From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-2.9 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_PASS, URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 33859C1B0E3 for ; Wed, 11 Jul 2018 20:36:31 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id BDC3620C0C for ; Wed, 11 Jul 2018 20:36:30 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=chromium.org header.i=@chromium.org header.b="jOooXl2Y" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org BDC3620C0C Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=chromium.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2390046AbeGKUmb (ORCPT ); Wed, 11 Jul 2018 16:42:31 -0400 Received: from mail-pf0-f195.google.com ([209.85.192.195]:45346 "EHLO mail-pf0-f195.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2387708AbeGKUm3 (ORCPT ); Wed, 11 Jul 2018 16:42:29 -0400 Received: by mail-pf0-f195.google.com with SMTP id i26-v6so7712390pfo.12 for ; Wed, 11 Jul 2018 13:36:26 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=chromium.org; s=google; h=from:to:cc:subject:date:message-id:in-reply-to:references; bh=drpA6tkH0/4nnAgKnMLWfij+3JEItujTdy3T6O/cSWg=; b=jOooXl2YS63jg0hX5HiqXgFBhZ7sZKr2zOmv9WPVkbNuI9eOGWsVEfmI6yUfBj2g+I JAPX31h78QXMirqglHXLtgGBBrpmtyLbPicLUHkrJ9G1XsWWZ2DAt7kfp0D9q2A5vfe6 zphE09UwPfSCQpgcIm6J0ulXZUfJuT9cpUAgY= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references; bh=drpA6tkH0/4nnAgKnMLWfij+3JEItujTdy3T6O/cSWg=; b=rCXiNjn8Irn+lJg7i0ixEDvcX5aER5CnxevKWN2w4rKqa/xz145Yy9UuF6gZiBnGfQ eVRa8/l9KoVxkCbSDM0MuRMOobDWnpZr2G5Eesxddb51pBcJ8gOqve6cgEquga00K1qE QdvazvvA6sOoIxKQhFGZOGAccN5TTxYG8JliNAe86izkjHV+tr4GAGAhuSYnuMQ1OCw7 8OqTNEZPIf+BDO57E4KbKJ86b92MbPB9XibSTFN2/O9CqGvtFQLA1q9hvzvou4a79EUj E2HnDqUa6sjXHUj8dj/WPGQbz7rcSpVeKUrM9y4bjK7TZXvrXJB1slDNOImyBjdxvNzD CYdw== X-Gm-Message-State: AOUpUlFGZH+h1JX/3ixW1YUKZN7B7oqa/40hI9ZgJ6S7ikgGL1lzkNSs hgfnxBcRHAG3nNz8WloR2i/XmA== X-Google-Smtp-Source: AAOMgpdYGes3vQ2R8FLiK7l3+ivOZRYPU6V1EhrMJ7MCI9Sh0UT1yq7YBy/IbL5e66bit4PVOwbIkw== X-Received: by 2002:a62:3f44:: with SMTP id m65-v6mr167704pfa.98.1531341386147; Wed, 11 Jul 2018 13:36:26 -0700 (PDT) Received: from www.outflux.net (173-164-112-133-Oregon.hfc.comcastbusiness.net. [173.164.112.133]) by smtp.gmail.com with ESMTPSA id u2-v6sm31913749pfn.59.2018.07.11.13.36.22 (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Wed, 11 Jul 2018 13:36:23 -0700 (PDT) From: Kees Cook To: Herbert Xu Cc: Kees Cook , "Gustavo A. R. Silva" , Arnd Bergmann , Eric Biggers , Alasdair Kergon , Giovanni Cabiddu , Lars Persson , Mike Snitzer , Rabin Vincent , Tim Chen , "David S. Miller" , Masahiro Yamada , linux-crypto@vger.kernel.org, qat-linux@intel.com, dm-devel@redhat.com, linux-kernel@vger.kernel.org Subject: [PATCH v4 04/14] dm integrity: Remove VLA usage Date: Wed, 11 Jul 2018 13:36:09 -0700 Message-Id: <20180711203619.1020-5-keescook@chromium.org> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20180711203619.1020-1-keescook@chromium.org> References: <20180711203619.1020-1-keescook@chromium.org> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org In the quest to remove all stack VLA usage from the kernel[1], this uses the new SHASH_MAX_DIGESTSIZE from the crypto layer to allocate the upper bounds on stack usage. [1] https://lkml.kernel.org/r/CA+55aFzCG-zNmZwX4A2FQpadafLfEzK6CC=qPXydAacU1RqZWA@mail.gmail.com Signed-off-by: Kees Cook --- drivers/md/dm-integrity.c | 23 +++++++++++++++++------ 1 file changed, 17 insertions(+), 6 deletions(-) diff --git a/drivers/md/dm-integrity.c b/drivers/md/dm-integrity.c index 86438b2f10dd..85e8ce1625a2 100644 --- a/drivers/md/dm-integrity.c +++ b/drivers/md/dm-integrity.c @@ -521,7 +521,12 @@ static void section_mac(struct dm_integrity_c *ic, unsigned section, __u8 result } memset(result + size, 0, JOURNAL_MAC_SIZE - size); } else { - __u8 digest[size]; + __u8 digest[SHASH_MAX_DIGESTSIZE]; + + if (WARN_ON(size > sizeof(digest))) { + dm_integrity_io_error(ic, "digest_size", -EINVAL); + goto err; + } r = crypto_shash_final(desc, digest); if (unlikely(r)) { dm_integrity_io_error(ic, "crypto_shash_final", r); @@ -1244,7 +1249,7 @@ static void integrity_metadata(struct work_struct *w) struct bio *bio = dm_bio_from_per_bio_data(dio, sizeof(struct dm_integrity_io)); char *checksums; unsigned extra_space = unlikely(digest_size > ic->tag_size) ? digest_size - ic->tag_size : 0; - char checksums_onstack[ic->tag_size + extra_space]; + char checksums_onstack[SHASH_MAX_DIGESTSIZE]; unsigned sectors_to_process = dio->range.n_sectors; sector_t sector = dio->range.logical_sector; @@ -1253,8 +1258,14 @@ static void integrity_metadata(struct work_struct *w) checksums = kmalloc((PAGE_SIZE >> SECTOR_SHIFT >> ic->sb->log2_sectors_per_block) * ic->tag_size + extra_space, GFP_NOIO | __GFP_NORETRY | __GFP_NOWARN); - if (!checksums) + if (!checksums) { checksums = checksums_onstack; + if (WARN_ON(extra_space && + digest_size > sizeof(checksums_onstack))) { + r = -EINVAL; + goto error; + } + } __bio_for_each_segment(bv, bio, iter, dio->orig_bi_iter) { unsigned pos; @@ -1466,7 +1477,7 @@ static bool __journal_read_write(struct dm_integrity_io *dio, struct bio *bio, } while (++s < ic->sectors_per_block); #ifdef INTERNAL_VERIFY if (ic->internal_hash) { - char checksums_onstack[max(crypto_shash_digestsize(ic->internal_hash), ic->tag_size)]; + char checksums_onstack[max(SHASH_MAX_DIGESTSIZE, MAX_TAG_SIZE)]; integrity_sector_checksum(ic, logical_sector, mem + bv.bv_offset, checksums_onstack); if (unlikely(memcmp(checksums_onstack, journal_entry_tag(ic, je), ic->tag_size))) { @@ -1516,7 +1527,7 @@ static bool __journal_read_write(struct dm_integrity_io *dio, struct bio *bio, if (ic->internal_hash) { unsigned digest_size = crypto_shash_digestsize(ic->internal_hash); if (unlikely(digest_size > ic->tag_size)) { - char checksums_onstack[digest_size]; + char checksums_onstack[SHASH_MAX_DIGESTSIZE]; integrity_sector_checksum(ic, logical_sector, (char *)js, checksums_onstack); memcpy(journal_entry_tag(ic, je), checksums_onstack, ic->tag_size); } else @@ -1937,7 +1948,7 @@ static void do_journal_write(struct dm_integrity_c *ic, unsigned write_start, unlikely(from_replay) && #endif ic->internal_hash) { - char test_tag[max(crypto_shash_digestsize(ic->internal_hash), ic->tag_size)]; + char test_tag[max_t(size_t, SHASH_MAX_DIGESTSIZE, MAX_TAG_SIZE)]; integrity_sector_checksum(ic, sec + ((l - j) << ic->sb->log2_sectors_per_block), (char *)access_journal_data(ic, i, l), test_tag); -- 2.17.1