From 790762e5487114341cccc5bffcec4cb3c022c3cd Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Philippe=20Mathieu-Daud=C3=A9?= Date: Thu, 4 Jun 2020 19:22:29 +0200 Subject: [PATCH] hw/sd/sdcard: Do not switch to ReceivingData if address is invalid MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Only move the state machine to ReceivingData if there is no pending error. This avoids later OOB access while processing commands queued. "SD Specifications Part 1 Physical Layer Simplified Spec. v3.01" 4.3.3 Data Read Read command is rejected if BLOCK_LEN_ERROR or ADDRESS_ERROR occurred and no data transfer is performed. 4.3.4 Data Write Write command is rejected if BLOCK_LEN_ERROR or ADDRESS_ERROR occurred and no data transfer is performed. WP_VIOLATION errors are not modified: the error bit is set, we stay in receive-data state, wait for a stop command. All further data transfer is ignored. See the check on sd->card_status at the beginning of sd_read_data() and sd_write_data(). Fixes: CVE-2020-13253 Cc: qemu-stable@nongnu.org Reported-by: Alexander Bulekov Buglink: https://bugs.launchpad.net/qemu/+bug/1880822 Reviewed-by: Peter Maydell Signed-off-by: Philippe Mathieu-Daudé Reviewed-by: Alistair Francis Message-Id: <20200630133912.9428-6-f4bug@amsat.org> Upstram-Status: Backport: https://git.qemu.org/?p=qemu.git;a=commit;h=790762e5487114341cccc5bffcec4cb3c022c3cd CVE: CVE-2020-13253 Signed-off-by: Davide Gardenal --- hw/sd/sd.c | 38 ++++++++++++++++++++++++-------------- 1 file changed, 24 insertions(+), 14 deletions(-) diff --git a/hw/sd/sd.c b/hw/sd/sd.c index f4f76f8fd2..fad9cf1ee7 100644 --- a/hw/sd/sd.c +++ b/hw/sd/sd.c @@ -1171,13 +1171,15 @@ static sd_rsp_type_t sd_normal_command(SDState *sd, SDRequest req) case 17: /* CMD17: READ_SINGLE_BLOCK */ switch (sd->state) { case sd_transfer_state: - sd->state = sd_sendingdata_state; - sd->data_start = addr; - sd->data_offset = 0; - if (sd->data_start + sd->blk_len > sd->size) { + if (addr + sd->blk_len > sd->size) { sd->card_status |= ADDRESS_ERROR; + return sd_r1; } + + sd->state = sd_sendingdata_state; + sd->data_start = addr; + sd->data_offset = 0; return sd_r1; default: @@ -1188,13 +1190,15 @@ static sd_rsp_type_t sd_normal_command(SDState *sd, SDRequest req) case 18: /* CMD18: READ_MULTIPLE_BLOCK */ switch (sd->state) { case sd_transfer_state: - sd->state = sd_sendingdata_state; - sd->data_start = addr; - sd->data_offset = 0; - if (sd->data_start + sd->blk_len > sd->size) { + if (addr + sd->blk_len > sd->size) { sd->card_status |= ADDRESS_ERROR; + return sd_r1; } + + sd->state = sd_sendingdata_state; + sd->data_start = addr; + sd->data_offset = 0; return sd_r1; default: @@ -1234,14 +1238,17 @@ static sd_rsp_type_t sd_normal_command(SDState *sd, SDRequest req) /* Writing in SPI mode not implemented. */ if (sd->spi) break; + + if (addr + sd->blk_len > sd->size) { + sd->card_status |= ADDRESS_ERROR; + return sd_r1; + } + sd->state = sd_receivingdata_state; sd->data_start = addr; sd->data_offset = 0; sd->blk_written = 0; - if (sd->data_start + sd->blk_len > sd->size) { - sd->card_status |= ADDRESS_ERROR; - } if (sd_wp_addr(sd, sd->data_start)) { sd->card_status |= WP_VIOLATION; } @@ -1261,14 +1268,17 @@ static sd_rsp_type_t sd_normal_command(SDState *sd, SDRequest req) /* Writing in SPI mode not implemented. */ if (sd->spi) break; + + if (addr + sd->blk_len > sd->size) { + sd->card_status |= ADDRESS_ERROR; + return sd_r1; + } + sd->state = sd_receivingdata_state; sd->data_start = addr; sd->data_offset = 0; sd->blk_written = 0; - if (sd->data_start + sd->blk_len > sd->size) { - sd->card_status |= ADDRESS_ERROR; - } if (sd_wp_addr(sd, sd->data_start)) { sd->card_status |= WP_VIOLATION; } -- 2.32.0