Looking at the qcow2 code that is riddled with error_report() calls,
this is really how it should have been from the start.
Along the way, turn the target_version/current_version comparisons at
the beginning of qcow2_downgrade() into assertions (the caller has to
make sure these conditions are met), and rephrase the error message on
using compat=1.1 to get refcount widths other than 16 bits.
Signed-off-by: Max Reitz <mreitz@redhat.com>
Message-id: 20180509210023.20283-3-mreitz@redhat.com
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: John Snow <jsnow@redhat.com>
Signed-off-by: Max Reitz <mreitz@redhat.com>
'qemu-img check' cannot detect if a snapshot's L1 table is corrupted.
This patch checks the table's offset and size and reports corruption
if the values are not valid.
This patch doesn't add code to fix that corruption yet, only to detect
and report it.
Signed-off-by: Alberto Garcia <berto@igalia.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
This function deletes a snapshot from disk, removing its entry from
the snapshot table, freeing its L1 table and decreasing the refcounts
of all clusters.
The L1 table offset and size are however not validated. If we use
invalid values in this function we'll probably corrupt the image even
more, so we should return an error instead.
We now have a function to take care of this, so let's use it.
Signed-off-by: Alberto Garcia <berto@igalia.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
This function copies a snapshot's L1 table into the active one without
validating it first.
We now have a function to take care of this, so let's use it.
Cc: Eric Blake <eblake@redhat.com>
Signed-off-by: Alberto Garcia <berto@igalia.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
The inactive-l2 overlap check iterates uses the L1 tables from all
snapshots, but it does not validate them first.
We now have a function to take care of this, so let's use it.
Signed-off-by: Alberto Garcia <berto@igalia.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
This function iterates over all snapshots of a qcow2 file in order to
expand all zero clusters, but it does not validate the snapshots' L1
tables first.
We now have a function to take care of this, so let's use it.
We can also take the opportunity to replace the sector-based
bdrv_read() with bdrv_pread().
Cc: Eric Blake <eblake@redhat.com>
Signed-off-by: Alberto Garcia <berto@igalia.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
This function checks that the size of a snapshot's L1 table is not too
large, but it doesn't validate the offset.
We now have a function to take care of this, so let's use it.
Signed-off-by: Alberto Garcia <berto@igalia.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
This function checks that the offset and size of a table are valid.
While the offset checks are fine, the size check is too generic, since
it only verifies that the total size in bytes fits in a 64-bit
integer. In practice all tables used in qcow2 have much smaller size
limits, so the size needs to be checked again for each table using its
actual limit.
This patch generalizes this function by allowing the caller to specify
the maximum size for that table. In addition to that it allows passing
an Error variable.
The function is also renamed and made public since we're going to use
it in other parts of the code.
Signed-off-by: Alberto Garcia <berto@igalia.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
The result of openfile was not checked, leading to failure deep in the
actual command with confusing error message, and exiting with exit code 0.
Here is a simple example - trying to read with the wrong format:
$ touch file
$ qemu-io -f qcow2 -c 'read -P 1 0 1024' file; echo $?
can't open device file: Image is not in qcow2 format
no file open, try 'help open'
0
With this patch, we fail earlier with exit code 1:
$ ./qemu-io -f qcow2 -c 'read -P 1 0 1024' file; echo $?
can't open device file: Image is not in qcow2 format
1
Failing earlier, we don't log this error now:
no file open, try 'help open'
But some tests expected it; the line was removed from the test output.
Signed-off-by: Nir Soffer <nirsof@gmail.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-id: 20170201003120.23378-2-nirsof@gmail.com
Reviewed-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Max Reitz <mreitz@redhat.com>
Just three instances left.
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-Id: <1450452927-8346-16-git-send-email-armbru@redhat.com>
This is simply:
$ cd tests/qemu-iotests; sed -i -e 's/ *$//' *.out
Signed-off-by: Fam Zheng <famz@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
Message-id: 1418110684-19528-2-git-send-email-famz@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
After reading the extension header, offset is incremented, but not
checked against end_offset any more. This way an integer overflow could
happen when checking whether the extension end is within the allowed
range, effectively disabling the check.
This patch adds the missing check and a test case for it.
Cc: qemu-stable@nongnu.org
Reported-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Message-id: 1416935562-7760-2-git-send-email-kwolf@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
This avoids an unbounded allocation.
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
The qcow2 code assumes that s->snapshots is non-NULL if s->nb_snapshots
!= 0. By having the initialisation of both fields separated in
qcow2_open(), any error occuring in between would cause the error path
to dereference NULL in qcow2_free_snapshots() if the image had any
snapshots.
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
free_cluster_index is only correct if update_refcount() was called from
an allocation function, and even there it's brittle because it's used to
protect unfinished allocations which still have a refcount of 0 - if it
moves in the wrong place, the unfinished allocation can be corrupted.
So not using it any more seems to be a good idea. Instead, use the
first requested cluster to do the calculations. Return -EAGAIN if
unfinished allocations could become invalid and let the caller restart
its search for some free clusters.
The context of creating a snapsnot is one situation where
update_refcount() is called outside of a cluster allocation. For this
case, the change fixes a buffer overflow if a cluster is referenced in
an L2 table that cannot be represented by an existing refcount block.
(new_table[refcount_table_index] was out of bounds)
[Bump the qemu-iotests 026 refblock_alloc.write leak count from 10 to
11.
--Stefan]
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
len could become negative and would pass the check then. Nothing bad
happened because bdrv_pread() happens to return an error for negative
length values, but make variables for sizes unsigned anyway.
This patch also changes the behaviour to error out on invalid lengths
instead of silently truncating it to 1023.
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
This avoids an unbounded allocation.
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
This avoid unbounded memory allocation and fixes a potential buffer
overflow on 32 bit hosts.
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
The end of the refcount table must not exceed INT64_MAX so that integer
overflows are avoided.
Also check for misaligned refcount table. Such images are invalid and
probably the result of data corruption. Error out to avoid further
corruption.
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Limit the in-memory reference count table size to 8 MB, it's enough in
practice. This fixes an unbounded allocation as well as a buffer
overflow in qcow2_refcount_init().
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Header, header extension and the backing file name must all be stored in
the first cluster. Setting the backing file to a much higher value
allowed header extensions to become much bigger than we want them to be
(unbounded allocation).
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
This fixes an unbounded allocation for s->unknown_header_fields.
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
