All of lore.kernel.org
 help / color / mirror / Atom feed
From: Sweet Tea Dorminy <sweettea-kernel@dorminy.me>
To: Chris Mason <clm@fb.com>, Josef Bacik <josef@toxicpanda.com>,
	David Sterba <dsterba@suse.com>,
	"Theodore Y . Ts'o " <tytso@mit.edu>,
	Jaegeuk Kim <jaegeuk@kernel.org>,
	Eric Biggers <ebiggers@kernel.org>,
	linux-fscrypt@vger.kernel.org, linux-btrfs@vger.kernel.org,
	kernel-team@fb.com
Cc: Omar Sandoval <osandov@osandov.com>,
	Sweet Tea Dorminy <sweettea-kernel@dorminy.me>
Subject: [PATCH 09/21] btrfs: factor a fscrypt_name matching method
Date: Wed, 17 Aug 2022 10:49:53 -0400	[thread overview]
Message-ID: <1b11a53ab2979ffcf769d5a883d5f31ac4eb1d03.1660744500.git.sweettea-kernel@dorminy.me> (raw)
In-Reply-To: <cover.1660744500.git.sweettea-kernel@dorminy.me>

From: Omar Sandoval <osandov@osandov.com>

Now that everything in btrfs is dealing in fscrypt_names, fscrypt has a
useful function, fscrypt_match_name(), to check whether a fscrypt_name
matches a provided buffer. However, btrfs buffers are struct
extent_buffer rather than a raw char array, so we need to implement our
own imitation of fscrypt_match_name() that deals in extent_buffers,
falling back to a simple memcpy if fscrypt isn't compiled. We
can then use this matching method in btrfs_match_dir_item_name() and
other locations.

This also provides a useful occasion to introduce the new fscrypt file
for btrfs, handling the fscrypt-specific functions needed.

Signed-off-by: Omar Sandoval <osandov@osandov.com>
Signed-off-by: Sweet Tea Dorminy <sweettea-kernel@dorminy.me>
---
 fs/btrfs/Makefile     |  1 +
 fs/btrfs/dir-item.c   | 13 +++++++------
 fs/btrfs/extent_io.c  | 37 +++++++++++++++++++++++++++++++++++++
 fs/btrfs/extent_io.h  |  2 ++
 fs/btrfs/fscrypt.c    | 32 ++++++++++++++++++++++++++++++++
 fs/btrfs/fscrypt.h    | 25 +++++++++++++++++++++++++
 fs/btrfs/inode-item.c |  8 ++++----
 fs/btrfs/inode.c      | 11 ++++-------
 fs/btrfs/root-tree.c  |  7 ++++---
 9 files changed, 116 insertions(+), 20 deletions(-)
 create mode 100644 fs/btrfs/fscrypt.c
 create mode 100644 fs/btrfs/fscrypt.h

diff --git a/fs/btrfs/Makefile b/fs/btrfs/Makefile
index 99f9995670ea..b6444490cdbc 100644
--- a/fs/btrfs/Makefile
+++ b/fs/btrfs/Makefile
@@ -38,6 +38,7 @@ btrfs-$(CONFIG_BTRFS_FS_CHECK_INTEGRITY) += check-integrity.o
 btrfs-$(CONFIG_BTRFS_FS_REF_VERIFY) += ref-verify.o
 btrfs-$(CONFIG_BLK_DEV_ZONED) += zoned.o
 btrfs-$(CONFIG_FS_VERITY) += verity.o
+btrfs-$(CONFIG_FS_ENCRYPTION) += fscrypt.o
 
 btrfs-$(CONFIG_BTRFS_FS_RUN_SANITY_TESTS) += tests/free-space-tests.o \
 	tests/extent-buffer-tests.o tests/btrfs-tests.o \
diff --git a/fs/btrfs/dir-item.c b/fs/btrfs/dir-item.c
index b4c1e2a40401..8d7c3c32ed8e 100644
--- a/fs/btrfs/dir-item.c
+++ b/fs/btrfs/dir-item.c
@@ -5,6 +5,7 @@
 
 #include "ctree.h"
 #include "disk-io.h"
+#include "fscrypt.h"
 #include "transaction.h"
 
 /*
@@ -390,15 +391,15 @@ struct btrfs_dir_item *btrfs_match_dir_item_name(struct btrfs_fs_info *fs_info,
 
 	total_len = btrfs_item_size(leaf, path->slots[0]);
 	while (cur < total_len) {
-		unsigned long name_ptr = (unsigned long)(dir_item + 1);
-		this_len = sizeof(*dir_item) +
-			btrfs_dir_name_len(leaf, dir_item) +
+		int dir_name_len = btrfs_dir_name_len(leaf, dir_item);
+		this_len = sizeof(*dir_item) + dir_name_len +
 			btrfs_dir_data_len(leaf, dir_item);
 
-		if (btrfs_dir_name_len(leaf, dir_item) == fname_len(fname) &&
-		    memcmp_extent_buffer(leaf, fname_name(fname), name_ptr,
-					 fname_len(fname)) == 0)
+		if (btrfs_fscrypt_match_name(fname, leaf,
+					     (unsigned long)(dir_item + 1),
+					     dir_name_len)) {
 			return dir_item;
+		}
 
 		cur += this_len;
 		dir_item = (struct btrfs_dir_item *)((char *)dir_item +
diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c
index 6e8e936a8a1e..ff2b995ded6e 100644
--- a/fs/btrfs/extent_io.c
+++ b/fs/btrfs/extent_io.c
@@ -1,5 +1,6 @@
 // SPDX-License-Identifier: GPL-2.0
 
+#include <crypto/sha2.h>
 #include <linux/bitops.h>
 #include <linux/slab.h>
 #include <linux/bio.h>
@@ -6956,6 +6957,42 @@ void memzero_extent_buffer(const struct extent_buffer *eb, unsigned long start,
 	}
 }
 
+void extent_buffer_sha256(const struct extent_buffer *eb, unsigned long start,
+			  unsigned long len, u8 *out)
+{
+	size_t cur;
+	size_t offset;
+	struct page *page;
+	char *kaddr;
+	unsigned long i = get_eb_page_index(start);
+	struct sha256_state sctx;
+
+	if (check_eb_range(eb, start, len))
+		return;
+
+	offset = get_eb_offset_in_page(eb, start);
+
+	/*
+	 * TODO: This should maybe be using the crypto API, not the fallback,
+	 * but fscrypt uses the fallback and this is only used in emulation of
+	 * fscrypt's buffer sha256 method.
+	 */
+	sha256_init(&sctx);
+	while (len > 0) {
+		page = eb->pages[i];
+		assert_eb_page_uptodate(eb, page);
+
+		cur = min(len, PAGE_SIZE - offset);
+		kaddr = page_address(page);
+		sha256_update(&sctx, (u8 *)(kaddr + offset), cur);
+
+		len -= cur;
+		offset = 0;
+		i++;
+	}
+	sha256_final(&sctx, out);
+}
+
 void copy_extent_buffer_full(const struct extent_buffer *dst,
 			     const struct extent_buffer *src)
 {
diff --git a/fs/btrfs/extent_io.h b/fs/btrfs/extent_io.h
index 4bc72a87b9a9..b239f6ae2c80 100644
--- a/fs/btrfs/extent_io.h
+++ b/fs/btrfs/extent_io.h
@@ -223,6 +223,8 @@ void memmove_extent_buffer(const struct extent_buffer *dst,
 			   unsigned long len);
 void memzero_extent_buffer(const struct extent_buffer *eb, unsigned long start,
 			   unsigned long len);
+void extent_buffer_sha256(const struct extent_buffer *eb, unsigned long start,
+			  unsigned long len, u8 *out);
 int extent_buffer_test_bit(const struct extent_buffer *eb, unsigned long start,
 			   unsigned long pos);
 void extent_buffer_bitmap_set(const struct extent_buffer *eb, unsigned long start,
diff --git a/fs/btrfs/fscrypt.c b/fs/btrfs/fscrypt.c
new file mode 100644
index 000000000000..2ed844dd61d0
--- /dev/null
+++ b/fs/btrfs/fscrypt.c
@@ -0,0 +1,32 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2020 Facebook
+ */
+
+#include "ctree.h"
+#include "fscrypt.h"
+
+/* fscrypt_match_name() but for an extent_buffer. */
+bool btrfs_fscrypt_match_name(const struct fscrypt_name *fname,
+			      struct extent_buffer *leaf, unsigned long de_name,
+			      u32 de_name_len)
+{
+	const struct fscrypt_nokey_name *nokey_name =
+		(const void *)fname->crypto_buf.name;
+	u8 digest[SHA256_DIGEST_SIZE];
+
+	if (likely(fname->disk_name.name)) {
+		if (de_name_len != fname->disk_name.len)
+			return false;
+		return !memcmp_extent_buffer(leaf, fname->disk_name.name,
+					     de_name, de_name_len);
+	}
+	if (de_name_len <= sizeof(nokey_name->bytes))
+		return false;
+	if (memcmp_extent_buffer(leaf, nokey_name->bytes, de_name,
+				 sizeof(nokey_name->bytes)))
+		return false;
+	extent_buffer_sha256(leaf, de_name + sizeof(nokey_name->bytes),
+			     de_name_len - sizeof(nokey_name->bytes), digest);
+	return !memcmp(digest, nokey_name->sha256, sizeof(digest));
+}
diff --git a/fs/btrfs/fscrypt.h b/fs/btrfs/fscrypt.h
new file mode 100644
index 000000000000..7f24d12e6ee0
--- /dev/null
+++ b/fs/btrfs/fscrypt.h
@@ -0,0 +1,25 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+
+#ifndef BTRFS_FSCRYPT_H
+#define BTRFS_FSCRYPT_H
+
+#include <linux/fscrypt.h>
+
+#ifdef CONFIG_FS_ENCRYPTION
+bool btrfs_fscrypt_match_name(const struct fscrypt_name *fname,
+			      struct extent_buffer *leaf,
+			      unsigned long de_name, u32 de_name_len);
+
+#else
+static bool btrfs_fscrypt_match_name(const struct fscrypt_name *fname,
+				     struct extent_buffer *leaf,
+				     unsigned long de_name, u32 de_name_len)
+{
+	if (de_name_len != fname->disk_name.len)
+		return false;
+	return !memcmp_extent_buffer(leaf, fname->disk_name.name,
+				     de_name, de_name_len);
+}
+#endif
+
+#endif /* BTRFS_FSCRYPT_H */
diff --git a/fs/btrfs/inode-item.c b/fs/btrfs/inode-item.c
index 78053eb9589c..4ad75f9573aa 100644
--- a/fs/btrfs/inode-item.c
+++ b/fs/btrfs/inode-item.c
@@ -7,6 +7,7 @@
 #include "ctree.h"
 #include "inode-item.h"
 #include "disk-io.h"
+#include "fscrypt.h"
 #include "transaction.h"
 #include "print-tree.h"
 
@@ -62,10 +63,9 @@ struct btrfs_inode_extref *btrfs_find_name_in_ext_backref(
 		name_ptr = (unsigned long)(&extref->name);
 		ref_name_len = btrfs_inode_extref_name_len(leaf, extref);
 
-		if (ref_name_len == fname_len(fname) &&
-		    btrfs_inode_extref_parent(leaf, extref) == ref_objectid &&
-		    (memcmp_extent_buffer(leaf, fname_name(fname), name_ptr,
-					  fname_len(fname)) == 0))
+		if (btrfs_inode_extref_parent(leaf, extref) == ref_objectid &&
+		    btrfs_fscrypt_match_name(fname, leaf, name_ptr,
+					     ref_name_len))
 			return extref;
 
 		cur_offset += ref_name_len + sizeof(*extref);
diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index f3861c58309a..016b3fb856ce 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -55,6 +55,7 @@
 #include "zoned.h"
 #include "subpage.h"
 #include "inode-item.h"
+#include "fscrypt.h"
 
 struct btrfs_iget_args {
 	u64 ino;
@@ -5650,14 +5651,10 @@ static int fixup_tree_root_location(struct btrfs_fs_info *fs_info,
 
 	leaf = path->nodes[0];
 	ref = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_root_ref);
-	if (btrfs_root_ref_dirid(leaf, ref) != btrfs_ino(BTRFS_I(dir)) ||
-	    btrfs_root_ref_name_len(leaf, ref) != dentry->d_name.len)
+	if (btrfs_root_ref_dirid(leaf, ref) != btrfs_ino(BTRFS_I(dir)))
 		goto out;
-
-	ret = memcmp_extent_buffer(leaf, dentry->d_name.name,
-				   (unsigned long)(ref + 1),
-				   dentry->d_name.len);
-	if (ret)
+	if (!btrfs_fscrypt_match_name(&fname, leaf, (unsigned long)(ref + 1),
+				      btrfs_root_ref_name_len(leaf, ref)))
 		goto out;
 
 	btrfs_release_path(path);
diff --git a/fs/btrfs/root-tree.c b/fs/btrfs/root-tree.c
index 8eb6cbe19326..47c5572df8b1 100644
--- a/fs/btrfs/root-tree.c
+++ b/fs/btrfs/root-tree.c
@@ -8,6 +8,7 @@
 #include "ctree.h"
 #include "transaction.h"
 #include "disk-io.h"
+#include "fscrypt.h"
 #include "print-tree.h"
 #include "qgroup.h"
 #include "space-info.h"
@@ -352,14 +353,14 @@ int btrfs_del_root_ref(struct btrfs_trans_handle *trans, u64 root_id,
 	if (ret < 0)
 		goto out;
 	if (ret == 0) {
+		u32 name_len;
 		leaf = path->nodes[0];
 		ref = btrfs_item_ptr(leaf, path->slots[0],
 				     struct btrfs_root_ref);
 		ptr = (unsigned long)(ref + 1);
+		name_len = btrfs_root_ref_name_len(leaf, ref);
 		if ((btrfs_root_ref_dirid(leaf, ref) != dirid) ||
-		    (btrfs_root_ref_name_len(leaf, ref) != fname_len(fname)) ||
-		    memcmp_extent_buffer(leaf, fname_name(fname), ptr,
-					 fname_len(fname))) {
+		    !btrfs_fscrypt_match_name(fname, leaf, ptr, name_len)) {
 			err = -ENOENT;
 			goto out;
 		}
-- 
2.35.1


  parent reply	other threads:[~2022-08-17 14:50 UTC|newest]

Thread overview: 26+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-08-17 14:49 [PATCH 00/21] btrfs: add fscrypt integration Sweet Tea Dorminy
2022-08-17 14:49 ` [PATCH 01/21] fscrypt: expose fscrypt_nokey_name Sweet Tea Dorminy
2022-08-17 14:49 ` [PATCH 02/21] fscrypt: add flag allowing partially-encrypted directories Sweet Tea Dorminy
2022-08-17 14:49 ` [PATCH 03/21] fscrypt: add fscrypt_have_same_policy() to check inode's compatibility Sweet Tea Dorminy
2022-08-17 14:49 ` [PATCH 04/21] fscrypt: add a function for a filesystem to generate an IV Sweet Tea Dorminy
2022-08-17 14:49 ` [PATCH 05/21] fscrypt: add new encryption policy for btrfs Sweet Tea Dorminy
2022-08-17 15:54   ` Sweet Tea Dorminy
2022-08-18 22:07     ` Eric Biggers
2022-08-19  0:22       ` Sweet Tea Dorminy
2022-08-20  0:50         ` Eric Biggers
2022-08-17 14:49 ` [PATCH 06/21] btrfs: store directorys' encryption state Sweet Tea Dorminy
2022-08-17 14:49 ` [PATCH 07/21] btrfs: use fscrypt_name's instead of name/len everywhere Sweet Tea Dorminy
2022-08-17 14:49 ` [PATCH 08/21] btrfs: setup fscrypt_names from dentrys using helper Sweet Tea Dorminy
2022-08-17 14:49 ` Sweet Tea Dorminy [this message]
2022-08-17 14:49 ` [PATCH 10/21] btrfs: disable various operations on encrypted inodes Sweet Tea Dorminy
2022-08-17 14:49 ` [PATCH 11/21] btrfs: add fscrypt operation table to superblock Sweet Tea Dorminy
2022-08-17 14:49 ` [PATCH 12/21] btrfs: start using fscrypt hooks Sweet Tea Dorminy
2022-08-17 14:49 ` [PATCH 13/21] btrfs: add fscrypt_context items Sweet Tea Dorminy
2022-08-17 14:49 ` [PATCH 14/21] btrfs: translate btrfs encryption flags and encrypted inode flag Sweet Tea Dorminy
2022-08-17 14:49 ` [PATCH 15/21] btrfs: add iv generation function for fscrypt Sweet Tea Dorminy
2022-08-17 14:50 ` [PATCH 16/21] btrfs: store an IV per encrypted normal file extent Sweet Tea Dorminy
2022-08-17 14:50 ` [PATCH 17/21] btrfs: Add new FEATURE_INCOMPAT_FSCRYPT feature flag Sweet Tea Dorminy
2022-08-17 14:50 ` [PATCH 18/21] btrfs: reuse encrypted filename hash when possible Sweet Tea Dorminy
2022-08-17 14:50 ` [PATCH 19/21] btrfs: adapt directory read and lookup to potentially encrypted filenames Sweet Tea Dorminy
2022-08-17 14:50 ` [PATCH 20/21] btrfs: encrypt normal file extent data if appropriate Sweet Tea Dorminy
2022-08-17 14:50 ` [PATCH 21/21] btrfs: implement fscrypt ioctls Sweet Tea Dorminy

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=1b11a53ab2979ffcf769d5a883d5f31ac4eb1d03.1660744500.git.sweettea-kernel@dorminy.me \
    --to=sweettea-kernel@dorminy.me \
    --cc=clm@fb.com \
    --cc=dsterba@suse.com \
    --cc=ebiggers@kernel.org \
    --cc=jaegeuk@kernel.org \
    --cc=josef@toxicpanda.com \
    --cc=kernel-team@fb.com \
    --cc=linux-btrfs@vger.kernel.org \
    --cc=linux-fscrypt@vger.kernel.org \
    --cc=osandov@osandov.com \
    --cc=tytso@mit.edu \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body. 
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.