifs_info *c, struct page *page,
    >
    > dlen = le32_to_cpu(dn->ch.len) - UBIFS_DATA_NODE_SZ;
    > out_len = UBIFS_BLOCK_SIZE;
    > +
    > + if (ubifs_crypt_is_encrypted(inode)) {
    > + int clen = le16_to_cpu(dn->compr_size);
    > +
    > + if (clen <= 0 || clen > UBIFS_BLOCK_SIZE || clen > dlen)
    > + goto out_err;
    > +
    > + ubifs_assert(dlen <= UBIFS_BLOCK_SIZE);
    > + err = fscrypt_decrypt_buffer(inode, &dn->data, &dn->data, dlen, page_block, GFP_NOFS);
    > + if (err) {
    > + ubifs_err(c, "fscrypt_decrypt_buffer failed: %i", err);
    > + goto out_err;
    > + }
    > +
    > + ubifs_assert(clen <= dlen);
    > + dlen = clen;
    > + }
    > +
    > err = ubifs_decompress(c, &dn->data, dlen, addr, &out_len,
    > le16_to_cpu(dn->compr_type));
    > if (err || len != out_len)
    > diff --git a/fs/ubifs/journal.c b/fs/ubifs/journal.c
    > index a643de4e3d91..da694e520ec8 100644
    > --- a/fs/ubifs/journal.c
    > +++ b/fs/ubifs/journal.c
    > @@ -691,11 +691,15 @@ int ubifs_jnl_write_data(struct ubifs_info *c, const struct inode *inode,
    > int err, lnum, offs, compr_type, out_len;
    > int dlen = COMPRESSED_DATA_NODE_BUF_SZ, allocated = 1;
    > struct ubifs_inode *ui = ubifs_inode(inode);
    > + bool encrypted = ubifs_crypt_is_encrypted(inode);
    >
    > dbg_jnlk(key, "ino %lu, blk %u, len %d, key ",
    > (unsigned long)key_inum(c, key), key_block(c, key), len);
    > ubifs_assert(len <= UBIFS_BLOCK_SIZE);
    >
    > + if (encrypted)
    > + dlen += UBIFS_CIPHER_BLOCK_SIZE;
    > +
    > data = kmalloc(dlen, GFP_NOFS | __GFP_NOWARN);
    > if (!data) {
    > /*
    > @@ -724,6 +728,26 @@ int ubifs_jnl_write_data(struct ubifs_info *c, const struct inode *inode,
    > ubifs_compress(c, buf, len, &data->data, &out_len, &compr_type);

    Compress-before-encrypt is a hazard.

    http://www.iacr.org/cryptodb/archive/2002/FSE/3091/3091.pdf

    > ubifs_assert(out_len <= UBIFS_BLOCK_SIZE);
    >
    > + if (encrypted) {
    > + void *p = &data->data;
    > + int plen = round_up(out_len, UBIFS_CIPHER_BLOCK_SIZE);
    > +
    > + data->compr_size = cpu_to_le16(out_len);
    > +
    > + if (plen != out_len) {
    > + memset(p + out_len, 0, plen - out_len);
    > + out_len = plen;
    > + }
    > +
    > + err = fscrypt_encrypt_buffer(inode, &data->data, &data->data, out_len, key_block(c, key), GFP_NOFS);
    > + if (err) {
    > + ubifs_err(c, "fscrypt_encrypt_buffer failed: %i", err);
    > + goto out_free;
    > + }
    > + } else {
    > + data->compr_size = 0;
    > + }
    > +
    > dlen = UBIFS_DATA_NODE_SZ + out_len;
    > data->compr_type = cpu_to_le16(compr_type);
    >
    > @@ -1083,31 +1107,79 @@ out_free:
    > }
    >
    > /**
    > - * recomp_data_node - re-compress a truncated data node.
    > + * truncate_data_node - re-compress/encrypt a truncated data node.
    > + * @c: UBIFS file-system description object
    > + * @inode: inode which referes to the data node
    > + * @block: data block number
    > * @dn: data node to re-compress
    > * @new_len: new length
    > *
    > * This function is used when an inode is truncated and the last data node of
    > - * the inode has to be re-compressed and re-written.
    > + * the inode has to be re-compressed/encrypted and re-written.
    > */
    > -static int recomp_data_node(const struct ubifs_info *c,
    > - struct ubifs_data_node *dn, int *new_len)
    > +static int truncate_data_node(const struct ubifs_info *c, struct inode *inode,
    > + unsigned int block, struct ubifs_data_node *dn,
    > + int *new_len)
    > {
    > void *buf;
    > - int err, len, compr_type, out_len;
    > + int err, dlen, compr_type, out_len, old_dlen;
    >
    > out_len = le32_to_cpu(dn->size);
    > buf = kmalloc(out_len * WORST_COMPR_FACTOR, GFP_NOFS);
    > if (!buf)
    > return -ENOMEM;
    >
    > - len = le32_to_cpu(dn->ch.len) - UBIFS_DATA_NODE_SZ;
    > + dlen = old_dlen = le32_to_cpu(dn->ch.len) - UBIFS_DATA_NODE_SZ;
    > compr_type = le16_to_cpu(dn->compr_type);
    > - err = ubifs_decompress(c, &dn->data, len, buf, &out_len, compr_type);
    > - if (err)
    > - goto out;
    >
    > - ubifs_compress(c, buf, *new_len, &dn->data, &out_len, &compr_type);
    > + if (ubifs_crypt_is_encrypted(inode)) {
    > + int clen = le16_to_cpu(dn->compr_size);
    > +
    > + if (clen <= 0 || clen > UBIFS_BLOCK_SIZE || clen > dlen) {
    > + ubifs_err(c, "bad compr_size: %i", clen);
    > + err = -EINVAL;
    > + goto out;
    > + }
    > +
    > + err = fscrypt_decrypt_buffer(inode, &dn->data, &dn->data, dlen, block, GFP_NOFS);
    > + if (err) {
    > + ubifs_err(c, "fscrypt_decrypt_buffer failed: %i", err);
    > + goto out;
    > + }
    > +
    > + ubifs_assert(clen <= dlen);
    > + dlen = clen;
    > + }
    > +
    > + if (compr_type != UBIFS_COMPR_NONE) {
    > + err = ubifs_decompress(c, &dn->data, dlen, buf, &out_len, compr_type);
    > + if (err)
    > + goto out;
    > +
    > + ubifs_compress(c, buf, *new_len, &dn->data, &out_len, &compr_type);
    > + }
    > +
    > + if (ubifs_crypt_is_encrypted(inode)) {
    > + void *p = &dn->data;
    > + int plen = round_up(out_len, UBIFS_CIPHER_BLOCK_SIZE);
    > +
    > + ubifs_assert(old_dlen >= plen);
    > + dn->compr_size = cpu_to_le16(out_len);
    > +
    > + if (plen != out_len) {
    > + memset(p + out_len, 0, plen - out_len);
    > + out_len = plen;
    > + }
    > +
    > + err = fscrypt_encrypt_buffer(inode, &dn->data, &dn->data, out_len, block, GFP_NOFS);
    > + if (err) {
    > + ubifs_msg(c, "fscrypt_encrypt_buffer failed: %i", err);
    > + goto out;
    > + }
    > + } else {
    > + dn->compr_size = 0;
    > + }
    > +
    > ubifs_assert(out_len <= UBIFS_BLOCK_SIZE);
    > dn->compr_type = cpu_to_le16(compr_type);
    > dn->size = cpu_to_le32(*new_len);
    > @@ -1179,16 +1251,9 @@ int ubifs_jnl_truncate(struct ubifs_info *c, const struct inode *inode,
    > if (le32_to_cpu(dn->size) <= dlen)
    > dlen = 0; /* Nothing to do */
    > else {
    > - int compr_type = le16_to_cpu(dn->compr_type);
    > -
    > - if (compr_type != UBIFS_COMPR_NONE) {
    > - err = recomp_data_node(c, dn, &dlen);
    > - if (err)
    > - goto out_free;
    > - } else {
    > - dn->size = cpu_to_le32(dlen);
    > - dlen += UBIFS_DATA_NODE_SZ;
    > - }
    > + err = truncate_data_node(c, inode, blk, dn, &dlen);
    > + if (err)
    > + goto out_free;
    > }
    > }
    > }
    > diff --git a/fs/ubifs/super.c b/fs/ubifs/super.c
    > index a31222947265..ae25c908fbe5 100644
    > --- a/fs/ubifs/super.c
    > +++ b/fs/ubifs/super.c
    > @@ -1210,7 +1210,8 @@ static int mount_ubifs(struct ubifs_info *c)
    > bu_init(c);
    >
    > if (!c->ro_mount) {
    > - c->write_reserve_buf = kmalloc(COMPRESSED_DATA_NODE_BUF_SZ,
    > + c->write_reserve_buf = kmalloc(COMPRESSED_DATA_NODE_BUF_SZ + \
    > + UBIFS_CIPHER_BLOCK_SIZE,
    > GFP_KERNEL);
    > if (!c->write_reserve_buf)
    > goto out_free;
    > @@ -1623,7 +1624,8 @@ static int ubifs_remount_rw(struct ubifs_info *c)
    > goto out;
    > }
    >
    > - c->write_reserve_buf = kmalloc(COMPRESSED_DATA_NODE_BUF_SZ, GFP_KERNEL);
    > + c->write_reserve_buf = kmalloc(COMPRESSED_DATA_NODE_BUF_SZ + \
    > + UBIFS_CIPHER_BLOCK_SIZE, GFP_KERNEL);
    > if (!c->write_reserve_buf) {
    > err = -ENOMEM;
    > goto out;
    > diff --git a/fs/ubifs/ubifs.h b/fs/ubifs/ubifs.h
    > index 63dd027727ca..6c56a08afcd7 100644
    > --- a/fs/ubifs/ubifs.h
    > +++ b/fs/ubifs/ubifs.h
    > @@ -139,6 +139,12 @@
    > */
    > #define WORST_COMPR_FACTOR 2
    >
    > +#ifdef CONFIG_UBIFS_FS_ENCRYPTION
    > +#define UBIFS_CIPHER_BLOCK_SIZE FS_CRYPTO_BLOCK_SIZE
    > +#else
    > +#define UBIFS_CIPHER_BLOCK_SIZE 0
    > +#endif
    > +
    > /*
    > * How much memory is needed for a buffer where we compress a data node.
    > */
    > --
    > 2.7.3
    >
    > --
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