Patchwork qemu-char: Check for missing backend name

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Submitter Stefan Hajnoczi
Date Jan. 22, 2011, 1:07 p.m.
Message ID <1295701646-3022-1-git-send-email-stefanha@linux.vnet.ibm.com>
Download mbox | patch
Permalink /patch/80002/
State New
Headers show

Comments

Stefan Hajnoczi - Jan. 22, 2011, 1:07 p.m.
Check if the backend option is missing before searching the backend
table.  This fixes a NULL pointer dereference when QEMU is invoked with
the following invalid command-line:

  $ qemu -chardev id=foo,path=/tmp/socket

Previously QEMU would segfault, now it produces this error message:

  chardev: "foo" missing backend

Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
---
 qemu-char.c |    5 +++++
 1 files changed, 5 insertions(+), 0 deletions(-)
Aurelien Jarno - Feb. 20, 2011, 5:27 p.m.
On Sat, Jan 22, 2011 at 01:07:26PM +0000, Stefan Hajnoczi wrote:
> Check if the backend option is missing before searching the backend
> table.  This fixes a NULL pointer dereference when QEMU is invoked with
> the following invalid command-line:
> 
>   $ qemu -chardev id=foo,path=/tmp/socket
> 
> Previously QEMU would segfault, now it produces this error message:
> 
>   chardev: "foo" missing backend
> 
> Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
> ---
>  qemu-char.c |    5 +++++
>  1 files changed, 5 insertions(+), 0 deletions(-)

Thanks, applied.

> diff --git a/qemu-char.c b/qemu-char.c
> index edc9ad6..8a424d6 100644
> --- a/qemu-char.c
> +++ b/qemu-char.c
> @@ -2508,6 +2508,11 @@ CharDriverState *qemu_chr_open_opts(QemuOpts *opts,
>          return NULL;
>      }
>  
> +    if (qemu_opt_get(opts, "backend") == NULL) {
> +        fprintf(stderr, "chardev: \"%s\" missing backend\n",
> +                qemu_opts_id(opts));
> +        return NULL;
> +    }
>      for (i = 0; i < ARRAY_SIZE(backend_table); i++) {
>          if (strcmp(backend_table[i].name, qemu_opt_get(opts, "backend")) == 0)
>              break;
> -- 
> 1.7.2.3
> 
> 
>

Patch

diff --git a/qemu-char.c b/qemu-char.c
index edc9ad6..8a424d6 100644
--- a/qemu-char.c
+++ b/qemu-char.c
@@ -2508,6 +2508,11 @@  CharDriverState *qemu_chr_open_opts(QemuOpts *opts,
         return NULL;
     }
 
+    if (qemu_opt_get(opts, "backend") == NULL) {
+        fprintf(stderr, "chardev: \"%s\" missing backend\n",
+                qemu_opts_id(opts));
+        return NULL;
+    }
     for (i = 0; i < ARRAY_SIZE(backend_table); i++) {
         if (strcmp(backend_table[i].name, qemu_opt_get(opts, "backend")) == 0)
             break;