vl: Avoid crash when -mon is underspecified

[Qemu-devel] [PATCH] vl: Avoid crash when -mon is underspecified

Posted by Eric Blake 6 years, 11 months ago

A quick coredump on an incomplete command line:
./x86_64-softmmu/qemu-system-x86_64 -mon mode=control,pretty=on

 #0  0x00007ffff723d9e4 in g_str_hash () at /lib64/libglib-2.0.so.0
 #1  0x00007ffff723ce38 in g_hash_table_lookup () at /lib64/libglib-2.0.so.0
 #2  0x0000555555cc0073 in object_class_property_find (klass=0x5555566a94b0, name=0x0, errp=0x0) at qom/object.c:1135
 #3  0x0000555555cc004b in object_class_property_find (klass=0x5555566a9440, name=0x0, errp=0x0) at qom/object.c:1129
 #4  0x0000555555cbfe6e in object_property_find (obj=0x5555568348c0, name=0x0, errp=0x0) at qom/object.c:1080
 #5  0x0000555555cc183d in object_resolve_path_component (parent=0x5555568348c0, part=0x0) at qom/object.c:1762
 #6  0x0000555555d82071 in qemu_chr_find (name=0x0) at chardev/char.c:802
 #7  0x00005555559d77cb in mon_init_func (opaque=0x0, opts=0x5555566b65a0, errp=0x0) at vl.c:2291

Fix it to instead fail gracefully.

Signed-off-by: Eric Blake <eblake@redhat.com>
---
 vl.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/vl.c b/vl.c
index 4e25c78bff0..2ed8672eb79 100644
--- a/vl.c
+++ b/vl.c
@@ -2288,6 +2288,10 @@ static int mon_init_func(void *opaque, QemuOpts *opts, Error **errp)
     }

     chardev = qemu_opt_get(opts, "chardev");
+    if (!chardev) {
+        error_report("chardev is required");
+        exit(1);
+    }
     chr = qemu_chr_find(chardev);
     if (chr == NULL) {
         error_report("chardev \"%s\" not found", chardev);
-- 
2.17.2

Re: [Qemu-devel] [PATCH] vl: Avoid crash when -mon is underspecified

Posted by Paolo Bonzini 6 years, 11 months ago

On 23/10/2018 23:35, Eric Blake wrote:
> A quick coredump on an incomplete command line:
> ./x86_64-softmmu/qemu-system-x86_64 -mon mode=control,pretty=on
> 
>  #0  0x00007ffff723d9e4 in g_str_hash () at /lib64/libglib-2.0.so.0
>  #1  0x00007ffff723ce38 in g_hash_table_lookup () at /lib64/libglib-2.0.so.0
>  #2  0x0000555555cc0073 in object_class_property_find (klass=0x5555566a94b0, name=0x0, errp=0x0) at qom/object.c:1135
>  #3  0x0000555555cc004b in object_class_property_find (klass=0x5555566a9440, name=0x0, errp=0x0) at qom/object.c:1129
>  #4  0x0000555555cbfe6e in object_property_find (obj=0x5555568348c0, name=0x0, errp=0x0) at qom/object.c:1080
>  #5  0x0000555555cc183d in object_resolve_path_component (parent=0x5555568348c0, part=0x0) at qom/object.c:1762
>  #6  0x0000555555d82071 in qemu_chr_find (name=0x0) at chardev/char.c:802
>  #7  0x00005555559d77cb in mon_init_func (opaque=0x0, opts=0x5555566b65a0, errp=0x0) at vl.c:2291
> 
> Fix it to instead fail gracefully.
> 
> Signed-off-by: Eric Blake <eblake@redhat.com>
> ---
>  vl.c | 4 ++++
>  1 file changed, 4 insertions(+)
> 
> diff --git a/vl.c b/vl.c
> index 4e25c78bff0..2ed8672eb79 100644
> --- a/vl.c
> +++ b/vl.c
> @@ -2288,6 +2288,10 @@ static int mon_init_func(void *opaque, QemuOpts *opts, Error **errp)
>      }
> 
>      chardev = qemu_opt_get(opts, "chardev");
> +    if (!chardev) {
> +        error_report("chardev is required");
> +        exit(1);
> +    }
>      chr = qemu_chr_find(chardev);
>      if (chr == NULL) {
>          error_report("chardev \"%s\" not found", chardev);
> 

Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>

Re: [Qemu-devel] [PATCH] vl: Avoid crash when -mon is underspecified

Posted by Philippe Mathieu-Daudé 6 years, 11 months ago

On 23/10/18 23:35, Eric Blake wrote:
> A quick coredump on an incomplete command line:
> ./x86_64-softmmu/qemu-system-x86_64 -mon mode=control,pretty=on
> 
>   #0  0x00007ffff723d9e4 in g_str_hash () at /lib64/libglib-2.0.so.0
>   #1  0x00007ffff723ce38 in g_hash_table_lookup () at /lib64/libglib-2.0.so.0
>   #2  0x0000555555cc0073 in object_class_property_find (klass=0x5555566a94b0, name=0x0, errp=0x0) at qom/object.c:1135
>   #3  0x0000555555cc004b in object_class_property_find (klass=0x5555566a9440, name=0x0, errp=0x0) at qom/object.c:1129
>   #4  0x0000555555cbfe6e in object_property_find (obj=0x5555568348c0, name=0x0, errp=0x0) at qom/object.c:1080
>   #5  0x0000555555cc183d in object_resolve_path_component (parent=0x5555568348c0, part=0x0) at qom/object.c:1762
>   #6  0x0000555555d82071 in qemu_chr_find (name=0x0) at chardev/char.c:802
>   #7  0x00005555559d77cb in mon_init_func (opaque=0x0, opts=0x5555566b65a0, errp=0x0) at vl.c:2291
> 
> Fix it to instead fail gracefully.
> 
> Signed-off-by: Eric Blake <eblake@redhat.com>

Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>

> ---
>   vl.c | 4 ++++
>   1 file changed, 4 insertions(+)
> 
> diff --git a/vl.c b/vl.c
> index 4e25c78bff0..2ed8672eb79 100644
> --- a/vl.c
> +++ b/vl.c
> @@ -2288,6 +2288,10 @@ static int mon_init_func(void *opaque, QemuOpts *opts, Error **errp)
>       }
> 
>       chardev = qemu_opt_get(opts, "chardev");
> +    if (!chardev) {
> +        error_report("chardev is required");
> +        exit(1);
> +    }
>       chr = qemu_chr_find(chardev);
>       if (chr == NULL) {
>           error_report("chardev \"%s\" not found", chardev);
>

Re: [Qemu-devel] [PATCH] vl: Avoid crash when -mon is underspecified

Posted by Peter Xu 6 years, 11 months ago

On Tue, Oct 23, 2018 at 10:35:59PM +0100, Eric Blake wrote:
> A quick coredump on an incomplete command line:
> ./x86_64-softmmu/qemu-system-x86_64 -mon mode=control,pretty=on
> 
>  #0  0x00007ffff723d9e4 in g_str_hash () at /lib64/libglib-2.0.so.0
>  #1  0x00007ffff723ce38 in g_hash_table_lookup () at /lib64/libglib-2.0.so.0
>  #2  0x0000555555cc0073 in object_class_property_find (klass=0x5555566a94b0, name=0x0, errp=0x0) at qom/object.c:1135
>  #3  0x0000555555cc004b in object_class_property_find (klass=0x5555566a9440, name=0x0, errp=0x0) at qom/object.c:1129
>  #4  0x0000555555cbfe6e in object_property_find (obj=0x5555568348c0, name=0x0, errp=0x0) at qom/object.c:1080
>  #5  0x0000555555cc183d in object_resolve_path_component (parent=0x5555568348c0, part=0x0) at qom/object.c:1762
>  #6  0x0000555555d82071 in qemu_chr_find (name=0x0) at chardev/char.c:802
>  #7  0x00005555559d77cb in mon_init_func (opaque=0x0, opts=0x5555566b65a0, errp=0x0) at vl.c:2291
> 
> Fix it to instead fail gracefully.
> 
> Signed-off-by: Eric Blake <eblake@redhat.com>

Reviewed-by: Peter Xu <peterx@redhat.com>

-- 
Peter Xu

Re: [Qemu-devel] [PATCH] vl: Avoid crash when -mon is underspecified

Posted by Markus Armbruster 6 years, 11 months ago

Eric Blake <eblake@redhat.com> writes:

> A quick coredump on an incomplete command line:
> ./x86_64-softmmu/qemu-system-x86_64 -mon mode=control,pretty=on
>
>  #0  0x00007ffff723d9e4 in g_str_hash () at /lib64/libglib-2.0.so.0
>  #1  0x00007ffff723ce38 in g_hash_table_lookup () at /lib64/libglib-2.0.so.0
>  #2  0x0000555555cc0073 in object_class_property_find (klass=0x5555566a94b0, name=0x0, errp=0x0) at qom/object.c:1135
>  #3  0x0000555555cc004b in object_class_property_find (klass=0x5555566a9440, name=0x0, errp=0x0) at qom/object.c:1129
>  #4  0x0000555555cbfe6e in object_property_find (obj=0x5555568348c0, name=0x0, errp=0x0) at qom/object.c:1080
>  #5  0x0000555555cc183d in object_resolve_path_component (parent=0x5555568348c0, part=0x0) at qom/object.c:1762
>  #6  0x0000555555d82071 in qemu_chr_find (name=0x0) at chardev/char.c:802
>  #7  0x00005555559d77cb in mon_init_func (opaque=0x0, opts=0x5555566b65a0, errp=0x0) at vl.c:2291
>
> Fix it to instead fail gracefully.
>
> Signed-off-by: Eric Blake <eblake@redhat.com>

Queued.  Thanks!