Some code in the block layer makes potentially huge allocations. Failure
is not completely unexpected there, so avoid aborting qemu and handle
out-of-memory situations gracefully.
This patch addresses the allocations in the curl block driver.
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Benoit Canet <benoit@irqsave.net>
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
The curl block driver uses fd handlers, timers, and BHs. The fd
handlers and timers are managed on behalf of libcurl, which controls
them using callback functions that the block driver implements.
The simplest way to implement .bdrv_detach/attach_aio_context() is to
clean up libcurl in the old event loop and initialize it again in the
new event loop. We do not need to keep track of anything since there
are no pending requests when the AioContext is changed.
Also make sure to use aio_set_fd_handler() instead of
qemu_aio_set_fd_handler() and aio_bh_new() instead of qemu_bh_new() so
the current AioContext is passed in.
Cc: Alexander Graf <agraf@suse.de>
Cc: Fam Zheng <famz@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Fam Zheng <famz@redhat.com>
This allows qemu to use images over https with a self-signed certificate. It
defaults to verifying the certificate.
Signed-off-by: Matthew Booth <mbooth@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
The block layer now supports a generic json syntax for passing option parameters
explicitly, making parsing of options from the url redundant.
Signed-off-by: Matthew Booth <mbooth@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
When receiving a new aio read request, we first look for an existing
transaction whose range will cover the read request by the time it
completes. However, we weren't checking that the existing transaction
was still active. If it had timed out, we were adding the request to a
transaction which would never complete and had already been cancelled,
resulting in a hang.
Signed-off-by: Matthew Booth <mbooth@redhat.com>
Tested-by: Richard W.M. Jones <rjones@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
According to the documentation, the correct way to ensure all
informationals have been returned by curl_multi_info_read is to loop
until it returns NULL.
Signed-off-by: Matthew Booth <mbooth@redhat.com>
Tested-by: Richard W.M. Jones <rjones@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
curl_multi_socket_all is a deprecated catch-all which checks for
activities on all open curl sockets. We have enough information from
the event loop to check only the sockets with activity. This change
removes use of curl_multi_socket_all in favour of
curl_multi_socket_action called with the relevant handle.
At the same time, it also ensures that the driver only checks for
completion of read operations after reading from a socket, rather than
both reading and writing.
Signed-off-by: Matthew Booth <mbooth@redhat.com>
Tested-by: Richard W.M. Jones <rjones@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Remove calls to curl_multi_do where the relevant handles are already
registered to the event loop.
Ensure that we kick off socket handling with CURL_SOCKET_TIMEOUT after
adding a new handle.
Signed-off-by: Matthew Booth <mbooth@redhat.com>
Tested-by: Richard W.M. Jones <rjones@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
The driver will not start more than a fixed number of curl sessions.
If it needs more, it must wait for the completion of an existing one.
The driver was sleeping, which will prevent the main loop from
running, and therefore the event it's waiting on. It was also directly
calling its internal handler rather than waiting on existing
registered handlers to be called from the main loop.
This change causes it simply to wait for a period of time whilst
allowing the main loop to execute.
Signed-off-by: Matthew Booth <mbooth@redhat.com>
Tested-by: Richard W.M. Jones <rjones@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
A curl write callback is supposed to return the number of bytes it
handled. curl_read_cb would have erroneously reported it had handled
all bytes in the event that the internal curl state was invalid.
Signed-off-by: Matthew Booth <mbooth@redhat.com>
Tested-by: Richard W.M. Jones <rjones@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
This isn't any of the usually acceptable uses of goto.
Signed-off-by: Matthew Booth <mbooth@redhat.com>
Tested-by: Richard W.M. Jones <rjones@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
curl_read_cb is callback function for libcurl when data arrives. The
data size passed in here is not guaranteed to be within the range of
request we submitted, so we may overflow the guest IO buffer. Check the
real size we have before memcpy to buffer to avoid overflow.
Signed-off-by: Fam Zheng <famz@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
error_is_set(&var) is the same as var != NULL, but it takes
whole-program analysis to figure that out. Unnecessarily hard for
optimizers, static checkers, and human readers. Dumb it down to
obvious.
Gets rid of several dozen Coverity false positives.
Note that the obvious form is already used in many places.
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Andreas Färber <afaerber@suse.de>
Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com>
libcurl versions 7.16.0 and later have a timer callback interface which
must be implemented in order for libcurl to make forward progress (it
will sometimes rely on being called back on the timeout if there are
no file descriptors registered). Implement the callback, and use a
QEMU AIO timer to ensure we prod libcurl again when it asks us to.
Based on Peter's original patch plus my fix to add curl_multi_timeout_do.
Should compile just fine even on older versions of libcurl.
I also tried copy-on-read and streaming:
$ ./qemu-img create -f qcow2 -o \
backing_file=http://download.fedoraproject.org/pub/fedora/linux/releases/20/Live/x86_64/Fedora-Live-Desktop-x86_64-20-1.iso \
foo.qcow2 1G
$ x86_64-softmmu/qemu-system-x86_64 \
-drive if=none,file=foo.qcow2,copy-on-read=on,id=cd \
-device ide-cd,drive=cd --enable-kvm -m 1024
Direct http usage is probably too slow, but with copy-on-read ultimately
the image does boot!
After some time, streaming gets canceled by an EIO, which needs further
investigation.
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
This is a boiler-plate _nofail variant of qemu_opts_create. Remove and
use error_abort in call sites.
null/0 arguments needs to be added for the id and fail_if_exists fields
in affected callsites due to argument inconsistency between the normal and
no_fail variants.
Signed-off-by: Peter Crosthwaite <peter.crosthwaite@xilinx.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com>
Add an Error ** parameter to BlockDriver.bdrv_open and
BlockDriver.bdrv_file_open to allow more specific error messages.
Signed-off-by: Max Reitz <mreitz@redhat.com>
Drop error code path which cannot be taken since qemu_bh_new() does not
return NULL.
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>
The .io_flush() handler no longer exists and has no users. Drop the
io_flush argument to aio_set_fd_handler() and related functions.
The AioFlushEventNotifierHandler and AioFlushHandler typedefs are no
longer used and are dropped too.
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
.io_flush() is no longer called so drop curl_aio_flush(). The acb[]
array that the function checks is still used in other parts of
block/curl.c. Therefore we cannot remove acb[], it is needed.
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
CURL driver requests partial data from server on guest IO req. For HTTP
and HTTPS, it uses "Range: ***" in requests, and this will not work if
server not accepting range. This patch does this check when open.
* Removed curl_size_cb, which is not used: On one hand it's registered to
libcurl as CURLOPT_WRITEFUNCTION, instead of CURLOPT_HEADERFUNCTION,
which will get called with *data*, not *header*. On the other hand the
s->len is assigned unconditionally later.
In this gone function, the sscanf for "Content-Length: %zd", on
(void *)ptr, which is not guaranteed to be zero-terminated, is
potentially a security bug. So this patch fixes it as a side-effect. The
bug is reported as: https://bugs.launchpad.net/qemu/+bug/1188943
(Note the bug is marked "private" so you might not be able to see it)
* Introduced curl_header_cb, which is used to parse header and mark the
server as accepting range if "Accept-Ranges: bytes" line is seen from
response header. If protocol is HTTP or HTTPS, but server response has
no not this support, refuse to open this URL.
Note that python builtin module SimpleHTTPServer is an example of not
supporting range, if you need to test this driver, get a better server
or use internet URLs.
Signed-off-by: Fam Zheng <famz@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
(Found by Kamil Dudka)
Signed-off-by: Richard W.M. Jones <rjones@redhat.com>
Cc: Michael Tokarev <mjt@tls.msk.ru>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
As a bonus, going through the QemuOpts QEMU_OPT_SIZE parser for the
readahead option gives us proper error reporting that the previous use
of atoi() lacked.
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
The curl_easy_setopt(state->curl, CURLOPT_PROTOCOLS, ...) interface was
introduced in libcurl 7.19.4. Therefore we cannot protect against
CVE-2013-0249 when linking against an older libcurl.
This fixes the build failure introduced by
fb6d1bbd24.
Reported-by: Andreas Färber <afaerber@suse.de>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Tested-by: Andreas Färber <andreas.faeber@web.de>
Message-id: 1360743934-8337-1-git-send-email-stefanha@redhat.com
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
There is a buffer overflow in libcurl POP3/SMTP/IMAP. The workaround is
simple: disable extra protocols so that they cannot be exploited. Full
details here:
http://curl.haxx.se/docs/adv_20130206.html
QEMU only cares about HTTP, HTTPS, FTP, FTPS, and TFTP. I have tested
that this fix prevents the exploit on my host with
libcurl-7.27.0-5.fc18.
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
Now that AIOPool no longer keeps a freelist, it isn't really a "pool"
anymore. Rename it to AIOCBInfo and make it const since it no longer
needs to be modified.
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Report from smatch:
block/curl.c:546 curl_close(21) info: redundant null check on s->url calling free()
The check was redundant, and free was also wrong because the memory
was allocated using g_strdup.
Signed-off-by: Stefan Weil <sw@weilnetz.de>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Similar to
qemu_iovec_memset(QEMUIOVector *qiov, size_t offset,
int c, size_t bytes);
the new prototype is:
qemu_iovec_from_buf(QEMUIOVector *qiov, size_t offset,
const void *buf, size_t bytes);
The processing starts at offset bytes within qiov.
This way, we may copy a bounce buffer directly to
a middle of qiov.
This is exactly the same function as iov_from_buf() from
iov.c, so use the existing implementation and rename it
to qemu_iovec_from_buf() to be shorter and to match the
utility function.
As with utility implementation, we now assert that the
offset is inside actual iovec. Nothing changed for
current callers, because `offset' parameter is new.
While at it, stop using "bounce-qiov" in block/qcow2.c
and copy decrypted data directly from cluster_data
instead of recreating a temp qiov for doing that.
Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>
The function usleep is not available for all supported platforms:
at least some versions of MinGW don't support it.
usleep was also declared obsolete by POSIX.1-2001.
The function g_usleep is part of glib2.0, so it is available for
all supported platforms.
Using nanosleep would also be possible but needs more code.
Signed-off-by: Stefan Weil <sw@weilnetz.de>
Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
Initially done with the following semantic patch:
@ rule1 @
expression E;
statement S;
@@
E = qemu_aio_get (...);
(
- if (E == NULL) { ... }
|
- if (E)
{ <... S ...> }
)
which however missed occurrences in linux-aio.c and posix-aio-compat.c.
Those were done by hand.
The change in vdi_aio_setup's caller was also done by hand.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
The previous behaviour was to finish AIOCBs inside curl_aio_readv()
if the data was cached. This caused the following failed assertion
at hw/ide/pci.c:314: bmdma_cmd_writeb
"Assertion `bm->bus->dma->aiocb == ((void *)0)' failed."
By scheduling a QEMUBH and performing the completion inside the
callback, we avoid this problem.
Signed-off-by: Nick Thomas <nick@bytemark.co.uk>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Current behaviour if a read fails is for the acb to not get finished.
This causes an infinite loop in bdrv_read_em (block.c). The read failure
never gets reported to the guest and if the error condition clears, the
process never recovers.
With this patch, when curl reports a failure we finish the acb as a
failure. This results in the guest receiving an I/O error (rather than
the read hanging indefinitely) and if the error condition subsequently
clears, retries work as expected.
The simplest test is to put an ISO on a web server you have control over
and open it with qemu-io. Then move the ISO out of the way and attempt
to read some data - you should see behaviour matching the above.
Signed-off-by: Nick Thomas <nick@bytemark.co.uk>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Format drivers shouldn't need to bother with things like file names, but rather
just get an open BlockDriverState for the underlying protocol. This patch
introduces this behaviour for bdrv_open implementation. For protocols which
need to access the filename to open their file/device/connection/... a new
callback bdrv_file_open is introduced which doesn't get an underlying file
opened.
For now, also some of the more obscure formats use bdrv_file_open because they
open() the file themselves instead of using the block.c functions. They need to
be fixed in later patches.
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Most of these are obvious NULL-deref bug fixes, for example,
the ones in these files:
block/curl.c
net.c
slirp/misc.c
and the first one in block/vvfat.c.
The others in block/vvfat.c may not lead to an immediate segfault, but I
traced the two schedule_rename(..., strdup(path)) uses, and a failed
strdup would appear to trigger this assertion in handle_renames_and_mkdirs:
assert(commit->path);
The conversion to use qemu_strdup in envlist_to_environ is not technically
needed, but does avoid a theoretical leak in the caller when strdup fails
for one value, but later succeeds in allocating another buffer(plausible,
if one string length is much larger than the others). The caller does
not know the length of the returned list, and as such can only free
pointers until it hits the first NULL. If there are non-NULL pointers
beyond the first, their buffers would be leaked. This one is admittedly
far-fetched.
The two in linux-user/main.c are worth fixing to ensure that an
OOM error is diagnosed up front, rather than letting it provoke some
harder-to-diagnose secondary error, in case of exec failure, or worse, in
case the exec succeeds but with an invalid list of command line options.
However, considering how unlikely it is to encounter a failed strdup early
in main, this isn't a big deal. Note that adding the required uses of
qemu_strdup here and in envlist.c induce link failures because qemu_strdup
is not currently in any library they're linked with. So for now, I've
omitted those changes, as well as the fixes in target-i386/helper.c
and target-sparc/helper.c.
If you'd like to see the above discussion (or anything else)
in the commit log, just let me know and I'll be happy to adjust.
>From 9af42864fd1ea666bd25e2cecfdfae74c20aa8c7 Mon Sep 17 00:00:00 2001
From: Jim Meyering <meyering@redhat.com>
Date: Mon, 8 Feb 2010 18:29:29 +0100
Subject: [PATCH] don't dereference NULL after failed strdup
Handle failing strdup by replacing each use with qemu_strdup,
so as not to dereference NULL or trigger a failing assertion.
* block/curl.c (curl_open): s/\bstrdup\b/qemu_strdup/
* block/vvfat.c (init_directories): Likewise.
(get_cluster_count_for_direntry, check_directory_consistency): Likewise.
* net.c (parse_host_src_port): Likewise.
* slirp/misc.c (fork_exec): Likewise.
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
We'll leave some AIO completions unhandled when we can't call the callback.
qemu_aio_process_queue() is used later to run any callbacks that are left and
can be run then.
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
