qapi: Restrict strings to printable ASCII

RFC 8259 on string contents:

   All Unicode characters may be placed within the quotation marks,
   except for the characters that MUST be escaped: quotation mark,
   reverse solidus, and the control characters (U+0000 through
   U+001F).

The QAPI schema parser accepts both less and more than JSON: it
accepts only ASCII with \u (less), and accepts control characters
other than LF (new line) unescaped.  How it treats unescaped non-ASCII
input differs between Python 2 and Python 3.

Make it accept strictly less: require printable ASCII.  Drop support
for \b, \f, \n, \r, \t.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-Id: <20190913201349.24332-7-armbru@redhat.com>

11 files changed, 9 insertions, 4 deletions

diff --git a/tests/Makefile.include b/tests/Makefile.include
index 479664f..393cfd7 100644
--- a/tests/Makefile.include
+++ b/tests/Makefile.include
@@ -451,6 +451,8 @@ qapi-schema += returns-array-bad.json
 qapi-schema += returns-dict.json
 qapi-schema += returns-unknown.json
 qapi-schema += returns-whitelist.json
+qapi-schema += string-code-point-31.json
+qapi-schema += string-code-point-127.json
 qapi-schema += struct-base-clash-deep.json
 qapi-schema += struct-base-clash.json
 qapi-schema += struct-data-invalid.json
@@ -462,7 +464,6 @@ qapi-schema += type-bypass-bad-gen.json
 qapi-schema += unclosed-list.json
 qapi-schema += unclosed-object.json
 qapi-schema += unclosed-string.json
-qapi-schema += unicode-str.json
 qapi-schema += union-base-empty.json
 qapi-schema += union-base-no-discriminator.json
 qapi-schema += union-branch-case.json
diff --git a/tests/qapi-schema/string-code-point-127.err b/tests/qapi-schema/string-code-point-127.err
new file mode 100644
index 0000000..c310910
--- /dev/null
+++ b/tests/qapi-schema/string-code-point-127.err
@@ -0,0 +1 @@
+tests/qapi-schema/string-code-point-127.json:2:14: Funny character in string
diff --git a/tests/qapi-schema/unicode-str.exit b/tests/qapi-schema/string-code-point-127.exit
index d00491f..d00491f 100644
--- a/tests/qapi-schema/unicode-str.exit
+++ b/tests/qapi-schema/string-code-point-127.exit
diff --git a/tests/qapi-schema/string-code-point-127.json b/tests/qapi-schema/string-code-point-127.json
new file mode 100644
index 0000000..480318a
--- /dev/null
+++ b/tests/qapi-schema/string-code-point-127.json
@@ -0,0 +1,2 @@
+# We accept printable ASCII: code points 32..126.  Test code point 127:
+{ 'command': '' }
diff --git a/tests/qapi-schema/unicode-str.out b/tests/qapi-schema/string-code-point-127.out
index e69de29..e69de29 100644
--- a/tests/qapi-schema/unicode-str.out
+++ b/tests/qapi-schema/string-code-point-127.out
diff --git a/tests/qapi-schema/string-code-point-31.err b/tests/qapi-schema/string-code-point-31.err
new file mode 100644
index 0000000..4579792
--- /dev/null
+++ b/tests/qapi-schema/string-code-point-31.err
@@ -0,0 +1 @@
+tests/qapi-schema/string-code-point-31.json:2:14: Funny character in string
diff --git a/tests/qapi-schema/string-code-point-31.exit b/tests/qapi-schema/string-code-point-31.exit
new file mode 100644
index 0000000..d00491f
--- /dev/null
+++ b/tests/qapi-schema/string-code-point-31.exit
@@ -0,0 +1 @@
+1
diff --git a/tests/qapi-schema/string-code-point-31.json b/tests/qapi-schema/string-code-point-31.json
new file mode 100644
index 0000000..f186cbd
--- /dev/null
+++ b/tests/qapi-schema/string-code-point-31.json
@@ -0,0 +1,2 @@
+# We accept printable ASCII: code points 32..126.  Test code point 127:
+{ 'command': '' }
diff --git a/tests/qapi-schema/string-code-point-31.out b/tests/qapi-schema/string-code-point-31.out
new file mode 100644
index 0000000..e69de29
--- /dev/null
+++ b/tests/qapi-schema/string-code-point-31.out
diff --git a/tests/qapi-schema/unicode-str.err b/tests/qapi-schema/unicode-str.err
deleted file mode 100644
index f621cd6..0000000
--- a/tests/qapi-schema/unicode-str.err
+++ /dev/null
@@ -1 +0,0 @@
-tests/qapi-schema/unicode-str.json:2: 'command' uses invalid name 'é'
diff --git a/tests/qapi-schema/unicode-str.json b/tests/qapi-schema/unicode-str.json
deleted file mode 100644
index 5253a1b..0000000
--- a/tests/qapi-schema/unicode-str.json
+++ /dev/null
@@ -1,2 +0,0 @@
-# we don't support full Unicode strings, yet
-{ 'command': 'é' }