ASR_BASE
Change-Id: Icf3719cc0afe3eeb3edc7fa80a2eb5199ca9dda1
diff --git a/marvell/linux/fs/crypto/fname.c b/marvell/linux/fs/crypto/fname.c
new file mode 100644
index 0000000..027b1b6
--- /dev/null
+++ b/marvell/linux/fs/crypto/fname.c
@@ -0,0 +1,571 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * This contains functions for filename crypto management
+ *
+ * Copyright (C) 2015, Google, Inc.
+ * Copyright (C) 2015, Motorola Mobility
+ *
+ * Written by Uday Savagaonkar, 2014.
+ * Modified by Jaegeuk Kim, 2015.
+ *
+ * This has not yet undergone a rigorous security audit.
+ */
+
+#include <linux/namei.h>
+#include <linux/scatterlist.h>
+#include <crypto/hash.h>
+#include <crypto/sha.h>
+#include <crypto/skcipher.h>
+#include "fscrypt_private.h"
+
+/*
+ * struct fscrypt_nokey_name - identifier for directory entry when key is absent
+ *
+ * When userspace lists an encrypted directory without access to the key, the
+ * filesystem must present a unique "no-key name" for each filename that allows
+ * it to find the directory entry again if requested. Naively, that would just
+ * mean using the ciphertext filenames. However, since the ciphertext filenames
+ * can contain illegal characters ('\0' and '/'), they must be encoded in some
+ * way. We use base64. But that can cause names to exceed NAME_MAX (255
+ * bytes), so we also need to use a strong hash to abbreviate long names.
+ *
+ * The filesystem may also need another kind of hash, the "dirhash", to quickly
+ * find the directory entry. Since filesystems normally compute the dirhash
+ * over the on-disk filename (i.e. the ciphertext), it's not computable from
+ * no-key names that abbreviate the ciphertext using the strong hash to fit in
+ * NAME_MAX. It's also not computable if it's a keyed hash taken over the
+ * plaintext (but it may still be available in the on-disk directory entry);
+ * casefolded directories use this type of dirhash. At least in these cases,
+ * each no-key name must include the name's dirhash too.
+ *
+ * To meet all these requirements, we base64-encode the following
+ * variable-length structure. It contains the dirhash, or 0's if the filesystem
+ * didn't provide one; up to 149 bytes of the ciphertext name; and for
+ * ciphertexts longer than 149 bytes, also the SHA-256 of the remaining bytes.
+ *
+ * This ensures that each no-key name contains everything needed to find the
+ * directory entry again, contains only legal characters, doesn't exceed
+ * NAME_MAX, is unambiguous unless there's a SHA-256 collision, and that we only
+ * take the performance hit of SHA-256 on very long filenames (which are rare).
+ */
+struct fscrypt_nokey_name {
+ u32 dirhash[2];
+ u8 bytes[149];
+ u8 sha256[SHA256_DIGEST_SIZE];
+}; /* 189 bytes => 252 bytes base64-encoded, which is <= NAME_MAX (255) */
+
+/*
+ * Decoded size of max-size nokey name, i.e. a name that was abbreviated using
+ * the strong hash and thus includes the 'sha256' field. This isn't simply
+ * sizeof(struct fscrypt_nokey_name), as the padding at the end isn't included.
+ */
+#define FSCRYPT_NOKEY_NAME_MAX offsetofend(struct fscrypt_nokey_name, sha256)
+
+static inline bool fscrypt_is_dot_dotdot(const struct qstr *str)
+{
+ if (str->len == 1 && str->name[0] == '.')
+ return true;
+
+ if (str->len == 2 && str->name[0] == '.' && str->name[1] == '.')
+ return true;
+
+ return false;
+}
+
+/**
+ * fscrypt_fname_encrypt() - encrypt a filename
+ * @inode: inode of the parent directory (for regular filenames)
+ * or of the symlink (for symlink targets)
+ * @iname: the filename to encrypt
+ * @out: (output) the encrypted filename
+ * @olen: size of the encrypted filename. It must be at least @iname->len.
+ * Any extra space is filled with NUL padding before encryption.
+ *
+ * Return: 0 on success, -errno on failure
+ */
+int fscrypt_fname_encrypt(const struct inode *inode, const struct qstr *iname,
+ u8 *out, unsigned int olen)
+{
+ struct skcipher_request *req = NULL;
+ DECLARE_CRYPTO_WAIT(wait);
+ const struct fscrypt_info *ci = inode->i_crypt_info;
+ struct crypto_skcipher *tfm = ci->ci_enc_key.tfm;
+ union fscrypt_iv iv;
+ struct scatterlist sg;
+ int res;
+
+ /*
+ * Copy the filename to the output buffer for encrypting in-place and
+ * pad it with the needed number of NUL bytes.
+ */
+ if (WARN_ON(olen < iname->len))
+ return -ENOBUFS;
+ memcpy(out, iname->name, iname->len);
+ memset(out + iname->len, 0, olen - iname->len);
+
+ /* Initialize the IV */
+ fscrypt_generate_iv(&iv, 0, ci);
+
+ /* Set up the encryption request */
+ req = skcipher_request_alloc(tfm, GFP_NOFS);
+ if (!req)
+ return -ENOMEM;
+ skcipher_request_set_callback(req,
+ CRYPTO_TFM_REQ_MAY_BACKLOG | CRYPTO_TFM_REQ_MAY_SLEEP,
+ crypto_req_done, &wait);
+ sg_init_one(&sg, out, olen);
+ skcipher_request_set_crypt(req, &sg, &sg, olen, &iv);
+
+ /* Do the encryption */
+ res = crypto_wait_req(crypto_skcipher_encrypt(req), &wait);
+ skcipher_request_free(req);
+ if (res < 0) {
+ fscrypt_err(inode, "Filename encryption failed: %d", res);
+ return res;
+ }
+
+ return 0;
+}
+
+/**
+ * fname_decrypt() - decrypt a filename
+ * @inode: inode of the parent directory (for regular filenames)
+ * or of the symlink (for symlink targets)
+ * @iname: the encrypted filename to decrypt
+ * @oname: (output) the decrypted filename. The caller must have allocated
+ * enough space for this, e.g. using fscrypt_fname_alloc_buffer().
+ *
+ * Return: 0 on success, -errno on failure
+ */
+static int fname_decrypt(const struct inode *inode,
+ const struct fscrypt_str *iname,
+ struct fscrypt_str *oname)
+{
+ struct skcipher_request *req = NULL;
+ DECLARE_CRYPTO_WAIT(wait);
+ struct scatterlist src_sg, dst_sg;
+ const struct fscrypt_info *ci = inode->i_crypt_info;
+ struct crypto_skcipher *tfm = ci->ci_enc_key.tfm;
+ union fscrypt_iv iv;
+ int res;
+
+ /* Allocate request */
+ req = skcipher_request_alloc(tfm, GFP_NOFS);
+ if (!req)
+ return -ENOMEM;
+ skcipher_request_set_callback(req,
+ CRYPTO_TFM_REQ_MAY_BACKLOG | CRYPTO_TFM_REQ_MAY_SLEEP,
+ crypto_req_done, &wait);
+
+ /* Initialize IV */
+ fscrypt_generate_iv(&iv, 0, ci);
+
+ /* Create decryption request */
+ sg_init_one(&src_sg, iname->name, iname->len);
+ sg_init_one(&dst_sg, oname->name, oname->len);
+ skcipher_request_set_crypt(req, &src_sg, &dst_sg, iname->len, &iv);
+ res = crypto_wait_req(crypto_skcipher_decrypt(req), &wait);
+ skcipher_request_free(req);
+ if (res < 0) {
+ fscrypt_err(inode, "Filename decryption failed: %d", res);
+ return res;
+ }
+
+ oname->len = strnlen(oname->name, iname->len);
+ return 0;
+}
+
+static const char lookup_table[65] =
+ "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+,";
+
+#define BASE64_CHARS(nbytes) DIV_ROUND_UP((nbytes) * 4, 3)
+
+/**
+ * base64_encode() - base64-encode some bytes
+ * @src: the bytes to encode
+ * @len: number of bytes to encode
+ * @dst: (output) the base64-encoded string. Not NUL-terminated.
+ *
+ * Encodes the input string using characters from the set [A-Za-z0-9+,].
+ * The encoded string is roughly 4/3 times the size of the input string.
+ *
+ * Return: length of the encoded string
+ */
+static int base64_encode(const u8 *src, int len, char *dst)
+{
+ int i, bits = 0, ac = 0;
+ char *cp = dst;
+
+ for (i = 0; i < len; i++) {
+ ac += src[i] << bits;
+ bits += 8;
+ do {
+ *cp++ = lookup_table[ac & 0x3f];
+ ac >>= 6;
+ bits -= 6;
+ } while (bits >= 6);
+ }
+ if (bits)
+ *cp++ = lookup_table[ac & 0x3f];
+ return cp - dst;
+}
+
+static int base64_decode(const char *src, int len, u8 *dst)
+{
+ int i, bits = 0, ac = 0;
+ const char *p;
+ u8 *cp = dst;
+
+ for (i = 0; i < len; i++) {
+ p = strchr(lookup_table, src[i]);
+ if (p == NULL || src[i] == 0)
+ return -2;
+ ac += (p - lookup_table) << bits;
+ bits += 6;
+ if (bits >= 8) {
+ *cp++ = ac & 0xff;
+ ac >>= 8;
+ bits -= 8;
+ }
+ }
+ if (ac)
+ return -1;
+ return cp - dst;
+}
+
+bool fscrypt_fname_encrypted_size(const union fscrypt_policy *policy,
+ u32 orig_len, u32 max_len,
+ u32 *encrypted_len_ret)
+{
+ int padding = 4 << (fscrypt_policy_flags(policy) &
+ FSCRYPT_POLICY_FLAGS_PAD_MASK);
+ u32 encrypted_len;
+
+ if (orig_len > max_len)
+ return false;
+ encrypted_len = max(orig_len, (u32)FS_CRYPTO_BLOCK_SIZE);
+ encrypted_len = round_up(encrypted_len, padding);
+ *encrypted_len_ret = min(encrypted_len, max_len);
+ return true;
+}
+
+/**
+ * fscrypt_fname_alloc_buffer() - allocate a buffer for presented filenames
+ * @max_encrypted_len: maximum length of encrypted filenames the buffer will be
+ * used to present
+ * @crypto_str: (output) buffer to allocate
+ *
+ * Allocate a buffer that is large enough to hold any decrypted or encoded
+ * filename (null-terminated), for the given maximum encrypted filename length.
+ *
+ * Return: 0 on success, -errno on failure
+ */
+int fscrypt_fname_alloc_buffer(u32 max_encrypted_len,
+ struct fscrypt_str *crypto_str)
+{
+ const u32 max_encoded_len = BASE64_CHARS(FSCRYPT_NOKEY_NAME_MAX);
+ u32 max_presented_len;
+
+ max_presented_len = max(max_encoded_len, max_encrypted_len);
+
+ crypto_str->name = kmalloc(max_presented_len + 1, GFP_NOFS);
+ if (!crypto_str->name)
+ return -ENOMEM;
+ crypto_str->len = max_presented_len;
+ return 0;
+}
+EXPORT_SYMBOL(fscrypt_fname_alloc_buffer);
+
+/**
+ * fscrypt_fname_free_buffer() - free a buffer for presented filenames
+ * @crypto_str: the buffer to free
+ *
+ * Free a buffer that was allocated by fscrypt_fname_alloc_buffer().
+ */
+void fscrypt_fname_free_buffer(struct fscrypt_str *crypto_str)
+{
+ if (!crypto_str)
+ return;
+ kfree(crypto_str->name);
+ crypto_str->name = NULL;
+}
+EXPORT_SYMBOL(fscrypt_fname_free_buffer);
+
+/**
+ * fscrypt_fname_disk_to_usr() - convert an encrypted filename to
+ * user-presentable form
+ * @inode: inode of the parent directory (for regular filenames)
+ * or of the symlink (for symlink targets)
+ * @hash: first part of the name's dirhash, if applicable. This only needs to
+ * be provided if the filename is located in an indexed directory whose
+ * encryption key may be unavailable. Not needed for symlink targets.
+ * @minor_hash: second part of the name's dirhash, if applicable
+ * @iname: encrypted filename to convert. May also be "." or "..", which
+ * aren't actually encrypted.
+ * @oname: output buffer for the user-presentable filename. The caller must
+ * have allocated enough space for this, e.g. using
+ * fscrypt_fname_alloc_buffer().
+ *
+ * If the key is available, we'll decrypt the disk name. Otherwise, we'll
+ * encode it for presentation in fscrypt_nokey_name format.
+ * See struct fscrypt_nokey_name for details.
+ *
+ * Return: 0 on success, -errno on failure
+ */
+int fscrypt_fname_disk_to_usr(const struct inode *inode,
+ u32 hash, u32 minor_hash,
+ const struct fscrypt_str *iname,
+ struct fscrypt_str *oname)
+{
+ const struct qstr qname = FSTR_TO_QSTR(iname);
+ struct fscrypt_nokey_name nokey_name;
+ u32 size; /* size of the unencoded no-key name */
+
+ if (fscrypt_is_dot_dotdot(&qname)) {
+ oname->name[0] = '.';
+ oname->name[iname->len - 1] = '.';
+ oname->len = iname->len;
+ return 0;
+ }
+
+ if (iname->len < FS_CRYPTO_BLOCK_SIZE)
+ return -EUCLEAN;
+
+ if (fscrypt_has_encryption_key(inode))
+ return fname_decrypt(inode, iname, oname);
+
+ /*
+ * Sanity check that struct fscrypt_nokey_name doesn't have padding
+ * between fields and that its encoded size never exceeds NAME_MAX.
+ */
+ BUILD_BUG_ON(offsetofend(struct fscrypt_nokey_name, dirhash) !=
+ offsetof(struct fscrypt_nokey_name, bytes));
+ BUILD_BUG_ON(offsetofend(struct fscrypt_nokey_name, bytes) !=
+ offsetof(struct fscrypt_nokey_name, sha256));
+ BUILD_BUG_ON(BASE64_CHARS(FSCRYPT_NOKEY_NAME_MAX) > NAME_MAX);
+
+ nokey_name.dirhash[0] = hash;
+ nokey_name.dirhash[1] = minor_hash;
+ if (iname->len <= sizeof(nokey_name.bytes)) {
+ memcpy(nokey_name.bytes, iname->name, iname->len);
+ size = offsetof(struct fscrypt_nokey_name, bytes[iname->len]);
+ } else {
+ memcpy(nokey_name.bytes, iname->name, sizeof(nokey_name.bytes));
+ /* Compute strong hash of remaining part of name. */
+ sha256(&iname->name[sizeof(nokey_name.bytes)],
+ iname->len - sizeof(nokey_name.bytes),
+ nokey_name.sha256);
+ size = FSCRYPT_NOKEY_NAME_MAX;
+ }
+ oname->len = base64_encode((const u8 *)&nokey_name, size, oname->name);
+ return 0;
+}
+EXPORT_SYMBOL(fscrypt_fname_disk_to_usr);
+
+/**
+ * fscrypt_setup_filename() - prepare to search a possibly encrypted directory
+ * @dir: the directory that will be searched
+ * @iname: the user-provided filename being searched for
+ * @lookup: 1 if we're allowed to proceed without the key because it's
+ * ->lookup() or we're finding the dir_entry for deletion; 0 if we cannot
+ * proceed without the key because we're going to create the dir_entry.
+ * @fname: the filename information to be filled in
+ *
+ * Given a user-provided filename @iname, this function sets @fname->disk_name
+ * to the name that would be stored in the on-disk directory entry, if possible.
+ * If the directory is unencrypted this is simply @iname. Else, if we have the
+ * directory's encryption key, then @iname is the plaintext, so we encrypt it to
+ * get the disk_name.
+ *
+ * Else, for keyless @lookup operations, @iname should be a no-key name, so we
+ * decode it to get the struct fscrypt_nokey_name. Non-@lookup operations will
+ * be impossible in this case, so we fail them with ENOKEY.
+ *
+ * If successful, fscrypt_free_filename() must be called later to clean up.
+ *
+ * Return: 0 on success, -errno on failure
+ */
+int fscrypt_setup_filename(struct inode *dir, const struct qstr *iname,
+ int lookup, struct fscrypt_name *fname)
+{
+ struct fscrypt_nokey_name *nokey_name;
+ int ret;
+
+ memset(fname, 0, sizeof(struct fscrypt_name));
+ fname->usr_fname = iname;
+
+ if (!IS_ENCRYPTED(dir) || fscrypt_is_dot_dotdot(iname)) {
+ fname->disk_name.name = (unsigned char *)iname->name;
+ fname->disk_name.len = iname->len;
+ return 0;
+ }
+ ret = fscrypt_get_encryption_info(dir, lookup);
+ if (ret)
+ return ret;
+
+ if (fscrypt_has_encryption_key(dir)) {
+ if (!fscrypt_fname_encrypted_size(&dir->i_crypt_info->ci_policy,
+ iname->len,
+ dir->i_sb->s_cop->max_namelen,
+ &fname->crypto_buf.len))
+ return -ENAMETOOLONG;
+ fname->crypto_buf.name = kmalloc(fname->crypto_buf.len,
+ GFP_NOFS);
+ if (!fname->crypto_buf.name)
+ return -ENOMEM;
+
+ ret = fscrypt_fname_encrypt(dir, iname, fname->crypto_buf.name,
+ fname->crypto_buf.len);
+ if (ret)
+ goto errout;
+ fname->disk_name.name = fname->crypto_buf.name;
+ fname->disk_name.len = fname->crypto_buf.len;
+ return 0;
+ }
+ if (!lookup)
+ return -ENOKEY;
+ fname->is_nokey_name = true;
+
+ /*
+ * We don't have the key and we are doing a lookup; decode the
+ * user-supplied name
+ */
+
+ if (iname->len > BASE64_CHARS(FSCRYPT_NOKEY_NAME_MAX))
+ return -ENOENT;
+
+ fname->crypto_buf.name = kmalloc(FSCRYPT_NOKEY_NAME_MAX, GFP_KERNEL);
+ if (fname->crypto_buf.name == NULL)
+ return -ENOMEM;
+
+ ret = base64_decode(iname->name, iname->len, fname->crypto_buf.name);
+ if (ret < (int)offsetof(struct fscrypt_nokey_name, bytes[1]) ||
+ (ret > offsetof(struct fscrypt_nokey_name, sha256) &&
+ ret != FSCRYPT_NOKEY_NAME_MAX)) {
+ ret = -ENOENT;
+ goto errout;
+ }
+ fname->crypto_buf.len = ret;
+
+ nokey_name = (void *)fname->crypto_buf.name;
+ fname->hash = nokey_name->dirhash[0];
+ fname->minor_hash = nokey_name->dirhash[1];
+ if (ret != FSCRYPT_NOKEY_NAME_MAX) {
+ /* The full ciphertext filename is available. */
+ fname->disk_name.name = nokey_name->bytes;
+ fname->disk_name.len =
+ ret - offsetof(struct fscrypt_nokey_name, bytes);
+ }
+ return 0;
+
+errout:
+ kfree(fname->crypto_buf.name);
+ return ret;
+}
+EXPORT_SYMBOL(fscrypt_setup_filename);
+
+/**
+ * fscrypt_match_name() - test whether the given name matches a directory entry
+ * @fname: the name being searched for
+ * @de_name: the name from the directory entry
+ * @de_name_len: the length of @de_name in bytes
+ *
+ * Normally @fname->disk_name will be set, and in that case we simply compare
+ * that to the name stored in the directory entry. The only exception is that
+ * if we don't have the key for an encrypted directory and the name we're
+ * looking for is very long, then we won't have the full disk_name and instead
+ * we'll need to match against a fscrypt_nokey_name that includes a strong hash.
+ *
+ * Return: %true if the name matches, otherwise %false.
+ */
+bool fscrypt_match_name(const struct fscrypt_name *fname,
+ const u8 *de_name, u32 de_name_len)
+{
+ const struct fscrypt_nokey_name *nokey_name =
+ (const void *)fname->crypto_buf.name;
+ u8 digest[SHA256_DIGEST_SIZE];
+
+ if (likely(fname->disk_name.name)) {
+ if (de_name_len != fname->disk_name.len)
+ return false;
+ return !memcmp(de_name, fname->disk_name.name, de_name_len);
+ }
+ if (de_name_len <= sizeof(nokey_name->bytes))
+ return false;
+ if (memcmp(de_name, nokey_name->bytes, sizeof(nokey_name->bytes)))
+ return false;
+ sha256(&de_name[sizeof(nokey_name->bytes)],
+ de_name_len - sizeof(nokey_name->bytes), digest);
+ return !memcmp(digest, nokey_name->sha256, sizeof(digest));
+}
+EXPORT_SYMBOL_GPL(fscrypt_match_name);
+
+/**
+ * fscrypt_fname_siphash() - calculate the SipHash of a filename
+ * @dir: the parent directory
+ * @name: the filename to calculate the SipHash of
+ *
+ * Given a plaintext filename @name and a directory @dir which uses SipHash as
+ * its dirhash method and has had its fscrypt key set up, this function
+ * calculates the SipHash of that name using the directory's secret dirhash key.
+ *
+ * Return: the SipHash of @name using the hash key of @dir
+ */
+u64 fscrypt_fname_siphash(const struct inode *dir, const struct qstr *name)
+{
+ const struct fscrypt_info *ci = dir->i_crypt_info;
+
+ WARN_ON(!ci->ci_dirhash_key_initialized);
+
+ return siphash(name->name, name->len, &ci->ci_dirhash_key);
+}
+EXPORT_SYMBOL_GPL(fscrypt_fname_siphash);
+
+/*
+ * Validate dentries in encrypted directories to make sure we aren't potentially
+ * caching stale dentries after a key has been added.
+ */
+int fscrypt_d_revalidate(struct dentry *dentry, unsigned int flags)
+{
+ struct dentry *dir;
+ int err;
+ int valid;
+
+ /*
+ * Plaintext names are always valid, since fscrypt doesn't support
+ * reverting to no-key names without evicting the directory's inode
+ * -- which implies eviction of the dentries in the directory.
+ */
+ if (!(dentry->d_flags & DCACHE_NOKEY_NAME))
+ return 1;
+
+ /*
+ * No-key name; valid if the directory's key is still unavailable.
+ *
+ * Although fscrypt forbids rename() on no-key names, we still must use
+ * dget_parent() here rather than use ->d_parent directly. That's
+ * because a corrupted fs image may contain directory hard links, which
+ * the VFS handles by moving the directory's dentry tree in the dcache
+ * each time ->lookup() finds the directory and it already has a dentry
+ * elsewhere. Thus ->d_parent can be changing, and we must safely grab
+ * a reference to some ->d_parent to prevent it from being freed.
+ */
+
+ if (flags & LOOKUP_RCU)
+ return -ECHILD;
+
+ dir = dget_parent(dentry);
+ /*
+ * Pass allow_unsupported=true, so that files with an unsupported
+ * encryption policy can be deleted.
+ */
+ err = fscrypt_get_encryption_info(d_inode(dir), true);
+ valid = !fscrypt_has_encryption_key(d_inode(dir));
+ dput(dir);
+
+ if (err < 0)
+ return err;
+
+ return valid;
+}
+EXPORT_SYMBOL_GPL(fscrypt_d_revalidate);