Commit Graph

11 Commits

Author SHA1 Message Date
Paolo Bonzini a942d8fa01 json-streamer: fix double-free on exiting during a parse
Now that json-streamer tries not to leak tokens on incomplete parse,
the tokens can be freed twice if QEMU destroys the json-streamer
object during the parser->emit call.  To fix this, create the new
empty GQueue earlier, so that it is already in place when the old
one is passed to parser->emit.

Reported-by: Changlong Xie <xiecl.fnst@cn.fujitsu.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Message-Id: <1467636059-12557-1-git-send-email-pbonzini@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2016-07-12 18:31:27 +02:00
Eric Blake ba4dba5434 json-streamer: Don't leak tokens on incomplete parse
Valgrind complained about a number of leaks in
tests/check-qobject-json:

==12657==    definitely lost: 17,247 bytes in 1,234 blocks

All of which had the same root cause: on an incomplete parse,
we were abandoning the token queue without cleaning up the
allocated data within each queue element.  Introduced in
commit 95385fe, when we switched from QList (which recursively
frees contents) to g_queue (which does not).

We don't yet require glib 2.32 with its g_queue_free_full(),
so open-code it instead.

CC: qemu-stable@nongnu.org
Signed-off-by: Eric Blake <eblake@redhat.com>
Message-Id: <1463608012-12760-1-git-send-email-eblake@redhat.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
Signed-off-by: Markus Armbruster <armbru@redhat.com>
2016-06-30 15:24:36 +02:00
Peter Maydell f2ad72b30e qobject: Clean up includes
Clean up includes so that osdep.h is included first and headers
which it implies are not included manually.

This commit was created with scripts/clean-includes.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-id: 1454089805-5470-12-git-send-email-peter.maydell@linaro.org
2016-02-04 17:41:30 +00:00
Markus Armbruster df649835fe qjson: Limit number of tokens in addition to total size
Commit 29c75dd "json-streamer: limit the maximum recursion depth and
maximum token count" attempts to guard against excessive heap usage by
limiting total token size (it says "token count", but that's a lie).

Total token size is a rather imprecise predictor of heap usage: many
small tokens use more space than few large tokens with the same input
size, because there's a constant per-token overhead: 37 bytes on my
system.

Tighten this up: limit the token count to 2Mi.  Chosen to roughly
match the 64MiB total token size limit.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-Id: <1448486613-17634-13-git-send-email-armbru@redhat.com>
2015-11-26 10:07:07 +01:00
Paolo Bonzini 9bada89711 qjson: surprise, allocating 6 QObjects per token is expensive
Replace the contents of the tokens GQueue with a simple struct.  This cuts
the amount of memory allocated by tests/check-qjson from ~500MB to ~20MB,
and the execution time from 600ms to 80ms on my laptop.  Still a lot (some
could be saved by using an intrusive list, such as QSIMPLEQ, instead of
the GQueue), but the savings are already massive and the right thing to
do would probably be to get rid of json-streamer completely.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Message-Id: <1448300659-23559-5-git-send-email-pbonzini@redhat.com>
[Straightforwardly rebased on my patches]
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
2015-11-26 10:07:07 +01:00
Paolo Bonzini 95385fe9ac qjson: store tokens in a GQueue
Even though we still have the "streamer" concept, the tokens can now
be deleted as they are read.  While doing so convert from QList to
GQueue, since the next step will make tokens not a QObject and we
will have to do the conversion anyway.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Message-Id: <1448300659-23559-4-git-send-email-pbonzini@redhat.com>
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
2015-11-26 10:07:07 +01:00
Paolo Bonzini d2ca7c0b0d qjson: replace QString in JSONLexer with GString
JSONLexer only needs a simple resizable buffer.  json-streamer.c
can allocate memory for each token instead of relying on reference
counting of QStrings.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Message-Id: <1448300659-23559-2-git-send-email-pbonzini@redhat.com>
[Straightforwardly rebased on my patches, checkpatch made happy]
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
2015-11-26 09:31:22 +01:00
Markus Armbruster c54616608a qjson: Give each of the six structural chars its own token type
Simplifies things, because we always check for a specific one.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Message-Id: <1448486613-17634-6-git-send-email-armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
2015-11-26 09:22:54 +01:00
Markus Armbruster 0753113a26 qjson: Don't crash when input exceeds nesting limit
We limit nesting depth and input size to defend against input
triggering excessive heap or stack memory use (commit 29c75dd
json-streamer: limit the maximum recursion depth and maximum token
count).  However, when the nesting limit is exceeded,
parser_context_peek_token()'s assertion fails.

Broken in commit 65c0f1e "json-parser: don't replicate tokens at each
level of recursion".

To reproduce stuff 1025 open braces or brackets into QMP.

Fix by taking the error exit instead of the normal one.

Reported-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-Id: <1448486613-17634-3-git-send-email-armbru@redhat.com>
2015-11-26 09:18:04 +01:00
Markus Armbruster 4f2d31fbc0 qjson: Apply nesting limit more sanely
The nesting limit from commit 29c75dd "json-streamer: limit the
maximum recursion depth and maximum token count" applies separately to
braces and brackets.  This makes no sense.  Apply it to their sum,
because that's actually a measure of recursion depth.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-Id: <1448486613-17634-2-git-send-email-armbru@redhat.com>
2015-11-26 09:17:57 +01:00
Paolo Bonzini a372823a14 build: move qobject files to qobject/ and libqemuutil.a
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2013-01-12 18:42:50 +01:00