The idea is to send a victim request that will possibly block in the
server and to send a flush request to cancel the victim request.
This patch adds two test to verifiy that:
- the server does not reply to a victim request that was actually
cancelled
- the server replies to the flush request after replying to the
victim request if it could not cancel it
9p request cancellation reference:
http://man.cat-v.org/plan_9/5/flush
Signed-off-by: Greg Kurz <groug@kaod.org>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
(groug, change the test to only write a single byte to avoid
any alignment or endianess consideration)
# Background
I was investigating spurious non-deterministic EINTR returns from
various 9p file system operations in a Linux guest served from the
qemu 9p server.
## EINTR, ERESTARTSYS and the linux kernel
When a signal arrives that the Linux kernel needs to deliver to user-space
while a given thread is blocked (in the 9p case waiting for a reply to its
request in 9p_client_rpc -> wait_event_interruptible), it asks whatever
driver is currently running to abort its current operation (in the 9p case
causing the submission of a TFLUSH message) and return to user space.
In these situations, the error message reported is generally ERESTARTSYS.
If the userspace processes specified SA_RESTART, this means that the
system call will get restarted upon completion of the signal handler
delivery (assuming the signal handler doesn't modify the process state
in complicated ways not relevant here). If SA_RESTART is not specified,
ERESTARTSYS gets translated to EINTR and user space is expected to handle
the restart itself.
## The 9p TFLUSH command
The 9p TFLUSH commands requests that the server abort an ongoing operation.
The man page [1] specifies:
```
If it recognizes oldtag as the tag of a pending transaction, it should
abort any pending response and discard that tag.
[...]
When the client sends a Tflush, it must wait to receive the corresponding
Rflush before reusing oldtag for subsequent messages. If a response to the
flushed request is received before the Rflush, the client must honor the
response as if it had not been flushed, since the completed request may
signify a state change in the server
```
In particular, this means that the server must not send a reply with the
orignal tag in response to the cancellation request, because the client is
obligated to interpret such a reply as a coincidental reply to the original
request.
# The bug
When qemu receives a TFlush request, it sets the `cancelled` flag on the
relevant pdu. This flag is periodically checked, e.g. in
`v9fs_co_name_to_path`, and if set, the operation is aborted and the error
is set to EINTR. However, the server then violates the spec, by returning
to the client an Rerror response, rather than discarding the message
entirely. As a result, the client is required to assume that said Rerror
response is a result of the original request, not a result of the
cancellation and thus passes the EINTR error back to user space.
This is not the worst thing it could do, however as discussed above, the
correct error code would have been ERESTARTSYS, such that user space
programs with SA_RESTART set get correctly restarted upon completion of
the signal handler.
Instead, such programs get spurious EINTR results that they were not
expecting to handle.
It should be noted that there are plenty of user space programs that do not
set SA_RESTART and do not correctly handle EINTR either. However, that is
then a userspace bug. It should also be noted that this bug has been
mitigated by a recent commit to the Linux kernel [2], which essentially
prevents the kernel from sending Tflush requests unless the process is about
to die (in which case the process likely doesn't care about the response).
Nevertheless, for older kernels and to comply with the spec, I believe this
change is beneficial.
# Implementation
The fix is fairly simple, just skipping notification of a reply if
the pdu was previously cancelled. We do however, also notify the transport
layer that we're doing this, so it can clean up any resources it may be
holding. I also added a new trace event to distinguish
operations that caused an error reply from those that were cancelled.
One complication is that we only omit sending the message on EINTR errors in
order to avoid confusing the rest of the code (which may assume that a
client knows about a fid if it sucessfully passed it off to pud_complete
without checking for cancellation status). This does mean that if the server
acts upon the cancellation flag, it always needs to set err to EINTR. I
believe this is true of the current code.
[1] https://9fans.github.io/plan9port/man/man9/flush.html
[2] https://github.com/torvalds/linux/commit/9523feac272ccad2ad8186ba4fcc891
Signed-off-by: Keno Fischer <keno@juliacomputing.com>
Reviewed-by: Greg Kurz <groug@kaod.org>
[groug, send a zero-sized reply instead of detaching the buffer]
Signed-off-by: Greg Kurz <groug@kaod.org>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Stefano Stabellini <sstabellini@kernel.org>
No good reasons to do this outside of v9fs_device_realize_common().
Signed-off-by: Greg Kurz <groug@kaod.org>
Reviewed-by: Stefano Stabellini <sstabellini@kernel.org>
This patch changes some error messages in the backend init code and
convert backends to propagate QEMU Error objects instead of calling
error_report().
One notable improvement is that the local backend now provides a more
detailed error report when it fails to open the shared directory.
Signed-off-by: Greg Kurz <groug@kaod.org>
If we receive an unsupported request id, we first decide to
return -ENOTSUPP to the client, but since the request id
causes is_read_only_op() to return false, we change the
error to be -EROFS if the fsdev is read-only. This doesn't
make sense since we don't know what the client asked for.
This patch ensures that -EROFS can only be returned if the
request id is supported.
Signed-off-by: Greg Kurz <groug@kaod.org>
Reviewed-by: Eric Blake <eblake@redhat.com>
The return value of v9fs_mark_fids_unreclaim() is then propagated to
pdu_complete(). It should be a negative errno, not -1.
Signed-off-by: Greg Kurz <groug@kaod.org>
Reviewed-by: Eric Blake <eblake@redhat.com>
9p back-end first queries the size of an extended attribute,
allocates space for it via g_malloc() and then retrieves its
value into allocated buffer. Race between querying attribute
size and retrieving its could lead to memory bytes disclosure.
Use g_malloc0() to avoid it.
Reported-by: Tuomas Tynkkynen <tuomas.tynkkynen@iki.fi>
Signed-off-by: Prasad J Pandit <pjp@fedoraproject.org>
Signed-off-by: Greg Kurz <groug@kaod.org>
v9fs_do_readdir_with_stat() should check for a maximum buffer size
before an attempt to marshal gathered data. Otherwise, buffers assumed
as misconfigured and the transport would be broken.
The patch brings v9fs_do_readdir_with_stat() in conformity with
v9fs_do_readdir() behavior.
Signed-off-by: Jan Dakinevich <jan.dakinevich@gmail.com>
[groug, regression caused my commit 8d37de41ca # 2.10]
Signed-off-by: Greg Kurz <groug@kaod.org>
The third parameter of v9fs_co_name_to_path() must not contain `/'
character.
The issue is most likely related to 9p2000.u protocol only.
Signed-off-by: Jan Dakinevich <jan.dakinevich@gmail.com>
[groug, regression caused by commit f57f587857 # 2.10]
Signed-off-by: Greg Kurz <groug@kaod.org>
If the client is using 9p2000.u, the following occurs:
$ cd ${virtfs_shared_dir}
$ mkdir -p a/b/c
$ ls a/b
ls: cannot access 'a/b/a': No such file or directory
ls: cannot access 'a/b/b': No such file or directory
a b c
instead of the expected:
$ ls a/b
c
This is a regression introduced by commit f57f5878578a;
local_name_to_path() now resolves ".." and "." in paths,
and v9fs_do_readdir_with_stat()->stat_to_v9stat() then
copies the basename of the resulting path to the response.
With the example above, this means that "." and ".." are
turned into "b" and "a" respectively...
stat_to_v9stat() currently assumes it is passed a full
canonicalized path and uses it to do two different things:
1) to pass it to v9fs_co_readlink() in case the file is a symbolic
link
2) to set the name field of the V9fsStat structure to the basename
part of the given path
It only has two users: v9fs_stat() and v9fs_do_readdir_with_stat().
v9fs_stat() really needs 1) and 2) to be performed since it starts
with the full canonicalized path stored in the fid. It is different
for v9fs_do_readdir_with_stat() though because the name we want to
put into the V9fsStat structure is the d_name field of the dirent
actually (ie, we want to keep the "." and ".." special names). So,
we only need 1) in this case.
This patch hence adds a basename argument to stat_to_v9stat(), to
be used to set the name field of the V9fsStat structure, and moves
the basename logic to v9fs_stat().
Signed-off-by: Jan Dakinevich <jan.dakinevich@gmail.com>
(groug, renamed old name argument to path and updated changelog)
Signed-off-by: Greg Kurz <groug@kaod.org>
(note this is how other functions also handle the errors).
hw/9pfs/9p.c:948:18: warning: Loss of sign in implicit conversion
offset = err;
^~~
Reported-by: Clang Static Analyzer
Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Signed-off-by: Greg Kurz <groug@kaod.org>
Convert all uses of error_report("warning:"... to use warn_report()
instead. This helps standardise on a single method of printing warnings
to the user.
All of the warnings were changed using these two commands:
find ./* -type f -exec sed -i \
's|error_report(".*warning[,:] |warn_report("|Ig' {} +
Indentation fixed up manually afterwards.
The test-qdev-global-props test case was manually updated to ensure that
this patch passes make check (as the test cases are case sensitive).
Signed-off-by: Alistair Francis <alistair.francis@xilinx.com>
Suggested-by: Thomas Huth <thuth@redhat.com>
Cc: Jeff Cody <jcody@redhat.com>
Cc: Kevin Wolf <kwolf@redhat.com>
Cc: Max Reitz <mreitz@redhat.com>
Cc: Ronnie Sahlberg <ronniesahlberg@gmail.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Peter Lieven <pl@kamp.de>
Cc: Josh Durgin <jdurgin@redhat.com>
Cc: "Richard W.M. Jones" <rjones@redhat.com>
Cc: Markus Armbruster <armbru@redhat.com>
Cc: Peter Crosthwaite <crosthwaite.peter@gmail.com>
Cc: Richard Henderson <rth@twiddle.net>
Cc: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>
Cc: Greg Kurz <groug@kaod.org>
Cc: Rob Herring <robh@kernel.org>
Cc: Peter Maydell <peter.maydell@linaro.org>
Cc: Peter Chubb <peter.chubb@nicta.com.au>
Cc: Eduardo Habkost <ehabkost@redhat.com>
Cc: Marcel Apfelbaum <marcel@redhat.com>
Cc: "Michael S. Tsirkin" <mst@redhat.com>
Cc: Igor Mammedov <imammedo@redhat.com>
Cc: David Gibson <david@gibson.dropbear.id.au>
Cc: Alexander Graf <agraf@suse.de>
Cc: Gerd Hoffmann <kraxel@redhat.com>
Cc: Jason Wang <jasowang@redhat.com>
Cc: Marcelo Tosatti <mtosatti@redhat.com>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Cc: Cornelia Huck <cohuck@redhat.com>
Cc: Stefan Hajnoczi <stefanha@redhat.com>
Acked-by: David Gibson <david@gibson.dropbear.id.au>
Acked-by: Greg Kurz <groug@kaod.org>
Acked-by: Cornelia Huck <cohuck@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed by: Peter Chubb <peter.chubb@data61.csiro.au>
Acked-by: Max Reitz <mreitz@redhat.com>
Acked-by: Marcel Apfelbaum <marcel@redhat.com>
Message-Id: <e1cfa2cd47087c248dd24caca9c33d9af0c499b0.1499866456.git.alistair.francis@xilinx.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Contrary to what is written in the comment, a buggy guest can misconfigure
the transport buffers and pdu_marshal() may return an error. If this ever
happens, it is up to the transport layer to handle the situation (9P is
transport agnostic).
This fixes Coverity issue CID1348518.
Signed-off-by: Greg Kurz <groug@kaod.org>
Reviewed-by: Stefano Stabellini <sstabellini@kernel.org>
The 9P protocol is transport agnostic: if the guest misconfigured the
buffers, the best we can do is to set the broken flag on the device.
Signed-off-by: Greg Kurz <groug@kaod.org>
In mapped security modes, files are created with very restrictive
permissions (600 for files and 700 for directories). This makes
file sharing between virtual machines and users on the host rather
complicated. Imagine eg. a group of users that need to access data
produced by processes on a virtual machine. Giving those users access
to the data will be difficult since the group access mode is always 0.
This patch makes the default mode for both files and directories
configurable. Existing setups that don't know about the new parameters
keep using the current secure behavior.
Signed-off-by: Tobias Schramm <tobleminer@gmail.com>
Signed-off-by: Greg Kurz <groug@kaod.org>
These v9fs_co_name_to_path() call sites have always been around. I guess
no care was taken to check the return value because the name_to_path
operation could never fail at the time. This is no longer true: the
handle and synth backends can already fail this operation, and so will the
local backend soon.
Signed-off-by: Greg Kurz <groug@kaod.org>
Reviewed-by: Eric Blake <eblake@redhat.com>
Only pdu_complete() needs to notify the client that a request has completed.
Signed-off-by: Greg Kurz <groug@kaod.org>
Reviewed-by: Stefano Stabellini <sstabellini@kernel.org>
These bits aren't related to the transport so let's move them to the core
code.
Signed-off-by: Greg Kurz <groug@kaod.org>
Reviewed-by: Stefano Stabellini <sstabellini@kernel.org>
This allows us to remove lots of includes of migration/migration.h
Signed-off-by: Juan Quintela <quintela@redhat.com>
Reviewed-by: Peter Xu <peterx@redhat.com>
Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
The migration blocker survives a device reset: if the guest mounts a 9p
share and then gets rebooted with system_reset, it will be unmigratable
until it remounts and umounts the 9p share again.
This happens because the migration blocker is supposed to be cleared when
we put the last reference on the root fid, but virtfs_reset() wrongly calls
free_fid() instead of put_fid().
This patch fixes virtfs_reset() so that it honor the way fids are supposed
to be manipulated: first get a reference and later put it back when you're
done.
Signed-off-by: Greg Kurz <groug@kaod.org>
Reviewed-by: Li Qiang <liqiang6-s@360.cn>
If a client tries to flush the same outstanding request several times, only
the first flush completes. Subsequent ones keep waiting for the request
completion in v9fs_flush() and, therefore, leak a PDU. This will cause QEMU
to hang when draining active PDUs the next time the device is reset.
Let have each flush request wake up the next one if any. The last waiter
frees the cancelled PDU.
Signed-off-by: Greg Kurz <groug@kaod.org>
Reviewed-by: Eric Blake <eblake@redhat.com>
The v9fs_create() and v9fs_lcreate() functions are used to create a file
on the backend and to associate it to a fid. The fid shouldn't be already
in-use, otherwise both functions may silently leak a file descriptor or
allocated memory. The current code doesn't check that.
This patch ensures that the fid isn't already associated to anything
before using it.
Signed-off-by: Li Qiang <liqiang6-s@360.cn>
(reworded the changelog, Greg Kurz)
Signed-off-by: Greg Kurz <groug@kaod.org>
According to the 9P spec [*], when a client wants to cancel a pending I/O
request identified by a given tag (uint16), it must send a Tflush message
and wait for the server to respond with a Rflush message before reusing this
tag for another I/O. The server may still send a completion message for the
I/O if it wasn't actually cancelled but the Rflush message must arrive after
that.
QEMU hence waits for the flushed PDU to complete before sending the Rflush
message back to the client.
If a client sends 'Tflush tag oldtag' and tag == oldtag, QEMU will then
allocate a PDU identified by tag, find it in the PDU list and wait for
this same PDU to complete... i.e. wait for a completion that will never
happen. This causes a tag and ring slot leak in the guest, and a PDU
leak in QEMU, all of them limited by the maximal number of PDUs (128).
But, worse, this causes QEMU to hang on device reset since v9fs_reset()
wants to drain all pending I/O.
This insane behavior is likely to denote a bug in the client, and it would
deserve an Rerror message to be sent back. Unfortunately, the protocol
allows it and requires all flush requests to suceed (only a Tflush response
is expected).
The only option is to detect when we have to handle a self-referencing
flush request and report success to the client right away.
[*] http://man.cat-v.org/plan_9/5/flush
Reported-by: Al Viro <viro@ZenIV.linux.org.uk>
Signed-off-by: Greg Kurz <groug@kaod.org>
This patchset adds the throttle support for the 9p-local driver.
For now this functionality can be enabled only through qemu cli options.
QMP interface and support to other drivers need further extensions.
To make it simple for other 9p drivers, the throttle code has been put in
separate files.
Signed-off-by: Pradeep Jagadeesh <pradeep.jagadeesh@huawei.com>
Reviewed-by: Alberto Garcia <berto@igalia.com>
(pass extra NULL CoMutex * argument to qemu_co_queue_wait(),
added options to qemu-options.hx, Greg Kurz)
Signed-off-by: Greg Kurz <groug@kaod.org>
In this case, we are marshaling an error status instead of the errno value.
Reorganize the out and out_nofid labels to look like all the other cases.
Coverity reports this because the "err = -ENOENT" and "err = -EINVAL"
assignments above are dead, overwritten by the call to pdu_marshal.
(Coverity issues CID1348512 and CID1348513)
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
(also open-coded the success path since locking is a nop for us, Greg Kurz)
Signed-off-by: Greg Kurz <groug@kaod.org>
All that CoQueue needs in order to become thread-safe is help
from an external mutex. Add this to the API.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Fam Zheng <famz@redhat.com>
Message-id: 20170213181244.16297-6-pbonzini@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
cause 9p clients to hang. Other patches are minor enhancements.
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Merge remote-tracking branch 'remotes/gkurz/tags/for-upstream' into staging
This pull request fixes a 2.9 regression and a long standing bug that can
cause 9p clients to hang. Other patches are minor enhancements.
# gpg: Signature made Wed 25 Jan 2017 10:12:27 GMT
# gpg: using DSA key 0x02FC3AEB0101DBC2
# gpg: Good signature from "Greg Kurz <groug@kaod.org>"
# gpg: aka "Greg Kurz <groug@free.fr>"
# gpg: aka "Greg Kurz <gkurz@fr.ibm.com>"
# gpg: aka "Greg Kurz <gkurz@linux.vnet.ibm.com>"
# gpg: aka "Gregory Kurz (Groug) <groug@free.fr>"
# gpg: aka "Gregory Kurz (Cimai Technology) <gkurz@cimai.com>"
# gpg: aka "Gregory Kurz (Meiosys Technology) <gkurz@meiosys.com>"
# gpg: WARNING: This key is not certified with a trusted signature!
# gpg: There is no indication that the signature belongs to the owner.
# Primary key fingerprint: 2BD4 3B44 535E C0A7 9894 DBA2 02FC 3AEB 0101 DBC2
* remotes/gkurz/tags/for-upstream:
9pfs: fix offset error in v9fs_xattr_read()
9pfs: local: trivial cosmetic fix in pwritev op
9pfs: fix off-by-one error in PDU free list
tests: virtio-9p: improve error reporting
9pfs: add missing coroutine_fn annotations
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
The current code tries to copy `read_count' bytes starting at offset
`offset' from a `read_count`-sized iovec. This causes v9fs_pack() to
fail with ENOBUFS.
Since the PDU iovec is already partially filled with `offset' bytes,
let's skip them when creating `qiov_full' and have v9fs_pack() to
copy the whole of it. Moreover, this is consistent with the other
places where v9fs_init_qiov_from_pdu() is called.
This fixes commit "bcb8998fac16 9pfs: call v9fs_init_qiov_from_pdu
before v9fs_pack".
Signed-off-by: Greg Kurz <groug@kaod.org>
Reviewed-by: Stefano Stabellini <sstabellini@kernel.org>
The server can handle MAX_REQ - 1 PDUs at a time and the virtio-9p
device has a MAX_REQ sized virtqueue. If the client manages to fill
up the virtqueue, pdu_alloc() will fail and the request won't be
processed without any notice to the client (it actually causes the
linux 9p client to hang).
This has been there since the beginning (commit 9f10751365 "virtio-9p:
Add a virtio 9p device to qemu"), but it needs an agressive workload to
run in the guest to show up.
We actually allocate MAX_REQ PDUs and I see no reason not to link them
all into the free list, so let's fix the init loop.
Reported-by: Tuomas Tynkkynen <tuomas@tuxera.com>
Suggested-by: Al Viro <viro@ZenIV.linux.org.uk>
Signed-off-by: Greg Kurz <groug@kaod.org>
If a migration is already in progress and somebody attempts
to add a migration blocker, this should rightly fail.
Add an errp parameter and a retcode return value to migrate_add_blocker.
Signed-off-by: John Snow <jsnow@redhat.com>
Signed-off-by: Ashijeet Acharya <ashijeetacharya@gmail.com>
Message-Id: <1484566314-3987-5-git-send-email-ashijeetacharya@gmail.com>
Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Acked-by: Greg Kurz <groug@kaod.org>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Merged with recent 'Allow invtsc migration' change
If the user passes -device virtio-9p without the corresponding -fsdev, QEMU
dereferences a NULL pointer and crashes.
This is a 2.8 regression introduced by commit 702dbcc274.
Signed-off-by: Greg Kurz <groug@kaod.org>
Reviewed-by: Li Qiang <liq3ea@gmail.com>
Not all 9pfs transports share memory between request and response. For
those who don't, it is necessary to know how much memory is required in
the response.
Split the existing init_iov_from_pdu function in two:
init_out_iov_from_pdu (for writes) and init_in_iov_from_pdu (for reads).
init_in_iov_from_pdu takes an additional size parameter to specify the
memory required for the response message.
Signed-off-by: Stefano Stabellini <sstabellini@kernel.org>
Reviewed-by: Greg Kurz <groug@kaod.org>
Signed-off-by: Greg Kurz <groug@kaod.org>
v9fs_xattr_read should not access VirtQueueElement elems directly.
Move v9fs_init_qiov_from_pdu up in the file and call
v9fs_init_qiov_from_pdu before v9fs_pack. Use v9fs_pack on the new
iovec.
Signed-off-by: Stefano Stabellini <sstabellini@kernel.org>
Reviewed-by: Greg Kurz <groug@kaod.org>
Signed-off-by: Greg Kurz <groug@kaod.org>
Don't call virtio functions from 9pfs generic code, use generic function
callbacks instead.
Signed-off-by: Stefano Stabellini <sstabellini@kernel.org>
Reviewed-by: Greg Kurz <groug@kaod.org>
Signed-off-by: Greg Kurz <groug@kaod.org>
pdus are initialized and used in 9pfs common code. Move the array from
V9fsVirtioState to V9fsState.
Signed-off-by: Stefano Stabellini <sstabellini@kernel.org>
Reviewed-by: Greg Kurz <groug@kaod.org>
Signed-off-by: Greg Kurz <groug@kaod.org>
Currently, the backend of VirtFS doesn't have a cleanup
function. This will lead resource leak issues if the backed
driver allocates resources. This patch addresses this issue.
Signed-off-by: Li Qiang <liq3ea@gmail.com>
Reviewed-by: Greg Kurz <groug@kaod.org>
Signed-off-by: Greg Kurz <groug@kaod.org>
Unrealize should undo things that were set during realize in
reverse order. So should do in the error path in realize.
Signed-off-by: Li Qiang <liq3ea@gmail.com>
Reviewed-by: Greg Kurz <groug@kaod.org>
Signed-off-by: Greg Kurz <groug@kaod.org>
The virtfs_reset() function is called either when the virtio-9p device
gets reset, or when the client starts a new 9P session. In both cases,
if it finds fids from a previous session, the following is printed in
the monitor:
9pfs:virtfs_reset: One or more uncluncked fids found during reset
For example, if a linux guest with a mounted 9P share is reset from the
monitor with system_reset, the message will be printed. This is excessive
since these fids are now clunked and the state is clean.
Signed-off-by: Greg Kurz <groug@kaod.org>
Reviewed-by: Eric Blake <eblake@redhat.com>
A buggy or malicious guest could pass the id of an already opened fid and
cause QEMU to abort. Let's return EINVAL to the guest instead.
Signed-off-by: Greg Kurz <groug@kaod.org>
Reviewed-by: Eric Blake <eblake@redhat.com>
The xattrcreate operation only makes sense on a freshly cloned fid
actually, since any open state would be leaked because of the fid_type
change. This is indeed what the linux kernel client does:
fid = clone_fid(fid);
[...]
retval = p9_client_xattrcreate(fid, name, value_len, flags);
This patch also reverts commit ff55e94d23 since we are sure that a fid
with type P9_FID_NONE doesn't have a previously allocated xattr.
Signed-off-by: Greg Kurz <groug@kaod.org>
We shouldn't allow guests to create extended attribute with arbitrary sizes.
On linux hosts, the limit is XATTR_SIZE_MAX. Let's use it.
Signed-off-by: Greg Kurz <groug@kaod.org>
The v9fs_xattr_read() and v9fs_xattr_write() are passed a guest
originated offset: they must ensure this offset does not go beyond
the size of the extended attribute that was set in v9fs_xattrcreate().
Unfortunately, the current code implement these checks with unsafe
calculations on 32 and 64 bit values, which may allow a malicious
guest to cause OOB access anyway.
Fix this by comparing the offset and the xattr size, which are
both uint64_t, before trying to compute the effective number of bytes
to read or write.
Suggested-by: Greg Kurz <groug@kaod.org>
Signed-off-by: Li Qiang <liqiang6-s@360.cn>
Reviewed-by: Greg Kurz <groug@kaod.org>
Reviewed-By: Guido Günther <agx@sigxcpu.org>
Signed-off-by: Greg Kurz <groug@kaod.org>
Currently, 9pfs sets the 'copied_len' field in V9fsXattr
to -1 to tag xattr walk fid. As the 'copied_len' is also
used to account for copied bytes, this may make confusion. This patch
add a bool 'xattrwalk_fid' to tag the xattr walk fid.
Suggested-by: Greg Kurz <groug@kaod.org>
Signed-off-by: Li Qiang <liqiang6-s@360.cn>
Reviewed-by: Greg Kurz <groug@kaod.org>
Signed-off-by: Greg Kurz <groug@kaod.org>
If an error occurs when marshalling the transfer length to the guest, the
v9fs_write() function doesn't free an IO vector, thus leading to a memory
leak. This patch fixes the issue.
Signed-off-by: Li Qiang <liqiang6-s@360.cn>
Reviewed-by: Greg Kurz <groug@kaod.org>
[groug, rephrased the changelog]
Signed-off-by: Greg Kurz <groug@kaod.org>
The v9fs_link() function keeps a reference on the source fid object. This
causes a memory leak since the reference never goes down to 0. This patch
fixes the issue.
Signed-off-by: Li Qiang <liqiang6-s@360.cn>
Reviewed-by: Greg Kurz <groug@kaod.org>
[groug, rephrased the changelog]
Signed-off-by: Greg Kurz <groug@kaod.org>
The 'fs.xattr.value' field in V9fsFidState object doesn't consider the
situation that this field has been allocated previously. Every time, it
will be allocated directly. This leads to a host memory leak issue if
the client sends another Txattrcreate message with the same fid number
before the fid from the previous time got clunked.
Signed-off-by: Li Qiang <liqiang6-s@360.cn>
Reviewed-by: Greg Kurz <groug@kaod.org>
[groug, updated the changelog to indicate how the leak can occur]
Signed-off-by: Greg Kurz <groug@kaod.org>
9pfs uses g_malloc() to allocate the xattr memory space, if the guest
reads this memory before writing to it, this will leak host heap memory
to the guest. This patch avoid this.
Signed-off-by: Li Qiang <liqiang6-s@360.cn>
Reviewed-by: Greg Kurz <groug@kaod.org>
Signed-off-by: Greg Kurz <groug@kaod.org>
