Merge tag 'ecryptfs-3.11-rc1-cleanup' of git://git.kernel.org/pub/scm/linux/kernel/git/tyhicks/ecryptfs

Pull eCryptfs updates from Tyler Hicks:
 "Code cleanups and improved buffer handling during page crypto
  operations:
   - Remove redundant code by merging some encrypt and decrypt functions
   - Get rid of a helper page allocation during page decryption by using
     in-place decryption
   - Better use of entire pages during page crypto operations
   - Several code cleanups"

* tag 'ecryptfs-3.11-rc1-cleanup' of git://git.kernel.org/pub/scm/linux/kernel/git/tyhicks/ecryptfs:
  Use ecryptfs_dentry_to_lower_path in a couple of places
  eCryptfs: Make extent and scatterlist crypt function parameters similar
  eCryptfs: Collapse crypt_page_offset() into crypt_extent()
  eCryptfs: Merge ecryptfs_encrypt_extent() and ecryptfs_decrypt_extent()
  eCryptfs: Combine page_offset crypto functions
  eCryptfs: Combine encrypt_scatterlist() and decrypt_scatterlist()
  eCryptfs: Decrypt pages in-place
  eCryptfs: Accept one offset parameter in page offset crypto functions
  eCryptfs: Simplify lower file offset calculation
  eCryptfs: Read/write entire page during page IO
  eCryptfs: Use entire helper page during page crypto operations
  eCryptfs: Cocci spatch "memdup.spatch"

4 files changed, 85 insertions, 269 deletions

diff --git a/fs/ecryptfs/crypto.c b/fs/ecryptfs/crypto.c
index cfa109a4d5a2..d10757635b9c 100644
--- a/fs/ecryptfs/crypto.c
+++ b/fs/ecryptfs/crypto.c
@@ -37,16 +37,8 @@
 #include <asm/unaligned.h>
 #include "ecryptfs_kernel.h"
 
-static int
-ecryptfs_decrypt_page_offset(struct ecryptfs_crypt_stat *crypt_stat,
-                             struct page *dst_page, int dst_offset,
-                             struct page *src_page, int src_offset, int size,
-                             unsigned char *iv);
-static int
-ecryptfs_encrypt_page_offset(struct ecryptfs_crypt_stat *crypt_stat,
-                             struct page *dst_page, int dst_offset,
-                             struct page *src_page, int src_offset, int size,
-                             unsigned char *iv);
+#define DECRYPT         0
+#define ENCRYPT         1
 
 /**
  * ecryptfs_to_hex
@@ -336,19 +328,20 @@ static void extent_crypt_complete(struct crypto_async_request *req, int rc)
 }
 
 /**
- * encrypt_scatterlist
+ * crypt_scatterlist
  * @crypt_stat: Pointer to the crypt_stat struct to initialize.
- * @dest_sg: Destination of encrypted data
- * @src_sg: Data to be encrypted
- * @size: Length of data to be encrypted
- * @iv: iv to use during encryption
+ * @dst_sg: Destination of the data after performing the crypto operation
+ * @src_sg: Data to be encrypted or decrypted
+ * @size: Length of data
+ * @iv: IV to use
+ * @op: ENCRYPT or DECRYPT to indicate the desired operation
  *
- * Returns the number of bytes encrypted; negative value on error
+ * Returns the number of bytes encrypted or decrypted; negative value on error
  */
-static int encrypt_scatterlist(struct ecryptfs_crypt_stat *crypt_stat,
-                               struct scatterlist *dest_sg,
-                               struct scatterlist *src_sg, int size,
-                               unsigned char *iv)
+static int crypt_scatterlist(struct ecryptfs_crypt_stat *crypt_stat,
+                             struct scatterlist *dst_sg,
+                             struct scatterlist *src_sg, int size,
+                             unsigned char *iv, int op)
 {
         struct ablkcipher_request *req = NULL;
         struct extent_crypt_result ecr;
@@ -391,9 +384,9 @@ static int encrypt_scatterlist(struct ecryptfs_crypt_stat *crypt_stat,
                 crypt_stat->flags |= ECRYPTFS_KEY_SET;
         }
         mutex_unlock(&crypt_stat->cs_tfm_mutex);
-        ecryptfs_printk(KERN_DEBUG, "Encrypting [%d] bytes.\n", size);
-        ablkcipher_request_set_crypt(req, src_sg, dest_sg, size, iv);
-        rc = crypto_ablkcipher_encrypt(req);
+        ablkcipher_request_set_crypt(req, src_sg, dst_sg, size, iv);
+        rc = op == ENCRYPT ? crypto_ablkcipher_encrypt(req) :
+                             crypto_ablkcipher_decrypt(req);
         if (rc == -EINPROGRESS || rc == -EBUSY) {
                 struct extent_crypt_result *ecr = req->base.data;
 
@@ -407,41 +400,43 @@ out:
 }
 
 /**
- * ecryptfs_lower_offset_for_extent
+ * lower_offset_for_page
  *
  * Convert an eCryptfs page index into a lower byte offset
  */
-static void ecryptfs_lower_offset_for_extent(loff_t *offset, loff_t extent_num,
-                                             struct ecryptfs_crypt_stat *crypt_stat)
+static loff_t lower_offset_for_page(struct ecryptfs_crypt_stat *crypt_stat,
+                                    struct page *page)
 {
-        (*offset) = ecryptfs_lower_header_size(crypt_stat)
-                    + (crypt_stat->extent_size * extent_num);
+        return ecryptfs_lower_header_size(crypt_stat) +
+               (page->index << PAGE_CACHE_SHIFT);
 }
 
 /**
- * ecryptfs_encrypt_extent
- * @enc_extent_page: Allocated page into which to encrypt the data in
- *                   @page
+ * crypt_extent
  * @crypt_stat: crypt_stat containing cryptographic context for the
  *              encryption operation
- * @page: Page containing plaintext data extent to encrypt
+ * @dst_page: The page to write the result into
+ * @src_page: The page to read from
  * @extent_offset: Page extent offset for use in generating IV
+ * @op: ENCRYPT or DECRYPT to indicate the desired operation
  *
- * Encrypts one extent of data.
+ * Encrypts or decrypts one extent of data.
  *
  * Return zero on success; non-zero otherwise
  */
-static int ecryptfs_encrypt_extent(struct page *enc_extent_page,
-                                   struct ecryptfs_crypt_stat *crypt_stat,
-                                   struct page *page,
-                                   unsigned long extent_offset)
+static int crypt_extent(struct ecryptfs_crypt_stat *crypt_stat,
+                        struct page *dst_page,
+                        struct page *src_page,
+                        unsigned long extent_offset, int op)
 {
+        pgoff_t page_index = op == ENCRYPT ? src_page->index : dst_page->index;
         loff_t extent_base;
         char extent_iv[ECRYPTFS_MAX_IV_BYTES];
+        struct scatterlist src_sg, dst_sg;
+        size_t extent_size = crypt_stat->extent_size;
         int rc;
 
-        extent_base = (((loff_t)page->index)
-                       * (PAGE_CACHE_SIZE / crypt_stat->extent_size));
+        extent_base = (((loff_t)page_index) * (PAGE_CACHE_SIZE / extent_size));
         rc = ecryptfs_derive_iv(extent_iv, crypt_stat,
                                 (extent_base + extent_offset));
         if (rc) {
@@ -450,15 +445,21 @@ static int ecryptfs_encrypt_extent(struct page *enc_extent_page,
                         (unsigned long long)(extent_base + extent_offset), rc);
                 goto out;
         }
-        rc = ecryptfs_encrypt_page_offset(crypt_stat, enc_extent_page, 0,
-                                          page, (extent_offset
-                                                 * crypt_stat->extent_size),
-                                          crypt_stat->extent_size, extent_iv);
+
+        sg_init_table(&src_sg, 1);
+        sg_init_table(&dst_sg, 1);
+
+        sg_set_page(&src_sg, src_page, extent_size,
+                    extent_offset * extent_size);
+        sg_set_page(&dst_sg, dst_page, extent_size,
+                    extent_offset * extent_size);
+
+        rc = crypt_scatterlist(crypt_stat, &dst_sg, &src_sg, extent_size,
+                               extent_iv, op);
         if (rc < 0) {
-                printk(KERN_ERR "%s: Error attempting to encrypt page with "
-                       "page->index = [%ld], extent_offset = [%ld]; "
-                       "rc = [%d]\n", __func__, page->index, extent_offset,
-                       rc);
+                printk(KERN_ERR "%s: Error attempting to crypt page with "
+                       "page_index = [%ld], extent_offset = [%ld]; "
+                       "rc = [%d]\n", __func__, page_index, extent_offset, rc);
                 goto out;
         }
         rc = 0;
@@ -489,6 +490,7 @@ int ecryptfs_encrypt_page(struct page *page)
         char *enc_extent_virt;
         struct page *enc_extent_page = NULL;
         loff_t extent_offset;
+        loff_t lower_offset;
         int rc = 0;
 
         ecryptfs_inode = page->mapping->host;
@@ -502,75 +504,35 @@ int ecryptfs_encrypt_page(struct page *page)
                                 "encrypted extent\n");
                 goto out;
         }
-        enc_extent_virt = kmap(enc_extent_page);
+
         for (extent_offset = 0;
              extent_offset < (PAGE_CACHE_SIZE / crypt_stat->extent_size);
              extent_offset++) {
-                loff_t offset;
-
-                rc = ecryptfs_encrypt_extent(enc_extent_page, crypt_stat, page,
-                                             extent_offset);
+                rc = crypt_extent(crypt_stat, enc_extent_page, page,
+                                  extent_offset, ENCRYPT);
                 if (rc) {
                         printk(KERN_ERR "%s: Error encrypting extent; "
                                "rc = [%d]\n", __func__, rc);
                         goto out;
                 }
-                ecryptfs_lower_offset_for_extent(
-                        &offset, ((((loff_t)page->index)
-                                   * (PAGE_CACHE_SIZE
-                                      / crypt_stat->extent_size))
-                                  + extent_offset), crypt_stat);
-                rc = ecryptfs_write_lower(ecryptfs_inode, enc_extent_virt,
-                                          offset, crypt_stat->extent_size);
-                if (rc < 0) {
-                        ecryptfs_printk(KERN_ERR, "Error attempting "
-                                        "to write lower page; rc = [%d]"
-                                        "\n", rc);
-                        goto out;
-                }
-        }
-        rc = 0;
-out:
-        if (enc_extent_page) {
-                kunmap(enc_extent_page);
-                __free_page(enc_extent_page);
         }
-        return rc;
-}
 
-static int ecryptfs_decrypt_extent(struct page *page,
-                                   struct ecryptfs_crypt_stat *crypt_stat,
-                                   struct page *enc_extent_page,
-                                   unsigned long extent_offset)
-{
-        loff_t extent_base;
-        char extent_iv[ECRYPTFS_MAX_IV_BYTES];
-        int rc;
-
-        extent_base = (((loff_t)page->index)
-                       * (PAGE_CACHE_SIZE / crypt_stat->extent_size));
-        rc = ecryptfs_derive_iv(extent_iv, crypt_stat,
-                                (extent_base + extent_offset));
-        if (rc) {
-                ecryptfs_printk(KERN_ERR, "Error attempting to derive IV for "
-                        "extent [0x%.16llx]; rc = [%d]\n",
-                        (unsigned long long)(extent_base + extent_offset), rc);
-                goto out;
-        }
-        rc = ecryptfs_decrypt_page_offset(crypt_stat, page,
-                                          (extent_offset
-                                           * crypt_stat->extent_size),
-                                          enc_extent_page, 0,
-                                          crypt_stat->extent_size, extent_iv);
+        lower_offset = lower_offset_for_page(crypt_stat, page);
+        enc_extent_virt = kmap(enc_extent_page);
+        rc = ecryptfs_write_lower(ecryptfs_inode, enc_extent_virt, lower_offset,
+                                  PAGE_CACHE_SIZE);
+        kunmap(enc_extent_page);
         if (rc < 0) {
-                printk(KERN_ERR "%s: Error attempting to decrypt to page with "
-                       "page->index = [%ld], extent_offset = [%ld]; "
-                       "rc = [%d]\n", __func__, page->index, extent_offset,
-                       rc);
+                ecryptfs_printk(KERN_ERR,
+                        "Error attempting to write lower page; rc = [%d]\n",
+                        rc);
                 goto out;
         }
         rc = 0;
 out:
+        if (enc_extent_page) {
+                __free_page(enc_extent_page);
+        }
         return rc;
 }
 
@@ -594,43 +556,33 @@ int ecryptfs_decrypt_page(struct page *page)
 {
         struct inode *ecryptfs_inode;
         struct ecryptfs_crypt_stat *crypt_stat;
-        char *enc_extent_virt;
-        struct page *enc_extent_page = NULL;
+        char *page_virt;
         unsigned long extent_offset;
+        loff_t lower_offset;
         int rc = 0;
 
         ecryptfs_inode = page->mapping->host;
         crypt_stat =
                 &(ecryptfs_inode_to_private(ecryptfs_inode)->crypt_stat);
         BUG_ON(!(crypt_stat->flags & ECRYPTFS_ENCRYPTED));
-        enc_extent_page = alloc_page(GFP_USER);
-        if (!enc_extent_page) {
-                rc = -ENOMEM;
-                ecryptfs_printk(KERN_ERR, "Error allocating memory for "
-                                "encrypted extent\n");
+
+        lower_offset = lower_offset_for_page(crypt_stat, page);
+        page_virt = kmap(page);
+        rc = ecryptfs_read_lower(page_virt, lower_offset, PAGE_CACHE_SIZE,
+                                 ecryptfs_inode);
+        kunmap(page);
+        if (rc < 0) {
+                ecryptfs_printk(KERN_ERR,
+                        "Error attempting to read lower page; rc = [%d]\n",
+                        rc);
                 goto out;
         }
-        enc_extent_virt = kmap(enc_extent_page);
+
         for (extent_offset = 0;
              extent_offset < (PAGE_CACHE_SIZE / crypt_stat->extent_size);
              extent_offset++) {
-                loff_t offset;
-
-                ecryptfs_lower_offset_for_extent(
-                        &offset, ((page->index * (PAGE_CACHE_SIZE
-                                                  / crypt_stat->extent_size))
-                                  + extent_offset), crypt_stat);
-                rc = ecryptfs_read_lower(enc_extent_virt, offset,
-                                         crypt_stat->extent_size,
-                                         ecryptfs_inode);
-                if (rc < 0) {
-                        ecryptfs_printk(KERN_ERR, "Error attempting "
-                                        "to read lower page; rc = [%d]"
-                                        "\n", rc);
-                        goto out;
-                }
-                rc = ecryptfs_decrypt_extent(page, crypt_stat, enc_extent_page,
-                                             extent_offset);
+                rc = crypt_extent(crypt_stat, page, page,
+                                  extent_offset, DECRYPT);
                 if (rc) {
                         printk(KERN_ERR "%s: Error encrypting extent; "
                                "rc = [%d]\n", __func__, rc);
@@ -638,140 +590,7 @@ int ecryptfs_decrypt_page(struct page *page)
                 }
         }
 out:
-        if (enc_extent_page) {
-                kunmap(enc_extent_page);
-                __free_page(enc_extent_page);
-        }
-        return rc;
-}
-
-/**
- * decrypt_scatterlist
- * @crypt_stat: Cryptographic context
- * @dest_sg: The destination scatterlist to decrypt into
- * @src_sg: The source scatterlist to decrypt from
- * @size: The number of bytes to decrypt
- * @iv: The initialization vector to use for the decryption
- *
- * Returns the number of bytes decrypted; negative value on error
- */
-static int decrypt_scatterlist(struct ecryptfs_crypt_stat *crypt_stat,
-                               struct scatterlist *dest_sg,
-                               struct scatterlist *src_sg, int size,
-                               unsigned char *iv)
-{
-        struct ablkcipher_request *req = NULL;
-        struct extent_crypt_result ecr;
-        int rc = 0;
-
-        BUG_ON(!crypt_stat || !crypt_stat->tfm
-               || !(crypt_stat->flags & ECRYPTFS_STRUCT_INITIALIZED));
-        if (unlikely(ecryptfs_verbosity > 0)) {
-                ecryptfs_printk(KERN_DEBUG, "Key size [%zd]; key:\n",
-                                crypt_stat->key_size);
-                ecryptfs_dump_hex(crypt_stat->key,
-                                  crypt_stat->key_size);
-        }
-
-        init_completion(&ecr.completion);
-
-        mutex_lock(&crypt_stat->cs_tfm_mutex);
-        req = ablkcipher_request_alloc(crypt_stat->tfm, GFP_NOFS);
-        if (!req) {
-                mutex_unlock(&crypt_stat->cs_tfm_mutex);
-                rc = -ENOMEM;
-                goto out;
-        }
-
-        ablkcipher_request_set_callback(req,
-                        CRYPTO_TFM_REQ_MAY_BACKLOG | CRYPTO_TFM_REQ_MAY_SLEEP,
-                        extent_crypt_complete, &ecr);
-        /* Consider doing this once, when the file is opened */
-        if (!(crypt_stat->flags & ECRYPTFS_KEY_SET)) {
-                rc = crypto_ablkcipher_setkey(crypt_stat->tfm, crypt_stat->key,
-                                              crypt_stat->key_size);
-                if (rc) {
-                        ecryptfs_printk(KERN_ERR,
-                                        "Error setting key; rc = [%d]\n",
-                                        rc);
-                        mutex_unlock(&crypt_stat->cs_tfm_mutex);
-                        rc = -EINVAL;
-                        goto out;
-                }
-                crypt_stat->flags |= ECRYPTFS_KEY_SET;
-        }
-        mutex_unlock(&crypt_stat->cs_tfm_mutex);
-        ecryptfs_printk(KERN_DEBUG, "Decrypting [%d] bytes.\n", size);
-        ablkcipher_request_set_crypt(req, src_sg, dest_sg, size, iv);
-        rc = crypto_ablkcipher_decrypt(req);
-        if (rc == -EINPROGRESS || rc == -EBUSY) {
-                struct extent_crypt_result *ecr = req->base.data;
-
-                wait_for_completion(&ecr->completion);
-                rc = ecr->rc;
-                INIT_COMPLETION(ecr->completion);
-        }
-out:
-        ablkcipher_request_free(req);
         return rc;
-
-}
-
-/**
- * ecryptfs_encrypt_page_offset
- * @crypt_stat: The cryptographic context
- * @dst_page: The page to encrypt into
- * @dst_offset: The offset in the page to encrypt into
- * @src_page: The page to encrypt from
- * @src_offset: The offset in the page to encrypt from
- * @size: The number of bytes to encrypt
- * @iv: The initialization vector to use for the encryption
- *
- * Returns the number of bytes encrypted
- */
-static int
-ecryptfs_encrypt_page_offset(struct ecryptfs_crypt_stat *crypt_stat,
-                             struct page *dst_page, int dst_offset,
-                             struct page *src_page, int src_offset, int size,
-                             unsigned char *iv)
-{
-        struct scatterlist src_sg, dst_sg;
-
-        sg_init_table(&src_sg, 1);
-        sg_init_table(&dst_sg, 1);
-
-        sg_set_page(&src_sg, src_page, size, src_offset);
-        sg_set_page(&dst_sg, dst_page, size, dst_offset);
-        return encrypt_scatterlist(crypt_stat, &dst_sg, &src_sg, size, iv);
-}
-
-/**
- * ecryptfs_decrypt_page_offset
- * @crypt_stat: The cryptographic context
- * @dst_page: The page to decrypt into
- * @dst_offset: The offset in the page to decrypt into
- * @src_page: The page to decrypt from
- * @src_offset: The offset in the page to decrypt from
- * @size: The number of bytes to decrypt
- * @iv: The initialization vector to use for the decryption
- *
- * Returns the number of bytes decrypted
- */
-static int
-ecryptfs_decrypt_page_offset(struct ecryptfs_crypt_stat *crypt_stat,
-                             struct page *dst_page, int dst_offset,
-                             struct page *src_page, int src_offset, int size,
-                             unsigned char *iv)
-{
-        struct scatterlist src_sg, dst_sg;
-
-        sg_init_table(&src_sg, 1);
-        sg_set_page(&src_sg, src_page, size, src_offset);
-
-        sg_init_table(&dst_sg, 1);
-        sg_set_page(&dst_sg, dst_page, size, dst_offset);
-
-        return decrypt_scatterlist(crypt_stat, &dst_sg, &src_sg, size, iv);
 }
 
 #define ECRYPTFS_MAX_SCATTERLIST_LEN 4
diff --git a/fs/ecryptfs/file.c b/fs/ecryptfs/file.c
index 24f1105fda3a..992cf95830b5 100644
--- a/fs/ecryptfs/file.c
+++ b/fs/ecryptfs/file.c
@@ -49,7 +49,7 @@ static ssize_t ecryptfs_read_update_atime(struct kiocb *iocb,
                                 unsigned long nr_segs, loff_t pos)
 {
         ssize_t rc;
-        struct path lower;
+        struct path *path;
         struct file *file = iocb->ki_filp;
 
         rc = generic_file_aio_read(iocb, iov, nr_segs, pos);
@@ -60,9 +60,8 @@ static ssize_t ecryptfs_read_update_atime(struct kiocb *iocb,
         if (-EIOCBQUEUED == rc)
                 rc = wait_on_sync_kiocb(iocb);
         if (rc >= 0) {
-                lower.dentry = ecryptfs_dentry_to_lower(file->f_path.dentry);
-                lower.mnt = ecryptfs_dentry_to_lower_mnt(file->f_path.dentry);
-                touch_atime(&lower);
+                path = ecryptfs_dentry_to_lower_path(file->f_path.dentry);
+                touch_atime(path);
         }
         return rc;
 }
diff --git a/fs/ecryptfs/main.c b/fs/ecryptfs/main.c
index e924cf45aad9..eb1c5979ecaf 100644
--- a/fs/ecryptfs/main.c
+++ b/fs/ecryptfs/main.c
@@ -120,16 +120,15 @@ static int ecryptfs_init_lower_file(struct dentry *dentry,
                                     struct file **lower_file)
 {
         const struct cred *cred = current_cred();
-        struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry);
-        struct vfsmount *lower_mnt = ecryptfs_dentry_to_lower_mnt(dentry);
+        struct path *path = ecryptfs_dentry_to_lower_path(dentry);
         int rc;
 
-        rc = ecryptfs_privileged_open(lower_file, lower_dentry, lower_mnt,
+        rc = ecryptfs_privileged_open(lower_file, path->dentry, path->mnt,
                                       cred);
         if (rc) {
                 printk(KERN_ERR "Error opening lower file "
                        "for lower_dentry [0x%p] and lower_mnt [0x%p]; "
-                       "rc = [%d]\n", lower_dentry, lower_mnt, rc);
+                       "rc = [%d]\n", path->dentry, path->mnt, rc);
                 (*lower_file) = NULL;
         }
         return rc;
diff --git a/fs/ecryptfs/messaging.c b/fs/ecryptfs/messaging.c
index 49ff8ea08f1c..e57380e5f6bd 100644
--- a/fs/ecryptfs/messaging.c
+++ b/fs/ecryptfs/messaging.c
@@ -247,14 +247,13 @@ int ecryptfs_process_response(struct ecryptfs_daemon *daemon,
                 goto unlock;
         }
         msg_size = (sizeof(*msg) + msg->data_len);
-        msg_ctx->msg = kmalloc(msg_size, GFP_KERNEL);
+        msg_ctx->msg = kmemdup(msg, msg_size, GFP_KERNEL);
         if (!msg_ctx->msg) {
                 rc = -ENOMEM;
                 printk(KERN_ERR "%s: Failed to allocate [%zd] bytes of "
                        "GFP_KERNEL memory\n", __func__, msg_size);
                 goto unlock;
         }
-        memcpy(msg_ctx->msg, msg, msg_size);
         msg_ctx->state = ECRYPTFS_MSG_CTX_STATE_DONE;
         wake_up_process(msg_ctx->task);
         rc = 0;