From: Eric Biggers <ebiggers@kernel.org> To: linux-fscrypt@vger.kernel.org Cc: linux-fsdevel@vger.kernel.org, linux-ext4@vger.kernel.org, linux-f2fs-devel@lists.sourceforge.net, linux-btrfs@vger.kernel.org Subject: [PATCH 5/6] fs/buffer.c: support fsverity in block_read_full_folio() Date: Fri, 28 Oct 2022 15:45:38 -0700 [thread overview] Message-ID: <20221028224539.171818-6-ebiggers@kernel.org> (raw) In-Reply-To: <20221028224539.171818-1-ebiggers@kernel.org> From: Eric Biggers <ebiggers@google.com> After each filesystem block (as represented by a buffer_head) has been read from disk by block_read_full_folio(), verify it if needed. The verification is done on the fsverity_read_workqueue. Also allow reads of verity metadata past i_size, as required by ext4. This is needed to support fsverity on ext4 filesystems where the filesystem block size is less than the page size. The new code is compiled away when CONFIG_FS_VERITY=n. Signed-off-by: Eric Biggers <ebiggers@google.com> --- fs/buffer.c | 66 +++++++++++++++++++++++++++++++++++++++++++++-------- 1 file changed, 56 insertions(+), 10 deletions(-) diff --git a/fs/buffer.c b/fs/buffer.c index d9c6d1fbb6dde..bea0f63031129 100644 --- a/fs/buffer.c +++ b/fs/buffer.c @@ -48,6 +48,7 @@ #include <linux/sched/mm.h> #include <trace/events/block.h> #include <linux/fscrypt.h> +#include <linux/fsverity.h> #include "internal.h" @@ -295,20 +296,51 @@ static void end_buffer_async_read(struct buffer_head *bh, int uptodate) return; } -struct decrypt_bh_ctx { +struct postprocess_bh_ctx { struct work_struct work; struct buffer_head *bh; }; +static void verify_bh(struct work_struct *work) +{ + struct postprocess_bh_ctx *ctx = + container_of(work, struct postprocess_bh_ctx, work); + struct buffer_head *bh = ctx->bh; + bool valid; + + valid = fsverity_verify_blocks(bh->b_page, bh->b_size, bh_offset(bh)); + end_buffer_async_read(bh, valid); + kfree(ctx); +} + +static bool need_fsverity(struct buffer_head *bh) +{ + struct inode *inode = bh->b_page->mapping->host; + + return fsverity_active(inode) && + /* needed by ext4 */ + bh->b_page->index < DIV_ROUND_UP(inode->i_size, PAGE_SIZE); +} + static void decrypt_bh(struct work_struct *work) { - struct decrypt_bh_ctx *ctx = - container_of(work, struct decrypt_bh_ctx, work); + struct postprocess_bh_ctx *ctx = + container_of(work, struct postprocess_bh_ctx, work); struct buffer_head *bh = ctx->bh; int err; err = fscrypt_decrypt_pagecache_blocks(bh->b_page, bh->b_size, bh_offset(bh)); + if (err == 0 && need_fsverity(bh)) { + /* + * 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. + */ + INIT_WORK(&ctx->work, verify_bh); + fsverity_enqueue_verify_work(&ctx->work); + return; + } end_buffer_async_read(bh, err == 0); kfree(ctx); } @@ -319,15 +351,24 @@ static void decrypt_bh(struct work_struct *work) */ static void end_buffer_async_read_io(struct buffer_head *bh, int uptodate) { - /* Decrypt if needed */ - if (uptodate && - fscrypt_inode_uses_fs_layer_crypto(bh->b_page->mapping->host)) { - struct decrypt_bh_ctx *ctx = kmalloc(sizeof(*ctx), GFP_ATOMIC); + struct inode *inode = bh->b_page->mapping->host; + bool decrypt = fscrypt_inode_uses_fs_layer_crypto(inode); + bool verify = need_fsverity(bh); + + /* Decrypt (with fscrypt) and/or verify (with fsverity) if needed. */ + if (uptodate && (decrypt || verify)) { + struct postprocess_bh_ctx *ctx = + kmalloc(sizeof(*ctx), GFP_ATOMIC); if (ctx) { - INIT_WORK(&ctx->work, decrypt_bh); ctx->bh = bh; - fscrypt_enqueue_decrypt_work(&ctx->work); + if (decrypt) { + INIT_WORK(&ctx->work, decrypt_bh); + fscrypt_enqueue_decrypt_work(&ctx->work); + } else { + INIT_WORK(&ctx->work, verify_bh); + fsverity_enqueue_verify_work(&ctx->work); + } return; } uptodate = 0; @@ -2245,6 +2286,11 @@ int block_read_full_folio(struct folio *folio, get_block_t *get_block) int nr, i; int fully_mapped = 1; bool page_error = false; + loff_t limit = i_size_read(inode); + + /* This is needed for ext4. */ + if (IS_ENABLED(CONFIG_FS_VERITY) && IS_VERITY(inode)) + limit = inode->i_sb->s_maxbytes; VM_BUG_ON_FOLIO(folio_test_large(folio), folio); @@ -2253,7 +2299,7 @@ int block_read_full_folio(struct folio *folio, get_block_t *get_block) bbits = block_size_bits(blocksize); iblock = (sector_t)folio->index << (PAGE_SHIFT - bbits); - lblock = (i_size_read(inode)+blocksize-1) >> bbits; + lblock = (limit+blocksize-1) >> bbits; bh = head; nr = 0; i = 0; -- 2.38.0
WARNING: multiple messages have this Message-ID (diff)
From: Eric Biggers <ebiggers@kernel.org> To: linux-fscrypt@vger.kernel.org Cc: linux-fsdevel@vger.kernel.org, linux-ext4@vger.kernel.org, linux-btrfs@vger.kernel.org, linux-f2fs-devel@lists.sourceforge.net Subject: [f2fs-dev] [PATCH 5/6] fs/buffer.c: support fsverity in block_read_full_folio() Date: Fri, 28 Oct 2022 15:45:38 -0700 [thread overview] Message-ID: <20221028224539.171818-6-ebiggers@kernel.org> (raw) In-Reply-To: <20221028224539.171818-1-ebiggers@kernel.org> From: Eric Biggers <ebiggers@google.com> After each filesystem block (as represented by a buffer_head) has been read from disk by block_read_full_folio(), verify it if needed. The verification is done on the fsverity_read_workqueue. Also allow reads of verity metadata past i_size, as required by ext4. This is needed to support fsverity on ext4 filesystems where the filesystem block size is less than the page size. The new code is compiled away when CONFIG_FS_VERITY=n. Signed-off-by: Eric Biggers <ebiggers@google.com> --- fs/buffer.c | 66 +++++++++++++++++++++++++++++++++++++++++++++-------- 1 file changed, 56 insertions(+), 10 deletions(-) diff --git a/fs/buffer.c b/fs/buffer.c index d9c6d1fbb6dde..bea0f63031129 100644 --- a/fs/buffer.c +++ b/fs/buffer.c @@ -48,6 +48,7 @@ #include <linux/sched/mm.h> #include <trace/events/block.h> #include <linux/fscrypt.h> +#include <linux/fsverity.h> #include "internal.h" @@ -295,20 +296,51 @@ static void end_buffer_async_read(struct buffer_head *bh, int uptodate) return; } -struct decrypt_bh_ctx { +struct postprocess_bh_ctx { struct work_struct work; struct buffer_head *bh; }; +static void verify_bh(struct work_struct *work) +{ + struct postprocess_bh_ctx *ctx = + container_of(work, struct postprocess_bh_ctx, work); + struct buffer_head *bh = ctx->bh; + bool valid; + + valid = fsverity_verify_blocks(bh->b_page, bh->b_size, bh_offset(bh)); + end_buffer_async_read(bh, valid); + kfree(ctx); +} + +static bool need_fsverity(struct buffer_head *bh) +{ + struct inode *inode = bh->b_page->mapping->host; + + return fsverity_active(inode) && + /* needed by ext4 */ + bh->b_page->index < DIV_ROUND_UP(inode->i_size, PAGE_SIZE); +} + static void decrypt_bh(struct work_struct *work) { - struct decrypt_bh_ctx *ctx = - container_of(work, struct decrypt_bh_ctx, work); + struct postprocess_bh_ctx *ctx = + container_of(work, struct postprocess_bh_ctx, work); struct buffer_head *bh = ctx->bh; int err; err = fscrypt_decrypt_pagecache_blocks(bh->b_page, bh->b_size, bh_offset(bh)); + if (err == 0 && need_fsverity(bh)) { + /* + * 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. + */ + INIT_WORK(&ctx->work, verify_bh); + fsverity_enqueue_verify_work(&ctx->work); + return; + } end_buffer_async_read(bh, err == 0); kfree(ctx); } @@ -319,15 +351,24 @@ static void decrypt_bh(struct work_struct *work) */ static void end_buffer_async_read_io(struct buffer_head *bh, int uptodate) { - /* Decrypt if needed */ - if (uptodate && - fscrypt_inode_uses_fs_layer_crypto(bh->b_page->mapping->host)) { - struct decrypt_bh_ctx *ctx = kmalloc(sizeof(*ctx), GFP_ATOMIC); + struct inode *inode = bh->b_page->mapping->host; + bool decrypt = fscrypt_inode_uses_fs_layer_crypto(inode); + bool verify = need_fsverity(bh); + + /* Decrypt (with fscrypt) and/or verify (with fsverity) if needed. */ + if (uptodate && (decrypt || verify)) { + struct postprocess_bh_ctx *ctx = + kmalloc(sizeof(*ctx), GFP_ATOMIC); if (ctx) { - INIT_WORK(&ctx->work, decrypt_bh); ctx->bh = bh; - fscrypt_enqueue_decrypt_work(&ctx->work); + if (decrypt) { + INIT_WORK(&ctx->work, decrypt_bh); + fscrypt_enqueue_decrypt_work(&ctx->work); + } else { + INIT_WORK(&ctx->work, verify_bh); + fsverity_enqueue_verify_work(&ctx->work); + } return; } uptodate = 0; @@ -2245,6 +2286,11 @@ int block_read_full_folio(struct folio *folio, get_block_t *get_block) int nr, i; int fully_mapped = 1; bool page_error = false; + loff_t limit = i_size_read(inode); + + /* This is needed for ext4. */ + if (IS_ENABLED(CONFIG_FS_VERITY) && IS_VERITY(inode)) + limit = inode->i_sb->s_maxbytes; VM_BUG_ON_FOLIO(folio_test_large(folio), folio); @@ -2253,7 +2299,7 @@ int block_read_full_folio(struct folio *folio, get_block_t *get_block) bbits = block_size_bits(blocksize); iblock = (sector_t)folio->index << (PAGE_SHIFT - bbits); - lblock = (i_size_read(inode)+blocksize-1) >> bbits; + lblock = (limit+blocksize-1) >> bbits; bh = head; nr = 0; i = 0; -- 2.38.0 _______________________________________________ Linux-f2fs-devel mailing list Linux-f2fs-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel
next prev parent reply other threads:[~2022-10-28 22:47 UTC|newest] Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top 2022-10-28 22:45 [PATCH 0/6] fsverity: support for non-4K pages Eric Biggers 2022-10-28 22:45 ` [f2fs-dev] " Eric Biggers 2022-10-28 22:45 ` [PATCH 1/6] fsverity: support verification with tree block size < PAGE_SIZE Eric Biggers 2022-10-28 22:45 ` [f2fs-dev] " Eric Biggers 2022-10-28 22:45 ` [PATCH 2/6] fsverity: support enabling " Eric Biggers 2022-10-28 22:45 ` [f2fs-dev] " Eric Biggers 2022-10-28 22:45 ` [PATCH 3/6] ext4: simplify ext4_readpage_limit() Eric Biggers 2022-10-28 22:45 ` [f2fs-dev] " Eric Biggers 2022-10-28 22:45 ` [PATCH 4/6] f2fs: simplify f2fs_readpage_limit() Eric Biggers 2022-10-28 22:45 ` [f2fs-dev] " Eric Biggers 2022-10-28 22:45 ` Eric Biggers [this message] 2022-10-28 22:45 ` [f2fs-dev] [PATCH 5/6] fs/buffer.c: support fsverity in block_read_full_folio() Eric Biggers 2022-10-28 22:45 ` [PATCH 6/6] ext4: allow verity with fs block size < PAGE_SIZE Eric Biggers 2022-10-28 22:45 ` [f2fs-dev] " Eric Biggers
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