[Qemu-devel] [PATCH] sd: sdhci: check data length during dma_memory_read

[P J P <ppandit@redhat.com>]

From: Prasad J Pandit <pjp@fedoraproject.org>

While doing multi block SDMA transfer in routine
'sdhci_sdma_transfer_multi_blocks', the 's->fifo_buffer' starting
index 'begin' and data length 's->data_count' could end up to be same.
This could lead to an OOB access issue. Correct transfer data length
to avoid it.

Reported-by: Jiang Xin <jiangxin1@huawei.com>
Signed-off-by: Prasad J Pandit <pjp@fedoraproject.org>
---
 hw/sd/sdhci.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/hw/sd/sdhci.c b/hw/sd/sdhci.c
index 01fbf22..5bd5ab6 100644
--- a/hw/sd/sdhci.c
+++ b/hw/sd/sdhci.c
@@ -536,7 +536,7 @@ static void sdhci_sdma_transfer_multi_blocks(SDHCIState *s)
                 boundary_count -= block_size - begin;
             }
             dma_memory_read(&address_space_memory, s->sdmasysad,
-                            &s->fifo_buffer[begin], s->data_count);
+                            &s->fifo_buffer[begin], s->data_count - begin);
             s->sdmasysad += s->data_count - begin;
             if (s->data_count == block_size) {
                 for (n = 0; n < block_size; n++) {
-- 
2.9.3