--- /dev/null
+/*
+ * linux/fs/ext4/crypto_fname.c
+ *
+ * Copyright (C) 2015, Google, Inc.
+ *
+ * This contains functions for filename crypto management in ext4
+ *
+ * Written by Uday Savagaonkar, 2014.
+ *
+ * This has not yet undergone a rigorous security audit.
+ *
+ */
+
+#include <crypto/hash.h>
+#include <crypto/sha.h>
+#include <keys/encrypted-type.h>
+#include <keys/user-type.h>
+#include <linux/crypto.h>
+#include <linux/gfp.h>
+#include <linux/kernel.h>
+#include <linux/key.h>
+#include <linux/key.h>
+#include <linux/list.h>
+#include <linux/mempool.h>
+#include <linux/random.h>
+#include <linux/scatterlist.h>
+#include <linux/spinlock_types.h>
+
+#include "ext4.h"
+#include "ext4_crypto.h"
+#include "xattr.h"
+
+/**
+ * ext4_dir_crypt_complete() -
+ */
+static void ext4_dir_crypt_complete(struct crypto_async_request *req, int res)
+{
+ struct ext4_completion_result *ecr = req->data;
+
+ if (res == -EINPROGRESS)
+ return;
+ ecr->res = res;
+ complete(&ecr->completion);
+}
+
+bool ext4_valid_filenames_enc_mode(uint32_t mode)
+{
+ return (mode == EXT4_ENCRYPTION_MODE_AES_256_CTS);
+}
+
+/**
+ * ext4_fname_encrypt() -
+ *
+ * This function encrypts the input filename, and returns the length of the
+ * ciphertext. Errors are returned as negative numbers. We trust the caller to
+ * allocate sufficient memory to oname string.
+ */
+static int ext4_fname_encrypt(struct ext4_fname_crypto_ctx *ctx,
+ const struct qstr *iname,
+ struct ext4_str *oname)
+{
+ u32 ciphertext_len;
+ struct ablkcipher_request *req = NULL;
+ DECLARE_EXT4_COMPLETION_RESULT(ecr);
+ struct crypto_ablkcipher *tfm = ctx->ctfm;
+ int res = 0;
+ char iv[EXT4_CRYPTO_BLOCK_SIZE];
+ struct scatterlist sg[1];
+ int padding = 4 << (ctx->flags & EXT4_POLICY_FLAGS_PAD_MASK);
+ char *workbuf;
+
+ if (iname->len <= 0 || iname->len > ctx->lim)
+ return -EIO;
+
+ ciphertext_len = (iname->len < EXT4_CRYPTO_BLOCK_SIZE) ?
+ EXT4_CRYPTO_BLOCK_SIZE : iname->len;
+ ciphertext_len = ext4_fname_crypto_round_up(ciphertext_len, padding);
+ ciphertext_len = (ciphertext_len > ctx->lim)
+ ? ctx->lim : ciphertext_len;
+
+ /* Allocate request */
+ req = ablkcipher_request_alloc(tfm, GFP_NOFS);
+ if (!req) {
+ printk_ratelimited(
+ KERN_ERR "%s: crypto_request_alloc() failed\n", __func__);
+ return -ENOMEM;
+ }
+ ablkcipher_request_set_callback(req,
+ CRYPTO_TFM_REQ_MAY_BACKLOG | CRYPTO_TFM_REQ_MAY_SLEEP,
+ ext4_dir_crypt_complete, &ecr);
+
+ /* Map the workpage */
+ workbuf = kmap(ctx->workpage);
+
+ /* Copy the input */
+ memcpy(workbuf, iname->name, iname->len);
+ if (iname->len < ciphertext_len)
+ memset(workbuf + iname->len, 0, ciphertext_len - iname->len);
+
+ /* Initialize IV */
+ memset(iv, 0, EXT4_CRYPTO_BLOCK_SIZE);
+
+ /* Create encryption request */
+ sg_init_table(sg, 1);
+ sg_set_page(sg, ctx->workpage, PAGE_SIZE, 0);
+ ablkcipher_request_set_crypt(req, sg, sg, ciphertext_len, iv);
+ res = crypto_ablkcipher_encrypt(req);
+ if (res == -EINPROGRESS || res == -EBUSY) {
+ BUG_ON(req->base.data != &ecr);
+ wait_for_completion(&ecr.completion);
+ res = ecr.res;
+ }
+ if (res >= 0) {
+ /* Copy the result to output */
+ memcpy(oname->name, workbuf, ciphertext_len);
+ res = ciphertext_len;
+ }
+ kunmap(ctx->workpage);
+ ablkcipher_request_free(req);
+ if (res < 0) {
+ printk_ratelimited(
+ KERN_ERR "%s: Error (error code %d)\n", __func__, res);
+ }
+ oname->len = ciphertext_len;
+ return res;
+}
+
+/*
+ * ext4_fname_decrypt()
+ * This function decrypts the input filename, and returns
+ * the length of the plaintext.
+ * Errors are returned as negative numbers.
+ * We trust the caller to allocate sufficient memory to oname string.
+ */
+static int ext4_fname_decrypt(struct ext4_fname_crypto_ctx *ctx,
+ const struct ext4_str *iname,
+ struct ext4_str *oname)
+{
+ struct ext4_str tmp_in[2], tmp_out[1];
+ struct ablkcipher_request *req = NULL;
+ DECLARE_EXT4_COMPLETION_RESULT(ecr);
+ struct scatterlist sg[1];
+ struct crypto_ablkcipher *tfm = ctx->ctfm;
+ int res = 0;
+ char iv[EXT4_CRYPTO_BLOCK_SIZE];
+ char *workbuf;
+
+ if (iname->len <= 0 || iname->len > ctx->lim)
+ return -EIO;
+
+ tmp_in[0].name = iname->name;
+ tmp_in[0].len = iname->len;
+ tmp_out[0].name = oname->name;
+
+ /* Allocate request */
+ req = ablkcipher_request_alloc(tfm, GFP_NOFS);
+ if (!req) {
+ printk_ratelimited(
+ KERN_ERR "%s: crypto_request_alloc() failed\n", __func__);
+ return -ENOMEM;
+ }
+ ablkcipher_request_set_callback(req,
+ CRYPTO_TFM_REQ_MAY_BACKLOG | CRYPTO_TFM_REQ_MAY_SLEEP,
+ ext4_dir_crypt_complete, &ecr);
+
+ /* Map the workpage */
+ workbuf = kmap(ctx->workpage);
+
+ /* Copy the input */
+ memcpy(workbuf, iname->name, iname->len);
+
+ /* Initialize IV */
+ memset(iv, 0, EXT4_CRYPTO_BLOCK_SIZE);
+
+ /* Create encryption request */
+ sg_init_table(sg, 1);
+ sg_set_page(sg, ctx->workpage, PAGE_SIZE, 0);
+ ablkcipher_request_set_crypt(req, sg, sg, iname->len, iv);
+ res = crypto_ablkcipher_decrypt(req);
+ if (res == -EINPROGRESS || res == -EBUSY) {
+ BUG_ON(req->base.data != &ecr);
+ wait_for_completion(&ecr.completion);
+ res = ecr.res;
+ }
+ if (res >= 0) {
+ /* Copy the result to output */
+ memcpy(oname->name, workbuf, iname->len);
+ res = iname->len;
+ }
+ kunmap(ctx->workpage);
+ ablkcipher_request_free(req);
+ if (res < 0) {
+ printk_ratelimited(
+ KERN_ERR "%s: Error in ext4_fname_encrypt (error code %d)\n",
+ __func__, res);
+ return res;
+ }
+
+ oname->len = strnlen(oname->name, iname->len);
+ return oname->len;
+}
+
+static const char *lookup_table =
+ "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+,";
+
+/**
+ * ext4_fname_encode_digest() -
+ *
+ * Encodes the input digest using characters from the set [a-zA-Z0-9_+].
+ * The encoded string is roughly 4/3 times the size of the input string.
+ */
+static int digest_encode(const char *src, int len, char *dst)
+{
+ int i = 0, bits = 0, ac = 0;
+ char *cp = dst;
+
+ while (i < len) {
+ ac += (((unsigned char) src[i]) << bits);
+ bits += 8;
+ do {
+ *cp++ = lookup_table[ac & 0x3f];
+ ac >>= 6;
+ bits -= 6;
+ } while (bits >= 6);
+ i++;
+ }
+ if (bits)
+ *cp++ = lookup_table[ac & 0x3f];
+ return cp - dst;
+}
+
+static int digest_decode(const char *src, int len, char *dst)
+{
+ int i = 0, bits = 0, ac = 0;
+ const char *p;
+ char *cp = dst;
+
+ while (i < len) {
+ 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;
+ }
+ i++;
+ }
+ if (ac)
+ return -1;
+ return cp - dst;
+}
+
+/**
+ * ext4_free_fname_crypto_ctx() -
+ *
+ * Frees up a crypto context.
+ */
+void ext4_free_fname_crypto_ctx(struct ext4_fname_crypto_ctx *ctx)
+{
+ if (ctx == NULL || IS_ERR(ctx))
+ return;
+
+ if (ctx->ctfm && !IS_ERR(ctx->ctfm))
+ crypto_free_ablkcipher(ctx->ctfm);
+ if (ctx->htfm && !IS_ERR(ctx->htfm))
+ crypto_free_hash(ctx->htfm);
+ if (ctx->workpage && !IS_ERR(ctx->workpage))
+ __free_page(ctx->workpage);
+ kfree(ctx);
+}
+
+/**
+ * ext4_put_fname_crypto_ctx() -
+ *
+ * Return: The crypto context onto free list. If the free list is above a
+ * threshold, completely frees up the context, and returns the memory.
+ *
+ * TODO: Currently we directly free the crypto context. Eventually we should
+ * add code it to return to free list. Such an approach will increase
+ * efficiency of directory lookup.
+ */
+void ext4_put_fname_crypto_ctx(struct ext4_fname_crypto_ctx **ctx)
+{
+ if (*ctx == NULL || IS_ERR(*ctx))
+ return;
+ ext4_free_fname_crypto_ctx(*ctx);
+ *ctx = NULL;
+}
+
+/**
+ * ext4_search_fname_crypto_ctx() -
+ */
+static struct ext4_fname_crypto_ctx *ext4_search_fname_crypto_ctx(
+ const struct ext4_encryption_key *key)
+{
+ return NULL;
+}
+
+/**
+ * ext4_alloc_fname_crypto_ctx() -
+ */
+struct ext4_fname_crypto_ctx *ext4_alloc_fname_crypto_ctx(
+ const struct ext4_encryption_key *key)
+{
+ struct ext4_fname_crypto_ctx *ctx;
+
+ ctx = kmalloc(sizeof(struct ext4_fname_crypto_ctx), GFP_NOFS);
+ if (ctx == NULL)
+ return ERR_PTR(-ENOMEM);
+ if (key->mode == EXT4_ENCRYPTION_MODE_INVALID) {
+ /* This will automatically set key mode to invalid
+ * As enum for ENCRYPTION_MODE_INVALID is zero */
+ memset(&ctx->key, 0, sizeof(ctx->key));
+ } else {
+ memcpy(&ctx->key, key, sizeof(struct ext4_encryption_key));
+ }
+ ctx->has_valid_key = (EXT4_ENCRYPTION_MODE_INVALID == key->mode)
+ ? 0 : 1;
+ ctx->ctfm_key_is_ready = 0;
+ ctx->ctfm = NULL;
+ ctx->htfm = NULL;
+ ctx->workpage = NULL;
+ return ctx;
+}
+
+/**
+ * ext4_get_fname_crypto_ctx() -
+ *
+ * Allocates a free crypto context and initializes it to hold
+ * the crypto material for the inode.
+ *
+ * Return: NULL if not encrypted. Error value on error. Valid pointer otherwise.
+ */
+struct ext4_fname_crypto_ctx *ext4_get_fname_crypto_ctx(
+ struct inode *inode, u32 max_ciphertext_len)
+{
+ struct ext4_fname_crypto_ctx *ctx;
+ struct ext4_inode_info *ei = EXT4_I(inode);
+ int res;
+
+ /* Check if the crypto policy is set on the inode */
+ res = ext4_encrypted_inode(inode);
+ if (res == 0)
+ return NULL;
+
+ if (!ext4_has_encryption_key(inode))
+ ext4_generate_encryption_key(inode);
+
+ /* Get a crypto context based on the key.
+ * A new context is allocated if no context matches the requested key.
+ */
+ ctx = ext4_search_fname_crypto_ctx(&(ei->i_encryption_key));
+ if (ctx == NULL)
+ ctx = ext4_alloc_fname_crypto_ctx(&(ei->i_encryption_key));
+ if (IS_ERR(ctx))
+ return ctx;
+
+ ctx->flags = ei->i_crypt_policy_flags;
+ if (ctx->has_valid_key) {
+ if (ctx->key.mode != EXT4_ENCRYPTION_MODE_AES_256_CTS) {
+ printk_once(KERN_WARNING
+ "ext4: unsupported key mode %d\n",
+ ctx->key.mode);
+ return ERR_PTR(-ENOKEY);
+ }
+
+ /* As a first cut, we will allocate new tfm in every call.
+ * later, we will keep the tfm around, in case the key gets
+ * re-used */
+ if (ctx->ctfm == NULL) {
+ ctx->ctfm = crypto_alloc_ablkcipher("cts(cbc(aes))",
+ 0, 0);
+ }
+ if (IS_ERR(ctx->ctfm)) {
+ res = PTR_ERR(ctx->ctfm);
+ printk(
+ KERN_DEBUG "%s: error (%d) allocating crypto tfm\n",
+ __func__, res);
+ ctx->ctfm = NULL;
+ ext4_put_fname_crypto_ctx(&ctx);
+ return ERR_PTR(res);
+ }
+ if (ctx->ctfm == NULL) {
+ printk(
+ KERN_DEBUG "%s: could not allocate crypto tfm\n",
+ __func__);
+ ext4_put_fname_crypto_ctx(&ctx);
+ return ERR_PTR(-ENOMEM);
+ }
+ if (ctx->workpage == NULL)
+ ctx->workpage = alloc_page(GFP_NOFS);
+ if (IS_ERR(ctx->workpage)) {
+ res = PTR_ERR(ctx->workpage);
+ printk(
+ KERN_DEBUG "%s: error (%d) allocating work page\n",
+ __func__, res);
+ ctx->workpage = NULL;
+ ext4_put_fname_crypto_ctx(&ctx);
+ return ERR_PTR(res);
+ }
+ if (ctx->workpage == NULL) {
+ printk(
+ KERN_DEBUG "%s: could not allocate work page\n",
+ __func__);
+ ext4_put_fname_crypto_ctx(&ctx);
+ return ERR_PTR(-ENOMEM);
+ }
+ ctx->lim = max_ciphertext_len;
+ crypto_ablkcipher_clear_flags(ctx->ctfm, ~0);
+ crypto_tfm_set_flags(crypto_ablkcipher_tfm(ctx->ctfm),
+ CRYPTO_TFM_REQ_WEAK_KEY);
+
+ /* If we are lucky, we will get a context that is already
+ * set up with the right key. Else, we will have to
+ * set the key */
+ if (!ctx->ctfm_key_is_ready) {
+ /* Since our crypto objectives for filename encryption
+ * are pretty weak,
+ * we directly use the inode master key */
+ res = crypto_ablkcipher_setkey(ctx->ctfm,
+ ctx->key.raw, ctx->key.size);
+ if (res) {
+ ext4_put_fname_crypto_ctx(&ctx);
+ return ERR_PTR(-EIO);
+ }
+ ctx->ctfm_key_is_ready = 1;
+ } else {
+ /* In the current implementation, key should never be
+ * marked "ready" for a context that has just been
+ * allocated. So we should never reach here */
+ BUG();
+ }
+ }
+ if (ctx->htfm == NULL)
+ ctx->htfm = crypto_alloc_hash("sha256", 0, CRYPTO_ALG_ASYNC);
+ if (IS_ERR(ctx->htfm)) {
+ res = PTR_ERR(ctx->htfm);
+ printk(KERN_DEBUG "%s: error (%d) allocating hash tfm\n",
+ __func__, res);
+ ctx->htfm = NULL;
+ ext4_put_fname_crypto_ctx(&ctx);
+ return ERR_PTR(res);
+ }
+ if (ctx->htfm == NULL) {
+ printk(KERN_DEBUG "%s: could not allocate hash tfm\n",
+ __func__);
+ ext4_put_fname_crypto_ctx(&ctx);
+ return ERR_PTR(-ENOMEM);
+ }
+
+ return ctx;
+}
+
+/**
+ * ext4_fname_crypto_round_up() -
+ *
+ * Return: The next multiple of block size
+ */
+u32 ext4_fname_crypto_round_up(u32 size, u32 blksize)
+{
+ return ((size+blksize-1)/blksize)*blksize;
+}
+
+/**
+ * ext4_fname_crypto_namelen_on_disk() -
+ */
+int ext4_fname_crypto_namelen_on_disk(struct ext4_fname_crypto_ctx *ctx,
+ u32 namelen)
+{
+ u32 ciphertext_len;
+ int padding = 4 << (ctx->flags & EXT4_POLICY_FLAGS_PAD_MASK);
+
+ if (ctx == NULL)
+ return -EIO;
+ if (!(ctx->has_valid_key))
+ return -EACCES;
+ ciphertext_len = (namelen < EXT4_CRYPTO_BLOCK_SIZE) ?
+ EXT4_CRYPTO_BLOCK_SIZE : namelen;
+ ciphertext_len = ext4_fname_crypto_round_up(ciphertext_len, padding);
+ ciphertext_len = (ciphertext_len > ctx->lim)
+ ? ctx->lim : ciphertext_len;
+ return (int) ciphertext_len;
+}
+
+/**
+ * ext4_fname_crypto_alloc_obuff() -
+ *
+ * Allocates an output buffer that is sufficient for the crypto operation
+ * specified by the context and the direction.
+ */
+int ext4_fname_crypto_alloc_buffer(struct ext4_fname_crypto_ctx *ctx,
+ u32 ilen, struct ext4_str *crypto_str)
+{
+ unsigned int olen;
+ int padding = 4 << (ctx->flags & EXT4_POLICY_FLAGS_PAD_MASK);
+
+ if (!ctx)
+ return -EIO;
+ if (padding < EXT4_CRYPTO_BLOCK_SIZE)
+ padding = EXT4_CRYPTO_BLOCK_SIZE;
+ olen = ext4_fname_crypto_round_up(ilen, padding);
+ crypto_str->len = olen;
+ if (olen < EXT4_FNAME_CRYPTO_DIGEST_SIZE*2)
+ olen = EXT4_FNAME_CRYPTO_DIGEST_SIZE*2;
+ /* Allocated buffer can hold one more character to null-terminate the
+ * string */
+ crypto_str->name = kmalloc(olen+1, GFP_NOFS);
+ if (!(crypto_str->name))
+ return -ENOMEM;
+ return 0;
+}
+
+/**
+ * ext4_fname_crypto_free_buffer() -
+ *
+ * Frees the buffer allocated for crypto operation.
+ */
+void ext4_fname_crypto_free_buffer(struct ext4_str *crypto_str)
+{
+ if (!crypto_str)
+ return;
+ kfree(crypto_str->name);
+ crypto_str->name = NULL;
+}
+
+/**
+ * ext4_fname_disk_to_usr() - converts a filename from disk space to user space
+ */
+int _ext4_fname_disk_to_usr(struct ext4_fname_crypto_ctx *ctx,
+ struct dx_hash_info *hinfo,
+ const struct ext4_str *iname,
+ struct ext4_str *oname)
+{
+ char buf[24];
+ int ret;
+
+ if (ctx == NULL)
+ return -EIO;
+ if (iname->len < 3) {
+ /*Check for . and .. */
+ if (iname->name[0] == '.' && iname->name[iname->len-1] == '.') {
+ oname->name[0] = '.';
+ oname->name[iname->len-1] = '.';
+ oname->len = iname->len;
+ return oname->len;
+ }
+ }
+ if (ctx->has_valid_key)
+ return ext4_fname_decrypt(ctx, iname, oname);
+
+ if (iname->len <= EXT4_FNAME_CRYPTO_DIGEST_SIZE) {
+ ret = digest_encode(iname->name, iname->len, oname->name);
+ oname->len = ret;
+ return ret;
+ }
+ if (hinfo) {
+ memcpy(buf, &hinfo->hash, 4);
+ memcpy(buf+4, &hinfo->minor_hash, 4);
+ } else
+ memset(buf, 0, 8);
+ memcpy(buf + 8, iname->name + iname->len - 16, 16);
+ oname->name[0] = '_';
+ ret = digest_encode(buf, 24, oname->name+1);
+ oname->len = ret + 1;
+ return ret + 1;
+}
+
+int ext4_fname_disk_to_usr(struct ext4_fname_crypto_ctx *ctx,
+ struct dx_hash_info *hinfo,
+ const struct ext4_dir_entry_2 *de,
+ struct ext4_str *oname)
+{
+ struct ext4_str iname = {.name = (unsigned char *) de->name,
+ .len = de->name_len };
+
+ return _ext4_fname_disk_to_usr(ctx, hinfo, &iname, oname);
+}
+
+
+/**
+ * ext4_fname_usr_to_disk() - converts a filename from user space to disk space
+ */
+int ext4_fname_usr_to_disk(struct ext4_fname_crypto_ctx *ctx,
+ const struct qstr *iname,
+ struct ext4_str *oname)
+{
+ int res;
+
+ if (ctx == NULL)
+ return -EIO;
+ if (iname->len < 3) {
+ /*Check for . and .. */
+ if (iname->name[0] == '.' &&
+ iname->name[iname->len-1] == '.') {
+ oname->name[0] = '.';
+ oname->name[iname->len-1] = '.';
+ oname->len = iname->len;
+ return oname->len;
+ }
+ }
+ if (ctx->has_valid_key) {
+ res = ext4_fname_encrypt(ctx, iname, oname);
+ return res;
+ }
+ /* Without a proper key, a user is not allowed to modify the filenames
+ * in a directory. Consequently, a user space name cannot be mapped to
+ * a disk-space name */
+ return -EACCES;
+}
+
+/*
+ * Calculate the htree hash from a filename from user space
+ */
+int ext4_fname_usr_to_hash(struct ext4_fname_crypto_ctx *ctx,
+ const struct qstr *iname,
+ struct dx_hash_info *hinfo)
+{
+ struct ext4_str tmp;
+ int ret = 0;
+ char buf[EXT4_FNAME_CRYPTO_DIGEST_SIZE+1];
+
+ if (!ctx ||
+ ((iname->name[0] == '.') &&
+ ((iname->len == 1) ||
+ ((iname->name[1] == '.') && (iname->len == 2))))) {
+ ext4fs_dirhash(iname->name, iname->len, hinfo);
+ return 0;
+ }
+
+ if (!ctx->has_valid_key && iname->name[0] == '_') {
+ if (iname->len != 33)
+ return -ENOENT;
+ ret = digest_decode(iname->name+1, iname->len, buf);
+ if (ret != 24)
+ return -ENOENT;
+ memcpy(&hinfo->hash, buf, 4);
+ memcpy(&hinfo->minor_hash, buf + 4, 4);
+ return 0;
+ }
+
+ if (!ctx->has_valid_key && iname->name[0] != '_') {
+ if (iname->len > 43)
+ return -ENOENT;
+ ret = digest_decode(iname->name, iname->len, buf);
+ ext4fs_dirhash(buf, ret, hinfo);
+ return 0;
+ }
+
+ /* First encrypt the plaintext name */
+ ret = ext4_fname_crypto_alloc_buffer(ctx, iname->len, &tmp);
+ if (ret < 0)
+ return ret;
+
+ ret = ext4_fname_encrypt(ctx, iname, &tmp);
+ if (ret >= 0) {
+ ext4fs_dirhash(tmp.name, tmp.len, hinfo);
+ ret = 0;
+ }
+
+ ext4_fname_crypto_free_buffer(&tmp);
+ return ret;
+}
+
+int ext4_fname_match(struct ext4_fname_crypto_ctx *ctx, struct ext4_str *cstr,
+ int len, const char * const name,
+ struct ext4_dir_entry_2 *de)
+{
+ int ret = -ENOENT;
+ int bigname = (*name == '_');
+
+ if (ctx->has_valid_key) {
+ if (cstr->name == NULL) {
+ struct qstr istr;
+
+ ret = ext4_fname_crypto_alloc_buffer(ctx, len, cstr);
+ if (ret < 0)
+ goto errout;
+ istr.name = name;
+ istr.len = len;
+ ret = ext4_fname_encrypt(ctx, &istr, cstr);
+ if (ret < 0)
+ goto errout;
+ }
+ } else {
+ if (cstr->name == NULL) {
+ cstr->name = kmalloc(32, GFP_KERNEL);
+ if (cstr->name == NULL)
+ return -ENOMEM;
+ if ((bigname && (len != 33)) ||
+ (!bigname && (len > 43)))
+ goto errout;
+ ret = digest_decode(name+bigname, len-bigname,
+ cstr->name);
+ if (ret < 0) {
+ ret = -ENOENT;
+ goto errout;
+ }
+ cstr->len = ret;
+ }
+ if (bigname) {
+ if (de->name_len < 16)
+ return 0;
+ ret = memcmp(de->name + de->name_len - 16,
+ cstr->name + 8, 16);
+ return (ret == 0) ? 1 : 0;
+ }
+ }
+ if (de->name_len != cstr->len)
+ return 0;
+ ret = memcmp(de->name, cstr->name, cstr->len);
+ return (ret == 0) ? 1 : 0;
+errout:
+ kfree(cstr->name);
+ cstr->name = NULL;
+ return ret;
+}
Code Review / kvmfornfv.git / blobdiff