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Commit 95ea68b4 authored by Theodore Ts'o's avatar Theodore Ts'o
Browse files

ext4 crypto: fix memory leaks in ext4_encrypted_zeroout 



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()
and fix up error handling if mempool_alloc() fails.

Signed-off-by: default avatarTheodore Ts'o <tytso@mit.edu>
parent c936e1ec

fs/ext4/crypto.c

+31 −31
Original line number Original line Diff line number Diff line
@@ -314,6 +314,26 @@ static int ext4_page_crypto(struct ext4_crypto_ctx *ctx, 
	return 0;

	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 (ciphertext_page == NULL)

			return ERR_PTR(-ENOMEM);

		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

 * ext4_encrypt() - Encrypts a page

 * @inode:          The inode for which the encryption should take place

 * @inode:          The inode for which the encryption should take place
@@ -343,28 +363,17 @@ struct page *ext4_encrypt(struct inode *inode, 
		return (struct page *) ctx;

		return (struct page *) ctx;





	/* The encryption operation will require a bounce page. */

	/* The encryption operation will require a bounce page. */

	ciphertext_page = alloc_page(GFP_NOFS);

	ciphertext_page = alloc_bounce_page(ctx);

	if (!ciphertext_page) {

	if (IS_ERR(ciphertext_page))

		/* This is a potential bottleneck, but at least we'll have

		goto errout;

		 * 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;

	ctx->w.control_page = plaintext_page;

	ctx->w.control_page = plaintext_page;

	err = ext4_page_crypto(ctx, inode, EXT4_ENCRYPT, plaintext_page->index,

	err = ext4_page_crypto(ctx, inode, EXT4_ENCRYPT, plaintext_page->index,

			       plaintext_page, ciphertext_page);

			       plaintext_page, ciphertext_page);

	if (err) {

	if (err) {

		ciphertext_page = ERR_PTR(err);

	errout:

		ext4_release_crypto_ctx(ctx);

		ext4_release_crypto_ctx(ctx);

		return ERR_PTR(err);

		return ciphertext_page;

	}

	}

	SetPagePrivate(ciphertext_page);

	SetPagePrivate(ciphertext_page);

	set_page_private(ciphertext_page, (unsigned long)ctx);

	set_page_private(ciphertext_page, (unsigned long)ctx);
@@ -424,21 +433,11 @@ int ext4_encrypted_zeroout(struct inode *inode, struct ext4_extent *ex) 
	if (IS_ERR(ctx))

	if (IS_ERR(ctx))

		return PTR_ERR(ctx);

		return PTR_ERR(ctx);





	ciphertext_page = alloc_page(GFP_NOFS);

	ciphertext_page = alloc_bounce_page(ctx);

	if (!ciphertext_page) {

	if (IS_ERR(ciphertext_page)) {

		/* This is a potential bottleneck, but at least we'll have

		err = PTR_ERR(ciphertext_page);

		 * forward progress. */

		goto errout;

		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;





	while (len--) {

	while (len--) {

		err = ext4_page_crypto(ctx, inode, EXT4_ENCRYPT, lblk,

		err = ext4_page_crypto(ctx, inode, EXT4_ENCRYPT, lblk,
@@ -460,6 +459,7 @@ int ext4_encrypted_zeroout(struct inode *inode, struct ext4_extent *ex) 
			goto errout;

			goto errout;

		}

		}

		err = submit_bio_wait(WRITE, bio);

		err = submit_bio_wait(WRITE, bio);

		bio_put(bio);

		if (err)

		if (err)

			goto errout;

			goto errout;

	}

	}