Commit 0be839a2 authored by Michael S. Tsirkin's avatar Michael S. Tsirkin Committed by Amit Shah

migration: fix parameter validation on ram load

During migration, the values read from migration stream during ram load
are not validated. Especially offset in host_from_stream_offset() and
also the length of the writes in the callers of said function.

To fix this, we need to make sure that the [offset, offset + length]
range fits into one of the allocated memory regions.

Validating addr < len should be sufficient since data seems to always be
managed in TARGET_PAGE_SIZE chunks.

Fixes: CVE-2014-7840

Note: follow-up patches add extra checks on each block->host access.
Signed-off-by: default avatarMichael S. Tsirkin <>
Reviewed-by: default avatarPaolo Bonzini <>
Reviewed-by: default avatarDr. David Alan Gilbert <>
Signed-off-by: default avatarAmit Shah <>
parent d6be29e3
......@@ -1006,7 +1006,7 @@ static inline void *host_from_stream_offset(QEMUFile *f,
uint8_t len;
if (!block) {
if (!block || block->length <= offset) {
error_report("Ack, bad migration stream!");
return NULL;
......@@ -1019,8 +1019,9 @@ static inline void *host_from_stream_offset(QEMUFile *f,
id[len] = 0;
QTAILQ_FOREACH(block, &ram_list.blocks, next) {
if (!strncmp(id, block->idstr, sizeof(id)))
if (!strncmp(id, block->idstr, sizeof(id)) && block->length > offset) {
return memory_region_get_ram_ptr(block->mr) + offset;
error_report("Can't find block %s!", id);
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