From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 3ED6913B29C; Tue, 27 Feb 2024 14:16:35 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1709043396; cv=none; b=uizV248vEgzh4WUYHTzf/zx1qzTgqjKcUzgktxt7kbyxVQinW0GuMvQO34Gosl8hC8+rmUGEe6W4U57w3Zj2Hg1epUQEIWhEraekuRb78CenCxYRD+pJkftbVAOkuarLYxLwk43IHgdiRj1kcPkMVGv0KDs9FbvkNIDVwGAYiJc= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1709043396; c=relaxed/simple; bh=InxdeiCWvlXIrjgI7zGeFmbE5u06p+7trh2G1dt9SK0=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=X74HlEgRsW6lFKp7mOsIuc7jIvmGaNkX6Y/p4eupTVcwZt0xJ6Utdq08n3hJ6u15E8Hu/H5/fI60a+5pOrne8ybBlppBgZVcDh2F0P0YLJigmAKUrzwIqf+ZvbN28Ek5m+RjcGQ/+HkQ5QKS0fTwa212+mpGjjsYV/TMm3yiu2M= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=vijwO35G; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="vijwO35G" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 67B85C433A6; Tue, 27 Feb 2024 14:16:35 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1709043395; bh=InxdeiCWvlXIrjgI7zGeFmbE5u06p+7trh2G1dt9SK0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=vijwO35GjV4uQpjH0Qz6NKHJutrj7cTJepLoUQqJLQr0C5k0UdEAgFQXJdJqr2wV1 JSf5zMY0OqZzQBQmSrub32jnJ0+E7PdCi3PvjfZD67XMHdnYOEhfyzAMOGjMXkq1IF UzRypis0L9egFgR94zuOAea0fpaqQ8Ucxe2HT+LU= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Mikulas Patocka , Mike Snitzer Subject: [PATCH 6.1 092/195] dm-verity: recheck the hash after a failure Date: Tue, 27 Feb 2024 14:25:53 +0100 Message-ID: <20240227131613.517406327@linuxfoundation.org> X-Mailer: git-send-email 2.44.0 In-Reply-To: <20240227131610.391465389@linuxfoundation.org> References: <20240227131610.391465389@linuxfoundation.org> User-Agent: quilt/0.67 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.1-stable review patch. If anyone has any objections, please let me know. ------------------ From: Mikulas Patocka commit 9177f3c0dea6143d05cac1bbd28668fd0e216d11 upstream. If a userspace process reads (with O_DIRECT) multiple blocks into the same buffer, dm-verity reports an error [1]. This commit fixes dm-verity, so that if hash verification fails, the data is read again into a kernel buffer (where userspace can't modify it) and the hash is rechecked. If the recheck succeeds, the content of the kernel buffer is copied into the user buffer; if the recheck fails, an error is reported. [1] https://people.redhat.com/~mpatocka/testcases/blk-auth-modify/read2.c Signed-off-by: Mikulas Patocka Cc: stable@vger.kernel.org Signed-off-by: Mike Snitzer Signed-off-by: Greg Kroah-Hartman --- drivers/md/dm-verity-target.c | 86 +++++++++++++++++++++++++++++++++++++++--- drivers/md/dm-verity.h | 6 ++ 2 files changed, 86 insertions(+), 6 deletions(-) --- a/drivers/md/dm-verity-target.c +++ b/drivers/md/dm-verity-target.c @@ -474,6 +474,63 @@ int verity_for_bv_block(struct dm_verity return 0; } +static int verity_recheck_copy(struct dm_verity *v, struct dm_verity_io *io, + u8 *data, size_t len) +{ + memcpy(data, io->recheck_buffer, len); + io->recheck_buffer += len; + + return 0; +} + +static int verity_recheck(struct dm_verity *v, struct dm_verity_io *io, + struct bvec_iter start, sector_t cur_block) +{ + struct page *page; + void *buffer; + int r; + struct dm_io_request io_req; + struct dm_io_region io_loc; + + page = mempool_alloc(&v->recheck_pool, GFP_NOIO); + buffer = page_to_virt(page); + + io_req.bi_opf = REQ_OP_READ; + io_req.mem.type = DM_IO_KMEM; + io_req.mem.ptr.addr = buffer; + io_req.notify.fn = NULL; + io_req.client = v->io; + io_loc.bdev = v->data_dev->bdev; + io_loc.sector = cur_block << (v->data_dev_block_bits - SECTOR_SHIFT); + io_loc.count = 1 << (v->data_dev_block_bits - SECTOR_SHIFT); + r = dm_io(&io_req, 1, &io_loc, NULL); + if (unlikely(r)) + goto free_ret; + + r = verity_hash(v, verity_io_hash_req(v, io), buffer, + 1 << v->data_dev_block_bits, + verity_io_real_digest(v, io), true); + if (unlikely(r)) + goto free_ret; + + if (memcmp(verity_io_real_digest(v, io), + verity_io_want_digest(v, io), v->digest_size)) { + r = -EIO; + goto free_ret; + } + + io->recheck_buffer = buffer; + r = verity_for_bv_block(v, io, &start, verity_recheck_copy); + if (unlikely(r)) + goto free_ret; + + r = 0; +free_ret: + mempool_free(page, &v->recheck_pool); + + return r; +} + static int verity_bv_zero(struct dm_verity *v, struct dm_verity_io *io, u8 *data, size_t len) { @@ -500,9 +557,7 @@ static int verity_verify_io(struct dm_ve { bool is_zero; struct dm_verity *v = io->v; -#if defined(CONFIG_DM_VERITY_FEC) struct bvec_iter start; -#endif struct bvec_iter iter_copy; struct bvec_iter *iter; struct crypto_wait wait; @@ -553,10 +608,7 @@ static int verity_verify_io(struct dm_ve if (unlikely(r < 0)) return r; -#if defined(CONFIG_DM_VERITY_FEC) - if (verity_fec_is_enabled(v)) - start = *iter; -#endif + start = *iter; r = verity_for_io_block(v, io, iter, &wait); if (unlikely(r < 0)) return r; @@ -578,6 +630,10 @@ static int verity_verify_io(struct dm_ve * tasklet since it may sleep, so fallback to work-queue. */ return -EAGAIN; + } else if (verity_recheck(v, io, start, cur_block) == 0) { + if (v->validated_blocks) + set_bit(cur_block, v->validated_blocks); + continue; #if defined(CONFIG_DM_VERITY_FEC) } else if (verity_fec_decode(v, io, DM_VERITY_BLOCK_TYPE_DATA, cur_block, NULL, &start) == 0) { @@ -928,6 +984,10 @@ static void verity_dtr(struct dm_target if (v->verify_wq) destroy_workqueue(v->verify_wq); + mempool_exit(&v->recheck_pool); + if (v->io) + dm_io_client_destroy(v->io); + if (v->bufio) dm_bufio_client_destroy(v->bufio); @@ -1364,6 +1424,20 @@ static int verity_ctr(struct dm_target * } v->hash_blocks = hash_position; + r = mempool_init_page_pool(&v->recheck_pool, 1, 0); + if (unlikely(r)) { + ti->error = "Cannot allocate mempool"; + goto bad; + } + + v->io = dm_io_client_create(); + if (IS_ERR(v->io)) { + r = PTR_ERR(v->io); + v->io = NULL; + ti->error = "Cannot allocate dm io"; + goto bad; + } + v->bufio = dm_bufio_client_create(v->hash_dev->bdev, 1 << v->hash_dev_block_bits, 1, sizeof(struct buffer_aux), dm_bufio_alloc_callback, NULL, --- a/drivers/md/dm-verity.h +++ b/drivers/md/dm-verity.h @@ -11,6 +11,7 @@ #ifndef DM_VERITY_H #define DM_VERITY_H +#include #include #include #include @@ -68,6 +69,9 @@ struct dm_verity { unsigned long *validated_blocks; /* bitset blocks validated */ char *signature_key_desc; /* signature keyring reference */ + + struct dm_io_client *io; + mempool_t recheck_pool; }; struct dm_verity_io { @@ -84,6 +88,8 @@ struct dm_verity_io { struct work_struct work; + char *recheck_buffer; + /* * Three variably-size fields follow this struct: *