[PATCH 1/8] ext4 crypto: fix memory leaks in ext4_encrypted_zeroout

Theodore Ts'o
2015-05-28T23:47:57Z

ext4_encrypted_zeroout() could end up leaking a bio and bounce page.
Fortunately it's not used much. While we're fixing things up,
refactor out common code into the static function alloc_bounce_page().

Signed-off-by: Theodore Ts'o <tytso@mit.edu>
---
fs/ext4/crypto.c | 56 +++++++++++++++++++++++++-------------------------------
1 file changed, 25 insertions(+), 31 deletions(-)

diff --git a/fs/ext4/crypto.c b/fs/ext4/crypto.c
index 68c7ab8..e43ed93 100644
--- a/fs/ext4/crypto.c
+++ b/fs/ext4/crypto.c
@@ -324,6 +324,28 @@ static int ext4_page_crypto(struct ext4_crypto_ctx *ctx,
return 0;
}

+static struct page *alloc_bounce_page(struct ext4_crypto_ctx *ctx)
+{
+ struct page *ciphertext_page = alloc_page(GFP_NOFS);
+
+ if (!ciphertext_page) {
+ /* This is a potential bottleneck, but at least we'll have
+ * forward progress. */
+ ciphertext_page = mempool_alloc(ext4_bounce_page_pool,
+ GFP_NOFS);
+ if (WARN_ON_ONCE(!ciphertext_page)) {
+ ciphertext_page = mempool_alloc(ext4_bounce_page_pool,
+ GFP_NOFS | __GFP_WAIT);
+ }
+ ctx->flags &= ~EXT4_BOUNCE_PAGE_REQUIRES_FREE_ENCRYPT_FL;
+ } else {
+ ctx->flags |= EXT4_BOUNCE_PAGE_REQUIRES_FREE_ENCRYPT_FL;
+ }
+ ctx->flags |= EXT4_WRITE_PATH_FL;
+ ctx->w.bounce_page = ciphertext_page;
+ return ciphertext_page;
+}
+
/**
* ext4_encrypt() - Encrypts a page
* @inode: The inode for which the encryption should take place
@@ -353,22 +375,7 @@ struct page *ext4_encrypt(struct inode *inode,
return (struct page *) ctx;

/* The encryption operation will require a bounce page. */
- ciphertext_page = alloc_page(GFP_NOFS);
- if (!ciphertext_page) {
- /* This is a potential bottleneck, but at least we'll have
- * forward progress. */
- ciphertext_page = mempool_alloc(ext4_bounce_page_pool,
- GFP_NOFS);
- if (WARN_ON_ONCE(!ciphertext_page)) {
- ciphertext_page = mempool_alloc(ext4_bounce_page_pool,
- GFP_NOFS | __GFP_WAIT);
- }
- ctx->flags &= ~EXT4_BOUNCE_PAGE_REQUIRES_FREE_ENCRYPT_FL;
- } else {
- ctx->flags |= EXT4_BOUNCE_PAGE_REQUIRES_FREE_ENCRYPT_FL;
- }
- ctx->flags |= EXT4_WRITE_PATH_FL;
- ctx->w.bounce_page = ciphertext_page;
+ ciphertext_page = alloc_bounce_page(ctx);
ctx->w.control_page = plaintext_page;
err = ext4_page_crypto(ctx, inode, EXT4_ENCRYPT, plaintext_page->index,
plaintext_page, ciphertext_page);
@@ -434,21 +441,7 @@ int ext4_encrypted_zeroout(struct inode *inode, struct ext4_extent *ex)
if (IS_ERR(ctx))
return PTR_ERR(ctx);

- ciphertext_page = alloc_page(GFP_NOFS);
- if (!ciphertext_page) {
- /* This is a potential bottleneck, but at least we'll have
- * forward progress. */
- ciphertext_page = mempool_alloc(ext4_bounce_page_pool,
- GFP_NOFS);
- if (WARN_ON_ONCE(!ciphertext_page)) {
- ciphertext_page = mempool_alloc(ext4_bounce_page_pool,
- GFP_NOFS | __GFP_WAIT);
- }
- ctx->flags &= ~EXT4_BOUNCE_PAGE_REQUIRES_FREE_ENCRYPT_FL;
- } else {
- ctx->flags |= EXT4_BOUNCE_PAGE_REQUIRES_FREE_ENCRYPT_FL;
- }
- ctx->w.bounce_page = ciphertext_page;
+ ciphertext_page = alloc_bounce_page(ctx);

while (len--) {
err = ext4_page_crypto(ctx, inode, EXT4_ENCRYPT, lblk,
@@ -470,6 +463,7 @@ int ext4_encrypted_zeroout(struct inode *inode, struct ext4_extent *ex)
goto errout;
}
err = submit_bio_wait(WRITE, bio);
+ bio_put(bio);
if (err)
goto errout;
}
--
2.3.0