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migration: fix parameter validation on ram load

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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: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Signed-off-by: Amit Shah <amit.shah@redhat.com>
This commit is contained in:
Michael S. Tsirkin 2014-11-12 11:44:39 +02:00 committed by Amit Shah
parent d6be29e3fb
commit 0be839a270
1 changed files with 3 additions and 2 deletions
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5
arch_init.c
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@ -1006,7 +1006,7 @@ static inline void *host_from_stream_offset(QEMUFile *f,
uint8_t len;
if (flags & RAM_SAVE_FLAG_CONTINUE) {
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);