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eCryptfs: Merge ecryptfs_encrypt_extent() and ecryptfs_decrypt_extent()

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They are identical except if the src_page or dst_page index is used, so
they can be merged safely if page_index is conditionally assigned.

Signed-off-by: Tyler Hicks <tyhicks@canonical.com>
This commit is contained in:
Tyler Hicks 2013-04-06 00:08:48 -07:00
parent a8ca90e207
commit d78de61896
1 changed files with 20 additions and 54 deletions
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74
fs/ecryptfs/crypto.c
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@ -416,28 +416,29 @@ static loff_t lower_offset_for_page(struct ecryptfs_crypt_stat *crypt_stat,
} }
/** /**
* ecryptfs_encrypt_extent * crypt_extent
* @enc_extent_page: Allocated page into which to encrypt the data in * @dst_page: The page to write the result into
* @page
* @crypt_stat: crypt_stat containing cryptographic context for the * @crypt_stat: crypt_stat containing cryptographic context for the
* encryption operation * encryption operation
* @page: Page containing plaintext data extent to encrypt * @src_page: The page to read from
* @extent_offset: Page extent offset for use in generating IV * @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 * Return zero on success; non-zero otherwise
*/ */
static int ecryptfs_encrypt_extent(struct page *enc_extent_page, static int crypt_extent(struct page *dst_page,
struct ecryptfs_crypt_stat *crypt_stat, struct ecryptfs_crypt_stat *crypt_stat,
struct page *page, struct page *src_page,
unsigned long extent_offset) unsigned long extent_offset, int op)
{ {
pgoff_t page_index = op == ENCRYPT ? src_page->index : dst_page->index;
loff_t extent_base; loff_t extent_base;
char extent_iv[ECRYPTFS_MAX_IV_BYTES]; char extent_iv[ECRYPTFS_MAX_IV_BYTES];
int rc; int rc;
extent_base = (((loff_t)page->index) extent_base = (((loff_t)page_index)
* (PAGE_CACHE_SIZE / crypt_stat->extent_size)); * (PAGE_CACHE_SIZE / crypt_stat->extent_size));
rc = ecryptfs_derive_iv(extent_iv, crypt_stat, rc = ecryptfs_derive_iv(extent_iv, crypt_stat,
(extent_base + extent_offset)); (extent_base + extent_offset));
@ -447,14 +448,13 @@ static int ecryptfs_encrypt_extent(struct page *enc_extent_page,
(unsigned long long)(extent_base + extent_offset), rc); (unsigned long long)(extent_base + extent_offset), rc);
goto out; goto out;
} }
rc = crypt_page_offset(crypt_stat, enc_extent_page, page, rc = crypt_page_offset(crypt_stat, dst_page, src_page,
(extent_offset * crypt_stat->extent_size), (extent_offset * crypt_stat->extent_size),
crypt_stat->extent_size, extent_iv, ENCRYPT); crypt_stat->extent_size, extent_iv, op);
if (rc < 0) { if (rc < 0) {
printk(KERN_ERR "%s: Error attempting to encrypt page with " printk(KERN_ERR "%s: Error attempting to crypt page with "
"page->index = [%ld], extent_offset = [%ld]; " "page_index = [%ld], extent_offset = [%ld]; "
"rc = [%d]\n", __func__, page->index, extent_offset, "rc = [%d]\n", __func__, page_index, extent_offset, rc);
rc);
goto out; goto out;
} }
rc = 0; rc = 0;
@ -503,8 +503,8 @@ int ecryptfs_encrypt_page(struct page *page)
for (extent_offset = 0; for (extent_offset = 0;
extent_offset < (PAGE_CACHE_SIZE / crypt_stat->extent_size); extent_offset < (PAGE_CACHE_SIZE / crypt_stat->extent_size);
extent_offset++) { extent_offset++) {
rc = ecryptfs_encrypt_extent(enc_extent_page, crypt_stat, page, rc = crypt_extent(enc_extent_page, crypt_stat, page,
extent_offset); extent_offset, ENCRYPT);
if (rc) { if (rc) {
printk(KERN_ERR "%s: Error encrypting extent; " printk(KERN_ERR "%s: Error encrypting extent; "
"rc = [%d]\n", __func__, rc); "rc = [%d]\n", __func__, rc);
@ -531,40 +531,6 @@ out:
return rc; 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 = crypt_page_offset(crypt_stat, page, enc_extent_page,
(extent_offset * crypt_stat->extent_size),
crypt_stat->extent_size, extent_iv, DECRYPT);
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);
goto out;
}
rc = 0;
out:
return rc;
}
/** /**
* ecryptfs_decrypt_page * ecryptfs_decrypt_page
* @page: Page mapped from the eCryptfs inode for the file; data read * @page: Page mapped from the eCryptfs inode for the file; data read
@ -610,8 +576,8 @@ int ecryptfs_decrypt_page(struct page *page)
for (extent_offset = 0; for (extent_offset = 0;
extent_offset < (PAGE_CACHE_SIZE / crypt_stat->extent_size); extent_offset < (PAGE_CACHE_SIZE / crypt_stat->extent_size);
extent_offset++) { extent_offset++) {
rc = ecryptfs_decrypt_extent(page, crypt_stat, page, rc = crypt_extent(page, crypt_stat, page,
extent_offset); extent_offset, DECRYPT);
if (rc) { if (rc) {
printk(KERN_ERR "%s: Error encrypting extent; " printk(KERN_ERR "%s: Error encrypting extent; "
"rc = [%d]\n", __func__, rc); "rc = [%d]\n", __func__, rc);