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authorEric Sandeen <sandeen@redhat.com>2008-07-28 15:46:39 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2008-07-28 16:30:21 -0700
commit7fcba054373d5dfc43d26e243a5c9b92069972ee (patch)
tree3503fba122a654946b5455bc95fa3978cbc4f68b
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>
-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 7b99917ffad..06db79d05c1 100644
--- a/fs/ecryptfs/crypto.c
+++ b/fs/ecryptfs/crypto.c
@@ -475,8 +475,8 @@ int ecryptfs_encrypt_page(struct page *page)
{
struct inode *ecryptfs_inode;
struct ecryptfs_crypt_stat *crypt_stat;
- char *enc_extent_virt = NULL;
- struct page *enc_extent_page;
+ char *enc_extent_virt;
+ struct page *enc_extent_page = NULL;
loff_t extent_offset;
int rc = 0;
@@ -492,14 +492,14 @@ int ecryptfs_encrypt_page(struct page *page)
page->index);
goto out;
}
- enc_extent_virt = kmalloc(PAGE_CACHE_SIZE, GFP_USER);
- if (!enc_extent_virt) {
+ enc_extent_page = alloc_page(GFP_USER);
+ if (!enc_extent_page) {
rc = -ENOMEM;
ecryptfs_printk(KERN_ERR, "Error allocating memory for "
"encrypted extent\n");
goto out;
}
- enc_extent_page = virt_to_page(enc_extent_virt);
+ enc_extent_virt = kmap(enc_extent_page);
for (extent_offset = 0;
extent_offset < (PAGE_CACHE_SIZE / crypt_stat->extent_size);
extent_offset++) {
@@ -527,7 +527,10 @@ int ecryptfs_encrypt_page(struct page *page)
}
}
out:
- kfree(enc_extent_virt);
+ if (enc_extent_page) {
+ kunmap(enc_extent_page);
+ __free_page(enc_extent_page);
+ }
return rc;
}
@@ -609,8 +612,8 @@ int ecryptfs_decrypt_page(struct page *page)
{
struct inode *ecryptfs_inode;
struct ecryptfs_crypt_stat *crypt_stat;
- char *enc_extent_virt = NULL;
- struct page *enc_extent_page;
+ char *enc_extent_virt;
+ struct page *enc_extent_page = NULL;
unsigned long extent_offset;
int rc = 0;
@@ -627,14 +630,14 @@ int ecryptfs_decrypt_page(struct page *page)
page->index);
goto out;
}
- enc_extent_virt = kmalloc(PAGE_CACHE_SIZE, GFP_USER);
- if (!enc_extent_virt) {
+ enc_extent_page = alloc_page(GFP_USER);
+ if (!enc_extent_page) {
rc = -ENOMEM;
ecryptfs_printk(KERN_ERR, "Error allocating memory for "
"encrypted extent\n");
goto out;
}
- enc_extent_page = virt_to_page(enc_extent_virt);
+ enc_extent_virt = kmap(enc_extent_page);
for (extent_offset = 0;
extent_offset < (PAGE_CACHE_SIZE / crypt_stat->extent_size);
extent_offset++) {
@@ -662,7 +665,10 @@ int ecryptfs_decrypt_page(struct page *page)
}
}
out:
- kfree(enc_extent_virt);
+ if (enc_extent_page) {
+ kunmap(enc_extent_page);
+ __free_page(enc_extent_page);
+ }
return rc;
}