Merge branch 'fscrypt' into origin

7 files changed, 124 insertions, 85 deletions

diff --git a/fs/crypto/crypto.c b/fs/crypto/crypto.c
index 98f87fe8f186..b6029785714c 100644
--- a/fs/crypto/crypto.c
+++ b/fs/crypto/crypto.c
@@ -88,7 +88,7 @@ EXPORT_SYMBOL(fscrypt_release_ctx);
  * Return: An allocated and initialized encryption context on success; error
  * value or NULL otherwise.
  */
-struct fscrypt_ctx *fscrypt_get_ctx(struct inode *inode, gfp_t gfp_flags)
+struct fscrypt_ctx *fscrypt_get_ctx(const struct inode *inode, gfp_t gfp_flags)
 {
 	struct fscrypt_ctx *ctx = NULL;
 	struct fscrypt_info *ci = inode->i_crypt_info;
@@ -146,9 +146,10 @@ typedef enum {
 	FS_ENCRYPT,
 } fscrypt_direction_t;
 
-static int do_page_crypto(struct inode *inode,
+static int do_page_crypto(const struct inode *inode,
 			fscrypt_direction_t rw, pgoff_t index,
 			struct page *src_page, struct page *dest_page,
+			unsigned int src_len, unsigned int src_offset,
 			gfp_t gfp_flags)
 {
 	struct {
@@ -179,10 +180,10 @@ static int do_page_crypto(struct inode *inode,
 	memset(xts_tweak.padding, 0, sizeof(xts_tweak.padding));
 
 	sg_init_table(&dst, 1);
-	sg_set_page(&dst, dest_page, PAGE_SIZE, 0);
+	sg_set_page(&dst, dest_page, src_len, src_offset);
 	sg_init_table(&src, 1);
-	sg_set_page(&src, src_page, PAGE_SIZE, 0);
-	skcipher_request_set_crypt(req, &src, &dst, PAGE_SIZE, &xts_tweak);
+	sg_set_page(&src, src_page, src_len, src_offset);
+	skcipher_request_set_crypt(req, &src, &dst, src_len, &xts_tweak);
 	if (rw == FS_DECRYPT)
 		res = crypto_skcipher_decrypt(req);
 	else
@@ -213,12 +214,17 @@ static struct page *alloc_bounce_page(struct fscrypt_ctx *ctx, gfp_t gfp_flags)
 
 /**
  * fscypt_encrypt_page() - Encrypts a page
- * @inode:          The inode for which the encryption should take place
- * @plaintext_page: The page to encrypt. Must be locked.
- * @gfp_flags:      The gfp flag for memory allocation
+ * @inode:            The inode for which the encryption should take place
+ * @plaintext_page:   The page to encrypt. Must be locked.
+ * @plaintext_len:    Length of plaintext within page
+ * @plaintext_offset: Offset of plaintext within page
+ * @index:            Index for encryption. This is mainly the page index, but
+ *                    but might be different for multiple calls on same page.
+ * @gfp_flags:        The gfp flag for memory allocation
  *
- * Allocates a ciphertext page and encrypts plaintext_page into it using the ctx
- * encryption context.
+ * Encrypts plaintext_page using the ctx encryption context. If
+ * the filesystem supports it, encryption is performed in-place, otherwise a
+ * new ciphertext_page is allocated and returned.
  *
  * Called on the page write path.  The caller must call
  * fscrypt_restore_control_page() on the returned ciphertext page to
@@ -227,35 +233,44 @@ static struct page *alloc_bounce_page(struct fscrypt_ctx *ctx, gfp_t gfp_flags)
  * Return: An allocated page with the encrypted content on success. Else, an
  * error value or NULL.
  */
-struct page *fscrypt_encrypt_page(struct inode *inode,
-				struct page *plaintext_page, gfp_t gfp_flags)
+struct page *fscrypt_encrypt_page(const struct inode *inode,
+				struct page *plaintext_page,
+				unsigned int plaintext_len,
+				unsigned int plaintext_offset,
+				pgoff_t index, gfp_t gfp_flags)
+
 {
 	struct fscrypt_ctx *ctx;
-	struct page *ciphertext_page = NULL;
+	struct page *ciphertext_page = plaintext_page;
 	int err;
 
-	BUG_ON(!PageLocked(plaintext_page));
+	BUG_ON(plaintext_len % FS_CRYPTO_BLOCK_SIZE != 0);
 
 	ctx = fscrypt_get_ctx(inode, gfp_flags);
 	if (IS_ERR(ctx))
 		return (struct page *)ctx;
 
-	/* The encryption operation will require a bounce page. */
-	ciphertext_page = alloc_bounce_page(ctx, gfp_flags);
-	if (IS_ERR(ciphertext_page))
-		goto errout;
+	if (!(inode->i_sb->s_cop->flags & FS_CFLG_INPLACE_ENCRYPTION)) {
+		/* The encryption operation will require a bounce page. */
+		ciphertext_page = alloc_bounce_page(ctx, gfp_flags);
+		if (IS_ERR(ciphertext_page))
+			goto errout;
+	}
 
 	ctx->w.control_page = plaintext_page;
-	err = do_page_crypto(inode, FS_ENCRYPT, plaintext_page->index,
+	err = do_page_crypto(inode, FS_ENCRYPT, index,
 					plaintext_page, ciphertext_page,
+					plaintext_len, plaintext_offset,
 					gfp_flags);
 	if (err) {
 		ciphertext_page = ERR_PTR(err);
 		goto errout;
 	}
-	SetPagePrivate(ciphertext_page);
-	set_page_private(ciphertext_page, (unsigned long)ctx);
-	lock_page(ciphertext_page);
+	if (!(inode->i_sb->s_cop->flags & FS_CFLG_INPLACE_ENCRYPTION)) {
+		SetPagePrivate(ciphertext_page);
+		set_page_private(ciphertext_page, (unsigned long)ctx);
+		lock_page(ciphertext_page);
+	}
 	return ciphertext_page;
 
 errout:
@@ -265,8 +280,12 @@ errout:
 EXPORT_SYMBOL(fscrypt_encrypt_page);
 
 /**
- * f2crypt_decrypt_page() - Decrypts a page in-place
- * @page: The page to decrypt. Must be locked.
+ * fscrypt_decrypt_page() - Decrypts a page in-place
+ * @inode: Encrypted inode to decrypt.
+ * @page:  The page to decrypt. Must be locked.
+ * @len:   Number of bytes in @page to be decrypted.
+ * @offs:  Start of data in @page.
+ * @index: Index for encryption.
  *
  * Decrypts page in-place using the ctx encryption context.
  *
@@ -274,16 +293,15 @@ EXPORT_SYMBOL(fscrypt_encrypt_page);
  *
  * Return: Zero on success, non-zero otherwise.
  */
-int fscrypt_decrypt_page(struct page *page)
+int fscrypt_decrypt_page(const struct inode *inode, struct page *page,
+			unsigned int len, unsigned int offs, pgoff_t index)
 {
-	BUG_ON(!PageLocked(page));
-
-	return do_page_crypto(page->mapping->host,
-			FS_DECRYPT, page->index, page, page, GFP_NOFS);
+	return do_page_crypto(inode, FS_DECRYPT, page->index, page, page, len, offs,
+			GFP_NOFS);
 }
 EXPORT_SYMBOL(fscrypt_decrypt_page);
 
-int fscrypt_zeroout_range(struct inode *inode, pgoff_t lblk,
+int fscrypt_zeroout_range(const struct inode *inode, pgoff_t lblk,
 				sector_t pblk, unsigned int len)
 {
 	struct fscrypt_ctx *ctx;
@@ -306,7 +324,7 @@ int fscrypt_zeroout_range(struct inode *inode, pgoff_t lblk,
 	while (len--) {
 		err = do_page_crypto(inode, FS_ENCRYPT, lblk,
 					ZERO_PAGE(0), ciphertext_page,
-					GFP_NOFS);
+					PAGE_SIZE, 0, GFP_NOFS);
 		if (err)
 			goto errout;
 
@@ -414,7 +432,8 @@ static void completion_pages(struct work_struct *work)
 
 	bio_for_each_segment_all(bv, bio, i) {
 		struct page *page = bv->bv_page;
-		int ret = fscrypt_decrypt_page(page);
+		int ret = fscrypt_decrypt_page(page->mapping->host, page,
+				PAGE_SIZE, 0, page->index);
 
 		if (ret) {
 			WARN_ON_ONCE(1);
diff --git a/fs/crypto/fname.c b/fs/crypto/fname.c
index 9a28133ac3b8..6b45d9caeeb0 100644
--- a/fs/crypto/fname.c
+++ b/fs/crypto/fname.c
@@ -39,65 +39,54 @@ static void fname_crypt_complete(struct crypto_async_request *req, int res)
 static int fname_encrypt(struct inode *inode,
 			const struct qstr *iname, struct fscrypt_str *oname)
 {
-	u32 ciphertext_len;
 	struct skcipher_request *req = NULL;
 	DECLARE_FS_COMPLETION_RESULT(ecr);
 	struct fscrypt_info *ci = inode->i_crypt_info;
 	struct crypto_skcipher *tfm = ci->ci_ctfm;
 	int res = 0;
 	char iv[FS_CRYPTO_BLOCK_SIZE];
-	struct scatterlist src_sg, dst_sg;
+	struct scatterlist sg;
 	int padding = 4 << (ci->ci_flags & FS_POLICY_FLAGS_PAD_MASK);
-	char *workbuf, buf[32], *alloc_buf = NULL;
-	unsigned lim;
+	unsigned int lim;
+	unsigned int cryptlen;
 
 	lim = inode->i_sb->s_cop->max_namelen(inode);
 	if (iname->len <= 0 || iname->len > lim)
 		return -EIO;
 
-	ciphertext_len = max(iname->len, (u32)FS_CRYPTO_BLOCK_SIZE);
-	ciphertext_len = round_up(ciphertext_len, padding);
-	ciphertext_len = min(ciphertext_len, lim);
+	/*
+	 * Copy the filename to the output buffer for encrypting in-place and
+	 * pad it with the needed number of NUL bytes.
+	 */
+	cryptlen = max_t(unsigned int, iname->len, FS_CRYPTO_BLOCK_SIZE);
+	cryptlen = round_up(cryptlen, padding);
+	cryptlen = min(cryptlen, lim);
+	memcpy(oname->name, iname->name, iname->len);
+	memset(oname->name + iname->len, 0, cryptlen - iname->len);
 
-	if (ciphertext_len <= sizeof(buf)) {
-		workbuf = buf;
-	} else {
-		alloc_buf = kmalloc(ciphertext_len, GFP_NOFS);
-		if (!alloc_buf)
-			return -ENOMEM;
-		workbuf = alloc_buf;
-	}
+	/* Initialize the IV */
+	memset(iv, 0, FS_CRYPTO_BLOCK_SIZE);
 
-	/* Allocate request */
+	/* Set up the encryption request */
 	req = skcipher_request_alloc(tfm, GFP_NOFS);
 	if (!req) {
 		printk_ratelimited(KERN_ERR
-			"%s: crypto_request_alloc() failed\n", __func__);
-		kfree(alloc_buf);
+			"%s: skcipher_request_alloc() failed\n", __func__);
 		return -ENOMEM;
 	}
 	skcipher_request_set_callback(req,
 			CRYPTO_TFM_REQ_MAY_BACKLOG | CRYPTO_TFM_REQ_MAY_SLEEP,
 			fname_crypt_complete, &ecr);
+	sg_init_one(&sg, oname->name, cryptlen);
+	skcipher_request_set_crypt(req, &sg, &sg, cryptlen, iv);
 
-	/* Copy the input */
-	memcpy(workbuf, iname->name, iname->len);
-	if (iname->len < ciphertext_len)
-		memset(workbuf + iname->len, 0, ciphertext_len - iname->len);
-
-	/* Initialize IV */
-	memset(iv, 0, FS_CRYPTO_BLOCK_SIZE);
-
-	/* Create encryption request */
-	sg_init_one(&src_sg, workbuf, ciphertext_len);
-	sg_init_one(&dst_sg, oname->name, ciphertext_len);
-	skcipher_request_set_crypt(req, &src_sg, &dst_sg, ciphertext_len, iv);
+	/* Do the encryption */
 	res = crypto_skcipher_encrypt(req);
 	if (res == -EINPROGRESS || res == -EBUSY) {
+		/* Request is being completed asynchronously; wait for it */
 		wait_for_completion(&ecr.completion);
 		res = ecr.res;
 	}
-	kfree(alloc_buf);
 	skcipher_request_free(req);
 	if (res < 0) {
 		printk_ratelimited(KERN_ERR
@@ -105,7 +94,7 @@ static int fname_encrypt(struct inode *inode,
 		return res;
 	}
 
-	oname->len = ciphertext_len;
+	oname->len = cryptlen;
 	return 0;
 }
 
@@ -220,7 +209,7 @@ static int digest_decode(const char *src, int len, char *dst)
 	return cp - dst;
 }
 
-u32 fscrypt_fname_encrypted_size(struct inode *inode, u32 ilen)
+u32 fscrypt_fname_encrypted_size(const struct inode *inode, u32 ilen)
 {
 	int padding = 32;
 	struct fscrypt_info *ci = inode->i_crypt_info;
@@ -238,7 +227,7 @@ EXPORT_SYMBOL(fscrypt_fname_encrypted_size);
  * Allocates an output buffer that is sufficient for the crypto operation
  * specified by the context and the direction.
  */
-int fscrypt_fname_alloc_buffer(struct inode *inode,
+int fscrypt_fname_alloc_buffer(const struct inode *inode,
 				u32 ilen, struct fscrypt_str *crypto_str)
 {
 	unsigned int olen = fscrypt_fname_encrypted_size(inode, ilen);
diff --git a/fs/crypto/keyinfo.c b/fs/crypto/keyinfo.c
index 82f0285f5d08..67fb6d8876d0 100644
--- a/fs/crypto/keyinfo.c
+++ b/fs/crypto/keyinfo.c
@@ -185,7 +185,7 @@ int get_crypt_info(struct inode *inode)
 	struct crypto_skcipher *ctfm;
 	const char *cipher_str;
 	int keysize;
-	u8 raw_key[FS_MAX_KEY_SIZE];
+	u8 *raw_key = NULL;
 	int res;
 
 	res = fscrypt_initialize();
@@ -238,6 +238,15 @@ retry:
 	if (res)
 		goto out;
 
+	/*
+	 * This cannot be a stack buffer because it is passed to the scatterlist
+	 * crypto API as part of key derivation.
+	 */
+	res = -ENOMEM;
+	raw_key = kmalloc(FS_MAX_KEY_SIZE, GFP_NOFS);
+	if (!raw_key)
+		goto out;
+
 	if (fscrypt_dummy_context_enabled(inode)) {
 		memset(raw_key, 0x42, FS_AES_256_XTS_KEY_SIZE);
 		goto got_key;
@@ -276,7 +285,8 @@ got_key:
 	if (res)
 		goto out;
 
-	memzero_explicit(raw_key, sizeof(raw_key));
+	kzfree(raw_key);
+	raw_key = NULL;
 	if (cmpxchg(&inode->i_crypt_info, NULL, crypt_info) != NULL) {
 		put_crypt_info(crypt_info);
 		goto retry;
@@ -287,7 +297,7 @@ out:
 	if (res == -ENOKEY)
 		res = 0;
 	put_crypt_info(crypt_info);
-	memzero_explicit(raw_key, sizeof(raw_key));
+	kzfree(raw_key);
 	return res;
 }
 
diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index 3d58b2b477e8..48fbdfc43c10 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -1169,7 +1169,8 @@ static int ext4_block_write_begin(struct page *page, loff_t pos, unsigned len,
 	if (unlikely(err))
 		page_zero_new_buffers(page, from, to);
 	else if (decrypt)
-		err = fscrypt_decrypt_page(page);
+		err = fscrypt_decrypt_page(page->mapping->host, page,
+				PAGE_SIZE, 0, page->index);
 	return err;
 }
 #endif
@@ -3746,7 +3747,9 @@ static int __ext4_block_zero_page_range(handle_t *handle,
 			/* We expect the key to be set. */
 			BUG_ON(!fscrypt_has_encryption_key(inode));
 			BUG_ON(blocksize != PAGE_SIZE);
-			WARN_ON_ONCE(fscrypt_decrypt_page(page));
+			BUG_ON(!PageLocked(page));
+			WARN_ON_ONCE(fscrypt_decrypt_page(page->mapping->host,
+						page, PAGE_SIZE, 0, page->index));
 		}
 	}
 	if (ext4_should_journal_data(inode)) {
diff --git a/fs/ext4/page-io.c b/fs/ext4/page-io.c
index 0094923e5ebf..902a3e3059b3 100644
--- a/fs/ext4/page-io.c
+++ b/fs/ext4/page-io.c
@@ -470,7 +470,8 @@ int ext4_bio_write_page(struct ext4_io_submit *io,
 		gfp_t gfp_flags = GFP_NOFS;
 
 	retry_encrypt:
-		data_page = fscrypt_encrypt_page(inode, page, gfp_flags);
+		data_page = fscrypt_encrypt_page(inode, page, PAGE_SIZE, 0,
+						page->index, gfp_flags);
 		if (IS_ERR(data_page)) {
 			ret = PTR_ERR(data_page);
 			if (ret == -ENOMEM && wbc->sync_mode == WB_SYNC_ALL) {
diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
index 9ae194fd2fdb..435590c4b341 100644
--- a/fs/f2fs/data.c
+++ b/fs/f2fs/data.c
@@ -1194,8 +1194,11 @@ int do_write_data_page(struct f2fs_io_info *fio)
 		f2fs_wait_on_encrypted_page_writeback(F2FS_I_SB(inode),
 							fio->old_blkaddr);
 retry_encrypt:
+		BUG_ON(!PageLocked(fio->page));
 		fio->encrypted_page = fscrypt_encrypt_page(inode, fio->page,
-								gfp_flags);
+							PAGE_SIZE, 0,
+							fio->page->index,
+							gfp_flags);
 		if (IS_ERR(fio->encrypted_page)) {
 			err = PTR_ERR(fio->encrypted_page);
 			if (err == -ENOMEM) {
diff --git a/include/linux/fscrypto.h b/include/linux/fscrypto.h
index ff8b11b26f31..98c71e973a96 100644
--- a/include/linux/fscrypto.h
+++ b/include/linux/fscrypto.h
@@ -154,9 +154,15 @@ struct fscrypt_name {
 #define fname_len(p)		((p)->disk_name.len)
 
 /*
+ * fscrypt superblock flags
+ */
+#define FS_CFLG_INPLACE_ENCRYPTION (1U << 1)
+
+/*
  * crypto opertions for filesystems
  */
 struct fscrypt_operations {
+	unsigned int flags;
 	int (*get_context)(struct inode *, void *, size_t);
 	int (*key_prefix)(struct inode *, u8 **);
 	int (*prepare_context)(struct inode *);
@@ -206,7 +212,7 @@ static inline struct page *fscrypt_control_page(struct page *page)
 #endif
 }
 
-static inline int fscrypt_has_encryption_key(struct inode *inode)
+static inline int fscrypt_has_encryption_key(const struct inode *inode)
 {
 #if IS_ENABLED(CONFIG_FS_ENCRYPTION)
 	return (inode->i_crypt_info != NULL);
@@ -240,14 +246,17 @@ static inline void fscrypt_set_d_op(struct dentry *dentry)
 extern struct kmem_cache *fscrypt_info_cachep;
 int fscrypt_initialize(void);
 
-extern struct fscrypt_ctx *fscrypt_get_ctx(struct inode *, gfp_t);
+extern struct fscrypt_ctx *fscrypt_get_ctx(const struct inode *, gfp_t);
 extern void fscrypt_release_ctx(struct fscrypt_ctx *);
-extern struct page *fscrypt_encrypt_page(struct inode *, struct page *, gfp_t);
-extern int fscrypt_decrypt_page(struct page *);
+extern struct page *fscrypt_encrypt_page(const struct inode *, struct page *,
+						unsigned int, unsigned int,
+						pgoff_t, gfp_t);
+extern int fscrypt_decrypt_page(const struct inode *, struct page *, unsigned int,
+				unsigned int, pgoff_t);
 extern void fscrypt_decrypt_bio_pages(struct fscrypt_ctx *, struct bio *);
 extern void fscrypt_pullback_bio_page(struct page **, bool);
 extern void fscrypt_restore_control_page(struct page *);
-extern int fscrypt_zeroout_range(struct inode *, pgoff_t, sector_t,
+extern int fscrypt_zeroout_range(const struct inode *, pgoff_t, sector_t,
 						unsigned int);
 /* policy.c */
 extern int fscrypt_process_policy(struct file *, const struct fscrypt_policy *);
@@ -264,8 +273,8 @@ extern void fscrypt_put_encryption_info(struct inode *, struct fscrypt_info *);
 extern int fscrypt_setup_filename(struct inode *, const struct qstr *,
 				int lookup, struct fscrypt_name *);
 extern void fscrypt_free_filename(struct fscrypt_name *);
-extern u32 fscrypt_fname_encrypted_size(struct inode *, u32);
-extern int fscrypt_fname_alloc_buffer(struct inode *, u32,
+extern u32 fscrypt_fname_encrypted_size(const struct inode *, u32);
+extern int fscrypt_fname_alloc_buffer(const struct inode *, u32,
 				struct fscrypt_str *);
 extern void fscrypt_fname_free_buffer(struct fscrypt_str *);
 extern int fscrypt_fname_disk_to_usr(struct inode *, u32, u32,
@@ -275,7 +284,7 @@ extern int fscrypt_fname_usr_to_disk(struct inode *, const struct qstr *,
 #endif
 
 /* crypto.c */
-static inline struct fscrypt_ctx *fscrypt_notsupp_get_ctx(struct inode *i,
+static inline struct fscrypt_ctx *fscrypt_notsupp_get_ctx(const struct inode *i,
 							gfp_t f)
 {
 	return ERR_PTR(-EOPNOTSUPP);
@@ -286,13 +295,18 @@ static inline void fscrypt_notsupp_release_ctx(struct fscrypt_ctx *c)
 	return;
 }
 
-static inline struct page *fscrypt_notsupp_encrypt_page(struct inode *i,
-						struct page *p, gfp_t f)
+static inline struct page *fscrypt_notsupp_encrypt_page(const struct inode *i,
+						struct page *p,
+						unsigned int len,
+						unsigned int offs,
+						pgoff_t index, gfp_t f)
 {
 	return ERR_PTR(-EOPNOTSUPP);
 }
 
-static inline int fscrypt_notsupp_decrypt_page(struct page *p)
+static inline int fscrypt_notsupp_decrypt_page(const struct inode *i, struct page *p,
+						unsigned int len, unsigned int offs,
+						pgoff_t index)
 {
 	return -EOPNOTSUPP;
 }
@@ -313,7 +327,7 @@ static inline void fscrypt_notsupp_restore_control_page(struct page *p)
 	return;
 }
 
-static inline int fscrypt_notsupp_zeroout_range(struct inode *i, pgoff_t p,
+static inline int fscrypt_notsupp_zeroout_range(const struct inode *i, pgoff_t p,
 					sector_t s, unsigned int f)
 {
 	return -EOPNOTSUPP;