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envelope-from=armenon@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.001, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H4=0.001, RCVD_IN_MSPIKE_WL=0.001, SPF_HELO_PASS=-0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: qemu development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org From: Arun Menon In GLib, GByteArray is an object managed by the library. Currently, migrating a GByteArray requires treating it as a raw C struct and using VMSTATE_VBUFFER_ALLOC_UINT32. For example, see vmstate_vdba in ui/vdagent.c QEMU cannot pretend that GByteArray is a C struct and simply use VMS_ALLOC to g_malloc() the buffer. This is because, VMS_ALLOC blindly overwrites the data pointer with a newly allocated buffer, thereby leaking the previous memory. Besides, GLib tracks the array's capacity in a hidden alloc field. Bypassing GLib APIs leave this capacity out of sync with the newly allocated buffer, potentially leading to heap buffer overflows during subsequent g_byte_array_append() calls. This commit introduces VMSTATE_GBYTEARRAY which uses specific library API calls (g_byte_array_set_size()) to safely resize and populate the buffer. Signed-off-by: Arun Menon Fix-Suggested-by: Marc-André Lureau Reviewed-by: Marc-André Lureau --- include/migration/vmstate.h | 10 ++++++++++ migration/vmstate-types.c | 37 +++++++++++++++++++++++++++++++++++++ 2 files changed, 47 insertions(+) diff --git a/include/migration/vmstate.h b/include/migration/vmstate.h index 62c2abd0c4..f503a40ec0 100644 --- a/include/migration/vmstate.h +++ b/include/migration/vmstate.h @@ -265,6 +265,7 @@ extern const VMStateInfo vmstate_info_bitmap; extern const VMStateInfo vmstate_info_qtailq; extern const VMStateInfo vmstate_info_gtree; extern const VMStateInfo vmstate_info_qlist; +extern const VMStateInfo vmstate_info_g_byte_array; #define type_check_2darray(t1,t2,n,m) ((t1(*)[n][m])0 - (t2*)0) /* @@ -892,6 +893,15 @@ extern const VMStateInfo vmstate_info_qlist; .start = offsetof(_type, _next), \ } +#define VMSTATE_GBYTEARRAY(_field, _state, _version) { \ + .name = (stringify(_field)), \ + .version_id = (_version), \ + .size = sizeof(GByteArray), \ + .info = &vmstate_info_g_byte_array, \ + .flags = VMS_SINGLE, \ + .offset = vmstate_offset_pointer(_state, _field, GByteArray), \ +} + /* _f : field name _f_n : num of elements field_name _n : num of elements diff --git a/migration/vmstate-types.c b/migration/vmstate-types.c index 89cb211472..e3a47e60b1 100644 --- a/migration/vmstate-types.c +++ b/migration/vmstate-types.c @@ -942,3 +942,40 @@ const VMStateInfo vmstate_info_qlist = { .get = get_qlist, .put = put_qlist, }; + +static int get_g_byte_array(QEMUFile *f, void *pv, size_t size, + const VMStateField *field) +{ + GByteArray **byte_array = (GByteArray **)pv; + uint32_t len = qemu_get_be32(f); + + assert(*byte_array != NULL); + + g_byte_array_set_size(*byte_array, len); + if (len > 0) { + qemu_get_buffer(f, (*byte_array)->data, len); + } + return 0; +} + +static int put_g_byte_array(QEMUFile *f, void *pv, size_t size, + const VMStateField *field, JSONWriter *vmdesc) +{ + GByteArray *byte_array = *(GByteArray **)pv; + uint32_t len; + assert(byte_array != NULL); + + len = byte_array ? byte_array->len : 0; + qemu_put_be32(f, len); + if (len > 0) { + qemu_put_buffer(f, byte_array->data, len); + } + + return 0; +} + +const VMStateInfo vmstate_info_g_byte_array = { + .name = "GByteArray", + .get = get_g_byte_array, + .put = put_g_byte_array, +}; -- 2.53.0