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authorEric Sandeen <sandeen@redhat.com>2008-07-28 18:46:39 -0400
committerLinus Torvalds <torvalds@linux-foundation.org>2008-07-28 19:30:21 -0400
commit7fcba054373d5dfc43d26e243a5c9b92069972ee (patch)
tree3503fba122a654946b5455bc95fa3978cbc4f68b /fs
parent25947d5ac56004378d8c2d31ebf22600d5bc0c02 (diff)
eCryptfs: use page_alloc not kmalloc to get a page of memory
With SLUB debugging turned on in 2.6.26, I was getting memory corruption when testing eCryptfs. The root cause turned out to be that eCryptfs was doing kmalloc(PAGE_CACHE_SIZE); virt_to_page() and treating that as a nice page-aligned chunk of memory. But at least with SLUB debugging on, this is not always true, and the page we get from virt_to_page does not necessarily match the PAGE_CACHE_SIZE worth of memory we got from kmalloc. My simple testcase was 2 loops doing "rm -f fileX; cp /tmp/fileX ." for 2 different multi-megabyte files. With this change I no longer see the corruption. Signed-off-by: Eric Sandeen <sandeen@redhat.com> Acked-by: Michael Halcrow <mhalcrow@us.ibm.com> Acked-by: Rik van Riel <riel@redhat.com> Cc: <stable@kernel.org> [2.6.25.x, 2.6.26.x] Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'fs')
-rw-r--r--fs/ecryptfs/crypto.c30
1 files changed, 18 insertions, 12 deletions
diff --git a/fs/ecryptfs/crypto.c b/fs/ecryptfs/crypto.c
index 7b99917ffadc..06db79d05c12 100644
--- a/fs/ecryptfs/crypto.c
+++ b/fs/ecryptfs/crypto.c
@@ -475,8 +475,8 @@ int ecryptfs_encrypt_page(struct page *page)
475{ 475{
476 struct inode *ecryptfs_inode; 476 struct inode *ecryptfs_inode;
477 struct ecryptfs_crypt_stat *crypt_stat; 477 struct ecryptfs_crypt_stat *crypt_stat;
478 char *enc_extent_virt = NULL; 478 char *enc_extent_virt;
479 struct page *enc_extent_page; 479 struct page *enc_extent_page = NULL;
480 loff_t extent_offset; 480 loff_t extent_offset;
481 int rc = 0; 481 int rc = 0;
482 482
@@ -492,14 +492,14 @@ int ecryptfs_encrypt_page(struct page *page)
492 page->index); 492 page->index);
493 goto out; 493 goto out;
494 } 494 }
495 enc_extent_virt = kmalloc(PAGE_CACHE_SIZE, GFP_USER); 495 enc_extent_page = alloc_page(GFP_USER);
496 if (!enc_extent_virt) { 496 if (!enc_extent_page) {
497 rc = -ENOMEM; 497 rc = -ENOMEM;
498 ecryptfs_printk(KERN_ERR, "Error allocating memory for " 498 ecryptfs_printk(KERN_ERR, "Error allocating memory for "
499 "encrypted extent\n"); 499 "encrypted extent\n");
500 goto out; 500 goto out;
501 } 501 }
502 enc_extent_page = virt_to_page(enc_extent_virt); 502 enc_extent_virt = kmap(enc_extent_page);
503 for (extent_offset = 0; 503 for (extent_offset = 0;
504 extent_offset < (PAGE_CACHE_SIZE / crypt_stat->extent_size); 504 extent_offset < (PAGE_CACHE_SIZE / crypt_stat->extent_size);
505 extent_offset++) { 505 extent_offset++) {
@@ -527,7 +527,10 @@ int ecryptfs_encrypt_page(struct page *page)
527 } 527 }
528 } 528 }
529out: 529out:
530 kfree(enc_extent_virt); 530 if (enc_extent_page) {
531 kunmap(enc_extent_page);
532 __free_page(enc_extent_page);
533 }
531 return rc; 534 return rc;
532} 535}
533 536
@@ -609,8 +612,8 @@ int ecryptfs_decrypt_page(struct page *page)
609{ 612{
610 struct inode *ecryptfs_inode; 613 struct inode *ecryptfs_inode;
611 struct ecryptfs_crypt_stat *crypt_stat; 614 struct ecryptfs_crypt_stat *crypt_stat;
612 char *enc_extent_virt = NULL; 615 char *enc_extent_virt;
613 struct page *enc_extent_page; 616 struct page *enc_extent_page = NULL;
614 unsigned long extent_offset; 617 unsigned long extent_offset;
615 int rc = 0; 618 int rc = 0;
616 619
@@ -627,14 +630,14 @@ int ecryptfs_decrypt_page(struct page *page)
627 page->index); 630 page->index);
628 goto out; 631 goto out;
629 } 632 }
630 enc_extent_virt = kmalloc(PAGE_CACHE_SIZE, GFP_USER); 633 enc_extent_page = alloc_page(GFP_USER);
631 if (!enc_extent_virt) { 634 if (!enc_extent_page) {
632 rc = -ENOMEM; 635 rc = -ENOMEM;
633 ecryptfs_printk(KERN_ERR, "Error allocating memory for " 636 ecryptfs_printk(KERN_ERR, "Error allocating memory for "
634 "encrypted extent\n"); 637 "encrypted extent\n");
635 goto out; 638 goto out;
636 } 639 }
637 enc_extent_page = virt_to_page(enc_extent_virt); 640 enc_extent_virt = kmap(enc_extent_page);
638 for (extent_offset = 0; 641 for (extent_offset = 0;
639 extent_offset < (PAGE_CACHE_SIZE / crypt_stat->extent_size); 642 extent_offset < (PAGE_CACHE_SIZE / crypt_stat->extent_size);
640 extent_offset++) { 643 extent_offset++) {
@@ -662,7 +665,10 @@ int ecryptfs_decrypt_page(struct page *page)
662 } 665 }
663 } 666 }
664out: 667out:
665 kfree(enc_extent_virt); 668 if (enc_extent_page) {
669 kunmap(enc_extent_page);
670 __free_page(enc_extent_page);
671 }
666 return rc; 672 return rc;
667} 673}
668 674