From c7fd5f3841f14c24e442fb6968c9f2d9e016f28a Mon Sep 17 00:00:00 2001 From: Prasad J Pandit Date: Mon, 21 Jun 2021 09:22:35 +0800 Subject: [PATCH] ide: ahci: add check to avoid null dereference (CVE-2019-12067) Fix CVE-2019-12067 AHCI emulator while committing DMA buffer in ahci_commit_buf() may do a NULL dereference if the command header 'ad->cur_cmd' is null. Add check to avoid it. Reported-by: Bugs SysSec Signed-off-by: Prasad J Pandit Signed-off-by: Jiajie Li --- hw/ide/ahci.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/hw/ide/ahci.c b/hw/ide/ahci.c index 6aaf66534a..a7be0ae4fe 100644 --- a/hw/ide/ahci.c +++ b/hw/ide/ahci.c @@ -1455,8 +1455,10 @@ static void ahci_commit_buf(IDEDMA *dma, uint32_t tx_bytes) { AHCIDevice *ad = DO_UPCAST(AHCIDevice, dma, dma); - tx_bytes += le32_to_cpu(ad->cur_cmd->status); - ad->cur_cmd->status = cpu_to_le32(tx_bytes); + if (ad->cur_cmd) { + tx_bytes += le32_to_cpu(ad->cur_cmd->status); + ad->cur_cmd->status = cpu_to_le32(tx_bytes); + } } static int ahci_dma_rw_buf(IDEDMA *dma, int is_write) -- 2.27.0