From c9a71afe182be5b62bd2ccdaf861695e0ec0731a Mon Sep 17 00:00:00 2001 From: Prasad J Pandit Date: Mon, 18 Jan 2021 17:21:30 +0530 Subject: [PATCH] ide: atapi: check logical block address and read size (CVE-2020-29443) While processing ATAPI cmd_read/cmd_read_cd commands, Logical Block Address (LBA) maybe invalid OR closer to the last block, leading to an OOB access issues. Add range check to avoid it. Fixes: CVE-2020-29443 Reported-by: Wenxiang Qian Suggested-by: Paolo Bonzini Reviewed-by: Paolo Bonzini Signed-off-by: Prasad J Pandit Message-Id: <20210118115130.457044-1-ppandit@redhat.com> Signed-off-by: Paolo Bonzini Upstream-Status: Backport [b8d7f1bc59276fec85e4d09f1567613a3e14d31e] CVE: CVE-2020-29443 Signed-off-by: Sakib Sajal --- hw/ide/atapi.c | 30 ++++++++++++++++++++++++------ 1 file changed, 24 insertions(+), 6 deletions(-) diff --git a/hw/ide/atapi.c b/hw/ide/atapi.c index e79157863..b626199e3 100644 --- a/hw/ide/atapi.c +++ b/hw/ide/atapi.c @@ -322,6 +322,8 @@ static void ide_atapi_cmd_reply(IDEState *s, int size, int max_size) static void ide_atapi_cmd_read_pio(IDEState *s, int lba, int nb_sectors, int sector_size) { + assert(0 <= lba && lba < (s->nb_sectors >> 2)); + s->lba = lba; s->packet_transfer_size = nb_sectors * sector_size; s->elementary_transfer_size = 0; @@ -420,6 +422,8 @@ eot: static void ide_atapi_cmd_read_dma(IDEState *s, int lba, int nb_sectors, int sector_size) { + assert(0 <= lba && lba < (s->nb_sectors >> 2)); + s->lba = lba; s->packet_transfer_size = nb_sectors * sector_size; s->io_buffer_size = 0; @@ -973,35 +977,49 @@ static void cmd_prevent_allow_medium_removal(IDEState *s, uint8_t* buf) static void cmd_read(IDEState *s, uint8_t* buf) { - int nb_sectors, lba; + unsigned int nb_sectors, lba; + + /* Total logical sectors of ATAPI_SECTOR_SIZE(=2048) bytes */ + uint64_t total_sectors = s->nb_sectors >> 2; if (buf[0] == GPCMD_READ_10) { nb_sectors = lduw_be_p(buf + 7); } else { nb_sectors = ldl_be_p(buf + 6); } - - lba = ldl_be_p(buf + 2); if (nb_sectors == 0) { ide_atapi_cmd_ok(s); return; } + lba = ldl_be_p(buf + 2); + if (lba >= total_sectors || lba + nb_sectors - 1 >= total_sectors) { + ide_atapi_cmd_error(s, ILLEGAL_REQUEST, ASC_LOGICAL_BLOCK_OOR); + return; + } + ide_atapi_cmd_read(s, lba, nb_sectors, 2048); } static void cmd_read_cd(IDEState *s, uint8_t* buf) { - int nb_sectors, lba, transfer_request; + unsigned int nb_sectors, lba, transfer_request; - nb_sectors = (buf[6] << 16) | (buf[7] << 8) | buf[8]; - lba = ldl_be_p(buf + 2); + /* Total logical sectors of ATAPI_SECTOR_SIZE(=2048) bytes */ + uint64_t total_sectors = s->nb_sectors >> 2; + nb_sectors = (buf[6] << 16) | (buf[7] << 8) | buf[8]; if (nb_sectors == 0) { ide_atapi_cmd_ok(s); return; } + lba = ldl_be_p(buf + 2); + if (lba >= total_sectors || lba + nb_sectors - 1 >= total_sectors) { + ide_atapi_cmd_error(s, ILLEGAL_REQUEST, ASC_LOGICAL_BLOCK_OOR); + return; + } + transfer_request = buf[9] & 0xf8; if (transfer_request == 0x00) { /* nothing */ -- 2.29.2