| Message ID | 20190807142114.17569-4-danielhb413@gmail.com |
|---|---|
| State | New |
| Headers | show |
| Series | delete created files when block_crypto_co_create_opts_luks fails | expand |
On 8/7/19 10:21 AM, Daniel Henrique Barboza wrote: > 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 <bssrikanth@in.ibm.com> > Suggested-by: Kevin Wolf <kwolf@redhat.com> > Signed-off-by: Daniel Henrique Barboza <danielhb413@gmail.com> > --- > block/crypto.c | 20 ++++++++++++++++++++ > 1 file changed, 20 insertions(+) > > diff --git a/block/crypto.c b/block/crypto.c > index 8237424ae6..8ffca81df6 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; > @@ -575,6 +576,25 @@ fail: > bdrv_unref(bs); > qapi_free_QCryptoBlockCreateOptions(create_opts); > qobject_unref(cryptoopts); > + > + /* > + * If an error occurred, delete the file. Even if the file existed > + * beforehand, it has been truncated and corrupted in the process. > + */ > + if (ret) { > + Error *local_err; > + int r_del = bdrv_delete_file(filename, &local_err); > + /* > + * ENOTSUP will happen if the block driver doesn't support > + * 'bdrv_co_delete_file'. ENOENT will happen if the file > + * doesn't exist. Both are predictable and shouldn't be > + * reported back to the user. > + */ Hm, actually, didn't you use ENOENT to mean that we couldn't figure out which driver to use? > + if ((r_del < 0) && (r_del != -ENOTSUP) && (r_del != -ENOENT)) { > + error_reportf_err(local_err, "%s: ", bs->filename); > + }> + } > + > return ret; > } > >
On 8/28/19 11:10 PM, John Snow wrote: > > On 8/7/19 10:21 AM, Daniel Henrique Barboza wrote: >> 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 <bssrikanth@in.ibm.com> >> Suggested-by: Kevin Wolf <kwolf@redhat.com> >> Signed-off-by: Daniel Henrique Barboza <danielhb413@gmail.com> >> --- >> block/crypto.c | 20 ++++++++++++++++++++ >> 1 file changed, 20 insertions(+) >> >> diff --git a/block/crypto.c b/block/crypto.c >> index 8237424ae6..8ffca81df6 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; >> @@ -575,6 +576,25 @@ fail: >> bdrv_unref(bs); >> qapi_free_QCryptoBlockCreateOptions(create_opts); >> qobject_unref(cryptoopts); >> + >> + /* >> + * If an error occurred, delete the file. Even if the file existed >> + * beforehand, it has been truncated and corrupted in the process. >> + */ >> + if (ret) { >> + Error *local_err; >> + int r_del = bdrv_delete_file(filename, &local_err); >> + /* >> + * ENOTSUP will happen if the block driver doesn't support >> + * 'bdrv_co_delete_file'. ENOENT will happen if the file >> + * doesn't exist. Both are predictable and shouldn't be >> + * reported back to the user. >> + */ > Hm, actually, didn't you use ENOENT to mean that we couldn't figure out > which driver to use? True. In this context though I am referring to the co_routine function that deletes the file: ------- (file-posix.c) static int coroutine_fn raw_co_delete_file(BlockDriverState *bs, Error **errp) { struct stat st; int ret; if (!(stat(bs->filename, &st) == 0) || !S_ISREG(st.st_mode)) { ret = -ENOENT; error_setg_errno(errp, -ret, "%s is not a regular file", bs->filename); goto done; } (...) ----- I'll make it clearer in the comment where ENOENT is coming from. (In fact, this is a good reason to change the !drv error in patch 2 from ENOENT to ENOMEDIUM ....) > >> + if ((r_del < 0) && (r_del != -ENOTSUP) && (r_del != -ENOENT)) { >> + error_reportf_err(local_err, "%s: ", bs->filename); >> + }> + } >> + >> return ret; >> } >> >>
diff --git a/block/crypto.c b/block/crypto.c index 8237424ae6..8ffca81df6 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; @@ -575,6 +576,25 @@ fail: bdrv_unref(bs); qapi_free_QCryptoBlockCreateOptions(create_opts); qobject_unref(cryptoopts); + + /* + * If an error occurred, delete the file. Even if the file existed + * beforehand, it has been truncated and corrupted in the process. + */ + if (ret) { + Error *local_err; + int r_del = bdrv_delete_file(filename, &local_err); + /* + * ENOTSUP will happen if the block driver doesn't support + * 'bdrv_co_delete_file'. ENOENT will happen if the file + * doesn't exist. Both are predictable and shouldn't be + * reported back to the user. + */ + if ((r_del < 0) && (r_del != -ENOTSUP) && (r_del != -ENOENT)) { + error_reportf_err(local_err, "%s: ", bs->filename); + } + } + return ret; }
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 <bssrikanth@in.ibm.com> Suggested-by: Kevin Wolf <kwolf@redhat.com> Signed-off-by: Daniel Henrique Barboza <danielhb413@gmail.com> --- block/crypto.c | 20 ++++++++++++++++++++ 1 file changed, 20 insertions(+)