diff options
Diffstat (limited to 'fs/ecryptfs/crypto.c')
| -rw-r--r-- | fs/ecryptfs/crypto.c | 427 |
1 files changed, 235 insertions, 192 deletions
diff --git a/fs/ecryptfs/crypto.c b/fs/ecryptfs/crypto.c index e3d2118fafad..7f788ea5da2b 100644 --- a/fs/ecryptfs/crypto.c +++ b/fs/ecryptfs/crypto.c @@ -467,8 +467,91 @@ out: } /** + * ecryptfs_lower_offset_for_extent + * + * Convert an eCryptfs page index into a lower byte offset + */ +void ecryptfs_lower_offset_for_extent(loff_t *offset, loff_t extent_num, + struct ecryptfs_crypt_stat *crypt_stat) +{ + (*offset) = ((crypt_stat->extent_size + * crypt_stat->num_header_extents_at_front) + + (crypt_stat->extent_size * extent_num)); +} + +/** + * ecryptfs_encrypt_extent + * @enc_extent_page: Allocated page into which to encrypt the data in + * @page + * @crypt_stat: crypt_stat containing cryptographic context for the + * encryption operation + * @page: Page containing plaintext data extent to encrypt + * @extent_offset: Page extent offset for use in generating IV + * + * Encrypts 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) +{ + unsigned long extent_base; + char extent_iv[ECRYPTFS_MAX_IV_BYTES]; + int rc; + + extent_base = (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%.16x]; " + "rc = [%d]\n", (extent_base + extent_offset), + rc); + goto out; + } + if (unlikely(ecryptfs_verbosity > 0)) { + ecryptfs_printk(KERN_DEBUG, "Encrypting extent " + "with iv:\n"); + ecryptfs_dump_hex(extent_iv, crypt_stat->iv_bytes); + ecryptfs_printk(KERN_DEBUG, "First 8 bytes before " + "encryption:\n"); + ecryptfs_dump_hex((char *) + (page_address(page) + + (extent_offset * crypt_stat->extent_size)), + 8); + } + rc = ecryptfs_encrypt_page_offset(crypt_stat, enc_extent_page, 0, + page, (extent_offset + * crypt_stat->extent_size), + crypt_stat->extent_size, extent_iv); + if (rc < 0) { + printk(KERN_ERR "%s: Error attempting to encrypt page with " + "page->index = [%ld], extent_offset = [%ld]; " + "rc = [%d]\n", __FUNCTION__, page->index, extent_offset, + rc); + goto out; + } + rc = 0; + if (unlikely(ecryptfs_verbosity > 0)) { + ecryptfs_printk(KERN_DEBUG, "Encrypt extent [0x%.16x]; " + "rc = [%d]\n", (extent_base + extent_offset), + rc); + ecryptfs_printk(KERN_DEBUG, "First 8 bytes after " + "encryption:\n"); + ecryptfs_dump_hex((char *)(page_address(enc_extent_page)), 8); + } +out: + return rc; +} + +/** * ecryptfs_encrypt_page - * @ctx: The context of the page + * @page: Page mapped from the eCryptfs inode for the file; contains + * decrypted content that needs to be encrypted (to a temporary + * page; not in place) and written out to the lower file * * Encrypt an eCryptfs page. This is done on a per-extent basis. Note * that eCryptfs pages may straddle the lower pages -- for instance, @@ -478,128 +561,121 @@ out: * file, 24K of page 0 of the lower file will be read and decrypted, * and then 8K of page 1 of the lower file will be read and decrypted. * - * The actual operations performed on each page depends on the - * contents of the ecryptfs_page_crypt_context struct. - * * Returns zero on success; negative on error */ -int ecryptfs_encrypt_page(struct ecryptfs_page_crypt_context *ctx) +int ecryptfs_encrypt_page(struct page *page) { - char extent_iv[ECRYPTFS_MAX_IV_BYTES]; - unsigned long base_extent; - unsigned long extent_offset = 0; - unsigned long lower_page_idx = 0; - unsigned long prior_lower_page_idx = 0; - struct page *lower_page; - struct inode *lower_inode; - struct ecryptfs_inode_info *inode_info; + struct inode *ecryptfs_inode; struct ecryptfs_crypt_stat *crypt_stat; + char *enc_extent_virt = NULL; + struct page *enc_extent_page; + loff_t extent_offset; int rc = 0; - int lower_byte_offset = 0; - int orig_byte_offset = 0; - int num_extents_per_page; -#define ECRYPTFS_PAGE_STATE_UNREAD 0 -#define ECRYPTFS_PAGE_STATE_READ 1 -#define ECRYPTFS_PAGE_STATE_MODIFIED 2 -#define ECRYPTFS_PAGE_STATE_WRITTEN 3 - int page_state; - - lower_inode = ecryptfs_inode_to_lower(ctx->page->mapping->host); - inode_info = ecryptfs_inode_to_private(ctx->page->mapping->host); - crypt_stat = &inode_info->crypt_stat; + + ecryptfs_inode = page->mapping->host; + crypt_stat = + &(ecryptfs_inode_to_private(ecryptfs_inode)->crypt_stat); if (!(crypt_stat->flags & ECRYPTFS_ENCRYPTED)) { - rc = ecryptfs_copy_page_to_lower(ctx->page, lower_inode, - ctx->param.lower_file); + rc = ecryptfs_write_lower_page_segment(ecryptfs_inode, page, + 0, PAGE_CACHE_SIZE); if (rc) - ecryptfs_printk(KERN_ERR, "Error attempting to copy " - "page at index [0x%.16x]\n", - ctx->page->index); + printk(KERN_ERR "%s: Error attempting to copy " + "page at index [%ld]\n", __FUNCTION__, + page->index); goto out; } - num_extents_per_page = PAGE_CACHE_SIZE / crypt_stat->extent_size; - base_extent = (ctx->page->index * num_extents_per_page); - page_state = ECRYPTFS_PAGE_STATE_UNREAD; - while (extent_offset < num_extents_per_page) { - ecryptfs_extent_to_lwr_pg_idx_and_offset( - &lower_page_idx, &lower_byte_offset, crypt_stat, - (base_extent + extent_offset)); - if (prior_lower_page_idx != lower_page_idx - && page_state == ECRYPTFS_PAGE_STATE_MODIFIED) { - rc = ecryptfs_write_out_page(ctx, lower_page, - lower_inode, - orig_byte_offset, - (PAGE_CACHE_SIZE - - orig_byte_offset)); - if (rc) { - ecryptfs_printk(KERN_ERR, "Error attempting " - "to write out page; rc = [%d]" - "\n", rc); - goto out; - } - page_state = ECRYPTFS_PAGE_STATE_WRITTEN; - } - if (page_state == ECRYPTFS_PAGE_STATE_UNREAD - || page_state == ECRYPTFS_PAGE_STATE_WRITTEN) { - rc = ecryptfs_read_in_page(ctx, &lower_page, - lower_inode, lower_page_idx, - lower_byte_offset); - if (rc) { - ecryptfs_printk(KERN_ERR, "Error attempting " - "to read in lower page with " - "index [0x%.16x]; rc = [%d]\n", - lower_page_idx, rc); - goto out; - } - orig_byte_offset = lower_byte_offset; - prior_lower_page_idx = lower_page_idx; - page_state = ECRYPTFS_PAGE_STATE_READ; - } - BUG_ON(!(page_state == ECRYPTFS_PAGE_STATE_MODIFIED - || page_state == ECRYPTFS_PAGE_STATE_READ)); - rc = ecryptfs_derive_iv(extent_iv, crypt_stat, - (base_extent + extent_offset)); + enc_extent_virt = kmalloc(PAGE_CACHE_SIZE, GFP_USER); + if (!enc_extent_virt) { + rc = -ENOMEM; + ecryptfs_printk(KERN_ERR, "Error allocating memory for " + "encrypted extent\n"); + goto out; + } + enc_extent_page = virt_to_page(enc_extent_virt); + 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); if (rc) { - ecryptfs_printk(KERN_ERR, "Error attempting to " - "derive IV for extent [0x%.16x]; " - "rc = [%d]\n", - (base_extent + extent_offset), rc); + printk(KERN_ERR "%s: Error encrypting extent; " + "rc = [%d]\n", __FUNCTION__, rc); goto out; } - if (unlikely(ecryptfs_verbosity > 0)) { - ecryptfs_printk(KERN_DEBUG, "Encrypting extent " - "with iv:\n"); - ecryptfs_dump_hex(extent_iv, crypt_stat->iv_bytes); - ecryptfs_printk(KERN_DEBUG, "First 8 bytes before " - "encryption:\n"); - ecryptfs_dump_hex((char *) - (page_address(ctx->page) - + (extent_offset - * crypt_stat->extent_size)), 8); - } - rc = ecryptfs_encrypt_page_offset( - crypt_stat, lower_page, lower_byte_offset, ctx->page, - (extent_offset * crypt_stat->extent_size), - crypt_stat->extent_size, extent_iv); - ecryptfs_printk(KERN_DEBUG, "Encrypt extent [0x%.16x]; " - "rc = [%d]\n", - (base_extent + extent_offset), rc); - if (unlikely(ecryptfs_verbosity > 0)) { - ecryptfs_printk(KERN_DEBUG, "First 8 bytes after " - "encryption:\n"); - ecryptfs_dump_hex((char *)(page_address(lower_page) - + lower_byte_offset), 8); + ecryptfs_lower_offset_for_extent( + &offset, ((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) { + ecryptfs_printk(KERN_ERR, "Error attempting " + "to write lower page; rc = [%d]" + "\n", rc); + goto out; } - page_state = ECRYPTFS_PAGE_STATE_MODIFIED; extent_offset++; } - BUG_ON(orig_byte_offset != 0); - rc = ecryptfs_write_out_page(ctx, lower_page, lower_inode, 0, - (lower_byte_offset - + crypt_stat->extent_size)); +out: + kfree(enc_extent_virt); + 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) +{ + unsigned long extent_base; + char extent_iv[ECRYPTFS_MAX_IV_BYTES]; + int rc; + + extent_base = (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 write out " - "page; rc = [%d]\n", rc); - goto out; + ecryptfs_printk(KERN_ERR, "Error attempting to " + "derive IV for extent [0x%.16x]; " + "rc = [%d]\n", (extent_base + extent_offset), + rc); + goto out; + } + if (unlikely(ecryptfs_verbosity > 0)) { + ecryptfs_printk(KERN_DEBUG, "Decrypting extent " + "with iv:\n"); + ecryptfs_dump_hex(extent_iv, crypt_stat->iv_bytes); + ecryptfs_printk(KERN_DEBUG, "First 8 bytes before " + "decryption:\n"); + ecryptfs_dump_hex((char *) + (page_address(enc_extent_page) + + (extent_offset * crypt_stat->extent_size)), + 8); + } + rc = ecryptfs_decrypt_page_offset(crypt_stat, page, + (extent_offset + * crypt_stat->extent_size), + enc_extent_page, 0, + crypt_stat->extent_size, extent_iv); + if (rc < 0) { + printk(KERN_ERR "%s: Error attempting to decrypt to page with " + "page->index = [%ld], extent_offset = [%ld]; " + "rc = [%d]\n", __FUNCTION__, page->index, extent_offset, + rc); + goto out; + } + rc = 0; + if (unlikely(ecryptfs_verbosity > 0)) { + ecryptfs_printk(KERN_DEBUG, "Decrypt extent [0x%.16x]; " + "rc = [%d]\n", (extent_base + extent_offset), + rc); + ecryptfs_printk(KERN_DEBUG, "First 8 bytes after " + "decryption:\n"); + ecryptfs_dump_hex((char *)(page_address(page) + + (extent_offset + * crypt_stat->extent_size)), 8); } out: return rc; @@ -607,8 +683,9 @@ out: /** * ecryptfs_decrypt_page - * @file: The ecryptfs file - * @page: The page in ecryptfs to decrypt + * @page: Page mapped from the eCryptfs inode for the file; data read + * and decrypted from the lower file will be written into this + * page * * Decrypt an eCryptfs page. This is done on a per-extent basis. Note * that eCryptfs pages may straddle the lower pages -- for instance, @@ -620,103 +697,69 @@ out: * * Returns zero on success; negative on error */ -int ecryptfs_decrypt_page(struct file *file, struct page *page) +int ecryptfs_decrypt_page(struct page *page) { - char extent_iv[ECRYPTFS_MAX_IV_BYTES]; - unsigned long base_extent; - unsigned long extent_offset = 0; - unsigned long lower_page_idx = 0; - unsigned long prior_lower_page_idx = 0; - struct page *lower_page; - char *lower_page_virt = NULL; - struct inode *lower_inode; + struct inode *ecryptfs_inode; struct ecryptfs_crypt_stat *crypt_stat; + char *enc_extent_virt = NULL; + struct page *enc_extent_page; + unsigned long extent_offset; int rc = 0; - int byte_offset; - int num_extents_per_page; - int page_state; - crypt_stat = &(ecryptfs_inode_to_private( - page->mapping->host)->crypt_stat); - lower_inode = ecryptfs_inode_to_lower(page->mapping->host); + ecryptfs_inode = page->mapping->host; + crypt_stat = + &(ecryptfs_inode_to_private(ecryptfs_inode)->crypt_stat); if (!(crypt_stat->flags & ECRYPTFS_ENCRYPTED)) { - rc = ecryptfs_do_readpage(file, page, page->index); + rc = ecryptfs_read_lower_page_segment(page, page->index, 0, + PAGE_CACHE_SIZE, + ecryptfs_inode); if (rc) - ecryptfs_printk(KERN_ERR, "Error attempting to copy " - "page at index [0x%.16x]\n", - page->index); - goto out; + printk(KERN_ERR "%s: Error attempting to copy " + "page at index [%ld]\n", __FUNCTION__, + page->index); + goto out_clear_uptodate; } - num_extents_per_page = PAGE_CACHE_SIZE / crypt_stat->extent_size; - base_extent = (page->index * num_extents_per_page); - lower_page_virt = kmem_cache_alloc(ecryptfs_lower_page_cache, - GFP_KERNEL); - if (!lower_page_virt) { + enc_extent_virt = kmalloc(PAGE_CACHE_SIZE, GFP_USER); + if (!enc_extent_virt) { rc = -ENOMEM; - ecryptfs_printk(KERN_ERR, "Error getting page for encrypted " - "lower page(s)\n"); - goto out; - } - lower_page = virt_to_page(lower_page_virt); - page_state = ECRYPTFS_PAGE_STATE_UNREAD; - while (extent_offset < num_extents_per_page) { - ecryptfs_extent_to_lwr_pg_idx_and_offset( - &lower_page_idx, &byte_offset, crypt_stat, - (base_extent + extent_offset)); - if (prior_lower_page_idx != lower_page_idx - || page_state == ECRYPTFS_PAGE_STATE_UNREAD) { - rc = ecryptfs_do_readpage(file, lower_page, - lower_page_idx); - if (rc) { - ecryptfs_printk(KERN_ERR, "Error reading " - "lower encrypted page; rc = " - "[%d]\n", rc); - goto out; - } - prior_lower_page_idx = lower_page_idx; - page_state = ECRYPTFS_PAGE_STATE_READ; - } - rc = ecryptfs_derive_iv(extent_iv, crypt_stat, - (base_extent + extent_offset)); + ecryptfs_printk(KERN_ERR, "Error allocating memory for " + "encrypted extent\n"); + goto out_clear_uptodate; + } + enc_extent_page = virt_to_page(enc_extent_virt); + 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) { - ecryptfs_printk(KERN_ERR, "Error attempting to " - "derive IV for extent [0x%.16x]; rc = " - "[%d]\n", - (base_extent + extent_offset), rc); - goto out; - } - if (unlikely(ecryptfs_verbosity > 0)) { - ecryptfs_printk(KERN_DEBUG, "Decrypting extent " - "with iv:\n"); - ecryptfs_dump_hex(extent_iv, crypt_stat->iv_bytes); - ecryptfs_printk(KERN_DEBUG, "First 8 bytes before " - "decryption:\n"); - ecryptfs_dump_hex((lower_page_virt + byte_offset), 8); + ecryptfs_printk(KERN_ERR, "Error attempting " + "to read lower page; rc = [%d]" + "\n", rc); + goto out_clear_uptodate; } - rc = ecryptfs_decrypt_page_offset(crypt_stat, page, - (extent_offset - * crypt_stat->extent_size), - lower_page, byte_offset, - crypt_stat->extent_size, - extent_iv); - if (rc != crypt_stat->extent_size) { - ecryptfs_printk(KERN_ERR, "Error attempting to " - "decrypt extent [0x%.16x]\n", - (base_extent + extent_offset)); - goto out; - } - rc = 0; - if (unlikely(ecryptfs_verbosity > 0)) { - ecryptfs_printk(KERN_DEBUG, "First 8 bytes after " - "decryption:\n"); - ecryptfs_dump_hex((char *)(page_address(page) - + byte_offset), 8); + rc = ecryptfs_decrypt_extent(page, crypt_stat, enc_extent_page, + extent_offset); + if (rc) { + printk(KERN_ERR "%s: Error encrypting extent; " + "rc = [%d]\n", __FUNCTION__, rc); + goto out_clear_uptodate; } extent_offset++; } + SetPageUptodate(page); + goto out; +out_clear_uptodate: + ClearPageUptodate(page); out: - if (lower_page_virt) - kmem_cache_free(ecryptfs_lower_page_cache, lower_page_virt); + kfree(enc_extent_virt); return rc; } |