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[Qemu-block] [PULL 14/16] block/qcow2: Fix corruption introduced by comm
From: |
Max Reitz |
Subject: |
[Qemu-block] [PULL 14/16] block/qcow2: Fix corruption introduced by commit 8ac0f15f335 |
Date: |
Mon, 16 Sep 2019 16:22:44 +0200 |
From: Maxim Levitsky <address@hidden>
This fixes subtle corruption introduced by luks threaded encryption
in commit 8ac0f15f335
Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=1745922
The corruption happens when we do a write that
* writes to two or more unallocated clusters at once
* doesn't fully cover the first sector
* doesn't fully cover the last sector
* uses luks encryption
In this case, when allocating the new clusters we COW both areas
prior to the write and after the write, and we encrypt them.
The above mentioned commit accidentally made it so we encrypt the
second COW area using the physical cluster offset of the first area.
The problem is that offset_in_cluster in do_perform_cow_encrypt
can be larger that the cluster size, thus cluster_offset
will no longer point to the start of the cluster at which encrypted
area starts.
Next patch in this series will refactor the code to avoid all these
assumptions.
In the bugreport that was triggered by rebasing a luks image to new,
zero filled base, which lot of such writes, and causes some files
with zero areas to contain garbage there instead.
But as described above it can happen elsewhere as well
Signed-off-by: Maxim Levitsky <address@hidden>
Reviewed-by: Vladimir Sementsov-Ogievskiy <address@hidden>
Message-id: address@hidden
Reviewed-by: Max Reitz <address@hidden>
Signed-off-by: Max Reitz <address@hidden>
---
block/qcow2-cluster.c | 7 ++++---
1 file changed, 4 insertions(+), 3 deletions(-)
diff --git a/block/qcow2-cluster.c b/block/qcow2-cluster.c
index cb44b6c6ba..cac0b6c7ba 100644
--- a/block/qcow2-cluster.c
+++ b/block/qcow2-cluster.c
@@ -474,9 +474,10 @@ static bool coroutine_fn
do_perform_cow_encrypt(BlockDriverState *bs,
assert(QEMU_IS_ALIGNED(offset_in_cluster, BDRV_SECTOR_SIZE));
assert(QEMU_IS_ALIGNED(bytes, BDRV_SECTOR_SIZE));
assert(s->crypto);
- if (qcow2_co_encrypt(bs, cluster_offset,
- src_cluster_offset + offset_in_cluster,
- buffer, bytes) < 0) {
+ if (qcow2_co_encrypt(bs,
+ start_of_cluster(s, cluster_offset + offset_in_cluster),
+ src_cluster_offset + offset_in_cluster,
+ buffer, bytes) < 0) {
return false;
}
}
--
2.21.0
- [Qemu-block] [PULL 04/16] tests/Makefile: Do not print the name of the check-block.sh shell script, (continued)
- [Qemu-block] [PULL 04/16] tests/Makefile: Do not print the name of the check-block.sh shell script, Max Reitz, 2019/09/16
- [Qemu-block] [PULL 06/16] curl: Keep pointer to the CURLState in CURLSocket, Max Reitz, 2019/09/16
- [Qemu-block] [PULL 05/16] tests/qemu-iotests: Fix qemu-io related output in 026.out.nocache, Max Reitz, 2019/09/16
- [Qemu-block] [PULL 07/16] curl: Keep *socket until the end of curl_sock_cb(), Max Reitz, 2019/09/16
- [Qemu-block] [PULL 08/16] curl: Check completion in curl_multi_do(), Max Reitz, 2019/09/16
- [Qemu-block] [PULL 09/16] curl: Pass CURLSocket to curl_multi_do(), Max Reitz, 2019/09/16
- [Qemu-block] [PULL 10/16] curl: Report only ready sockets, Max Reitz, 2019/09/16
- [Qemu-block] [PULL 11/16] curl: Handle success in multi_check_completion, Max Reitz, 2019/09/16
- [Qemu-block] [PULL 12/16] curl: Check curl_multi_add_handle()'s return code, Max Reitz, 2019/09/16
- [Qemu-block] [PULL 13/16] blockjob: update nodes head while removing all bdrv, Max Reitz, 2019/09/16
- [Qemu-block] [PULL 14/16] block/qcow2: Fix corruption introduced by commit 8ac0f15f335,
Max Reitz <=
- [Qemu-block] [PULL 15/16] block/qcow2: refactor encryption code, Max Reitz, 2019/09/16
- [Qemu-block] [PULL 16/16] qemu-iotests: Add test for bz #1745922, Max Reitz, 2019/09/16
- Re: [Qemu-block] [Qemu-devel] [PULL 00/16] Block patches, no-reply, 2019/09/16
- Re: [Qemu-block] [PULL 00/16] Block patches, Peter Maydell, 2019/09/17