From 1bba30da24e1124ceeb0693c81382a0d77e20ca5 Mon Sep 17 00:00:00 2001 From: Daniel Henrique Barboza Date: Thu, 30 Jan 2020 18:39:06 -0300 Subject: [PATCH] crypto.c: cleanup created file when block_crypto_co_create_opts_luks fails When using a non-UTF8 secret to create a volume using qemu-img, the following error happens: $ 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 Formatting '/var/tmp/pool_target/vol_1', fmt=luks size=10485760 key-secret=vol_1_encrypt0 qemu-img: /var/tmp/pool_target/vol_1: Data from secret vol_1_encrypt0 is not valid UTF-8 However, the created file '/var/tmp/pool_target/vol_1' is left behind in the file system after the failure. This behavior can be observed when creating the volume using Libvirt, via 'virsh vol-create', and then getting "volume target path already exist" errors when trying to re-create the volume. The volume file is created inside block_crypto_co_create_opts_luks(), in block/crypto.c. If the bdrv_create_file() call is successful but any succeeding step fails*, the existing 'fail' label does not take into account the created file, leaving it behind. This patch changes block_crypto_co_create_opts_luks() to delete 'filename' in case of failure. A failure in this point means that the volume is now truncated/corrupted, so even if 'filename' was an existing volume before calling qemu-img, it is now unusable. Deleting the file it is not much worse than leaving it in the filesystem in this scenario, and we don't have to deal with checking the file pre-existence in the code. * in our case, block_crypto_co_create_generic calls qcrypto_block_create, which calls qcrypto_block_luks_create, and this function fails when calling qcrypto_secret_lookup_as_utf8. Reported-by: Srikanth Aithal Suggested-by: Kevin Wolf Signed-off-by: Daniel Henrique Barboza Message-Id: <20200130213907.2830642-4-danielhb413@gmail.com> Signed-off-by: Kevin Wolf --- block/crypto.c | 18 ++++++++++++++++++ 1 file changed, 18 insertions(+) diff --git a/block/crypto.c b/block/crypto.c index 24823835c1..00e8ec537d 100644 --- a/block/crypto.c +++ b/block/crypto.c @@ -30,6 +30,7 @@ #include "qapi/error.h" #include "qemu/module.h" #include "qemu/option.h" +#include "qemu/cutils.h" #include "crypto.h" typedef struct BlockCrypto BlockCrypto; @@ -596,6 +597,23 @@ static int coroutine_fn block_crypto_co_create_opts_luks(const char *filename, ret = 0; fail: + /* + * If an error occurred, delete 'filename'. Even if the file existed + * beforehand, it has been truncated and corrupted in the process. + */ + if (ret && bs) { + Error *local_delete_err = NULL; + int r_del = bdrv_co_delete_file(bs, &local_delete_err); + /* + * ENOTSUP will happen if the block driver doesn't support + * the 'bdrv_co_delete_file' interface. This is a predictable + * scenario and shouldn't be reported back to the user. + */ + if ((r_del < 0) && (r_del != -ENOTSUP)) { + error_report_err(local_delete_err); + } + } + bdrv_unref(bs); qapi_free_QCryptoBlockCreateOptions(create_opts); qobject_unref(cryptoopts); -- GitLab