[Qemu-devel] [PATCHv3] migration: catch unknown flags in ram_load

[Qemu-devel] [PATCHv3] migration: catch unknown flags in ram_load

[Peter Lieven]

if a saved vm has unknown flags in the memory data qemu
currently simply ignores this flag and continues which
yields in an unpredictable result.

this patch catches all unknown flags and
aborts the loading of the vm.

CC: qemu-stable@nongnu.org
Signed-off-by: Peter Lieven <pl@kamp.de>
---
v2->v3: - reworked last case in the if statement
        - added an error_report in case of an unknown flag [David]
v1->v2: rework loop from do ... while to while [Juan]

 arch_init.c |   34 +++++++++++++++-------------------
 1 file changed, 15 insertions(+), 19 deletions(-)

diff --git a/arch_init.c b/arch_init.c
index 9f1a174..93a1191 100644
--- a/arch_init.c
+++ b/arch_init.c
@@ -1041,17 +1041,15 @@ static int ram_load(QEMUFile *f, void *opaque, int version_id)
 {
     ram_addr_t addr;
     int flags, ret = 0;
-    int error;
     static uint64_t seq_iter;
 
     seq_iter++;
 
     if (version_id != 4) {
         ret = -EINVAL;
-        goto done;
     }
 
-    do {
+    while (!ret) {
         addr = qemu_get_be64(f);
 
         flags = addr & ~TARGET_PAGE_MASK;
@@ -1079,7 +1077,6 @@ static int ram_load(QEMUFile *f, void *opaque, int version_id)
                                          " in != " RAM_ADDR_FMT, id, length,
                                          block->length);
                             ret =  -EINVAL;
-                            goto done;
                         }
                         break;
                     }
@@ -1089,21 +1086,21 @@ static int ram_load(QEMUFile *f, void *opaque, int version_id)
                     error_report("Unknown ramblock \"%s\", cannot "
                                  "accept migration", id);
                     ret = -EINVAL;
-                    goto done;
+                }
+                if (ret) {
+                    break;
                 }
 
                 total_ram_bytes -= length;
             }
-        }
-
-        if (flags & RAM_SAVE_FLAG_COMPRESS) {
+        } else if (flags & RAM_SAVE_FLAG_COMPRESS) {
             void *host;
             uint8_t ch;
 
             host = host_from_stream_offset(f, addr, flags);
             if (!host) {
                 ret = -EINVAL;
-                goto done;
+                break;
             }
 
             ch = qemu_get_byte(f);
@@ -1114,7 +1111,7 @@ static int ram_load(QEMUFile *f, void *opaque, int version_id)
             host = host_from_stream_offset(f, addr, flags);
             if (!host) {
                 ret = -EINVAL;
-                goto done;
+                break;
             }
 
             qemu_get_buffer(f, host, TARGET_PAGE_SIZE);
@@ -1122,24 +1119,23 @@ static int ram_load(QEMUFile *f, void *opaque, int version_id)
             void *host = host_from_stream_offset(f, addr, flags);
             if (!host) {
                 ret = -EINVAL;
-                goto done;
+                break;
             }
 
             if (load_xbzrle(f, addr, host) < 0) {
                 ret = -EINVAL;
-                goto done;
+                break;
             }
         } else if (flags & RAM_SAVE_FLAG_HOOK) {
             ram_control_load_hook(f, flags);
+        } else if (!(flags & RAM_SAVE_FLAG_EOS)) {
+            error_report("Unknown migration flags: %#x", flags);
+            ret = -EINVAL;
+            break;
         }
-        error = qemu_file_get_error(f);
-        if (error) {
-            ret = error;
-            goto done;
-        }
-    } while (!(flags & RAM_SAVE_FLAG_EOS));
+        ret = qemu_file_get_error(f);
+    }
 
-done:
     DPRINTF("Completed load of VM with exit code %d seq iteration "
             "%" PRIu64 "\n", ret, seq_iter);
     return ret;
-- 
1.7.9.5

Re: [Qemu-devel] [PATCHv3] migration: catch unknown flags in ram_load

[Amit Shah]

On (Tue) 10 Jun 2014 [10:04:23], Peter Lieven wrote:
> if a saved vm has unknown flags in the memory data qemu
> currently simply ignores this flag and continues which
> yields in an unpredictable result.
> 
> this patch catches all unknown flags and
> aborts the loading of the vm.
> 
> CC: qemu-stable@nongnu.org
> Signed-off-by: Peter Lieven <pl@kamp.de>

Reviewed-by: Amit Shah <amit.shah@redhat.com>

> ---
> v2->v3: - reworked last case in the if statement
>         - added an error_report in case of an unknown flag [David]

Thanks.  Would be nice to get an error_report() for the other error
conditions, too.  It's not fun to learn migration has failed, w/o any
clue of why or where.

		Amit

Re: [Qemu-devel] [PATCHv3] migration: catch unknown flags in ram_load

[Peter Lieven]

On 10.06.2014 10:45, Amit Shah wrote:
> On (Tue) 10 Jun 2014 [10:04:23], Peter Lieven wrote:
>> if a saved vm has unknown flags in the memory data qemu
>> currently simply ignores this flag and continues which
>> yields in an unpredictable result.
>>
>> this patch catches all unknown flags and
>> aborts the loading of the vm.
>>
>> CC: qemu-stable@nongnu.org
>> Signed-off-by: Peter Lieven <pl@kamp.de>
> Reviewed-by: Amit Shah <amit.shah@redhat.com>
>
>> ---
>> v2->v3: - reworked last case in the if statement
>>          - added an error_report in case of an unknown flag [David]
> Thanks.  Would be nice to get an error_report() for the other error
> conditions, too.  It's not fun to learn migration has failed, w/o any
> clue of why or where.

Ok, will send v4.

Peter

>
> 		Amit


-- 

Mit freundlichen Grüßen

Peter Lieven

...........................................................

   KAMP Netzwerkdienste GmbH
   Vestische Str. 89-91 | 46117 Oberhausen
   Tel: +49 (0) 208.89 402-50 | Fax: +49 (0) 208.89 402-40
   pl@kamp.de | http://www.kamp.de

   Geschäftsführer: Heiner Lante | Michael Lante
   Amtsgericht Duisburg | HRB Nr. 12154
   USt-Id-Nr.: DE 120607556

...........................................................

Re: [Qemu-devel] [PATCHv3] migration: catch unknown flags in ram_load

[Amit Shah]

On (Tue) 10 Jun 2014 [10:47:56], Peter Lieven wrote:
> On 10.06.2014 10:45, Amit Shah wrote:
> >On (Tue) 10 Jun 2014 [10:04:23], Peter Lieven wrote:
> >>if a saved vm has unknown flags in the memory data qemu
> >>currently simply ignores this flag and continues which
> >>yields in an unpredictable result.
> >>
> >>this patch catches all unknown flags and
> >>aborts the loading of the vm.
> >>
> >>CC: qemu-stable@nongnu.org
> >>Signed-off-by: Peter Lieven <pl@kamp.de>
> >Reviewed-by: Amit Shah <amit.shah@redhat.com>
> >
> >>---
> >>v2->v3: - reworked last case in the if statement
> >>         - added an error_report in case of an unknown flag [David]
> >Thanks.  Would be nice to get an error_report() for the other error
> >conditions, too.  It's not fun to learn migration has failed, w/o any
> >clue of why or where.
> 
> Ok, will send v4.

Thank you!

		Amit

Re: [Qemu-devel] [PATCHv3] migration: catch unknown flags in ram_load

[Juan Quintela]

Peter Lieven <pl@kamp.de> wrote:
> On 10.06.2014 10:45, Amit Shah wrote:
>> On (Tue) 10 Jun 2014 [10:04:23], Peter Lieven wrote:
>>> if a saved vm has unknown flags in the memory data qemu
>>> currently simply ignores this flag and continues which
>>> yields in an unpredictable result.
>>>
>>> this patch catches all unknown flags and
>>> aborts the loading of the vm.
>>>
>>> CC: qemu-stable@nongnu.org
>>> Signed-off-by: Peter Lieven <pl@kamp.de>
>> Reviewed-by: Amit Shah <amit.shah@redhat.com>
>>
>>> ---
>>> v2->v3: - reworked last case in the if statement
>>>          - added an error_report in case of an unknown flag [David]
>> Thanks.  Would be nice to get an error_report() for the other error
>> conditions, too.  It's not fun to learn migration has failed, w/o any
>> clue of why or where.
>
> Ok, will send v4.
>
> Peter

Thanks very much.