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Ts'o" , Jaegeuk Kim , Eric Biggers , Chris Mason , Josef Bacik , David Sterba , linux-fscrypt@vger.kernel.org, linux-btrfs@vger.kernel.org, kernel-team@fb.com Cc: Omar Sandoval , Sweet Tea Dorminy Subject: [PATCH v2 10/20] btrfs: factor a fscrypt_name matching method Date: Mon, 5 Sep 2022 20:35:25 -0400 Message-Id: <685c8abce7bdb110bc306752314b4fb0e7867290.1662420176.git.sweettea-kernel@dorminy.me> In-Reply-To: References: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-fscrypt@vger.kernel.org From: Omar Sandoval 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 Signed-off-by: Sweet Tea Dorminy --- 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 591c191a58bc..a467a7553bd9 100644 --- a/fs/btrfs/extent_io.c +++ b/fs/btrfs/extent_io.c @@ -1,5 +1,6 @@ // SPDX-License-Identifier: GPL-2.0 +#include #include #include #include @@ -6892,6 +6893,42 @@ 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 69a86ae6fd50..d6c1b91cd690 100644 --- a/fs/btrfs/extent_io.h +++ b/fs/btrfs/extent_io.h @@ -222,6 +222,8 @@ 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 + +#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 761293d763b6..482c5b3d9e70 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; @@ -5646,14 +5647,10 @@ 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 f44f02c22027..bbb215007896 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" @@ -351,14 +352,14 @@ int btrfs_del_root_ref(struct btrfs_trans_handle *trans, u64 root_id, if (ret < 0) { goto out; } else 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)) { ret = -ENOENT; goto out; } -- 2.35.1