[Qemu-devel] [PATCH] json-parser: Fix segfault on malformed input

[Qemu-devel] [PATCH] json-parser: Fix segfault on malformed input

[Kevin Wolf]

If the parser fails to parse the key in parse_pair, it will access a NULL
pointer. A simple way to trigger this is sending {foo} via QMP. This patch
turns the segfault into a syntax error reply.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
---
 json-parser.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/json-parser.c b/json-parser.c
index f3debcb..579928f 100644
--- a/json-parser.c
+++ b/json-parser.c
@@ -264,7 +264,7 @@ static int parse_pair(JSONParserContext *ctxt, QDict *dict, QList **tokens, va_l
 
     peek = qlist_peek(working);
     key = parse_value(ctxt, &working, ap);
-    if (qobject_type(key) != QTYPE_QSTRING) {
+    if (!key || qobject_type(key) != QTYPE_QSTRING) {
         parse_error(ctxt, peek, "key is not a string in object");
         goto out;
     }
-- 
1.6.6.1

Re: [Qemu-devel] [PATCH] json-parser: Fix segfault on malformed input

[Aurelien Jarno]

On Wed, Feb 24, 2010 at 04:17:58PM +0100, Kevin Wolf wrote:
> If the parser fails to parse the key in parse_pair, it will access a NULL
> pointer. A simple way to trigger this is sending {foo} via QMP. This patch
> turns the segfault into a syntax error reply.
> 
> Signed-off-by: Kevin Wolf <kwolf@redhat.com>

Thanks, applied.

> ---
>  json-parser.c |    2 +-
>  1 files changed, 1 insertions(+), 1 deletions(-)
> 
> diff --git a/json-parser.c b/json-parser.c
> index f3debcb..579928f 100644
> --- a/json-parser.c
> +++ b/json-parser.c
> @@ -264,7 +264,7 @@ static int parse_pair(JSONParserContext *ctxt, QDict *dict, QList **tokens, va_l
>  
>      peek = qlist_peek(working);
>      key = parse_value(ctxt, &working, ap);
> -    if (qobject_type(key) != QTYPE_QSTRING) {
> +    if (!key || qobject_type(key) != QTYPE_QSTRING) {
>          parse_error(ctxt, peek, "key is not a string in object");
>          goto out;
>      }
> -- 
> 1.6.6.1
> 
> 
> 
> 

-- 
Aurelien Jarno                          GPG: 1024D/F1BCDB73
aurelien@aurel32.net                 http://www.aurel32.net