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qcow2: Do not overflow when writing an L1 sector 

While writing an L1 table sector, qcow2_write_l1_entry() copies the
respective range from s->l1_table to the local "buf" array. The size of
s->l1_table does not have to be a multiple of L1_ENTRIES_PER_SECTOR;
thus, limit the index which is used for copying all entries to the L1
size.

Cc: qemu-stable@nongnu.org
Signed-off-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Peter Lieven <pl@kamp.de>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
This commit is contained in:
Max Reitz 2014-10-16 15:25:56 +02:00 committed by Kevin Wolf
parent 925bb3238d
commit a1391444fe
1 changed files with 4 additions and 2 deletions
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6
block/qcow2-cluster.c
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@ -164,12 +164,14 @@ static int l2_load(BlockDriverState *bs, uint64_t l2_offset,
int qcow2_write_l1_entry(BlockDriverState *bs, int l1_index)
{
BDRVQcowState *s = bs->opaque;
uint64_t buf[L1_ENTRIES_PER_SECTOR];
uint64_t buf[L1_ENTRIES_PER_SECTOR] = { 0 };
int l1_start_index;
int i, ret;
l1_start_index = l1_index & ~(L1_ENTRIES_PER_SECTOR - 1);
for (i = 0; i < L1_ENTRIES_PER_SECTOR; i++) {
for (i = 0; i < L1_ENTRIES_PER_SECTOR && l1_start_index + i < s->l1_size;
i++)
{
buf[i] = cpu_to_be64(s->l1_table[l1_start_index + i]);
}