Commit Graph

63577 Commits

Author SHA1 Message Date
Markus Armbruster
da09cfbf9d json: Enforce token count and size limits more tightly
Token count and size limits exist to guard against excessive heap
usage.  We check them only after we created the token on the heap.
That's assigning a cowboy to the barn to lasso the horse after it has
bolted.  Close the barn door instead: check before we create the
token.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-Id: <20180823164025.12553-49-armbru@redhat.com>
2018-08-24 20:26:37 +02:00
Markus Armbruster
dd98e84819 qjson: Have qobject_from_json() & friends reject empty and blank
The last case where qobject_from_json() & friends return null without
setting an error is empty or blank input.  Callers:

* block.c's parse_json_protocol() reports "Could not parse the JSON
  options".  It's marked as a work-around, because it also covered
  actual bugs, but they got fixed in the previous few commits.

* qobject_input_visitor_new_str() reports "JSON parse error".  Also
  marked as work-around.  The recent fixes have made this unreachable,
  because it currently gets called only for input starting with '{'.

* check-qjson.c's empty_input() and blank_input() demonstrate the
  behavior.

* The other callers are not affected since they only pass input with
  exactly one JSON value or, in the case of negative tests, one error.

Fail with "Expecting a JSON value" instead of returning null, and
simplify callers.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-Id: <20180823164025.12553-48-armbru@redhat.com>
2018-08-24 20:26:37 +02:00
Markus Armbruster
5d50113cf6 json: Assert json_parser_parse() consumes all tokens on success
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-Id: <20180823164025.12553-47-armbru@redhat.com>
2018-08-24 20:26:37 +02:00
Markus Armbruster
f9277915ee json: Fix streamer not to ignore trailing unterminated structures
json_message_process_token() accumulates tokens until it got the
sequence of tokens that comprise a single JSON value (it counts curly
braces and square brackets to decide).  It feeds those token sequences
to json_parser_parse().  If a non-empty sequence of tokens remains at
the end of the parse, it's silently ignored.  check-qjson.c cases
unterminated_array(), unterminated_array_comma(), unterminated_dict(),
unterminated_dict_comma() demonstrate this bug.

Fix as follows.  Introduce a JSON_END_OF_INPUT token.  When the
streamer receives it, it feeds the accumulated tokens to
json_parser_parse().

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-Id: <20180823164025.12553-46-armbru@redhat.com>
2018-08-24 20:26:37 +02:00
Markus Armbruster
e06d008ac8 json: Fix latent parser aborts at end of input
json-parser.c carefully reports end of input like this:

    token = parser_context_pop_token(ctxt);
    if (token == NULL) {
        parse_error(ctxt, NULL, "premature EOI");
        goto out;
    }

Except parser_context_pop_token() can't return null, it fails its
assertion instead.  Same for parser_context_peek_token().  Broken in
commit 65c0f1e955, and faithfully preserved in commit 95385fe9ac.
Only a latent bug, because the streamer throws away any input that
could trigger it.

Drop the assertions, so we can fix the streamer in the next commit.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-Id: <20180823164025.12553-45-armbru@redhat.com>
2018-08-24 20:26:37 +02:00
Markus Armbruster
2a4794ba14 qjson: Fix qobject_from_json() & friends for multiple values
qobject_from_json() & friends use the consume_json() callback to
receive either a value or an error from the parser.

When they are fed a string that contains more than either one JSON
value or one JSON syntax error, consume_json() gets called multiple
times.

When the last call receives a value, qobject_from_json() returns that
value.  Any other values are leaked.

When any call receives an error, qobject_from_json() sets the first
error received.  Any other errors are thrown away.

When values follow errors, qobject_from_json() returns both a value
and sets an error.  That's bad.  Impact:

* block.c's parse_json_protocol() ignores and leaks the value.  It's
  used to to parse pseudo-filenames starting with "json:".  The
  pseudo-filenames can come from the user or from image meta-data such
  as a QCOW2 image's backing file name.

* vl.c's parse_display_qapi() ignores and leaks the error.  It's used
  to parse the argument of command line option -display.

* vl.c's main() case QEMU_OPTION_blockdev ignores the error and leaves
  it in @err.  main() will then pass a pointer to a non-null Error *
  to net_init_clients(), which is forbidden.  It can lead to assertion
  failure or other misbehavior.

* check-qjson.c's multiple_values() demonstrates the badness.

* The other callers are not affected since they only pass strings with
  exactly one JSON value or, in the case of negative tests, one
  error.

The impact on the _nofail() functions is relatively harmless.  They
abort when any call receives an error.  Else they return the last
value, and leak the others, if any.

Fix consume_json() as follows.  On the first call, save value and
error as before.  On subsequent calls, if any, don't save them.  If
the first call saved a value, the next call, if any, replaces the
value by an "Expecting at most one JSON value" error.  Take care not
to leak values or errors that aren't saved.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-Id: <20180823164025.12553-44-armbru@redhat.com>
2018-08-24 20:26:37 +02:00
Markus Armbruster
4d40066142 json: Improve names of lexer states related to numbers
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-Id: <20180823164025.12553-43-armbru@redhat.com>
2018-08-24 20:26:37 +02:00
Markus Armbruster
53a0d616fe json: Replace %I64d, %I64u by %PRId64, %PRIu64
Support for %I64d got added in commit 2c0d4b36e7 "json: fix PRId64 on
Win32".  We had to hard-code I64d because we used the lexer's finite
state machine to check interpolations.  No more, so clean this up.

Additional conversion specifications would be easy enough to implement
when needed.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-Id: <20180823164025.12553-42-armbru@redhat.com>
2018-08-24 20:26:37 +02:00
Markus Armbruster
f7617d45d4 json: Leave rejecting invalid interpolation to parser
Both lexer and parser reject invalid interpolation specifications.
The parser's check is useless.

The lexer ends the token right after the first bad character.  This
tends to lead to suboptimal error reporting.  For instance, input

    [ %04d ]

produces the tokens

    JSON_LSQUARE  [
    JSON_ERROR    %0
    JSON_INTEGER  4
    JSON_KEYWORD  d
    JSON_RSQUARE  ]

The parser then yields an error, an object and two more errors:

    error: Invalid JSON syntax
    object: 4
    error: JSON parse error, invalid keyword
    error: JSON parse error, expecting value

Dumb down the lexer to accept [A-Za-z0-9]*.  The parser's check is now
used.  Emit a proper error there.

The lexer now produces

    JSON_LSQUARE  [
    JSON_INTERP   %04d
    JSON_RSQUARE  ]

and the parser reports just

    JSON parse error, invalid interpolation '%04d'

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-Id: <20180823164025.12553-41-armbru@redhat.com>
2018-08-24 20:26:37 +02:00
Markus Armbruster
84a56f38b2 json: Pass lexical errors and limit violations to callback
The callback to consume JSON values takes QObject *json, Error *err.
If both are null, the callback is supposed to make up an error by
itself.  This sucks.

qjson.c's consume_json() neglects to do so, which makes
qobject_from_json() null instead of failing.  I consider that a bug.

The culprit is json_message_process_token(): it passes two null
pointers when it runs into a lexical error or a limit violation.  Fix
it to pass a proper Error object then.  Update the callbacks:

* monitor.c's handle_qmp_command(): the code to make up an error is
  now dead, drop it.

* qga/main.c's process_event(): lumps the "both null" case together
  with the "not a JSON object" case.  The former is now gone.  The
  error message "Invalid JSON syntax" is misleading for the latter.
  Improve it to "Input must be a JSON object".

* qobject/qjson.c's consume_json(): no update; check-qjson
  demonstrates qobject_from_json() now sets an error on lexical
  errors, but still doesn't on some other errors.

* tests/libqtest.c's qmp_response(): the Error object is now reliable,
  so use it to improve the error message.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-Id: <20180823164025.12553-40-armbru@redhat.com>
2018-08-24 20:26:37 +02:00
Markus Armbruster
2cbd15aa6f json: Treat unwanted interpolation as lexical error
The JSON parser optionally supports interpolation.  The lexer
recognizes interpolation tokens unconditionally.  The parser rejects
them when interpolation is disabled, in parse_interpolation().
However, it neglects to set an error then, which can make
json_parser_parse() fail without setting an error.

Move the check for unwanted interpolation from the parser's
parse_interpolation() into the lexer's finite state machine.  When
interpolation is disabled, '%' is now handled like any other
unexpected character.

The next commit will improve how such lexical errors are handled.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-Id: <20180823164025.12553-39-armbru@redhat.com>
2018-08-24 20:26:37 +02:00
Markus Armbruster
61030280ca json: Rename token JSON_ESCAPE & friends to JSON_INTERP
The JSON parser optionally supports interpolation.  The code calls it
"escape".  Awkward, because it uses the same term for escape sequences
within strings.  The latter usage is consistent with RFC 8259 "The
JavaScript Object Notation (JSON) Data Interchange Format" and ISO C.
Call the former "interpolation" instead.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-Id: <20180823164025.12553-38-armbru@redhat.com>
2018-08-24 20:26:37 +02:00
Markus Armbruster
269e57ae28 json: Don't create JSON_ERROR tokens that won't be used
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-Id: <20180823164025.12553-37-armbru@redhat.com>
2018-08-24 20:26:37 +02:00
Markus Armbruster
ff281a272f json: Don't pass null @tokens to json_parser_parse()
json_parser_parse() normally returns the QObject on success.  Except
it returns null when its @tokens argument is null.

Its only caller json_message_process_token() passes null @tokens when
emitting a lexical error.  The call is a rather opaque way to say json
= NULL then.

Simplify matters by lifting the assignment to json out of the emit
path: initialize json to null, set it to the value of
json_parser_parse() when there's no lexical error.  Drop the special
case from json_parser_parse().

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-Id: <20180823164025.12553-36-armbru@redhat.com>
2018-08-24 20:26:37 +02:00
Markus Armbruster
62815d85ae json: Redesign the callback to consume JSON values
The classical way to structure parser and lexer is to have the client
call the parser to get an abstract syntax tree, the parser call the
lexer to get the next token, and the lexer call some function to get
input characters.

Another way to structure them would be to have the client feed
characters to the lexer, the lexer feed tokens to the parser, and the
parser feed abstract syntax trees to some callback provided by the
client.  This way is more easily integrated into an event loop that
dispatches input characters as they arrive.

Our JSON parser is kind of between the two.  The lexer feeds tokens to
a "streamer" instead of a real parser.  The streamer accumulates
tokens until it got the sequence of tokens that comprise a single JSON
value (it counts curly braces and square brackets to decide).  It
feeds those token sequences to a callback provided by the client.  The
callback passes each token sequence to the parser, and gets back an
abstract syntax tree.

I figure it was done that way to make a straightforward recursive
descent parser possible.  "Get next token" becomes "pop the first
token off the token sequence".  Drawback: we need to store a complete
token sequence.  Each token eats 13 + input characters + malloc
overhead bytes.

Observations:

1. This is not the only way to use recursive descent.  If we replaced
   "get next token" by a coroutine yield, we could do without a
   streamer.

2. The lexer reports errors by passing a JSON_ERROR token to the
   streamer.  This communicates the offending input characters and
   their location, but no more.

3. The streamer reports errors by passing a null token sequence to the
   callback.  The (already poor) lexical error information is thrown
   away.

4. Having the callback receive a token sequence duplicates the code to
   convert token sequence to abstract syntax tree in every callback.

5. Known bug: the streamer silently drops incomplete token sequences.

This commit rectifies 4. by lifting the call of the parser from the
callbacks into the streamer.  Later commits will address 3. and 5.

The lifting removes a bug from qjson.c's parse_json(): it passed a
pointer to a non-null Error * in certain cases, as demonstrated by
check-qjson.c.

json_parser_parse() is now unused.  It's a stupid wrapper around
json_parser_parse_err().  Drop it, and rename json_parser_parse_err()
to json_parser_parse().

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-Id: <20180823164025.12553-35-armbru@redhat.com>
2018-08-24 20:26:37 +02:00
Markus Armbruster
037f244088 json: Have lexer call streamer directly
json_lexer_init() takes the function to process a token as an
argument.  It's always json_message_process_token().  Makes the code
harder to understand for no actual gain.  Drop the indirection.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-Id: <20180823164025.12553-34-armbru@redhat.com>
2018-08-24 20:26:37 +02:00
Marc-André Lureau
e8b19d7d73 json-parser: simplify and avoid JSONParserContext allocation
parser_context_new/free() are only used from json_parser_parse(). We
can fold the code there and avoid an allocation altogether.

Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Message-Id: <20180719184111.5129-9-marcandre.lureau@redhat.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
Message-Id: <20180823164025.12553-33-armbru@redhat.com>
2018-08-24 20:26:37 +02:00
Marc-André Lureau
7c1e1d5481 json: remove useless return value from lexer/parser
The lexer always returns 0 when char feeding. Furthermore, none of the
caller care about the return value.

Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Message-Id: <20180326150916.9602-10-marcandre.lureau@redhat.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Thomas Huth <thuth@redhat.com>
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Message-Id: <20180823164025.12553-32-armbru@redhat.com>
2018-08-24 20:26:37 +02:00
Markus Armbruster
c473c379e1 check-qjson: Fix and enable utf8_string()'s disabled part
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-Id: <20180823164025.12553-31-armbru@redhat.com>
2018-08-24 20:26:37 +02:00
Markus Armbruster
dc45a07c36 json: Fix \uXXXX for surrogate pairs
The JSON parser treats each half of a surrogate pair as unpaired
surrogate.  Fix it to recognize surrogate pairs.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-Id: <20180823164025.12553-30-armbru@redhat.com>
2018-08-24 20:26:37 +02:00
Markus Armbruster
46a628b139 json: Reject invalid \uXXXX, fix \u0000
The JSON parser translates invalid \uXXXX to garbage instead of
rejecting it, and swallows \u0000.

Fix by using mod_utf8_encode() instead of flawed wchar_to_utf8().

Valid surrogate pairs are now differently broken: they're rejected
instead of translated to garbage.  The next commit will fix them.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-Id: <20180823164025.12553-29-armbru@redhat.com>
2018-08-24 20:26:37 +02:00
Markus Armbruster
de6decfe8e json: Simplify parse_string()
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-Id: <20180823164025.12553-28-armbru@redhat.com>
2018-08-24 20:26:37 +02:00
Markus Armbruster
b2da4a4d75 json: Leave rejecting invalid escape sequences to parser
Both lexer and parser reject invalid escape sequences in strings.  The
parser's check is useless.

The lexer ends the token right after the first non-well-formed byte.
This tends to lead to suboptimal error reporting.  For instance, input

    {"abc\@ijk": 1}

produces the tokens

    JSON_LCURLY   {
    JSON_ERROR    "abc\@
    JSON_KEYWORD  ijk
    JSON_ERROR   ": 1}\n

The parser then reports three errors

    Invalid JSON syntax
    JSON parse error, invalid keyword 'ijk'
    Invalid JSON syntax

before it recovers at the newline.

Drop the lexer's escape sequence checking, and make it accept the same
characters after backslash it accepts elsewhere in strings.  It now
produces

    JSON_LCURLY   {
    JSON_STRING   "abc\@ijk"
    JSON_COLON    :
    JSON_INTEGER  1
    JSON_RCURLY

and the parser reports just

    JSON parse error, invalid escape sequence in string

While there, fix parse_string()'s inaccurate function comment.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-Id: <20180823164025.12553-27-armbru@redhat.com>
2018-08-24 20:26:37 +02:00
Markus Armbruster
4b1c0cd7c7 json: Accept overlong \xC0\x80 as U+0000 ("modified UTF-8")
Since the JSON grammer doesn't accept U+0000 anywhere, this merely
exchanges one kind of parse error for another.  It's purely for
consistency with qobject_to_json(), which accepts \xC0\x80 (see commit
e2ec3f9768).

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-Id: <20180823164025.12553-26-armbru@redhat.com>
2018-08-24 20:26:37 +02:00
Markus Armbruster
de930f45cb json: Leave rejecting invalid UTF-8 to parser
Both the lexer and the parser (attempt to) validate UTF-8 in JSON
strings.

The lexer rejects bytes that can't occur in valid UTF-8: \xC0..\xC1,
\xF5..\xFF.  This rejects some, but not all invalid UTF-8.  It also
rejects ASCII control characters \x00..\x1F, in accordance with RFC
8259 (see recent commit "json: Reject unescaped control characters").

When the lexer rejects, it ends the token right after the first bad
byte.  Good when the bad byte is a newline.  Not so good when it's
something like an overlong sequence in the middle of a string.  For
instance, input

    {"abc\xC0\xAFijk": 1}\n

produces the tokens

    JSON_LCURLY   {
    JSON_ERROR    "abc\xC0
    JSON_ERROR    \xAF
    JSON_KEYWORD  ijk
    JSON_ERROR   ": 1}\n

The parser then reports four errors

    Invalid JSON syntax
    Invalid JSON syntax
    JSON parse error, invalid keyword 'ijk'
    Invalid JSON syntax

before it recovers at the newline.

The commit before previous made the parser reject invalid UTF-8
sequences.  Since then, anything the lexer rejects, the parser would
reject as well.  Thus, the lexer's rejecting is unnecessary for
correctness, and harmful for error reporting.

However, we want to keep rejecting ASCII control characters in the
lexer, because that produces the behavior we want for unclosed
strings.

We also need to keep rejecting \xFF in the lexer, because we
documented that as a way to reset the JSON parser
(docs/interop/qmp-spec.txt section 2.6 QGA Synchronization), which
means we can't change how we recover from this error now.  I wish we
hadn't done that.

I think we should treat \xFE the same as \xFF.

Change the lexer to accept \xC0..\xC1 and \xF5..\xFD.  It now rejects
only \x00..\x1F and \xFE..\xFF.  Error reporting for invalid UTF-8 in
strings is much improved, except for \xFE and \xFF.  For the example
above, the lexer now produces

    JSON_LCURLY   {
    JSON_STRING   "abc\xC0\xAFijk"
    JSON_COLON    :
    JSON_INTEGER  1
    JSON_RCURLY

and the parser reports just

    JSON parse error, invalid UTF-8 sequence in string

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-Id: <20180823164025.12553-25-armbru@redhat.com>
2018-08-24 20:26:37 +02:00
Markus Armbruster
574bf16ff1 json: Report first rather than last parse error
Quiz time!  When a parser reports multiple errors, but the user gets
to see just one, which one is (on average) the least useful one?

Yes, you're right, it's the last one!  You're clearly familiar with
compilers.

Which one does QEMU report?

Right again, the last one!  You're clearly familiar with QEMU.

Reproducer: feeding

    {"abc\xC2ijk": 1}\n

to QMP produces

    {"error": {"class": "GenericError", "desc": "JSON parse error, key is not a string in object"}}

Report the first error instead.  The reproducer now produces

    {"error": {"class": "GenericError", "desc": "JSON parse error, invalid UTF-8 sequence in string"}}

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-Id: <20180823164025.12553-24-armbru@redhat.com>
2018-08-24 20:26:37 +02:00
Markus Armbruster
e59f39d403 json: Reject invalid UTF-8 sequences
We reject bytes that can't occur in valid UTF-8 (\xC0..\xC1,
\xF5..\xFF in the lexer.  That's insufficient; there's plenty of
invalid UTF-8 not containing these bytes, as demonstrated by
check-qjson:

* Malformed sequences

  - Unexpected continuation bytes

  - Missing continuation bytes after start bytes other than
    \xC0..\xC1, \xF5..\xFD.

* Overlong sequences with start bytes other than \xC0..\xC1,
  \xF5..\xFD.

* Invalid code points

Fixing this in the lexer would be bothersome.  Fixing it in the parser
is straightforward, so do that.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-Id: <20180823164025.12553-23-armbru@redhat.com>
2018-08-24 20:26:37 +02:00
Markus Armbruster
a89d3104a2 check-qjson: Document we expect invalid UTF-8 to be rejected
The JSON parser rejects some invalid sequences, but accepts others
without correcting the problem.

We should either reject all invalid sequences, or minimize overlong
sequences and replace all other invalid sequences by a suitable
replacement character.  A common choice for replacement is U+FFFD.

I'm going to implement the former.  Update the comments in
utf8_string() to expect this.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-Id: <20180823164025.12553-22-armbru@redhat.com>
2018-08-24 20:26:37 +02:00
Markus Armbruster
00ea57fadc json: Tighten and simplify qstring_from_escaped_str()'s loop
Simplify loop control, and assert that the string ends with the
appropriate quote (the lexer ensures it does).

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-Id: <20180823164025.12553-21-armbru@redhat.com>
2018-08-24 20:26:37 +02:00
Markus Armbruster
eddc0a7f0a json: Revamp lexer documentation
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-Id: <20180823164025.12553-20-armbru@redhat.com>
2018-08-24 20:26:37 +02:00
Markus Armbruster
340db1ed82 json: Reject unescaped control characters
Fix the lexer to reject unescaped control characters in JSON strings,
in accordance with RFC 8259 "The JavaScript Object Notation (JSON)
Data Interchange Format".

Bonus: we now recover more nicely from unclosed strings.  E.g.

    {"one: 1}\n{"two": 2}

now recovers cleanly after the newline, where before the lexer
remained confused until the next unpaired double quote or lexical
error.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-Id: <20180823164025.12553-19-armbru@redhat.com>
2018-08-24 20:26:37 +02:00
Markus Armbruster
a2ec6be72b json: Fix lexer to include the bad character in JSON_ERROR token
json_lexer[] maps (lexer state, input character) to the new lexer
state.  The input character is consumed unless the new state is
terminal and the input character doesn't belong to this token,
i.e. the state transition uses look-ahead.  When this is the case,
input character '\0' would result in the same state transition.
TERMINAL_NEEDED_LOOKAHEAD() exploits this.

Except this is wrong for transitions to IN_ERROR.  There, the
offending input character is in fact consumed: case IN_ERROR returns.
It isn't added to the JSON_ERROR token, though.

Fix that by making TERMINAL_NEEDED_LOOKAHEAD() return false for
transitions to IN_ERROR.

There's a slight complication.  json_lexer_flush() passes input
character '\0' to flush an incomplete token.  If this results in
JSON_ERROR, we'd now add the '\0' to the token.  Suppress that.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-Id: <20180823164025.12553-18-armbru@redhat.com>
2018-08-24 20:26:37 +02:00
Markus Armbruster
2e933f5701 check-qjson: Cover interpolation more thoroughly
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-Id: <20180823164025.12553-17-armbru@redhat.com>
2018-08-24 20:26:37 +02:00
Markus Armbruster
6bc93a3401 check-qjson qmp-test: Cover control characters more thoroughly
RFC 8259 "The JavaScript Object Notation (JSON) Data Interchange
Format" requires control characters in strings to be escaped.
Demonstrate the JSON parser accepts U+0001 .. U+001F unescaped.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-Id: <20180823164025.12553-16-armbru@redhat.com>
2018-08-24 20:26:37 +02:00
Markus Armbruster
5f454e662e check-qjson: Fix utf8_string() to test all invalid sequences
Some of utf8_string()'s test_cases[] contain multiple invalid
sequences.  Testing that qobject_from_json() fails only tests we
reject at least one invalid sequence.  That's incomplete.

Additionally test each non-space sequence in isolation.

This demonstrates that the JSON parser accepts invalid sequences
starting with \xC2..\xF4.  Add a FIXME comment.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-Id: <20180823164025.12553-15-armbru@redhat.com>
2018-08-24 20:26:37 +02:00
Markus Armbruster
32846e9304 check-qjson: Simplify utf8_string()
The previous commit made utf8_string()'s test_cases[].utf8_in
superfluous: we can use .json_in instead.  Except for the case testing
U+0000.  \x00 doesn't work in C strings, so it tests \\u0000 instead.
But testing \\uXXXX is escaped_string()'s job.  It's covered there.
Test U+0001 here, and drop .utf8_in.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-Id: <20180823164025.12553-14-armbru@redhat.com>
2018-08-24 20:26:37 +02:00
Markus Armbruster
6ad8444f6a check-qjson: Cover UTF-8 in single quoted strings
utf8_string() tests only double quoted strings.  Cover single quoted
strings, too: store the strings to test without quotes, then wrap them
in either kind of quote.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-Id: <20180823164025.12553-13-armbru@redhat.com>
2018-08-24 20:26:37 +02:00
Markus Armbruster
069946f402 check-qjson: Consolidate partly redundant string tests
simple_string() and single_quote_string() have become redundant with
escaped_string(), except for embedded single and double quotes.
Replace them by a test that covers just that.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-Id: <20180823164025.12553-12-armbru@redhat.com>
2018-08-24 20:26:37 +02:00
Markus Armbruster
e0fe2a978e check-qjson: Cover escaped characters more thoroughly, part 2
Cover escaped single quote, surrogates, invalid escapes, and
noncharacters.  This demonstrates that valid surrogate pairs are
misinterpreted, and invalid surrogates and noncharacters aren't
rejected.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-Id: <20180823164025.12553-11-armbru@redhat.com>
2018-08-24 20:26:37 +02:00
Markus Armbruster
f3cfdd3a30 check-qjson: Streamline escaped_string()'s test strings
Merge a few closely related test strings, and drop a few redundant
ones.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-Id: <20180823164025.12553-10-armbru@redhat.com>
2018-08-24 20:26:37 +02:00
Markus Armbruster
4e1df9b734 check-qjson: Cover escaped characters more thoroughly, part 1
escaped_string() first tests double quoted strings, then repeats a few
tests with single quotes.  Repeat all of them: store the strings to
test without quotes, and wrap them in either kind of quote for
testing.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-Id: <20180823164025.12553-9-armbru@redhat.com>
2018-08-24 20:26:37 +02:00
Markus Armbruster
e2f64a688b test-qga: Clean up how we test QGA synchronization
To permit recovering from arbitrary JSON parse errors, the JSON parser
resets itself on lexical errors.  We recommend sending a 0xff byte for
that purpose, and test-qga covers this usage since commit 5229564b83.
That commit had to add an ugly hack to qmp_fd_vsend() to make capable
of sending this byte (it's designed to send only valid JSON).

The previous commit added a way to send arbitrary text.  Put that to
use for this purpose, and drop the hack from qmp_fd_vsend().

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-Id: <20180823164025.12553-8-armbru@redhat.com>
2018-08-24 20:26:37 +02:00
Markus Armbruster
aed877c53b qmp-test: Cover syntax and lexical errors
qmp-test neglects to cover QMP input that isn't valid JSON.  libqtest
doesn't let us send such input.  Add qtest_qmp_send_raw() for this
purpose, and put it to use in qmp-test.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-Id: <20180823164025.12553-7-armbru@redhat.com>
[Commit message typo fixed]
2018-08-24 20:26:37 +02:00
Markus Armbruster
d93bb9d5c3 qmp-cmd-test: Split off qmp-test
qmp-test is for QMP protocol tests.  Commit e4a426e75e added generic,
basic tests of query commands to it.  Move them to their own test
program qmp-cmd-test, to keep qmp-test focused on the protocol.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-Id: <20180823164025.12553-6-armbru@redhat.com>
2018-08-24 20:25:48 +02:00
Markus Armbruster
5365490879 check-qjson: Cover whitespace more thoroughly
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-Id: <20180823164025.12553-5-armbru@redhat.com>
2018-08-24 20:25:48 +02:00
Markus Armbruster
a3694181e3 check-qjson: Cover blank and lexically erroneous input
qobject_from_json() can return null without setting an error on
lexical errors.  I call that a bug.  Add test coverage to demonstrate
it.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-Id: <20180823164025.12553-4-armbru@redhat.com>
2018-08-24 20:25:48 +02:00
Markus Armbruster
956a104a6c check-qjson: Cover multiple JSON objects in same string
qobject_from_json() & friends misbehave when the JSON text has more
than one JSON value.  Add test coverage to demonstrate the bugs.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-Id: <20180823164025.12553-3-armbru@redhat.com>
2018-08-24 20:25:48 +02:00
Markus Armbruster
72e9e569d0 docs/interop/qmp-spec: How to force known good parser state
Section "QGA Synchronization" specifies that sending "a raw 0xFF
sentinel byte" makes the server "reset its state and discard all
pending data prior to the sentinel."  What actually happens there is a
lexical error, which will produce one or more error responses.
Moreover, it's not specific to QGA.

Create new section "Forcing the JSON parser into known-good state" to
document the technique properly.  Rewrite section "QGA
Synchronization" to document just the other direction, i.e. command
guest-sync-delimited.

Section "Protocol Specification" mentions "synchronization bytes
(documented below)".  Delete that.

While there, fix it not to claim '"Server" is QEMU itself', but
'"Server" is either QEMU or the QEMU Guest Agent'.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-Id: <20180823164025.12553-2-armbru@redhat.com>
2018-08-24 20:25:48 +02:00
Peter Maydell
1dfb85a875 check/next for 20180822
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Merge remote-tracking branch 'remotes/juanquintela/tags/check/20180822' into staging

check/next for 20180822

# gpg: Signature made Wed 22 Aug 2018 09:03:40 BST
# gpg:                using RSA key F487EF185872D723
# gpg: Good signature from "Juan Quintela <quintela@redhat.com>"
# gpg:                 aka "Juan Quintela <quintela@trasno.org>"
# Primary key fingerprint: 1899 FF8E DEBF 58CC EE03  4B82 F487 EF18 5872 D723

* remotes/juanquintela/tags/check/20180822:
  check: Only test tpm devices when they are compiled in
  check: Only test usb-ehci when it is compiled in
  check: Only test usb-uhci devices when they are compiled in
  check: Only test usb-ohci when it is compiled in
  check: Only test nvme when it is compiled in
  check: Only test pvpanic when it is compiled in
  check: Only test wdt_ib700 when it is compiled in
  check: Only test sdhci when it is compiled in
  check: Only test i82801b11 when it is compiled in
  check: Only test ioh3420 when it is compiled in
  check: Only test ipack when it is compiled in
  check: Only test hda when it is compiled in
  check: Only test ac97 when it is compiled in
  check: Only test es1370 when it is compiled in
  check: Only test rtl8139 when it is compiled in
  check: Only test pcnet when it is compiled in
  check: Only test eepro100 when it is compiled in
  check: Only test ne2000 when it is compiled in
  check: Only test vmxnet3 when it is compiled in

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
2018-08-24 14:46:31 +01:00
Peter Maydell
f4e8428b9a target-arm queue:
* Fix rounding errors in scaling float-to-int and int-to-float operations
  * Connect virtualization-related IRQs and memory regions of GICv2
    in boards that use Cortex-A7 or Cortex-A15
  * Support taking exceptions to AArch32 Hyp mode
  * Clear CPSR.IL and CPSR.J on 32-bit exception entry
    (a minor bug fix that won't affect non-buggy guest code)
  * mps2-an505: Implement various missing devices:
    dual timer, watchdogs, counters in the FPGAIO registers,
    some missing ID/control registers, TrustZone Master Security
    Controllers, PL081 DMA controllers, PL022 SPI controllers
  * correct ID register values for mps2-an385, -an511, -an505
  * fix some hardcoded tabs in untouched backwaters of the
    target/arm codebase
  * raspi: Refactor framebuffer property handling code and implement
    support for the virtual framebuffer/viewport
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Merge remote-tracking branch 'remotes/pmaydell/tags/pull-target-arm-20180824-1' into staging

target-arm queue:
 * Fix rounding errors in scaling float-to-int and int-to-float operations
 * Connect virtualization-related IRQs and memory regions of GICv2
   in boards that use Cortex-A7 or Cortex-A15
 * Support taking exceptions to AArch32 Hyp mode
 * Clear CPSR.IL and CPSR.J on 32-bit exception entry
   (a minor bug fix that won't affect non-buggy guest code)
 * mps2-an505: Implement various missing devices:
   dual timer, watchdogs, counters in the FPGAIO registers,
   some missing ID/control registers, TrustZone Master Security
   Controllers, PL081 DMA controllers, PL022 SPI controllers
 * correct ID register values for mps2-an385, -an511, -an505
 * fix some hardcoded tabs in untouched backwaters of the
   target/arm codebase
 * raspi: Refactor framebuffer property handling code and implement
   support for the virtual framebuffer/viewport

# gpg: Signature made Fri 24 Aug 2018 13:19:04 BST
# gpg:                using RSA key 3C2525ED14360CDE
# gpg: Good signature from "Peter Maydell <peter.maydell@linaro.org>"
# gpg:                 aka "Peter Maydell <pmaydell@gmail.com>"
# gpg:                 aka "Peter Maydell <pmaydell@chiark.greenend.org.uk>"
# Primary key fingerprint: E1A5 C593 CD41 9DE2 8E83  15CF 3C25 25ED 1436 0CDE

* remotes/pmaydell/tags/pull-target-arm-20180824-1: (52 commits)
  hw/arm/mps2: Fix ID register errors on AN511 and AN385
  hw/display/bcm2835_fb: Validate bcm2835_fb_mbox_push() config
  hw/display/bcm2835_fb: Validate config settings
  hw/display/bcm2835_fb: Fix handling of virtual framebuffer
  hw/display/bcm2835_fb: Abstract out calculation of pitch, size
  hw/display/bcm2835_fb: Reset resolution, etc correctly
  hw/display/bcm2835_fb: Drop unused size and pitch fields
  hw/misc/bcm2835_property: Track fb settings using BCM2835FBConfig
  hw/misc/bcm2835_fb: Move config fields to their own struct
  target/arm: Remove a handful of stray tabs
  target/arm: Untabify iwmmxt_helper.c
  target/arm: Untabify translate.c
  hw/arm/mps2-tz: Fix MPS2 SCC config register values
  hw/arm/mps2-tz: Instantiate SPI controllers
  hw/ssi/pl022: Correct wrong DMACR and ICR handling
  hw/ssi/pl022: Correct wrong value for PL022_INT_RT
  hw/ssi/pl022: Use DeviceState::realize rather than SysBusDevice::init
  hw/ssi/pl022: Don't directly call vmstate_register()
  hw/ssi/pl022: Set up reset function in class init
  hw/ssi/pl022: Allow use as embedded-struct device
  ...

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
2018-08-24 13:29:07 +01:00