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Blame SOURCES/kvm-crypto.c-cleanup-created-file-when-block_crypto_co_c.patch

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From 043decff5812c1f46ed44dd0f82099e3b8bb6a28 Mon Sep 17 00:00:00 2001
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From: Maxim Levitsky <mlevitsk@redhat.com>
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Date: Sun, 31 May 2020 16:40:35 +0100
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Subject: [PATCH 7/7] crypto.c: cleanup created file when
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 block_crypto_co_create_opts_luks fails
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RH-Author: Maxim Levitsky <mlevitsk@redhat.com>
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Message-id: <20200531164035.34188-4-mlevitsk@redhat.com>
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Patchwork-id: 97060
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O-Subject: [RHEL-AV-8.2.1 qemu-kvm PATCH 3/3] crypto.c: cleanup created file when block_crypto_co_create_opts_luks fails
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Bugzilla: 1827630
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RH-Acked-by: Sergio Lopez Pascual <slp@redhat.com>
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RH-Acked-by: John Snow <jsnow@redhat.com>
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RH-Acked-by: Eric Blake <eblake@redhat.com>
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From: Daniel Henrique Barboza <danielhb413@gmail.com>
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When using a non-UTF8 secret to create a volume using qemu-img, the
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following error happens:
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$ qemu-img create -f luks --object secret,id=vol_1_encrypt0,file=vol_resize_pool.vol_1.secret.qzVQrI -o key-secret=vol_1_encrypt0 /var/tmp/pool_target/vol_1 10240K
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Formatting '/var/tmp/pool_target/vol_1', fmt=luks size=10485760 key-secret=vol_1_encrypt0
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qemu-img: /var/tmp/pool_target/vol_1: Data from secret vol_1_encrypt0 is not valid UTF-8
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However, the created file '/var/tmp/pool_target/vol_1' is left behind in the
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file system after the failure. This behavior can be observed when creating
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the volume using Libvirt, via 'virsh vol-create', and then getting "volume
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target path already exist" errors when trying to re-create the volume.
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The volume file is created inside block_crypto_co_create_opts_luks(), in
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block/crypto.c. If the bdrv_create_file() call is successful but any
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succeeding step fails*, the existing 'fail' label does not take into
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account the created file, leaving it behind.
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This patch changes block_crypto_co_create_opts_luks() to delete
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'filename' in case of failure. A failure in this point means that
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the volume is now truncated/corrupted, so even if 'filename' was an
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existing volume before calling qemu-img, it is now unusable. Deleting
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the file it is not much worse than leaving it in the filesystem in
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this scenario, and we don't have to deal with checking the file
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pre-existence in the code.
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* in our case, block_crypto_co_create_generic calls qcrypto_block_create,
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which calls qcrypto_block_luks_create, and this function fails when
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calling qcrypto_secret_lookup_as_utf8.
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Reported-by: Srikanth Aithal <bssrikanth@in.ibm.com>
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Suggested-by: Kevin Wolf <kwolf@redhat.com>
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Signed-off-by: Daniel Henrique Barboza <danielhb413@gmail.com>
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Message-Id: <20200130213907.2830642-4-danielhb413@gmail.com>
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Signed-off-by: Kevin Wolf <kwolf@redhat.com>
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(cherry picked from commit 1bba30da24e1124ceeb0693c81382a0d77e20ca5)
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Signed-off-by: Maxim Levitsky <mlevitsk@redhat.com>
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Signed-off-by: Danilo C. L. de Paula <ddepaula@redhat.com>
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---
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 block/crypto.c | 18 ++++++++++++++++++
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 1 file changed, 18 insertions(+)
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diff --git a/block/crypto.c b/block/crypto.c
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index 970d463..5e3b15c 100644
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--- a/block/crypto.c
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+++ b/block/crypto.c
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@@ -30,6 +30,7 @@
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 #include "qapi/error.h"
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 #include "qemu/module.h"
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 #include "qemu/option.h"
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+#include "qemu/cutils.h"
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 #include "crypto.h"
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 typedef struct BlockCrypto BlockCrypto;
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@@ -597,6 +598,23 @@ static int coroutine_fn block_crypto_co_create_opts_luks(BlockDriver *drv,
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     ret = 0;
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 fail:
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+    /*
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+     * If an error occurred, delete 'filename'. Even if the file existed
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+     * beforehand, it has been truncated and corrupted in the process.
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+     */
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+    if (ret && bs) {
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+        Error *local_delete_err = NULL;
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+        int r_del = bdrv_co_delete_file(bs, &local_delete_err);
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+        /*
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+         * ENOTSUP will happen if the block driver doesn't support
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+         * the 'bdrv_co_delete_file' interface. This is a predictable
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+         * scenario and shouldn't be reported back to the user.
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+         */
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+        if ((r_del < 0) && (r_del != -ENOTSUP)) {
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+            error_report_err(local_delete_err);
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+        }
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+    }
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+
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     bdrv_unref(bs);
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     qapi_free_QCryptoBlockCreateOptions(create_opts);
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     qobject_unref(cryptoopts);
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-- 
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1.8.3.1
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