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Date: Wed, 23 Jul 2014 14:23:28 -0700
From: Michael Halcrow <mhalcrow@...gle.com>
To: linux-ext4@...r.kernel.org, linux-fsdevel@...r.kernel.org
Cc: zohar@...ux.vnet.ibm.com, mhalcrow@...gle.com,
herbert@...dor.apana.org.au, pavel@....cz, hch@...radead.org,
lczerner@...hat.com, tytso@....edu, tyhicks@...onical.com,
serge.hallyn@...onical.com
Subject: [PATCH 5/5] ext4: Implements real encryption in the EXT4 write and read paths
Implements real encryption in the EXT4 write and read paths.
Signed-off-by: Michael Halcrow <mhalcrow@...gle.com>
---
fs/ext4/crypto.c | 65 +++++++++++++++++++++++---------------------------------
fs/ext4/inode.c | 9 +++++++-
2 files changed, 34 insertions(+), 40 deletions(-)
diff --git a/fs/ext4/crypto.c b/fs/ext4/crypto.c
index 435f33f..a17b23b 100644
--- a/fs/ext4/crypto.c
+++ b/fs/ext4/crypto.c
@@ -353,9 +353,10 @@ struct page *ext4_encrypt(ext4_crypto_ctx_t *ctx, struct page *plaintext_page)
ciphertext_page = ERR_PTR(-ENOMEM);
goto out;
}
- ablkcipher_request_set_callback(req,
- CRYPTO_TFM_REQ_MAY_BACKLOG | CRYPTO_TFM_REQ_MAY_SLEEP,
- ext4_crypt_complete, &ecr);
+ ablkcipher_request_set_callback(
+ req,
+ CRYPTO_TFM_REQ_MAY_BACKLOG | CRYPTO_TFM_REQ_MAY_SLEEP,
+ ext4_crypt_complete, &ecr);
ext4_xts_tweak_for_page(xts_tweak, plaintext_page);
sg_init_table(&dst, 1);
sg_init_table(&src, 1);
@@ -363,20 +364,20 @@ struct page *ext4_encrypt(ext4_crypto_ctx_t *ctx, struct page *plaintext_page)
sg_set_page(&src, plaintext_page, PAGE_CACHE_SIZE, 0);
ablkcipher_request_set_crypt(req, &src, &dst, PAGE_CACHE_SIZE,
xts_tweak);
+ res = crypto_ablkcipher_encrypt(req);
+ if (res == -EINPROGRESS || res == -EBUSY) {
+ BUG_ON(req->base.data != &ecr);
+ wait_for_completion(&ecr.completion);
+ res = ecr.res;
+ reinit_completion(&ecr.completion);
+ }
ablkcipher_request_free(req);
-/* =======
- * TODO(mhalcrow): Removed real crypto so intermediate patch
- * for write path is still fully functional. */
- {
- /* TODO(mhalcrow): Temporary for testing */
- char *ciphertext_virt, *plaintext_virt;
- ciphertext_virt = kmap(ciphertext_page);
- plaintext_virt = kmap(plaintext_page);
- memcpy(ciphertext_virt, plaintext_virt, PAGE_CACHE_SIZE);
- kunmap(plaintext_page);
- kunmap(ciphertext_page);
+ if (res) {
+ printk_ratelimited(KERN_ERR "%s: crypto_ablkcipher_encrypt() "
+ "returned %d\n", __func__, res);
+ ciphertext_page = ERR_PTR(res);
+ goto out;
}
-/* ======= */
SetPageDirty(ciphertext_page);
SetPagePrivate(ciphertext_page);
ctx->control_page = plaintext_page;
@@ -410,9 +411,10 @@ int ext4_decrypt(ext4_crypto_ctx_t *ctx, struct page* page)
res = -ENOMEM;
goto out;
}
- ablkcipher_request_set_callback(req,
- CRYPTO_TFM_REQ_MAY_BACKLOG | CRYPTO_TFM_REQ_MAY_SLEEP,
- ext4_crypt_complete, &ecr);
+ ablkcipher_request_set_callback(
+ req,
+ CRYPTO_TFM_REQ_MAY_BACKLOG | CRYPTO_TFM_REQ_MAY_SLEEP,
+ ext4_crypt_complete, &ecr);
ext4_xts_tweak_for_page(xts_tweak, page);
sg_init_table(&dst, 1);
sg_init_table(&src, 1);
@@ -420,28 +422,13 @@ int ext4_decrypt(ext4_crypto_ctx_t *ctx, struct page* page)
sg_set_page(&src, page, PAGE_CACHE_SIZE, 0);
ablkcipher_request_set_crypt(req, &src, &dst, PAGE_CACHE_SIZE,
xts_tweak);
-/* =======
- * TODO(mhalcrow): Removed real crypto so intermediate patch for read
- * path is still fully functional. For now just doing something that
- * might expose a race condition. */
- {
- char *page_virt;
- char tmp;
- int i;
- page_virt = kmap(page);
- for (i = 0; i < PAGE_CACHE_SIZE / 2; ++i) {
- tmp = page_virt[i];
- page_virt[i] = page_virt[PAGE_CACHE_SIZE - i - 1];
- page_virt[PAGE_CACHE_SIZE - i - 1] = tmp;
- }
- for (i = 0; i < PAGE_CACHE_SIZE / 2; ++i) {
- tmp = page_virt[i];
- page_virt[i] = page_virt[PAGE_CACHE_SIZE - i - 1];
- page_virt[PAGE_CACHE_SIZE - i - 1] = tmp;
- }
- kunmap(page);
+ res = crypto_ablkcipher_decrypt(req);
+ if (res == -EINPROGRESS || res == -EBUSY) {
+ BUG_ON(req->base.data != &ecr);
+ wait_for_completion(&ecr.completion);
+ res = ecr.res;
+ reinit_completion(&ecr.completion);
}
-/* ======= */
ablkcipher_request_free(req);
out:
if (res)
diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index 6bf57d3..a0e80b7 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -2848,6 +2848,8 @@ static void ext4_completion_work(struct work_struct *work)
ext4_crypto_ctx_t *ctx = container_of(work, ext4_crypto_ctx_t, work);
struct page *page = ctx->control_page;
WARN_ON_ONCE(ext4_decrypt(ctx, page));
+ atomic_dec(&ctx->dbg_refcnt);
+ BUG_ON(atomic_read(&ctx->dbg_refcnt) != 0);
ext4_release_crypto_ctx(ctx);
SetPageUptodate(page);
unlock_page(page);
@@ -2859,6 +2861,8 @@ static int ext4_complete_cb(struct bio *bio, int res)
struct page *page = ctx->control_page;
BUG_ON(atomic_read(&ctx->dbg_refcnt) != 1);
if (res) {
+ atomic_dec(&ctx->dbg_refcnt);
+ BUG_ON(atomic_read(&ctx->dbg_refcnt) != 0);
ext4_release_crypto_ctx(ctx);
unlock_page(page);
return res;
@@ -2962,8 +2966,11 @@ static int ext4_read_full_page(struct page *page)
BUG_ON(ctx->control_page);
ctx->control_page = page;
BUG_ON(atomic_read(&ctx->dbg_refcnt) != 1);
- if (submit_bh_cb(READ, bh, ext4_complete_cb, ctx))
+ if (submit_bh_cb(READ, bh, ext4_complete_cb, ctx)) {
+ atomic_dec(&ctx->dbg_refcnt);
+ BUG_ON(atomic_read(&ctx->dbg_refcnt) != 0);
ext4_release_crypto_ctx(ctx);
+ }
}
}
return 0;
--
2.0.0.526.g5318336
--
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