dmg: prevent out-of-bounds array access on terminator

When a terminator is reached the base for offsets and sectors is stored.
The following records that are processed will use this base value.

If the first record we encounter is a terminator, then calculating the
base values would result in out-of-bounds array accesses.  Don't do
that.

Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
This commit is contained in:
Stefan Hajnoczi 2014-03-26 13:05:55 +01:00
parent 2c1885adcf
commit 73ed27ec28
1 changed files with 1 additions and 1 deletions

View File

@ -182,7 +182,7 @@ static int dmg_open(BlockDriverState *bs, QDict *options, int flags,
offset += 4;
if (s->types[i] != 0x80000005 && s->types[i] != 1 &&
s->types[i] != 2) {
if (s->types[i] == 0xffffffff) {
if (s->types[i] == 0xffffffff && i > 0) {
last_in_offset = s->offsets[i - 1] + s->lengths[i - 1];
last_out_offset = s->sectors[i - 1] +
s->sectorcounts[i - 1];