diff options
Diffstat (limited to 'fs/ext4')
| -rw-r--r-- | fs/ext4/Makefile | 1 | ||||
| -rw-r--r-- | fs/ext4/ext4.h | 23 | ||||
| -rw-r--r-- | fs/ext4/file.c | 4 | ||||
| -rw-r--r-- | fs/ext4/inode.c | 55 | ||||
| -rw-r--r-- | fs/ext4/ioctl.c | 13 | ||||
| -rw-r--r-- | fs/ext4/readpage.c | 211 | ||||
| -rw-r--r-- | fs/ext4/super.c | 18 | ||||
| -rw-r--r-- | fs/ext4/sysfs.c | 6 | ||||
| -rw-r--r-- | fs/ext4/verity.c | 367 |
9 files changed, 645 insertions, 53 deletions
diff --git a/fs/ext4/Makefile b/fs/ext4/Makefile index 8fdfcd3c3e04..b17ddc229ac5 100644 --- a/fs/ext4/Makefile +++ b/fs/ext4/Makefile @@ -13,3 +13,4 @@ ext4-y := balloc.o bitmap.o block_validity.o dir.o ext4_jbd2.o extents.o \ ext4-$(CONFIG_EXT4_FS_POSIX_ACL) += acl.o ext4-$(CONFIG_EXT4_FS_SECURITY) += xattr_security.o +ext4-$(CONFIG_FS_VERITY) += verity.o diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h index bf660aa7a9e0..9c7f4036021b 100644 --- a/fs/ext4/ext4.h +++ b/fs/ext4/ext4.h @@ -41,6 +41,7 @@ #endif #include <linux/fscrypt.h> +#include <linux/fsverity.h> #include <linux/compiler.h> @@ -395,6 +396,7 @@ struct flex_groups { #define EXT4_TOPDIR_FL 0x00020000 /* Top of directory hierarchies*/ #define EXT4_HUGE_FILE_FL 0x00040000 /* Set to each huge file */ #define EXT4_EXTENTS_FL 0x00080000 /* Inode uses extents */ +#define EXT4_VERITY_FL 0x00100000 /* Verity protected inode */ #define EXT4_EA_INODE_FL 0x00200000 /* Inode used for large EA */ #define EXT4_EOFBLOCKS_FL 0x00400000 /* Blocks allocated beyond EOF */ #define EXT4_INLINE_DATA_FL 0x10000000 /* Inode has inline data. */ @@ -402,7 +404,7 @@ struct flex_groups { #define EXT4_CASEFOLD_FL 0x40000000 /* Casefolded file */ #define EXT4_RESERVED_FL 0x80000000 /* reserved for ext4 lib */ -#define EXT4_FL_USER_VISIBLE 0x704BDFFF /* User visible flags */ +#define EXT4_FL_USER_VISIBLE 0x705BDFFF /* User visible flags */ #define EXT4_FL_USER_MODIFIABLE 0x604BC0FF /* User modifiable flags */ /* Flags we can manipulate with through EXT4_IOC_FSSETXATTR */ @@ -467,6 +469,7 @@ enum { EXT4_INODE_TOPDIR = 17, /* Top of directory hierarchies*/ EXT4_INODE_HUGE_FILE = 18, /* Set to each huge file */ EXT4_INODE_EXTENTS = 19, /* Inode uses extents */ + EXT4_INODE_VERITY = 20, /* Verity protected inode */ EXT4_INODE_EA_INODE = 21, /* Inode used for large EA */ EXT4_INODE_EOFBLOCKS = 22, /* Blocks allocated beyond EOF */ EXT4_INODE_INLINE_DATA = 28, /* Data in inode. */ @@ -512,6 +515,7 @@ static inline void ext4_check_flag_values(void) CHECK_FLAG_VALUE(TOPDIR); CHECK_FLAG_VALUE(HUGE_FILE); CHECK_FLAG_VALUE(EXTENTS); + CHECK_FLAG_VALUE(VERITY); CHECK_FLAG_VALUE(EA_INODE); CHECK_FLAG_VALUE(EOFBLOCKS); CHECK_FLAG_VALUE(INLINE_DATA); @@ -1560,6 +1564,7 @@ enum { EXT4_STATE_MAY_INLINE_DATA, /* may have in-inode data */ EXT4_STATE_EXT_PRECACHED, /* extents have been precached */ EXT4_STATE_LUSTRE_EA_INODE, /* Lustre-style ea_inode */ + EXT4_STATE_VERITY_IN_PROGRESS, /* building fs-verity Merkle tree */ }; #define EXT4_INODE_BIT_FNS(name, field, offset) \ @@ -1610,6 +1615,12 @@ static inline void ext4_clear_state_flags(struct ext4_inode_info *ei) #define EXT4_SB(sb) (sb) #endif +static inline bool ext4_verity_in_progress(struct inode *inode) +{ + return IS_ENABLED(CONFIG_FS_VERITY) && + ext4_test_inode_state(inode, EXT4_STATE_VERITY_IN_PROGRESS); +} + #define NEXT_ORPHAN(inode) EXT4_I(inode)->i_dtime /* @@ -1662,6 +1673,7 @@ static inline void ext4_clear_state_flags(struct ext4_inode_info *ei) #define EXT4_FEATURE_RO_COMPAT_METADATA_CSUM 0x0400 #define EXT4_FEATURE_RO_COMPAT_READONLY 0x1000 #define EXT4_FEATURE_RO_COMPAT_PROJECT 0x2000 +#define EXT4_FEATURE_RO_COMPAT_VERITY 0x8000 #define EXT4_FEATURE_INCOMPAT_COMPRESSION 0x0001 #define EXT4_FEATURE_INCOMPAT_FILETYPE 0x0002 @@ -1756,6 +1768,7 @@ EXT4_FEATURE_RO_COMPAT_FUNCS(bigalloc, BIGALLOC) EXT4_FEATURE_RO_COMPAT_FUNCS(metadata_csum, METADATA_CSUM) EXT4_FEATURE_RO_COMPAT_FUNCS(readonly, READONLY) EXT4_FEATURE_RO_COMPAT_FUNCS(project, PROJECT) +EXT4_FEATURE_RO_COMPAT_FUNCS(verity, VERITY) EXT4_FEATURE_INCOMPAT_FUNCS(compression, COMPRESSION) EXT4_FEATURE_INCOMPAT_FUNCS(filetype, FILETYPE) @@ -1813,7 +1826,8 @@ EXT4_FEATURE_INCOMPAT_FUNCS(casefold, CASEFOLD) EXT4_FEATURE_RO_COMPAT_BIGALLOC |\ EXT4_FEATURE_RO_COMPAT_METADATA_CSUM|\ EXT4_FEATURE_RO_COMPAT_QUOTA |\ - EXT4_FEATURE_RO_COMPAT_PROJECT) + EXT4_FEATURE_RO_COMPAT_PROJECT |\ + EXT4_FEATURE_RO_COMPAT_VERITY) #define EXTN_FEATURE_FUNCS(ver) \ static inline bool ext4_has_unknown_ext##ver##_compat_features(struct super_block *sb) \ @@ -3177,6 +3191,8 @@ static inline void ext4_set_de_type(struct super_block *sb, extern int ext4_mpage_readpages(struct address_space *mapping, struct list_head *pages, struct page *page, unsigned nr_pages, bool is_readahead); +extern int __init ext4_init_post_read_processing(void); +extern void ext4_exit_post_read_processing(void); /* symlink.c */ extern const struct inode_operations ext4_encrypted_symlink_inode_operations; @@ -3283,6 +3299,9 @@ extern int ext4_bio_write_page(struct ext4_io_submit *io, /* mmp.c */ extern int ext4_multi_mount_protect(struct super_block *, ext4_fsblk_t); +/* verity.c */ +extern const struct fsverity_operations ext4_verityops; + /* * Add new method to test whether block and inode bitmaps are properly * initialized. With uninit_bg reading the block from disk is not enough diff --git a/fs/ext4/file.c b/fs/ext4/file.c index 70b0438dbc94..b8a20bb9a145 100644 --- a/fs/ext4/file.c +++ b/fs/ext4/file.c @@ -457,6 +457,10 @@ static int ext4_file_open(struct inode * inode, struct file * filp) if (ret) return ret; + ret = fsverity_file_open(inode, filp); + if (ret) + return ret; + /* * Set up the jbd2_inode if we are opening the inode for * writing and the journal is present diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c index 006b7a2070bf..d0dc0e3463db 100644 --- a/fs/ext4/inode.c +++ b/fs/ext4/inode.c @@ -1340,6 +1340,9 @@ retry_journal: } if (ret) { + bool extended = (pos + len > inode->i_size) && + !ext4_verity_in_progress(inode); + unlock_page(page); /* * __block_write_begin may have instantiated a few blocks @@ -1349,11 +1352,11 @@ retry_journal: * Add inode to orphan list in case we crash before * truncate finishes */ - if (pos + len > inode->i_size && ext4_can_truncate(inode)) + if (extended && ext4_can_truncate(inode)) ext4_orphan_add(handle, inode); ext4_journal_stop(handle); - if (pos + len > inode->i_size) { + if (extended) { ext4_truncate_failed_write(inode); /* * If truncate failed early the inode might @@ -1406,6 +1409,7 @@ static int ext4_write_end(struct file *file, int ret = 0, ret2; int i_size_changed = 0; int inline_data = ext4_has_inline_data(inode); + bool verity = ext4_verity_in_progress(inode); trace_ext4_write_end(inode, pos, len, copied); if (inline_data) { @@ -1423,12 +1427,16 @@ static int ext4_write_end(struct file *file, /* * it's important to update i_size while still holding page lock: * page writeout could otherwise come in and zero beyond i_size. + * + * If FS_IOC_ENABLE_VERITY is running on this inode, then Merkle tree + * blocks are being written past EOF, so skip the i_size update. */ - i_size_changed = ext4_update_inode_size(inode, pos + copied); + if (!verity) + i_size_changed = ext4_update_inode_size(inode, pos + copied); unlock_page(page); put_page(page); - if (old_size < pos) + if (old_size < pos && !verity) pagecache_isize_extended(inode, old_size, pos); /* * Don't mark the inode dirty under page lock. First, it unnecessarily @@ -1439,7 +1447,7 @@ static int ext4_write_end(struct file *file, if (i_size_changed || inline_data) ext4_mark_inode_dirty(handle, inode); - if (pos + len > inode->i_size && ext4_can_truncate(inode)) + if (pos + len > inode->i_size && !verity && ext4_can_truncate(inode)) /* if we have allocated more blocks and copied * less. We will have blocks allocated outside * inode->i_size. So truncate them @@ -1450,7 +1458,7 @@ errout: if (!ret) ret = ret2; - if (pos + len > inode->i_size) { + if (pos + len > inode->i_size && !verity) { ext4_truncate_failed_write(inode); /* * If truncate failed early the inode might still be @@ -1511,6 +1519,7 @@ static int ext4_journalled_write_end(struct file *file, unsigned from, to; int size_changed = 0; int inline_data = ext4_has_inline_data(inode); + bool verity = ext4_verity_in_progress(inode); trace_ext4_journalled_write_end(inode, pos, len, copied); from = pos & (PAGE_SIZE - 1); @@ -1540,13 +1549,14 @@ static int ext4_journalled_write_end(struct file *file, if (!partial) SetPageUptodate(page); } - size_changed = ext4_update_inode_size(inode, pos + copied); + if (!verity) + size_changed = ext4_update_inode_size(inode, pos + copied); ext4_set_inode_state(inode, EXT4_STATE_JDATA); EXT4_I(inode)->i_datasync_tid = handle->h_transaction->t_tid; unlock_page(page); put_page(page); - if (old_size < pos) + if (old_size < pos && !verity) pagecache_isize_extended(inode, old_size, pos); if (size_changed || inline_data) { @@ -1555,7 +1565,7 @@ static int ext4_journalled_write_end(struct file *file, ret = ret2; } - if (pos + len > inode->i_size && ext4_can_truncate(inode)) + if (pos + len > inode->i_size && !verity && ext4_can_truncate(inode)) /* if we have allocated more blocks and copied * less. We will have blocks allocated outside * inode->i_size. So truncate them @@ -1566,7 +1576,7 @@ errout: ret2 = ext4_journal_stop(handle); if (!ret) ret = ret2; - if (pos + len > inode->i_size) { + if (pos + len > inode->i_size && !verity) { ext4_truncate_failed_write(inode); /* * If truncate failed early the inode might still be @@ -2162,7 +2172,8 @@ static int ext4_writepage(struct page *page, trace_ext4_writepage(page); size = i_size_read(inode); - if (page->index == size >> PAGE_SHIFT) + if (page->index == size >> PAGE_SHIFT && + !ext4_verity_in_progress(inode)) len = size & ~PAGE_MASK; else len = PAGE_SIZE; @@ -2246,7 +2257,8 @@ static int mpage_submit_page(struct mpage_da_data *mpd, struct page *page) * after page tables are updated. */ size = i_size_read(mpd->inode); - if (page->index == size >> PAGE_SHIFT) + if (page->index == size >> PAGE_SHIFT && + !ext4_verity_in_progress(mpd->inode)) len = size & ~PAGE_MASK; else len = PAGE_SIZE; @@ -2345,6 +2357,9 @@ static int mpage_process_page_bufs(struct mpage_da_data *mpd, ext4_lblk_t blocks = (i_size_read(inode) + i_blocksize(inode) - 1) >> inode->i_blkbits; + if (ext4_verity_in_progress(inode)) + blocks = EXT_MAX_BLOCKS; + do { BUG_ON(buffer_locked(bh)); @@ -3061,8 +3076,8 @@ static int ext4_da_write_begin(struct file *file, struct address_space *mapping, index = pos >> PAGE_SHIFT; - if (ext4_nonda_switch(inode->i_sb) || - S_ISLNK(inode->i_mode)) { + if (ext4_nonda_switch(inode->i_sb) || S_ISLNK(inode->i_mode) || + ext4_verity_in_progress(inode)) { *fsdata = (void *)FALL_BACK_TO_NONDELALLOC; return ext4_write_begin(file, mapping, pos, len, flags, pagep, fsdata); @@ -3897,6 +3912,8 @@ static ssize_t ext4_direct_IO(struct kiocb *iocb, struct iov_iter *iter) if (IS_ENCRYPTED(inode) && S_ISREG(inode->i_mode)) return 0; #endif + if (fsverity_active(inode)) + return 0; /* * If we are doing data journalling we don't support O_DIRECT @@ -4736,6 +4753,8 @@ static bool ext4_should_use_dax(struct inode *inode) return false; if (ext4_test_inode_flag(inode, EXT4_INODE_ENCRYPT)) return false; + if (ext4_test_inode_flag(inode, EXT4_INODE_VERITY)) + return false; return true; } @@ -4760,9 +4779,11 @@ void ext4_set_inode_flags(struct inode *inode) new_fl |= S_ENCRYPTED; if (flags & EXT4_CASEFOLD_FL) new_fl |= S_CASEFOLD; + if (flags & EXT4_VERITY_FL) + new_fl |= S_VERITY; inode_set_flags(inode, new_fl, S_SYNC|S_APPEND|S_IMMUTABLE|S_NOATIME|S_DIRSYNC|S_DAX| - S_ENCRYPTED|S_CASEFOLD); + S_ENCRYPTED|S_CASEFOLD|S_VERITY); } static blkcnt_t ext4_inode_blocks(struct ext4_inode *raw_inode, @@ -5552,6 +5573,10 @@ int ext4_setattr(struct dentry *dentry, struct iattr *attr) if (error) return error; + error = fsverity_prepare_setattr(dentry, attr); + if (error) + return error; + if (is_quota_modification(inode, attr)) { error = dquot_initialize(inode); if (error) diff --git a/fs/ext4/ioctl.c b/fs/ext4/ioctl.c index 5703d607f5af..5444d49cbf09 100644 --- a/fs/ext4/ioctl.c +++ b/fs/ext4/ioctl.c @@ -1198,6 +1198,17 @@ out: } case EXT4_IOC_SHUTDOWN: return ext4_shutdown(sb, arg); + + case FS_IOC_ENABLE_VERITY: + if (!ext4_has_feature_verity(sb)) + return -EOPNOTSUPP; + return fsverity_ioctl_enable(filp, (const void __user *)arg); + + case FS_IOC_MEASURE_VERITY: + if (!ext4_has_feature_verity(sb)) + return -EOPNOTSUPP; + return fsverity_ioctl_measure(filp, (void __user *)arg); + default: return -ENOTTY; } @@ -1265,6 +1276,8 @@ long ext4_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg) case FS_IOC_GET_ENCRYPTION_KEY_STATUS: case EXT4_IOC_SHUTDOWN: case FS_IOC_GETFSMAP: + case FS_IOC_ENABLE_VERITY: + case FS_IOC_MEASURE_VERITY: break; default: return -ENOIOCTLCMD; diff --git a/fs/ext4/readpage.c b/fs/ext4/readpage.c index c916017db334..a30b203fa461 100644 --- a/fs/ext4/readpage.c +++ b/fs/ext4/readpage.c @@ -47,13 +47,103 @@ #include "ext4.h" -static inline bool ext4_bio_encrypted(struct bio *bio) +#define NUM_PREALLOC_POST_READ_CTXS 128 + +static struct kmem_cache *bio_post_read_ctx_cache; +static mempool_t *bio_post_read_ctx_pool; + +/* postprocessing steps for read bios */ +enum bio_post_read_step { + STEP_INITIAL = 0, + STEP_DECRYPT, + STEP_VERITY, +}; + +struct bio_post_read_ctx { + struct bio *bio; + struct work_struct work; + unsigned int cur_step; + unsigned int enabled_steps; +}; + +static void __read_end_io(struct bio *bio) { -#ifdef CONFIG_FS_ENCRYPTION - return unlikely(bio->bi_private != NULL); -#else - return false; -#endif + struct page *page; + struct bio_vec *bv; + struct bvec_iter_all iter_all; + + bio_for_each_segment_all(bv, bio, iter_all) { + page = bv->bv_page; + + /* PG_error was set if any post_read step failed */ + if (bio->bi_status || PageError(page)) { + ClearPageUptodate(page); + /* will re-read again later */ + ClearPageError(page); + } else { + SetPageUptodate(page); + } + unlock_page(page); + } + if (bio->bi_private) + mempool_free(bio->bi_private, bio_post_read_ctx_pool); + bio_put(bio); +} + +static void bio_post_read_processing(struct bio_post_read_ctx *ctx); + +static void decrypt_work(struct work_struct *work) +{ + struct bio_post_read_ctx *ctx = + container_of(work, struct bio_post_read_ctx, work); + + fscrypt_decrypt_bio(ctx->bio); + + bio_post_read_processing(ctx); +} + +static void verity_work(struct work_struct *work) +{ + struct bio_post_read_ctx *ctx = + container_of(work, struct bio_post_read_ctx, work); + + fsverity_verify_bio(ctx->bio); + + bio_post_read_processing(ctx); +} + +static void bio_post_read_processing(struct bio_post_read_ctx *ctx) +{ + /* + * We use different work queues for decryption and for verity because + * verity may require reading metadata pages that need decryption, and + * we shouldn't recurse to the same workqueue. + */ + switch (++ctx->cur_step) { + case STEP_DECRYPT: + if (ctx->enabled_steps & (1 << STEP_DECRYPT)) { + INIT_WORK(&ctx->work, decrypt_work); + fscrypt_enqueue_decrypt_work(&ctx->work); + return; + } + ctx->cur_step++; + /* fall-through */ + case STEP_VERITY: + if (ctx->enabled_steps & (1 << STEP_VERITY)) { + INIT_WORK(&ctx->work, verity_work); + fsverity_enqueue_verify_work(&ctx->work); + return; + } + ctx->cur_step++; + /* fall-through */ + default: + __read_end_io(ctx->bio); + } +} + +static bool bio_post_read_required(struct bio *bio) +{ + return bio->bi_private && !bio->bi_status; } /* @@ -70,30 +160,53 @@ static inline bool ext4_bio_encrypted(struct bio *bio) */ static void mpage_end_io(struct bio *bio) { - struct bio_vec *bv; - struct bvec_iter_all iter_all; + if (bio_post_read_required(bio)) { + struct bio_post_read_ctx *ctx = bio->bi_private; - if (ext4_bio_encrypted(bio)) { - if (bio->bi_status) { - fscrypt_release_ctx(bio->bi_private); - } else { - fscrypt_enqueue_decrypt_bio(bio->bi_private, bio); - return; - } + ctx->cur_step = STEP_INITIAL; + bio_post_read_processing(ctx); + return; } - bio_for_each_segment_all(bv, bio, iter_all) { - struct page *page = bv->bv_page; + __read_end_io(bio); +} - if (!bio->bi_status) { - SetPageUptodate(page); - } else { - ClearPageUptodate(page); - SetPageError(page); - } - unlock_page(page); +static inline bool ext4_need_verity(const struct inode *inode, pgoff_t idx) +{ + return fsverity_active(inode) && + idx < DIV_ROUND_UP(inode->i_size, PAGE_SIZE); +} + +static struct bio_post_read_ctx *get_bio_post_read_ctx(struct inode *inode, + struct bio *bio, + pgoff_t first_idx) +{ + unsigned int post_read_steps = 0; + struct bio_post_read_ctx *ctx = NULL; + + if (IS_ENCRYPTED(inode) && S_ISREG(inode->i_mode)) + post_read_steps |= 1 << STEP_DECRYPT; + + if (ext4_need_verity(inode, first_idx)) + post_read_steps |= 1 << STEP_VERITY; + + if (post_read_steps) { + ctx = mempool_alloc(bio_post_read_ctx_pool, GFP_NOFS); + if (!ctx) + return ERR_PTR(-ENOMEM); + ctx->bio = bio; + ctx->enabled_steps = post_read_steps; + bio->bi_private = ctx; } + return ctx; +} - bio_put(bio); +static inline loff_t ext4_readpage_limit(struct inode *inode) +{ + if (IS_ENABLED(CONFIG_FS_VERITY) && + (IS_VERITY(inode) || ext4_verity_in_progress(inode))) + return inode->i_sb->s_maxbytes; + + return i_size_read(inode); } int ext4_mpage_readpages(struct address_space *mapping, @@ -141,7 +254,8 @@ int ext4_mpage_readpages(struct address_space *mapping, block_in_file = (sector_t)page->index << (PAGE_SHIFT - blkbits); last_block = block_in_file + nr_pages * blocks_per_page; - last_block_in_file = (i_size_read(inode) + blocksize - 1) >> blkbits; + last_block_in_file = (ext4_readpage_limit(inode) + + blocksize - 1) >> blkbits; if (last_block > last_block_in_file) last_block = last_block_in_file; page_block = 0; @@ -218,6 +332,9 @@ int ext4_mpage_readpages(struct address_space *mapping, zero_user_segment(page, first_hole << blkbits, PAGE_SIZE); if (first_hole == 0) { + if (ext4_need_verity(inode, page->index) && + !fsverity_verify_page(page)) + goto set_error_page; SetPageUptodate(page); unlock_page(page); goto next_page; @@ -241,18 +358,16 @@ int ext4_mpage_readpages(struct address_space *mapping, bio = NULL; } if (bio == NULL) { - struct fscrypt_ctx *ctx = NULL; + struct bio_post_read_ctx *ctx; - if (IS_ENCRYPTED(inode) && S_ISREG(inode->i_mode)) { - ctx = fscrypt_get_ctx(GFP_NOFS); - if (IS_ERR(ctx)) - goto set_error_page; - } bio = bio_alloc(GFP_KERNEL, min_t(int, nr_pages, BIO_MAX_PAGES)); - if (!bio) { - if (ctx) - fscrypt_release_ctx(ctx); + if (!bio) + goto set_error_page; + ctx = get_bio_post_read_ctx(inode, bio, page->index); + if (IS_ERR(ctx)) { + bio_put(bio); + bio = NULL; goto set_error_page; } bio_set_dev(bio, bdev); @@ -293,3 +408,29 @@ int ext4_mpage_readpages(struct address_space *mapping, submit_bio(bio); return 0; } + +int __init ext4_init_post_read_processing(void) +{ + bio_post_read_ctx_cache = + kmem_cache_create("ext4_bio_post_read_ctx", + sizeof(struct bio_post_read_ctx), 0, 0, NULL); + if (!bio_post_read_ctx_cache) + goto fail; + bio_post_read_ctx_pool = + mempool_create_slab_pool(NUM_PREALLOC_POST_READ_CTXS, + bio_post_read_ctx_cache); + if (!bio_post_read_ctx_pool) + goto fail_free_cache; + return 0; + +fail_free_cache: + kmem_cache_destroy(bio_post_read_ctx_cache); +fail: + return -ENOMEM; +} + +void ext4_exit_post_read_processing(void) +{ + mempool_destroy(bio_post_read_ctx_pool); + kmem_cache_destroy(bio_post_read_ctx_cache); +} diff --git a/fs/ext4/super.c b/fs/ext4/super.c index 757819139b8f..27cd622676e7 100644 --- a/fs/ext4/super.c +++ b/fs/ext4/super.c @@ -1182,6 +1182,7 @@ void ext4_clear_inode(struct inode *inode) EXT4_I(inode)->jinode = NULL; } fscrypt_put_encryption_info(inode); + fsverity_cleanup_inode(inode); } static struct inode *ext4_nfs_get_inode(struct super_block *sb, @@ -4275,6 +4276,9 @@ static int ext4_fill_super(struct super_block *sb, void *data, int silent) #ifdef CONFIG_FS_ENCRYPTION sb->s_cop = &ext4_cryptops; #endif +#ifdef CONFIG_FS_VERITY + sb->s_vop = &ext4_verityops; +#endif #ifdef CONFIG_QUOTA sb->dq_op = &ext4_quota_operations; if (ext4_has_feature_quota(sb)) @@ -4422,6 +4426,11 @@ no_journal: goto failed_mount_wq; } + if (ext4_has_feature_verity(sb) && blocksize != PAGE_SIZE) { + ext4_msg(sb, KERN_ERR, "Unsupported blocksize for fs-verity"); + goto failed_mount_wq; + } + if (DUMMY_ENCRYPTION_ENABLED(sbi) && !sb_rdonly(sb) && !ext4_has_feature_encrypt(sb)) { ext4_set_feature_encrypt(sb); @@ -6098,6 +6107,10 @@ static int __init ext4_init_fs(void) err = ext4_init_pending(); if (err) + goto out7; + + err = ext4_init_post_read_processing(); + if (err) goto out6; err = ext4_init_pageio(); @@ -6138,8 +6151,10 @@ out3: out4: ext4_exit_pageio(); out5: - ext4_exit_pending(); + ext4_exit_post_read_processing(); out6: + ext4_exit_pending(); +out7: ext4_exit_es(); return err; @@ -6156,6 +6171,7 @@ static void __exit ext4_exit_fs(void) ext4_exit_sysfs(); ext4_exit_system_zone(); ext4_exit_pageio(); + ext4_exit_post_read_processing(); ext4_exit_es(); ext4_exit_pending(); } diff --git a/fs/ext4/sysfs.c b/fs/ext4/sysfs.c index b3cd7655a6ff..eb1efad0e20a 100644 --- a/fs/ext4/sysfs.c +++ b/fs/ext4/sysfs.c @@ -242,6 +242,9 @@ EXT4_ATTR_FEATURE(encryption); #ifdef CONFIG_UNICODE EXT4_ATTR_FEATURE(casefold); #endif +#ifdef CONFIG_FS_VERITY +EXT4_ATTR_FEATURE(verity); +#endif EXT4_ATTR_FEATURE(metadata_csum_seed); static struct attribute *ext4_feat_attrs[] = { @@ -254,6 +257,9 @@ static struct attribute *ext4_feat_attrs[] = { #ifdef CONFIG_UNICODE ATTR_LIST(casefold), #endif +#ifdef CONFIG_FS_VERITY + ATTR_LIST(verity), +#endif ATTR_LIST(metadata_csum_seed), NULL, }; diff --git a/fs/ext4/verity.c b/fs/ext4/verity.c new file mode 100644 index 000000000000..d0d8a9795dd6 --- /dev/null +++ b/fs/ext4/verity.c @@ -0,0 +1,367 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * fs/ext4/verity.c: fs-verity support for ext4 + * + * Copyright 2019 Google LLC + */ + +/* + * Implementation of fsverity_operations for ext4. + * + * ext4 stores the verity metadata (Merkle tree and fsverity_descriptor) past + * the end of the file, starting at the first 64K boundary beyond i_size. This + * approach works because (a) verity files are readonly, and (b) pages fully + * beyond i_size aren't visible to userspace but can be read/written internally + * by ext4 with only some relatively small changes to ext4. This approach + * avoids having to depend on the EA_INODE feature and on rearchitecturing + * ext4's xattr support to support paging multi-gigabyte xattrs into memory, and + * to support encrypting xattrs. Note that the verity metadata *must* be + * encrypted when the file is, since it contains hashes of the plaintext data. + * + * Using a 64K boundary rather than a 4K one keeps things ready for + * architectures with 64K pages, and it doesn't necessarily waste space on-disk + * since there can be a hole between i_size and the start of the Merkle tree. + */ + +#include <linux/quotaops.h> + +#include "ext4.h" +#include "ext4_extents.h" +#include "ext4_jbd2.h" + +static inline loff_t ext4_verity_metadata_pos(const struct inode *inode) +{ + return round_up(inode->i_size, 65536); +} + +/* + * Read some verity metadata from the inode. __vfs_read() can't be used because + * we need to read beyond i_size. + */ +static int pagecache_read(struct inode *inode, void *buf, size_t count, + loff_t pos) +{ + while (count) { + size_t n = min_t(size_t, count, + PAGE_SIZE - offset_in_page(pos)); + struct page *page; + void *addr; + + page = read_mapping_page(inode->i_mapping, pos >> PAGE_SHIFT, + NULL); + if (IS_ERR(page)) + return PTR_ERR(page); + + addr = kmap_atomic(page); + memcpy(buf, addr + offset_in_page(pos), n); + kunmap_atomic(addr); + + put_page(page); + + buf += n; + pos += n; + count -= n; + } + return 0; +} + +/* + * Write some verity metadata to the inode for FS_IOC_ENABLE_VERITY. + * kernel_write() can't be used because the file descriptor is readonly. + */ +static int pagecache_write(struct inode *inode, const void *buf, size_t count, + loff_t pos) +{ + if (pos + count > inode->i_sb->s_maxbytes) + return -EFBIG; + + while (count) { + size_t n = min_t(size_t, count, + PAGE_SIZE - offset_in_page(pos)); + struct page *page; + void *fsdata; + void *addr; + int res; + + res = pagecache_write_begin(NULL, inode->i_mapping, pos, n, 0, + &page, &fsdata); + if (res) + return res; + + addr = kmap_atomic(page); + memcpy(addr + offset_in_page(pos), buf, n); + kunmap_atomic(addr); + + res = pagecache_write_end(NULL, inode->i_mapping, pos, n, n, + page, fsdata); + if (res < 0) + return res; + if (res != n) + return -EIO; + + buf += n; + pos += n; + count -= n; + } + return 0; +} + +static int ext4_begin_enable_verity(struct file *filp) +{ + struct inode *inode = file_inode(filp); + const int credits = 2; /* superblock and inode for ext4_orphan_add() */ + handle_t *handle; + int err; + + if (ext4_verity_in_progress(inode)) + return -EBUSY; + + /* + * Since the file was opened readonly, we have to initialize the jbd + * inode and quotas here and not rely on ->open() doing it. This must + * be done before evicting the inline data. + */ + + err = ext4_inode_attach_jinode(inode); + if (err) + return err; + + err = dquot_initialize(inode); + if (err) + return err; + + err = ext4_convert_inline_data(inode); + if (err) + return err; + + if (!ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)) { + ext4_warning_inode(inode, + "verity is only allowed on extent-based files"); + return -EOPNOTSUPP; + } + + /* + * ext4 uses the last allocated block to find the verity descriptor, so + * we must remove any other blocks past EOF which might confuse things. + */ + err = ext4_truncate(inode); + if (err) + return err; + + handle = ext4_journal_start(inode, EXT4_HT_INODE, credits); + if (IS_ERR(handle)) + return PTR_ERR(handle); + + err = ext4_orphan_add(handle, inode); + if (err == 0) + ext4_set_inode_state(inode, EXT4_STATE_VERITY_IN_PROGRESS); + + ext4_journal_stop(handle); + return err; +} + +/* + * ext4 stores the verity descriptor beginning on the next filesystem block + * boundary after the Merkle tree. Then, the descriptor size is stored in the + * last 4 bytes of the last allocated filesystem block --- which is either the + * block in which the descriptor ends, or the next block after that if there + * weren't at least 4 bytes remaining. + * + * We can't simply store the descriptor in an xattr because it *must* be + * encrypted when ext4 encryption is used, but ext4 encryption doesn't encrypt + * xattrs. Also, if the descriptor includes a large signature blob it may be + * too large to store in an xattr without the EA_INODE feature. + */ +static int ext4_write_verity_descriptor(struct inode *inode, const void *desc, + size_t desc_size, u64 merkle_tree_size) +{ + const u64 desc_pos = round_up(ext4_verity_metadata_pos(inode) + + merkle_tree_size, i_blocksize(inode)); + const u64 desc_end = desc_pos + desc_size; + const __le32 desc_size_disk = cpu_to_le32(desc_size); + const u64 desc_size_pos = round_up(desc_end + sizeof(desc_size_disk), + i_blocksize(inode)) - + sizeof(desc_size_disk); + int err; + + err = pagecache_write(inode, desc, desc_size, desc_pos); + if (err) + return err; + + return pagecache_write(inode, &desc_size_disk, sizeof(desc_size_disk), + desc_size_pos); +} + +static int ext4_end_enable_verity(struct file *filp, const void *desc, + size_t desc_size, u64 merkle_tree_size) +{ + struct inode *inode = file_inode(filp); + const int credits = 2; /* superblock and inode for ext4_orphan_del() */ + handle_t *handle; + int err = 0; + int err2; + + if (desc != NULL) { + /* Succeeded; write the verity descriptor. */ + err = ext4_write_verity_descriptor(inode, desc, desc_size, + merkle_tree_size); + + /* Write all pages before clearing VERITY_IN_PROGRESS. */ + if (!err) + err = filemap_write_and_wait(inode->i_mapping); + } + + /* If we failed, truncate anything we wrote past i_size. */ + if (desc == NULL || err) + ext4_truncate(inode); + + /* + * We must always clean up by clearing EXT4_STATE_VERITY_IN_PROGRESS and + * deleting the inode from the orphan list, even if something failed. + * If everything succeeded, we'll also set the verity bit in the same + * transaction. + */ + + ext4_clear_inode_state(inode, EXT4_STATE_VERITY_IN_PROGRESS); + + handle = ext4_journal_start(inode, EXT4_HT_INODE, credits); + if (IS_ERR(handle)) { + ext4_orphan_del(NULL, inode); + return PTR_ERR(handle); + } + + err2 = ext4_orphan_del(handle, inode); + if (err2) + goto out_stop; + + if (desc != NULL && !err) { + struct ext4_iloc iloc; + + err = ext4_reserve_inode_write(handle, inode, &iloc); + if (err) + goto out_stop; + ext4_set_inode_flag(inode, EXT4_INODE_VERITY); + ext4_set_inode_flags(inode); + err = ext4_mark_iloc_dirty(handle, inode, &iloc); + } +out_stop: + ext4_journal_stop(handle); + return err ?: err2; +} + +static int ext4_get_verity_descriptor_location(struct inode *inode, + size_t *desc_size_ret, + u64 *desc_pos_ret) +{ + struct ext4_ext_path *path; + struct ext4_extent *last_extent; + u32 end_lblk; + u64 desc_size_pos; + __le32 desc_size_disk; + u32 desc_size; + u64 desc_pos; + int err; + + /* + * Descriptor size is in last 4 bytes of last allocated block. + * See ext4_write_verity_descriptor(). + */ + + if (!ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)) { + EXT4_ERROR_INODE(inode, "verity file doesn't use extents"); + return -EFSCORRUPTED; + } + + path = ext4_find_extent(inode, EXT_MAX_BLOCKS - 1, NULL, 0); + if (IS_ERR(path)) + return PTR_ERR(path); + + last_extent = path[path->p_depth].p_ext; + if (!last_extent) { + EXT4_ERROR_INODE(inode, "verity file has no extents"); + ext4_ext_drop_refs(path); + kfree(path); + return -EFSCORRUPTED; + } + + end_lblk = le32_to_cpu(last_extent->ee_block) + + ext4_ext_get_actual_len(last_extent); + desc_size_pos = (u64)end_lblk << inode->i_blkbits; + ext4_ext_drop_refs(path); + kfree(path); + + if (desc_size_pos < sizeof(desc_size_disk)) + goto bad; + desc_size_pos -= sizeof(desc_size_disk); + + err = pagecache_read(inode, &desc_size_disk, sizeof(desc_size_disk), + desc_size_pos); + if (err) + return err; + desc_size = le32_to_cpu(desc_size_disk); + + /* + * The descriptor is stored just before the desc_size_disk, but starting + * on a filesystem block boundary. + */ + + if (desc_size > INT_MAX || desc_size > desc_size_pos) + goto bad; + + desc_pos = round_down(desc_size_pos - desc_size, i_blocksize(inode)); + if (desc_pos < ext4_verity_metadata_pos(inode)) + goto bad; + + *desc_size_ret = desc_size; + *desc_pos_ret = desc_pos; + return 0; + +bad: + EXT4_ERROR_INODE(inode, "verity file corrupted; can't find descriptor"); + return -EFSCORRUPTED; +} + +static int ext4_get_verity_descriptor(struct inode *inode, void *buf, + size_t buf_size) +{ + size_t desc_size = 0; + u64 desc_pos = 0; + int err; + + err = ext4_get_verity_descriptor_location(inode, &desc_size, &desc_pos); + if (err) + return err; + + if (buf_size) { + if (desc_size > buf_size) + return -ERANGE; + err = pagecache_read(inode, buf, desc_size, desc_pos); + if (err) + return err; + } + return desc_size; +} + +static struct page *ext4_read_merkle_tree_page(struct inode *inode, + pgoff_t index) +{ + index += ext4_verity_metadata_pos(inode) >> PAGE_SHIFT; + + return read_mapping_page(inode->i_mapping, index, NULL); +} + +static int ext4_write_merkle_tree_block(struct inode *inode, const void *buf, + u64 index, int log_blocksize) +{ + loff_t pos = ext4_verity_metadata_pos(inode) + (index << log_blocksize); + + return pagecache_write(inode, buf, 1 << log_blocksize, pos); +} + +const struct fsverity_operations ext4_verityops = { + .begin_enable_verity = ext4_begin_enable_verity, + .end_enable_verity = ext4_end_enable_verity, + .get_verity_descriptor = ext4_get_verity_descriptor, + .read_merkle_tree_page = ext4_read_merkle_tree_page, + .write_merkle_tree_block = ext4_write_merkle_tree_block, +}; 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